Nitrogen mineralization in selected Montana soils
by Raymond George Gavlak
A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in
Crop and Soil Science
Montana State University
© Copyright by Raymond George Gavlak (1985)
Abstract:
Mineral nitrogen (N) production from cultivated soils has decreased with the reduction in soil organic
matter. The ability to predict seasonal contributions of mineral N to the soil N pool would increase the
precision of fertilizer N recommendations. The objectives of the study were to quantify and model N
mineralization of selected Montana soils by field and laboratory incubation techniques and compare the
levels of mineral N predicted by the two models.
Soil A horizons containing 1.8, 2.4, 2.6, and 4.4% OM were incubated in the laboratory at 0, 14 and
28°C for 12 weeks. Results indicated that mineral N production was linear with time.
Laboratory data was combined with a soil temperature predictive equation. The resulting computer
model predicted that soils containing 1.8, 2.4, 2.6, and 4.4% OM mineralized an average of 20.4 kg N
ha^-1 per percent OM over a 61 day period and 39, 49, 53, and 84 kg N ha^-1 total mineral N,
respectively.
Field experiments were established on a coarse-loamy, mixed Borollic Calciorthid near East Helena,
Montana. Soil was sampled to 30 cm, mixed by 10 cm increments, placed in polyethylene bags and
returned to the original sample holes at three sites in 1983 and four sites in 1984« Triplicate bags were
removed from each site and soil temperature was monitored at 10, 20, and 50 cm on a weekly basis.
Bags were frozen on dry ice then air dried and analyzed for nitrate and ammonium N.
Stepwise multiple linear regression was used to analyze field data. An index of early season mineral N
content and time were the most important independent variables predicting growing season mineral N
production (R^2=0.83) in the upper 30 cm of soil. Measurement of early season mineral N content to
30 cm and an estimate of time (weeks) allows an accurate prediction of field N mineralization.
One of the soils used in the laboratory experiment was sampled from a site included in the field study,
and allowed for a comparison of the laboratory and field models. The laboratory and field models
predicted 46.7 and 42.2 kg N ha-'*, respectively. The addition of temporal soil water content should
improve the model. Examination of the model on different soils is needed to validate the model. NITROGEN MINERALIZATION IN
SELECTED MONTANA SOILS
by
RAYMOND GEORGE GAVLAK
A t h e s i s s u b m itte d i n p a r t i a l f u l f i l l m e n t
o f t h e r e q u i r e m e n ts f o r th e d e g re e
of
D o c to r o f P h ilo s o p h y
in
C rop a n d S o i l S c ie n c e
MONTANA STATE UNIVERSITY
Bo zem an, Monta n a
May 1985
ii
APPROVAL
o f a t h e s i s s u b m itte d by
Raymond G. G a v la k
T h is t h e s i s h a s b e e n r e a d by e a c h member o f th e t h e s i s c o m m ittee
a n d h a s b een fo u n d to be s a t i s f a c t o r y r e g a r d i n g c o n t e n t , E n g l is h u s a g e ,
f o r m a t,
c ita tio n s ,
b i b lio g r a p h ic s t y l e , and c o n s is te n c y , and i s rea d y
f o r s u b m is s io n to th e C o lle g e o f G ra d u a te S t u d i e s .
-_2>2--i^yj_z_L2Zr„___
D a te
0
A pproved f o r th e M ajo r D e p a rtm e n t
WUpz q
D a te
'
_
H ead , M ajo r D e p a rtm e n t
A pproved f o r t h e C o lle g e o f G ra d u a te S t u d i e s
S ' -/J— -
D ate
i
G ra d u a te Dean
iii
■ STATEMENT OF PERMISSION TO USE
In
m e n ts
th e
p re s e n tin g t h i s th e s is in p a r t i a l f u lf illm e n t o f
th e
f o r a d o c t o r a l d e g r e e a t M ontana S t a t e U n i v e r s i t y ,
L ib ra ry
L ib ra ry .
re q u ire ­
I a g re e t h a t
s h a l l make i t a v a i l a b l e t o b o r r o w e r s u n d e r r u l e s
of
th e
I f u r t h e r a g r e e t h a t c o p y in g o f t h i s t h e s i s i s a l l o w a b l e o n ly
f o r s c h o l a r l y p u r p o s e s , c o n s i s t e n t w ith " f a i r u s e " a s p r e s c r i b e d i n th e
U. S . C o p y rig h t-L a w .
R e q u e s ts f o r e x t e n s i v e c o p y in g o r r e p r o d u c t i o n o f
t h i s t h e s i s s h o u ld be r e f e r r e d t o U n i v e r s i t y M ic r o f ilm s
300 N o r th Zeeb R oad,
" th e
I n te r n a tio n a l,.
Ann A r b o r , M ic h ig a n 4 8 1 0 6 , to whom I have g r a n te d
e x c l u s i v e r i g h t t o r e p r o d u c e a n d d i s t r i b u t e c o p ie s o f th e d i s s e r ­
t a t i o n i n a n d fro m m ic r o f i lm a n d th e r i g h t to r e p r o d u c e a n d
by a b s t r a c t i n a n y f o r m a t ."
S ig n a tu re
D a te
<<£
_______________
d is trib u te
iv
TABLE OF CONTENTS
Page
APPROVAL ......................................................................................................................................
ii
STATEMENT OF PERMISSION TO U S E ........................ ........................................................ '
TABLE OF CONTENTS .................................................................................................................
iv
LIST OF TABLES ..........................................................................................
LIST OF F IG U R E S.....................................................................................................................
v
v ia
ABSTRACT ..............................................................................................' ....................................... v i i i
CHAPTER
I.
GENERAL INTRODUCTION ........................................................................................
1
I I . . LITERATURE REVIEW ................................................................................................
3
H I . NITROGEN MINERALIZATION MODEL OF SURFACE SOILS FROM LABOR­
ATORY INCUBATIONS ................................................................
IV . NITROGEN MINERALIZATION MODEL OF SURFACE SOILS FROM FIELD
INCUBATIONS ..............................................
I n t r o d u c t i o n .......................................................................................................
M a t e r i a l s an d M ethods .................................................................................
R e s u l t s and D i s c u s s i o n ..............................
V. GENERAL CONCLUSIONS .....................................................................................
fr- CO
I n t r o d u c t i o n ....................
M a t e r i a l s a n d M ethods
R e s u l t s a n d D is c u s s io n ...............................................................................
7
n
20
20
20
24
33
REFERENCES CITED .................................................
36
APPENDIX .......................................
39
V
LIST OF TABLES
T a b le
Page
1 . P h y s i c a l a n d c h e m ic a l c h a r a c t e r i s t i c s o f f i v e M ontana s o i l A
h o r i z o n s ...........................*............................................................................................
2 . L in e a r
te n t
9
e q u a t i o n s f o r mean d a i l y N m i n e r a l i z a t i o n by OM con­
-| Q
3 . L i n e a r e q u a t i o n s f o r c u m u la tiv e n e t N m i n e r a l i z a t i o n by o r ­
g a n ic m a t t e r c o n t e n t a t t h r e e t e m p e r a t u r e s .........................................
-] 5
4 . M in e r a li z e d N p r e d i c t e d from M m i n e r a l i z a t i o n m odel on a p e r ­
c e n t o r g a n i c m a t t e r b a s i s a t t h r e e d a t e s ..............................................
19
5 . C h e m ic a l p r o p e r t i e s o f s o i l s su b s a m p le d f o r f i e l d
in c u b a tio n
e x p e r im e n ts i n i t i a t e d i n 1983 a n d 1984 .....................................................
22
6 . V a r i a b l e s i n c l u d e d i n th e m u l t i p l e l i n e a r r e g r e s s i o n a n a l y s i s
( I = i n d e p e n d e n t , D = d e p e n d e n t)
......................................................................
25
7 . D e s c r i p t i o n o f i n d e p e n d e n t v a r i a b l e SITE u s e d i n t h e m odel . .
25
8 . D e s c r i p t i o n o f i n d e p e n d e n t v a r i a b l e WEEK u s e d i n t h e m odel . .
26
9 . R e s u lts o f m u ltip le l i n e a r r e g r e s s io n a n a ly s is ; F and c o e f f i­
c i e n t o f m u ltip le
d e t e r m i n a t i o n (R ^) f o r NO3NH4T a s th e
d e p e n d e n t v a r i a b l e ..................................................................................................
27
10.
M u l t i p l e l i n e a r r e g r e s s i o n e q u a t i o n f o r th e m odel c o n s i d e r i n g
N03NH4T th e d e p e n d e n t v a r i a b l e ....................; ...............................................
28
.1 1 . S t r a t i f i c a t i o n o f SITE by i n i t i a l ' m in e r a l n i t r o g e n l e v e l s f o r
d e p e n d e n t v a r i a b l e s N03NH4T and W03T .......................................................
28
1 2 . M u l t i p l e l i n e a r r e g r e s s i o n e q u a ti o n f o r th e m odel c o n s i d e r i n g
N03T a s th e d e p e n d e n t v a r i a b l e ......................................................................
30
13. R e s u lts o f m u ltip le l i n e a r r e g r e s s io n a n a ly s is ; F and c o e f f i­
c i e n t o f m u l t i p l e d e t e r m i n a t i o n (R2 ) f o r N03T a s th e d e p e n ­
d e n t v a r i a b l e ..............................................................................................................
1 4 . M u l t i p l e l i n e a r r e g r e s s i o n e q u a ti o n f o r th e m odel c o n s i d e r i n g
M03T a s th e d e p e n d e n t v a r i a b l e .....................................................................
3-1
vi
T a b le
Page
1 5 . R e s u lts o f m u ltip le l i n e a r r e g r e s s io n a n a ly s i s ; F and c o e f f i ­
c i e n t o f m u l t i p l e d e t e r m i n a t i o n (R2 ) f o r N03NH4T a s th e
d e p e n d e n t v a r i a b l e .................................................................
32
A p p endix T a b le
1 6 . P h y s i c a l a n d c h e m ic a l c h a r a c t e r i s t i c s o f f i v e M ontana s o i l s
.
40
1 7 . Sum m arized l a b o r a t o r y i n c u b a t i o n d a t a by s o i l h o r iz o n a t 0°C
(n = 5 ) .....................
41
1 8 . Sum m arized l a b o r a t o r y i n c u b a t i o n d a t a by. s o i l h o r iz o n a t 14°C
(n = 5 ) .................................................................................................................................
43
1 9 . Sum m arized l a b o r a t o r y i n c u b a t i o n d a t a by s o i l h o r iz o n a t 2 8 ° C
( n = 5) ................
45
2 0 . L i s t i n g o f n i t r o g e n m i n e r a l i z a t i o n c o m p u te r m odel .......................
47
2 1 . N i t r o g e n m i n e r a l i z a t i o n d a t a fro m f i e l d i n c u b a t i o n s by 10 cm
d e p th i n c r e m e n t s (n=3 ) .........................................................................................
48
2 2 . N itr o g e n m i n e r a l i z a t i o n d a t a fro m f i e l d i n c u b a t i o n s b y 10 cm
d e p th in c r e m e n ts ( n = 3 ) , t o t a l o f NH^-N an d NOyR ... ...................
52
2 3 . Summary o f mean w e e k ly a i r te m p e r a t u r e s (AIRTC) d e r i v e d from
H e le n a A i r p o r t c l i m a t o l o g i c a l d a t a f o r 1983 a n d 1984 by
J u l i a n D a te ........................ .............................................. 1..........................................
54
2 4 . Summary o f w eek ly s o i l
te m p e r a t u r e s (S 0IL T 10,
S0ILT20,
S0IL T 50) m e a su re d a t e a c h s i t e i n 1983 and 1984 by J u l i a n
D a te . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
56
2 5 . M u ltip le
l i n e a r r e g r e s s i o n m odel w i t h NH4T a s th e d e p e n d e n t
v a r i a b l e , " b e s t " 8 v a r i a b l e s ..........................................................................
60
v ii
■LIST OF FIGURES
F ig u r e
I•
P age
T o t a l c u m u la tiv e n e t N m i n e r a l i z a t i o n o f f i v e
c u ltiv a te d
s o i l s by l a b o r a t o r y i n c u b a t i o n a t t h r e e t e m p e r a t u r e s ..............
12
2.
S o i l M m i n e r a l i z a t i o n by l a b o r a t o r y i n c u b a t i o n a t two w eeks
14
3.
S o i l N m in e r a liz a t io n by la b o r a to r y in c u b a tio n a t tw e lv e
w eeks ...............................................................................................................................
15
C u m u la tiv e
la b o ra to ry
16
4.
5.
6.
n e t N m i n e r a l i z a t i o n o f f o u r c u l t i v a t e d s o i l s by
i n c u b a t i o n a t O0 C .........................................................................
C u m u la tiv e n e t M m i n e r a l i z a t i o n o f f o u r c u l t i v a t e d s o i l s
l a b o r a t o r y i n c u b a t i o n a t 14°C .................................
C u m u la tiv e
la b o ra to ry
by
n e t U m i n e r a l i z a t i o n o f f o u r c u l t i v a t e d s o i l s by
i n c u b a t i o n a t 2 8 ° C ......................................................................
r
17
18
v iii
ABSTRACT
M in e r a l n i t r o g e n (N) p r o d u c t i o n fro m c u l t i v a t e d s o i l s h a s d e c r e a s e d
w ith th e r e d u c tio n in s o i l o rg a n ic m a tte r .
The a b i l i t y t o p r e d i c t
s e a s o n a l c o n t r i b u t i o n s o f m in e r a l N to t h e s o i l N p o o l w ould i n c r e a s e
t h e p r e c i s i o n o f f e r t i l i z e r N r e c o m m e n d a tio n s .
The o b j e c t i v e s o f th e
s tu d y w ere to q u a n t i f y a n d m odel N m i n e r a l i z a t i o n o f s e l e c t e d M ontana
s o i l s by f i e l d a n d l a b o r a t o r y i n c u b a t i o n t e c h n i q u e s a n d c o m p a r e t h e
l e v e l s o f m i n e r a l N p r e d i c t e d by th e tw o m o d e ls .
S o i l A h o r i z o n s c o n t a i n i n g 1 .8 , 2 . 4 , 2 .6 , a n d 4 . 4 % CM w e r e i n c u ­
b a t e d i n t h e l a b o r a t o r y a t 0 , 14 a n d 2 8 °C f o r 12 w e e k s .
R e s u lts
i n d i c a t e d t h a t m in e r a l N p r o d u c t i o n w as l i n e a r w i t h tim e .
L a b o r a t o r y d a t a w as c o m b in e d w i t h a s o i l t e m p e r a t u r e p r e d i c t i v e
e q u a ti o n . The r e s u l t i n g c o m p u te r m odel p r e d i c t e d t h a t s o i l s c o n ta i n in g
1 .8 , 2 .4 , 2 .6 , a n d 4*4% OM m i n e r a l i z e d a n a v e r a g e o f 2 0 .4 k g N h a - "* p e r
p e r c e n t OM o v e r a 61 d a y p e r i o d a n d 3 9 , 4 9 , 5 3 , a n d 84 k g N h a -1 t o t a l
m in e r a l N, r e s p e c t i v e l y .
F i e l d e x p e r i m e n t s w ere e s t a b l i s h e d on a c o a r s e - lo a m y , m ixed B o r o lI i c C a l c i o r t h i d n e a r E a s t H e le n a , M ontana.
S o i l w as s a m p le d to 30 cm,
m ixed by 10 cm i n c r e m e n t s , p la c e d i n p o l y e t h y le n e b a g s an d r e t u r n e d to
th e o r i g i n a l s a m p le h o l e s a t t h r e e s i t e s i n 1983 a n d f o u r s i t e s i n
1984« T r i p l i c a t e b a g s w ere rem oved fro m e a c h s i t e a n d s o i l te m p e r a tu r e
w as m o n ito r e d a t 10, 2 0 , a n d 50 cm on a w e e k ly b a s i s . B ags w ere f r o z e n
on d r y i c e th e n a i r d r i e d a n d a n a ly z e d f o r n i t r a t e a n d amm onium N.
S te p w is e m u l t i p l e l i n e a r r e g r e s s i o n w as u se d to a n a ly z e f i e l d d a ta .
An i n d e x o f e a r l y s e a s o n m i n e r a l N c o n t e n t a n d t i m e w e re t h e m o s t
i m p o r t a n t in d e p e n d e n t v a r i a b l e s p r e d i c t i n g g r o w i n g s e a s o n m i n e r a l N
p r o d u c t i o n (R =0.83) i n th e u p p e r 30 cm o f s o i l .
M e a s u re m e n t o f e a r l y
s e a s o n m i n e r a l N c o n t e n t t o 30 cm a n d a n e s t i m a t e o f t i m e ( w e e k s )
a llo w s an a c c u ra te p r e d ic tio n o f f i e l d N m in e r a liz a tio n .
One o f th e s o i l s u s e d i n th e l a b o r a t o r y e x p e r im e n t w as sa m p le d fro m
a s i t e i n c l u d e d i n t h e f i e l d s tu d y , a n d a ll o w e d f o r a c o m p a r is o n o f th e
l a b o r a t o r y a n d f i e l d m o d e ls . The l a b o r a t o r y an d f i e l d m o d e ls p r e d i c t e d
4 6 .7 a n d 4 2 .2 k g N h a
, r e s p e c t i v e l y . T he a d d i t i o n o f t e m p o r a l s o i l
w a te r c o n t e n t s h o u ld im p ro v e th e m o d el.
E x a m in a tio n o f th e m odel on
d i f f e r e n t s o i l s i s n e e d e d t o v a l i d a t e t h e m odel.
1
CHAPTER I
GENERAL INTRODUCTION
O rg a n ic
m a t t e r (OM) i s a n e x tr e m e ly i m p o r t a n t s o i l co m p o n en t
c o n tr ib u te s to o v e r - a ll s o i l c a tio n exchange c a p a c ity
(C EC ),
th a t
enhances
w a te r r e l a t i o n s an d h e lp s m a i n ta i n good s o i l s t r u c t u r e , p a r t i c u l a r l y i n
fin e - te x tu r e d s o il s .
S o i l OM i s th e r e s e r v o i r f o r s u p p ly in g n e a r l y a l l
o f t h e n i t r o g e n (N) a n d some o f th e p h o s p h o ru s ,
n u trie n ts .
C o n v e rs io n
s u l f u r , a n d o t h e r c ro p
o f o r g a n i c a l l y a s s o c i a t e d N to p l a n t a v a i l a b l e
i n o r g a n i c fo rm s i s c a l l e d m i n e r a l i z a t i o n .
S o i l m ic r o o rg a n is m s c o n t r o l
th e m u lti- s ta g e p ro c e s s o f N m in e r a liz a tio n .
G r a s s la n d o r p r a i r i e
s o ils .
E a rly
s o i l s u s u a l l y c o n t a i n more OM t h a n c u l t i v a t e d
g r a i n f a r m e r s i n M ontana a n d o t h e r G r e a t P l a i n s
b e g a n c u l t i v a t i n g t h e s e v i r g i n p r a i r i e s o i l s a n d fo u n d them q u i t e
tile .
The
g ro w in g
s ta te s
fer­
p r a c t i c e o f c r o p - f a l l o w a llo w e d th e a c c u m u la tio n o f a f u l l
s e a s o n 's m i n e r a l i z e d N ( f a l l o w - y e a r ) f o r th e
fo llo w in g
c ro p .
T h is w orked w e ll a s many o f t h e v i r g i n s o i l s c o n ta i n e d b e tw e e n 5 and 10
p e rc e n t
OM.
c o n tin u a l
"M in in g "
re d u c tio n
t h i s s o i l N f o r o v e r h a lf a c e n tu ry
i n a b s o l u t e OM c o n t e n t a n d
f a l l o w - y e a r a c c u m u la te d N.
e x te n t,
w h ich
much
le s s
C o n s e q u e n tly , th e r e m a in in g OM, t o a l a r g e
i s a s t a b l e co m ponent o f hum us.
in c lu d e
re c e n tly ,
cau sed ' a
The l e s s s t a b l e OM com ponents
p l a n t r e s i d u e s have b e e n u t i l i z e d by m ic ro b e s an d
con­
v e r t e d to m in e r a l N.
The
n e e d t o f i n e - t u n e c ro p p r o d u c t i o n i n p u t s i s a p p a r e n t a s
farm
2
c o m m o d ity p r i c e s c o n t i n u a l l y f a i l
to a l l e v i a t e
th e
to p r o v id e
b u rd en o f e s c a l a t i n g
s u f f i c i e n t p r o f i t m a rg in
p ro d u c tio n
c o s ts .
N itro g e n
f e r t i l i z e r i s o n e o f t h e m a j o r i n p u t s , so m e o f w h ic h i s c o n t r i b u t e d
f r o m s o i l OM.
c re a se
By a s s e s s i n g a s o i l ' s a b i l i t y t o p r o v i d e N, we may i n ­
t h e p r e c i s i o n o f a c c u r a t e l y s u p p ly in g c r o p N r e q u i r e m e n t s .
T he o b j e c t i v e s o f t h e s t u d y w e r e t o q u a n t i f y N m i n e r a l i z a t i o n o f
M ontana s o i l s by l a b o r a t o r y a n d f i e l d i n c u b a t i o n t e c h n i q u e s w i t h d e v e l­
o p m e n t o f p r e d i c t i v e m o d e ls fro m f i e l d a n d l a b o r a t o r y d a t a .
P re d ic te d
N m i n e r a l i z a t i o n l e v e l s fro m m o d els w ould be c o m p a re d .
The f o l l o w i n g c h a p t e r s p r o v id e s u b s t a n t i a l e v id e n c e t h a t N m in e r ­
a liz a tio n
c a n be q u a n t i f i e d a n d m o s t i m p o r t a n t l y , be p r e d i c t e d .
t e r I I c o n t a i n s a r e v ie w o f p e r t i n e n t l i t e r a t u r e
ods u sed .
re la tin g
Chap­
to th e m eth ­
C h a p t e r s I I I a n d IV f o r m t h e c o r e o f t h e d i s s e r t a t i o n a n d
e l a b o r a t e on th e l a b o r a t o r y a n d f i e l d m e th o d o lo g y u s e d i n t h i s m o d e lin g
s tu d y .
C h a p te r V s u m m a riz e s th e r e s u l t s o f th e r e s e a r c h a c c o m p lis h e d .
C o n s id e r a b le d a t a h av e b e e n p la c e d i n
t h e A ppendix a n d t h e s e A ppendix
t a b l e s a r e c i t e d i n th e body o f th e t e x t .
3
CHAPTER I I
LITERATURE RE'VIEW
R e s e a r c h e r s h av e b e e n i n t e r e s t e d i n th e a v a i l a b i l i t y o f N from s o i l
o rg a n ic
(1 9 5 5 )
m a tte r
(CM) f o r d e c a d e s .
and
Hanway
d e s c r i b e d t h e a d v a n ta g e s o f a new m ethod o f e s t i m a t i n g M m in e r ­
a liz a tio n .
m u ltip le
They
used
a l a b o r a t o r y i n c u b a t i o n m ethod
le a c h in g
sam ple
E x c e s s w a te r was rem oved by
t h e s a m p le s w ere p l a c e d i n a 35°C i n c u b a t o r f o r two
The p r o c e s s was r e p e a t e d a t two week i n t e r v a l s .
q u a n tifie d
a llo w e d
S o i l s a m p le s were m ixed w i t h e x p a n d ed v e f m i c u l i t e p r i o r to
i n c u b a t i o n th e n le a c h e d w i t h w a t e r .
th e n
w h ich
m e a su re m e n ts o f n i t r a t e p r o d u c t i o n w ith th e same s o i l
o v e r tim e .
tio n
E a r l y w ork by S ta n f o r d
c o lo rim e tric a lly
suc­
w eek s.
L e a c h a te n i t r a t e
u s in g p h e n o l d i s u l f o n i c a c i d .
T h e ir
m ethod r e s u l t e d i n a 56% i n c r e a s e i n n i t r a t e p r o d u c t i o n
t h e p r e v i o u s m ethod o f i n c u b a t i o n a n d e x t r a c t i o n i n b o t t l e s .
was
new
over
In cre a se d
p r e c i s i o n was due t o e n h a n c e d a e r a t i o n a n d b e t t e r c o n t r o l o f s o i l w a te r
c o n te n t.
M ost i m p o r t a n t l y th e work p ro d u c e d a r a p i d m ethod o f a s s e s s ­
in g a s o i l s ' a b i l i t y
Legg
e t a l.
to s u p p ly m in e r a l H.
(1 9 7 1 ) m o d if ie d th e ab o v e p r o c e d u r e by e x c lu d in g
th e
e x p a n d e d v e r m i c u l i t e a n d i n c l u d e d l e a c h i n g w ith G.01M CaClg f o llo w e d by
t h e a d d i t i o n o f a m in u s N n u t r i e n t s o l u t i o n .
to
fro m
d e te r m in e
th e lo n g te rm m i n e r a l i z a t i o n o f
The s t u d y l a s t e d 40 w eeks
ta g g e d an d
p o t s m a in ta in e d u n d e r c o n tin u o u s o a t ( Avena s a t i v a L . )
Long p e r i o d s o f c o n ti n u o u s c ro p p in g d e p r e s s e d i n i t i a l N
to ta l
N
c r o p p in g .
m in e ra liz a tio n
4
ra te s
( a l l p l a n t m a t e r i a l r e t u r n e d to p o t s a f t e r s e e d
e v e r,
la te r
ra te s .
h a rv e s t),
how­
i n c u b a t i o n p e r i o d s had r e l a t i v e l y c o n s t a n t m i n e r a l i z a t i o n
D iffe rin g
r a t e s seem ed t o be r e l a t e d
to
excess
c a rb o n a c e o u s
m a t e r i a l w h ic h d i s s i p a t e d i n th e l o n g e r , c o n ti n u o u s ly c ro p p e d s o i l s .
The
and
i n c u b a t i o n m ethod o f Legg e t a l .
(1 9 7 1 ) was u s e d by
S ta n fo rd
S m ith (1 9 7 2 ) t o a s s e s s th e N m i n e r a l i z a t i o n p o t e n t i a l o f 39 w id e ly
d i f f e r i n g s o i l s o v e r a 30 week p e r i o d a t -35®C•
by
The m ethod was m o d if ie d
a d d in g q u a r t z sa n d e q u a l to t h e w e ig h t o f s o i l to e n h a n c e
p e rc o la tio n .
A d d itio n a lly ,
s o il
w a te r
c o n t e n t was
le a c h a te
e s ta b lis h e d
l e a c h i n g t u b e s w ith 80 kPa s u c t i o n f o l l o w i n g e a c h s u c c e s s i v e
in
le a c h in g .
N e t N m i n e r a l i z a t i o n was l i n e a r l y r e l a t e d t o th e s q u a re r o o t o f tim e i n
m o st
s o ils .
C u m u la tiv e N m i n e r a l i z a t i o n o b ey ed f i r s t o r d e r
k in e tic s
w here e q u a t i o n ( 2 ) i s o b t a i n e d from th e i n t e g r a t i o n o f e q u a t i o n ( l ) .
■
;
-
The
am o u n t
c o n s ta n t.
of
dN
— = kN
dt
(1 )
m i n e r a l i z a b l e N was d e n o te d a s N and
k
is
th e
I n t e g r a t i o n o f e q u a t i o n ( 1 ) p ro d u c e d
k
lo g (N0 - N+) = lo g N0 ------------------- ( t )
2 .3 0 3
w here
ra te
Nq
m in e ra liz e d
=
N m i n e r a l i z a t i o n p o t e n t i a l (u g g - 1 ) ,
i n tim e t ( w e e k s ) ,
Nt =
and k = m in e r a liz a tio n
(2 )
c u m u la tiv e
ra te
N
c o n s ta n t
( w eeks- '*) .
One
of
t h e m o st i m p o r t a n t f a c t o r s c o n t r o l l i n g th e
m in e r a l N n i t r o g e n i s t e m p e r a t u r e .
p ro d u c tio n
of -
A ll o f th e s t u d i e s re v ie w e d have a
5
s i m i l a r i n c u b a t i o n te m p e r a tu r e o f 3 5 ° C.
T y le r e t a l .
(1 9 5 9 ) in c u b a te d
fo u r
C a l i f o r n i a s o i l s w i t h s i x l e v e l s o f ammonium f e r t i l i z e r a t
7 .2 ,
an d 2 . 8 °C to q u a n t i f y th e e f f e c t o f te m p e r a tu r e on n i t r i f i c a t i o n .
N itrific a tio n
p ro ce e d e d
a t a m o d e ra te r a t e when in c u b a t e d
at
2 3 .9 ,
7 .2 ° C .
They c o n c lu d e d t h a t f a l l a p p l i c a t i o n o f am m onical f e r t i l i z e r s c o u ld
h azard o u s
( i n a r e a s w here t h e s o i l d o e s n o t f r e e z e ) when, a t t e m p t i n g to
m in im iz e
le a c h in g l o s s e s b ecau se o f c o n tin u in g
tio n a lly ,
t h e o v e r a l l Q-]q a p p ro a c h e d 2 .1 b e tw e e n 7 .2 an d 2 3 . 9° C
S ta n fo rd e t a l .
A ddi­
used
1 5 , and 25°C o v e r a 24 week p e r i o d to a s s e s s
te m p e ra tu re -m in e ra liz a tio n
when
n itrific a tio n .
(1 9 7 3 ) in c u b a t e d 11 o f th e o r i g i n a l 39 s o i l s
i n t h e i r 1972 s tu d y a t 5 ,
th e
be
re la tio n s h ip .
Q^q v a l u e s w ere n e a r
th e 5°C te m p e r a tu r e was o m itte d fro m th e r e g r e s s i o n o f lo g
k
2
on
1 /T (T i n d e g r e e s K e l v i n ) .
L a b o r a to r y
to
s u p p ly
m in e r a l
in c u b a tio n
a llo w e d
w eeks
was f i r s t r e p o r t e d b y Eno
c o n d itio n s .
(1 9 6 0 ).
u n d e r 10 cm s o i l ) t o e x p e r ie n c e f i e l d te m p e r a tu r e
s o ils
A
H is
fie ld
m ethod
fo r
in c u b a tio n .
The p o l y e t h y le n e u s e d was p e rm e a b le t o oxygen
d i o x id e b u t im p e rm e a b le to w a te r a n d n i t r a t e .
was c l o s e l y r e l a t e d t o c h a n g e s i n s o i l
6
flu c tu a tio n s .
N d e t e r m i n a t i o n was made on s o i l s a m p le s f o l l o w i n g 6 w eeks
c a rb o n
tio n
te c h n iq u e
N u n d e r r e l a t i v e l y o p tim a l
s o i l s a m p le s ( s e c u r e d i n p o l y e t h y le n e b a g s a n d b u r i e d
■Mineral
fie ld
i n c u b a t i o n s p r o v id e i n s i g h t i n t o th e c a p a c i t y o f
of
and
N i t r a t e p ro d u c ­
te m p e ra tu re ,
h o w e v e r,
a
tim e l a g e f f e c t was o b s e rv e d b e tw e en t e m p e r a tu r e change a n d m i n e r a l i z a ­
tio n .
W esterm ann
e v a lu a te
N
an d
C r o t h e r s (1 9 8 0 ) u s e d th e b u r ie d b ag
m i n e r a l i z a t i o n u n d e r i r r i g a t e d c ro p p e d
and
te c h n iq u e
fa llo w
to
fie ld
6
c o n d itio n s
se v era l
and
random
p rec u t
e s t i m a t e N u p ta k e d u r in g c ro p m a t u r a t i o n .
s o i l c o r e s to 45 cm*
l e n g t h s o f p o l y e t h y le n e t u b i n g .
s c r e e n e d th e
N . c o n ta i n e d
h i g h ly
th e n
to o k
fille d
. The s e a l e d b a g s ( t u b e s )
th e n p l a c e d i n t o t h e o r i g i n a l sam p le h o l e s .
m in e r a l
s o il
They
w ere
P e rio d ic q u a n tif ic a tio n o f
in th e b ag s and f i e l d s o i l
s a m p le s
s ig n if ic a n t lin e a r r e la tio n s h ip ( r= 0 .9 5 ) .
re v e a le d
N itr o g e n u p ta k e
a
in
th e c ro p p e d s i t e s was d e te r m in e d a s t h e d i f f e r e n c e b e tw e e n m in e r a l N i n
th e b a g s a n d t h a t i n th e s u r r o u n d in g s o i l .
E s t im a t e s g e n e r a l l y a g re e d
w ith r e s u l t s o f N u p ta k e d e te r m in e d b y p l a n t t i s s u e a n a l y s i s .
S m ith
fie ld
N
c o n te n t
e ig h t
e t a l.
(1 9 7 7 ) com bined l a b o r a t o r y i n c u b a t i o n
re s u lts
m i n e r a l i z a t i o n m e a su re m e n ts an d a d j u s t e d f o r b o t h s o i l
and
s o i l t e m p e r a t u r e i n e s t i m a t i n g m in e r a l
Oklahom a s o i l s .
N
w ith
w a te r
p ro d u c tio n
of
T h e i r " c a l c u l a t i o n " m ethod assu m ed a Q^q1 o f 2,
a n d m i n e r a l i z a t i o n r a t e c o n s t a n t s c a l c u l a t e d fro m th e k ( 0 .0 5 4 w eeks- "')
re p o rte d
b y S ta n f o r d a n d S m ith ( 1 9 7 2 ) .
" C a lc u l a t e d "
f a v o r a b l y t o a m o u n ts m e a su re d i n th e f i e l d ,
l e s s th a n 10 ug g- "*.
a m o u n ts
a g re e d
w ith d i f f e r e n c e s f r e q u e n t l y
7
CHAPTER I I I
NITROGEN MINERALIZATION MODEL OF SURFACE SOILS
FROM LABORATORY INCUBATIONS
In tro d u c tio n
N itr o g e n
fo rm s
of
fo rm s.
m in e ra liz a tio n
N
i s th e g e n e r a l p r o c e s s by
i n th e s o i l a r e c o n v e r te d t o
The
in o rg a n ic
w h ic h
p la n t
o r g a n ic
a v a ila b le
ra te " t h a t m in e r a liz a tio n o f o rg a n ic N o c c u rs in s o i l s
is
d e p e n d e n t on a num ber o f f a c t o r s i n c l u d i n g s u p p ly o f s u b s t r a t e , p o p u la ­
tio n
o f m ic r o o r g a n is m s ,
c o n te n t.
The
m ic ro b ia lly
N
te m p e ra tu re ,
m in e ra liz a tio n
r e a c tio n s f a l l in to th re e c a te g o rie s ,
tio n s
a e ra tio n ,
p ro ce ss i s a c tu a lly
m e d ia te d s e t o f i n t r i c a t e
n itrific a tio n .
pH,
r e a c tio n s .
d iz e d
to
S im p lifie d ,
( re q u ire
p r im a r ily b a c te r i a and f u n g i,
t o th e p o i n t t h a t p r o t e i n s - a r e c o n v e r te d to a m in e s ,
o r g a n is m s .
m u lti-s ta g e ,
th e s e
a m i n i z a t i o n , a m m o n if ic a tio n , and
by h e t e r o t r o p h i c o rg a n is m s
so u rc e s f o r e n e rg y ),
The
a
w a te r
A m in iz a tio n i s th e f i n a l r e a c t i o n i n a s e r i e s o f r e a c ­
c o n d u c te d
e n e rg y .
and s o i l
a m in e s
U nder
n itrite
o rg a n ic
w h ich decom pose OM
c a rb o n d i o x id e and
a r e th e n c o n v e r te d to ammonium by
h et e r o tro p h ic
i d e a l c o n d i t i o n s much o f th e ammonium w i l l be
p r i m a r i l y by th e a u t o t r o p h i c b a c t e r i a
o x i d a t i o n o f i n o r g a n i c s a l t s ) N itro s o m o n a s ,
c a rb o n
th is n i tr it e
o x i­
( e n e rg y
from
i s th e n
con­
v e r t e d to n i t r a t e p r i m a r i l y by N i t r o b a c t e r .
C o n d itio n s
f a v o r i n g m i n e r a l i z a t i o n o f OM a r e s i m i l a r t o c o n d i t i o n s
o p tim a l f o r c ro p g r o w th .
The C:N r a t i o m u st be i n a r a n g e n e a r t e n o r
8
th e ammonium p ro d u c e d d u r in g a m i n i z a t i o n w i l l be u t i l i z e d by th e h e t e r otro p h ic
p o p u l a t i o n d e c o m p o sin g OM.
m a i n ta i n e d
A d d itio n a lly ,
b e c a u s e m o le c u la r oxygen i s r e q u i r e d by th e
The s o i l pH c a n r a n g e w id e ly fro m 5 .5 t o 1 0 .0 ,
n e a r 8 .0 .
a e r a t i o n m u st
N itro b a c te ria .
h o w ev er, t h e optim um i s
T e m p e ra tu re f o r maximum N m i n e r a l i z a t i o n i s n e a r 35°C .
w a te r i s d i r e c t l y r e l a t e d t o th e l e v e l o f a e r a t i o n w i t h in a
s o il.
w ith
S o il
be
S o il
p a rtic u la r
w a te r c o n t e n t s n e a r f i e l d c a p a c i t y a r e c o n s id e r e d o p tim a l
d e c re a s in g m in e r a liz a tio n o c c u rin g a t d e c re a s in g
w a te r
c o n te n ts
( Cassm an a n d M unns, 1 9 8 0 ) .
The
e x p e r im e n t was d e s ig n e d t o d e te r m in e th e e f f e c t o f te m p e r a tu r e
a n d OM on t h e p r o d u c t i o n o f m in e r a l N.
m iz e
a ll
tio n .
T h is s tu d y a tt e m p t e d to
o f th e i m p o r t a n t f a c t o r s r e q u i r e d f o r maximum N
T h is
c h a p te r
su m m a riz es r e s u l t s c o n d u c te d on
o p ti­
m in e ra liz a ­
upper
M is s o u r i
R iv e r B a s in s u r f a c e s o i l s t o in d e x N m i n e r a l i z e d a s a f u n c t i o n o f
s o il
te m p e r a tu r e a n d OM c o n t e n t .
M a t e r i a l s a n d M ethods
S u rfa c e
h o r iz o n s o f f i v e d i f f e r e n t s o i l s (T a b le I ) w ere c o l l e c t e d
i n 1 9 8 3 , d r i e d a t 36°C , d i s a g g r e g a t e d an d s ie v e d th r o u g h a 2 mm s c r e e n .
S u b s u r f a c e h o r i z o n s w ere t r e a t e d s i m i l a r l y ,
c h e m ic a l a n d p h y s i c a l d a ta
f o r t h e s e h o r iz o n s a r e shown i n A ppendix T a b le 1 6 .
A
h o r iz o n w ere a n a ly z e d f o r OM c o n t e n t w i t h a
p ro ce d u re
(S im s an d Haby,
1 9 7 0 ),
S u b sa m p le s o f e a c h
m o d if ie d
W a lk le y -B la c k
and t o t a l N d i g e s t i o n b y s e m i-m ic ro
K j e l d a h l s i m i l a r t o B rem ner (1 9 6 5 ) w ith t h e c o l o r i m e t r i c p o r t i o n o f th e
K j e ld a h l
p ro c e d u re
on a T e c h n ic o n A uto A n a ly z e r
II
( T e c h n ic o n
M ethod No. 1 5 4 -7 1 W, Ammonia i n w a te r a n d s e a w a te r . F e b ., 1 9 7 3 ).
In d .
9
S o ils
w ere le a c h e d w i t h 0 .0 1 M CaClg by th e m ethod o f S t a n f o r d a n d
S m ith (1 9 7 2 ) e x c e p t t h a t p o s t —le a c h i n g s o i l w a te r p o t e n t i a l was b r o u g h t
to
18 k P a ,
w hich i s i n t h e c r i t i c a l s o i l w a te r ra n g e f o r a s s e s s i n g
m i n e r a l i z a t i o n ( Cassinan a n d Munns,
n itra te
1 9 8 0 ).
L e a c h a te s w ere a n a ly z e d f o r
by cadmium r e d u c t i o n ( T e c h n ic o n I n d .
tra te
and n i t r i t e
s im ila rly ,
i n w a te r
an d
M ethod No.
w a s te w a te r .
th o u g h w i t h o u t t h e cadmium c o lu m n ,
A n a ly z e r I I s y s te m .
N
S e p t.,
1 0 0 -7 0 W,
1 9 7 3 ),
N i­
n itrite
an d ammonium on a n Auto
M in e r a l n i t r o g e n i s t h e sum o f n i t r a t e ,
n itrite ,
a n d ammonium.
T a b le I .
P h y s i c a l a n d c h e m ic a l c h a r a c t e r i s t i c s o f f i v e M ontana s o i l
h o riz o n s .
S e rie s
C la s s ific a tio n
B r id g e r
f i n e , m ixed A rg ic
C r y o b o r o ll
5 .8 0
0 .4 8
12 .1
7 .0
Bozeman
f i n e , s i l t y , m ixed
P a c h ic A g r ib o r O ll
2 .5 0
0 .2 2
1 1 .6
7 .8
W illia m s y .
f in e - lo a m y , m ixed
T y p ic A r g i b o r o l l
1 .5 1
0 .1 5
1 0 .1
6 .6
S cobey
f i n e , m o n tm o rillo n itic
A rid ic A rg ib o ro ll
1 .3 9
0 .1 6
8 .7
7 .7
S a p p in g to n Amesha
c o a r s e - lo a m y , m ixed
B o ro llic C a lc io rth id
1 .0 4
0.11
9 .5
8 .3
T o ta l C
T o ta l N
C:N
is
e le v a tio n
th e
fo u n d
pH
-A r
S e l e c t e d s o i l s v a r i e d i n t h e i r h i s t o r i c a l m anagem ent.
s o il
A
The B r id g e r
t h e o n ly u n c u l t i v a t e d s o i l a n d i s fo u n d i n a r e l a t i v e l y
(1500 m) p r a i r i e s e t t i n g .
Of t h e f o u r c u l t i v a t e d s o i l s , o n ly
Bozeman s o i l h a s a h i s t o r y o f s m a ll g r a i n / a l f a l f a r o t a t i o n and
a t e l e v a t i o n s n e a r 1400 m.
h ig h
Scobey,
W illia m s
and
is
S a p p in g to n -
Amesha s o i l s h av e b e e n a l t e r n a t e l y c r o p —! a l l o w e d f o r many y e a r s and a r e
10
l o c a t e d i n s e m i - a r i d a r e a s a t 1075,
585 and 1200 m e l e v a t i o n ,
resp e c ­
tiv e ly .
The
tiv e
i n d e x i n g m odel i s a f i r s t a t t e m p t a t a p p r o x im a tin g th e
m a g n itu d e
of
N
v a r y i n g OM c o n t e n t s .
la b o ra to ry
m in e ra liz a tio n o f fo u r
c u ltiv a te d
d a ta
s o ils
w ith
S o i l N m i n e r a l i z a t i o n d a t a w ere g e n e r a t e d i n th e
u n d e r o p tim a l s o i l w a te r c o n d i t i o n s ( n e a r
w ith te m p e r a tu r e ( 0 , 1 4 , .2 8 ° c ) s t r i c t l y c o n t r o l l e d .
tio n
re la ­
fie ld
c a p a c ity )
L a b o r a to r y in c u b a ­
a r e sum m arized by s o i l h o r iz o n an d te m p e r a tu r e i n
A ppendix
T a b le s 17, 1 8 , a n d 19.
C u m u la tiv e
was
a v e ra g e d
lin e a r
n e t N m i n e r a l i z a t i o n a t e a c h te m p e r a tu r e a n d
o v e r th e 12 week i n c u b a t i o n p e r i o d
(8 4
OM l e v e l
d a y s).
r e g r e s s i o n o f mean c u m u la tiv e n e t N m i n e r a l i z a t i o n on
t u r e a t e a c h OM l e v e l p r o v id e d an e q u a ti o n f o r 1.8% ,
2.4% ,
S im ple
te m p e ra ­
2.6% ,
and
4 . 4% OM w i t h r 2 = 0 .9 9 ( T a b le 2 ) .
T a b le 2 .
L i n e a r e q u a t i o n s f o r mean d a i l y N m i n e r a l i z a t i o n by
m a tte r c o n te n t.
o r g a n ic
'' Cum. n e t M m in . d a y - '*
E q u a tio n w here
S e rie s
OM
0°c
14°C
kg N m in . h a -1 day-1
———————————— % —— — — — kg ha ** — — — — — — ———————————————————————
Bozeman
4 .4
0 .9 9 2
1 .3 3 0
=
0 .0 2 3 8 T0 C + 0 .9 9 2
W illia m s
2 .6
0 .3 8 5
0 .9 3 6
=
0 .0 3 9 3
T0 C + 0 .3 8 5
S cobey
2 .4
0 .4 5 0
0 .7 9 9
=
0 .0 2 4 9
T0 C + 0 .4 5 0
0 .2 5 2
0 .5 4 9
S . Am.
1.8
0 .0 2 4 4 T0 C + 0 .2 5 2
11
A
p r e d i c t i v e e q u a t i o n was em ployed ( M e ik le a n d T readw ay,
e s tim a te f i e l d
s o i l te m p e ra tu re .
1 979) to
The e q u a t i o n was d e v e lo p e d from 10 cm
d e p th s o i l t e m p e r a tu r e d a t a c o l l e c t e d o v e r a minimum t h r e e y e a r
p e rio d
a t 114 l o c a t i o n s i n th e U n ite d S t a t e s a n d i s shown by t h e e x p r e s s i o n :
T e m p e ra tu re ( 0F) = 3 0 .5 - ( 0 .4 0 1 )X + ( 9 .3 9 x 10~5 )X2 - ( 4 .1 7 x 1 0 -5 )
X3 + (,3.22 x 10“ 8 )X4
w here X i s t h e J u l i a n c a l e n d a r day ( J a n .
■
(1)
1=1,
t i a l r e g r e s s i o n c o e f f i c i e n t s f o r M o c c a s in ,
D ec. 31 = 3 6 5 ) .
P a r­
M ontana w ere s e l e c t e d (R2 =
0 .9 3 7 ) .
S t a r t i n g d a te f o r e s t i m a t i n g f i e l d N m i n e r a l i z a t i o n was s e l e c t e d a s
May
te n t
15 ( J u l i a n d a y 1 3 6 ) .
was
e x p re s s io n
d e te r m i n e d .
C u m u la tiv e N m i n e r a l i z a t i o n a t e a c h OM con­
Ten cm s o i l te m p e r a t u r e s from
d i d n o t e x c e e d 1 4 .0 3 °C ,
th e re fo re ,
th e
p o ly n o m ia l
o n ly th e 0 ° and
14°C
l a b o r a t o r y M m i n e r a l i z a t i o n d a ta w ere in c l u d e d i n th e m o d e l.
R e s u lt s and D is c u s s io n
S e le c te d
s o i l s r e f l e c t d i f f e r e n t c r o p p in g h i s t o r i e s r a n g i n g
from
v i r g i n g r a s s l a n d ( B r i d g e r ) to s m a ll g r a i n / a l f a l f a r o t a t i o n (Bozem an) to
many y e a r s o f c r o p / f a l l o w g r a i n p r o d u c t i o n ( S c o b e y ,
W illia m s ).
(10%
N itr o g e n
S a p p in g to n -A m e sh a ,
m i n e r a l i z a t i o n was g r e a t e s t i n th e B r id g e r
OM) a n d l e a s t i n t h e S a p p in g to n Amesha s o i l (1.8% ) OM a c r o s s
s o il
a ll
te m p e ra tu re s (F ig . 1 ) .
N et
fin a l
s o i l N m i n e r a l i z a t i o n d a ta a r e c o n t r a s t e d a t t h e i n i t i a l
l e a c h i n g d a te f o r th e
W illia m s
s o ils .
R e s u lts
Bozem an,
at
th e
Scobey,
S ap p in g to n -A m e sh a
2 week p e r i o d
of
th e
and
and
in c u b a tio n
CD 420
•
•
•
■
10.0 I
4.4
2.6 %OM
2 .4 1
T 1.8'
^
210-
TEMPERATURE (C)
F ig u r e I .
T o t a l c u m u la tiv e n e t N m i n e r a l i z a t i o n o f f i v e
la b o r a to r y in c u b a tio n a t th r e e te m p e ra tu re s .
s o ils
by
13
( F i g . 2 ) i n d i c a t e t h e s i g n i f i c a n t (P = 0 .0 5 , 2 S.D .) e f f e c t o f t e m p e r a ­
t u r e a n d OM c o n t e n t on th e a m o u n t o f N m i n e r a l i z e d .
tio n
was n o t s i g n i f i c a n t l y d i f f e r e n t a t 0 ° an d 1 4 ° C a t 12 w eeks ( F ig .
3) , h o w e v e r,
C.
S o il M m in e ra liz a ­
th e Bozem an s o i l d id p ro d u c e s i g n i f i c a n t l y m ore N a t 28°
T he l a c k o f o v e r a l l s t a t i s t i c a l d i f f e r e n c e s i n N m i n e r a l i z e d by
t w e lv e
w eeks i n d i c a t e s
t h a t th e d u r a t i o n
o f th e l a b o r a t o r y
i n c u b a t io n
was s u f f i c i e n t to rem o v e m o st o f th e " e a s i l y m i n e r a l i z a b l e " N.
R e a d ily
c o n v e r t i b l e o r g a n i c m a t e r i a l s i n t h e s e s o i l s p r o b a b ly had b e e n consum ed
a t 12 w eeks an d o n ly t h e hum us c o m p o n e n t r e m a in e d a s s u b s t r a t e .
I n c r e a s e d N m i n e r a l i z a t i o n w i t h t e m p e r a t u r e i s e x p e c te d ,
th e a m o u n t o f m i n e r a l i z e d N p ro d u c e d by a l l
i n g l y l a r g e ( F ig . 4)-
h o w ev er,
s o i l s a t O0 C was s u r p r i s ­
The s a m p le s w ere k e p t a t O0 C c o n t i n u a l l y ,
except
d u r in g l e a c h i n g (14 h o u r s a t room t e m p e r a t u r e ) .
M ic ro b e s p r o b a b ly c o u ld n o t a c c e l e r a t e m i n e r a l i z a t i o n t o th e e x t e n t
o b s e r v e d d u r i n g t h a t 14 h o u r t i m e p e r i o d .
c o lle c te d
f o llo w in g th e a d d itio n
S i n c e l e a c h a t e s w e re n o t
o f e a c h a d d e d i n c r e m e n t o f 0.0 1 M
CaCl2 , a n d t h e s e l e a c h a t e s w ere n o t a n a ly z e d i n d i v i d u a l l y a f t e r p a s s i n g
t h r o u g h s o i l c o l u m n s , t h e r e i s no r e c o r d o f l e a c h a t e c o n t e n t t h r o u g h
th e day.
S o i l s i n c u b a t e d a t O0 C m i n e r a l i z e d b e t w e e n 21 a n d 83 k g N
h a --*. The c r e d i b i l i t y o f u s in g f a l l s o i l N s t a t u s f o r p r e d i c t i n g s p r i n g
c ro p NOyN r e q u i r e m e n t s i s q u e s t i o n a b l e .
The c o m p u te r m odel (A p p en d ix T a b le 20) u s e d i n c l u d e d
la b o ra to ry
N
m i n e r a l i z a t i o n d a t a t o e s t i m a t e t h e d i f f e r e n c e s i n N m i n e r a l i z e d by
s o i l s v a r y i n g i n OM c o n t e n t .
R e s u l t s o f th e i n c u b a t i o n d a ta a r e sum­
m a riz e d by te m p e r a tu r e in F ig u r e s 4 , 5 , and 6 w ith th e e q u a tio n s f o r
e a c h l i n e d e p i c t e d i n T a b le 3-
14
• 4.4
TEMPERATURE (C)
F ig u r e 2
S o i l N m i n e r a l i z a t i o n by l a b o r a t o r y i n c u b a t i o n a t two w eek s.
15
12wk.
# 4.4
%0M
t e m p e r a t u r e (c )
F ig u r e 3«
S o il N
w eek s.
m i n e r a l i z a t i o n by l a b o r a t o r y i n c u b a t i o n
at
tw e lv e
16
%0M
94 * *
9?**
99**
.97**
10
o
F ig u r e 4»
T a b le 3 .
12
TIME (weeks)
C u m u la tiv e n e t N m i n e r a l i z a t i o n o f f o u r c u l t i v a t e d s o i l s by
l a b o r a t o r y i n c u b a t i o n a t 0 °C .
L i n e a r e q u a t i o n s f o r c u m u la tiv e n e t N m i n e r a l i z a t i o n by
g a n ic m a t t e r c o n t e n t a t t h r e e t e m p e r a t u r e s .
o r­
IO
I
28° C
I
i
I
OM
- %-
I
1 °o
I O
I
T e m p e ra tu re
S e rie s
Bozeman
4 -4
Y =
3.21X + 4 9 .1 3
4 .03X + 6 5 .8 0
9.77X + 9 1 .7 7
W illia m s
2 .6
Y =
2.68X +
0 .7 9
4 .60X + 2 5 .6 1
6.16X + 4 9 .4 7
S cobey
2 .4
Y =
1.56X + 2 0 .6 7
3.45X + 2 7 .4 9
6.91X + 4 1 .8 0
S a p p in g to n
Amesha
1 .8
Y =
1.02X +
3 .28X + 1 1 .7 6
7.12X + 3 0 .3 9
9 .8 8
%0M
10
12
TIME (weeks)
5.
CUM. NET N MIN. (kg ha'1)
f
CUM. NET N MIN. (kg ha"1)
17
F ig u r e 6 .
C u m u la tiv e n e t K m i n e r a l i z a t i o n o f f o u r c u l t i v a t e d s o i l s
l a b o r a t o r y i n c u b a t i o n a t 14°C .
%OM
by
r=.99
r=.99
r=.98
r=.99
8
10
12
TIME (weeks)
C u m u la tiv e n e t N m i n e r a l i z a t i o n o f f o u r c u l t i v a t e d s o i l s
l a b o r a t o r y i n c u b a t i o n a t 2 8 ° C.
by
18
F ie ld
s o i l t e m p e r a t u r e s u s e d i n th e m o d el w ere o b t a i n e d fro m a
p o ly n o m ia l e q u a ti o n d e s ig n e d to e s t i m a t e
10 cm d e p th s o i l
t e m p e r a tu r e
( 1 ).
The t e m p e r a t u r e e q u a t i o n show ed t h a t s o i l t e m p e r a t u r e s a t M occa­
s in ,
M ontana ra n g e d fro m 13.2°C on May 15 ( J u l i a n 136) t o a maximum o f
1 4 .0 2 ° C ( J u l i a n 1 5 3 ) , t o a m in im u m o f 7 .5 ° C on J u l y 1 5 .
T he o v e r a l l
m o d el p r e d i c t s M m i n e r a l i z e d fro m e q u a t i o n (2 )
N m i n e r a l i z e d (k g h a -1 d a y - 1 ) = - 0 .2 5 + 0.28(0M ) + 0 .0 3 (T ° C )
(2 )
T o ta l N m i n e r a l i z a t i o n o b ta in e d p r o v id e s a l i n e a r in d e x to th e
d i f f e r e n c e s i n N m i n e r a l i z a t i o n (T a b le 4 ).
P re d ic te d N m in e r a liz a tio n
v a l u e s f o r d a y 61 w e r e 3 9 , 4 9 , 5 3 , a n d 84 k g N h a -1
2.6% a n d 4-4% OM, r e s p e c t i v e l y .
f o r 1. 8 %, 2 . 4 %,
T he d i f f e r e n c e b e t w e e n 1.8% a n d 2.4%
OM was s m a l l a t 10 kg N h a - "* w h ile th e d i f f e r e n c e b e tw e e n 1.8% and 4. 4%
OM was 45 k g N h a- "*.
D iv id in g th e t o t a l p r e d i c t e d N m i n e r a l i z e d fro m
e a c h s o i l b y t h e a m o u n t o f OM c o n t a i n e d i n t h e s o i l s
(%) s h o w s t h a t
e a c h 1% OM p r o d u c e s n e a r l y 20 k g h a - "* o f p l a n t a v a i l a b l e N f o r t h e 61
d a y p e r i o d ( T a b l e 4)*
T h ese d a t a i n d i c a t e
th e re a re d if f e r e n c e s in s o i l N m in e r a liz a tio n
a s a f u n c t i o n o f OM c o n t e n t u n d e r o p tim u m c o n d i t i o n s a n d t h a t t h e
d iffe re n c e s
s tu d ie d .
a re
s u b s ta n tia l
a c ro ss
th e
ran g e
N itr o g e n m i n e r a l i z a t i o n i n c r e a s e s
f i e l d c o r r e la te d s o il te m p e ra tu re s .
of s o il
OM c o n t e n t s
w i t h tim e e v e n when u s in g
I r r i g a t e d c o n d it io n s p ro v id e a
m ore s u i t a b l e e n v ir o n m e n t f o r m i c r o b i a l a c t i v i t y t h e r e b y p r o lo n g in g th e
p e r i o d o f N m i n e r a l i z a t i o n ( E l- H a r is e t a l . ,
little
d a ta a v a ila b le
re la tin g
th e
u n d e r v a ry in g f i e l d c o n d itio n s .
1983).
H ow ever,
th e re i s
m a g n itu d e o f s o i l N m i n e r a l i z a t i o n
M ore r e s e a r c h i s n e e d e d t o q u a n t i f y
19
a c tu a l
s o il
N m in e ra liz a tio n
hance o u r a b i l i t y
T a b le 4 .
over
t im e .
T h is i n f o r m a t i o n s h o u ld e n ­
t o a c c u r a t e l y p r e d i c t c r o p N r e q u i r e m e n ts .
M in e r a li z e d N p r e d i c t e d fro m N m i n e r a l i z a t i o n m odel on a p e r ­
c e n t o rg a n ic m a tte r b a s is a t th re e d a te s .
D a te s
7 /1 6
7 /2 7
D a te s
8 /8
7 /1 6
7 /2 7
8 /8
S e rie s
OM
Bozeman . . . .
4 -4
84
97
109
4 .2
4 -0
3 .8
3 .6
' 80
77
74
. 70
92
88
84
80
104
99
• 94
90
1 9 .2
1 9 .3
1 9 .4
1 9 .5
2 2 .0
2 2 .2
2 2 .2
2 2 .3
2 4 .7
2 4 .8
2 4 .8
2 4 .9
3 .4
3 .2
3 .0
2 .8
67
63
60
56
76
72
68
64
85
80
75
70
1 9 .6
1.9.7
1 9 .9
2 0 .1
2 2 .4
2 2 .5
2 2 .7
2 2 .8
2 4 .9
2 5 .0
2 5 .1
2 5 .2
2 .6
53
60
66
2 0 .3
2 3 .0
2 5 .3
S cobey .......... 2 .4
49
56
61
2 0 .5
2 3 .2
2 5 .4
2 .2
2 .0
46
42
52
47
56
51
2 0 .8
2 1 .2
2 3 .5
2 3 .8
2 5 .6
2 5 .7
S . Am............... 1 .8
39
43
47
2 1 .6
2 4 .1
2 5 .9
Mean = 2 0 .0
2 2 .8
2 5 .1
W illia m s . . .
T o t a l p r e d i c t e d N m in .
B re d . N m in . by %0M
kg h a - ^ -------2 2 .0
1 9 .1
2 4 .7
20
CHAPTER IV
NITROGEN MINERALIZATION MODEL OF SURFACE SOILS
FROM FIELD INCUBATIONS
In tro d u c tio n •
L a b o r a to r y i n c u b a t i o n s t u d i e s a n d th e r e s u l t i n g m o d els r e l a t e
fere n t
tu re ,
s o ils ' a b ility
t o m i n e r a l i z e a maximum am ount o f
N.
d if­
Tem pera­
s o i l w a te r c o n t e n t a n d th e am ount o f OM p r e s e n t a r e v e ry im p o r­
t a n t i n c o n t r o l l i n g t h e breakdow n o f s o i l OM.
T re n d s i d e n t i f i e d u n d e r
l a b o r a t o r y c o n d i t i o n s n e e d to be t e s t e d i n th e h a r s h f i e l d e n v ir o n m e n t.
S e v e r a l w o rk e rs h av e d e s c r i b e d t e c h n i q u e s w h ich a t t e m p t t o q u a n t i f y th e
N m i n e r a l i z e d i n a p a r t i c u l a r c r o p p in g s y s te m (E n o , 19 6 0 , S m ith e t a l . ,
1 9 7 7 , W esterm ann a n d C f o t h e r s , 1 9 8 0 ) .
T h is
fie ld
i n c u b a t i o n s tu d y was i n i t i a t e d w i t h in t h e c o n f i n e s
of
a n o t h e r f i e l d r e s e a r c h p r o j e c t d e s ig n e d t o q u a n t i f y th e e f f e c t s o f s o i l
i n j e c t e d raw sew age s lu d g e on h eav y m e ta l u p ta k e by c r o p s .
in c u b a tio n
s tu d y
w ill
n o t a d d r e s s th e r e l a t i o n s h i p
of
The
fie ld
h eav y
m e ta l
a p p l i c a t i o n to s o i l N m i n e r a l i z a t i o n .
The o b j e c t i v e s o f th e f i e l d i n c u b a t i o n s tu d y i n c l u d e t h e
q u a n tifi­
c a t i o n o f g ro w in g s e a s o n s o i l N m i n e r a l i z a t i o n and th e d e v e lo p m e n t o f a
p r e d i c t i v e N m i n e r a l i z a t i o n m o d e l.
M a t e r i a l s a n d M ethods
F ie ld in c u b a tio n e x p e rim e n ts,
c o n d u c te d on th e D ie h l R anch l o c a t e d
21
5 k i l o m e t e r s e a s t o f E a s t H e le n a , M ontana (T10N, R2W), w ere e s t a b l i s h e d
at
sev en s i t e s ,
d e s i g n a t e d H,
t h r e e i n 1983 a n d f o u r i n 1 9 8 4 .
J a n d M.
S i t e s H a n d M e a c h had 7 3 ,0 0 0 l i t e r s h a-1
raw sew age s lu d g e a p p l i e d i n th e summer o f 1 9 8 2 .
c o m m e rc ia l f e r t i l i z e r .
I n 1984 s i t e s H,
w i t h a n a d d i t i o n a l s i t e , R.
R e s u lts
The 1983 s i t e s were
J,
S i t e J r e c e i v e d o n ly
an d M w ere r e e s t a b l i s h e d
O nly s i t e R r e c e i v e d s lu d g e i n 1 9 84.
o f su b sa m p le c h e m ic a l a n a l y s e s f o r th e 1983 a n d 1984 s i t e s
a r e shown i n T a b le 3 .
N itr o g e n s p e c i e s a n a l y s i s was a c c o m p lis h e d on an
A uto A n a ly z e r I I s y s te m w i t h th e NO-^-N by cadmium r e d u c t i o n ,
th e
B e rth e lo t
s im ila r
r e a c t i o n a n d t o t a l N d i g e s t i o n by
NH^-N
s e m i-m ic ro
by
K j e ld a h l
t o t h a t o f B rem ner (1 9 6 5 ) w ith th e c o l o r i m e t r i c p o r t i o n o f th e
K j e l d a h l p e rfo rm e d a s t h e B e r t h e l o t r e a c t i o n ( s e e C h a p te r I I I ) .
C arbon
was d e te r m in e d w ith a m o d if ie d H a lk le y - B la c k p r o c e d u r e (S im s a n d
1 9 7 0 ),
of
pH
by g la s s e le c tr o d e ( s o il:w a te r r a t i o 1 :2 ) ,
K fro m ammonium
a c e ta te e x tra c tio n
(B ow er,
sen,
EC b y H escan c o n d u c t i v i t y m e te r on a 1 : 2
1 9 5 4 ),
and
e t a l.,1 9 5 2 ) ,
H aby,
P by sodium b i c a r b o n a t e (O l­
s o il:w a te r
m ix tu r e ( R i c h a r d s , 1954)«
D e s c rip tio n s
o f m eth o d s f o r th e e s t a b l i s h m e n t o f i n c u b a t i o n
a p p ly t o a l l s i t e s i n b o t h y e a r s o f t h e e x p e r im e n t.
by
S o i l was
s ite s
rem oved
a. 5«7 cm o u t s i d e d i a m e te r s a m p lin g tu b e to a d e p th o f 30 cm.
c o re
was s p l i t i n t o 3 ,
c o r r e s p o n d in g
85
10 cm in c r e m e n ts a n d im m e d ia te ly
l i t e r p la s tic bags.
p la c e d
in to
T h ese l a r g e p l a s t i c b a g s
w ere
s e a l e d a f t e r e a c h s o i l c o r e p o r t i o n was a d m i t t e d to r e d u c e o f
tio n .
A p p ro x im a te ly
20
c o re s
m ixed
th o ro u g h ly ,
s u b s a m p le d ,
e v a p o ra ­
w ere rem oved p e r r e p l i c a t i o n
r e p l i c a t i o n s a s s ig n e d to ea ch s i t e .
th e n
E ach
w ith
3
S o i l i n th e l a r g e p l a s t i c b a g s was
in tro d u c e d
in to
tu b u la r
5
cm
22
T a b le 5 .
D ep th
C h em ical p r o p e r t i e s o f s o i l s su b sa m p le d f o r f i e l d i n c u b a t i o n
e x p e r im e n ts i n i t i a t e d i n 1983 a n d 1 9 84.
MH4-M
MO3-M
- cm ——
-
S ite H
5 /2 5 /8 3
0 -1 0
1 0 -2 0
2 0 -3 0
S ite J
0 -1 0
1 0 -2 0
2 0 -3 0
S ite M
0 -1 0
1 0 -2 0
2 0 -3 0
S ite H
0 -1 0
1 0 -2 0
2 0 -3 0
S ite J
0 -1 0
1 0 -2 0
2 0 -3 0
S ite M
0 -1 0
1 0 -2 0
2 0 -3 0
S ite R
0 -1 0
1 0 -2 0
2 0 -3 0
kg
C
M
OM
C:M
pH
h a -1 ■— — — — % — — — —
3 .0
7 .9
1 7 .4
EC
mmho cm*- ^
P
—
K
Ug
g~1
-
1 .0 4
0 .9 3
0 .8 1
0 .1 3
0.1 1
0 .1 1
1 .8 0
1 ,6 0
1 .4 0
8 .0 0
8 .4 5
7 .3 6
7 .6
7 .5
7 .6
0 .1
0 .1
0 .1
1 3 .7
7 .8
6 .0
442
210
158
5 .2
4 -4
4 .2
1 .8 6
1 .4 5
1 .1 6
0 .1 8
0 .1 5
0 .1 3
3 .2 0
2 .5 0
2 .0 0
1 0 .3 3
9 .6 7
8 .9 2
7 .4
7 .3
7 .4
0 .1
0 .1
0 .1
1 2 2 .0
5 2 .2
1 4 .9
354
206
118
3 .6
2 .7
3 .2
0 .9 3
0 .7 0
0 .7 2
0 .0 9
0 .0 9
0 .0 9
1 .6 0
1 .2 1
1 .2 5
1 0 .3 3
7 .7 8
8 .0 0
7 .6
7 .7
8 .4
0 .3
0 .2
0 .4
3 4 -7
1 0 .2
7 .2
670
530
322
1 .2 2
1 .0 4
0 .7 5
0 .1 3
0 .1 3
0 .1 0
2 .1 0
1 .8 0
1 .3 0
9 .3 8
8 .0 0
7 .5 0
8 .3
8 .3
8 .3
0 .5
0 .6
0 .6
1 6 .0
1 4 -4
1 3 .3
475
259
163
1 .9 1
1 .5 1
1.5 1
0 .1 8
0 .1 6
0 .1 5
3 .3 0
2 .6 0
2 .6 0
1 0 .6 0
9 .4 0
1 0 .1 0
8 .0
8 .1
8 .2
0 .5
0 .6
0 .6
3 8 .3
1 7 .9
2 4 .8
315
178
186
0 .8 7
0 .7 5
0 .6 4
0 .1 0
0 .0 9
0 .1 0
1 .5 0
1 .3 0
1 .1 0
8 .7 0
8 .3 0
6 .4 0
7 .8
7 .9
8 .2
0 .6
0 .7
0 .8
2 6 .3
1 9 .8
1 6 .5
450
378
'227
0 .8 1
0 .6 4
0 .1 0
0 .1 0
0 .1 0
1 .4 0
1 .1 0
1 .0 0
8 .1 0
6 .4 0
5 .8 0
8 .3
8 .2
8 .4
0 .5
0 .6
0 .9
1 9 .9
1 5 .5
1 0 .9
445
332
223
4-1
3 .0
3 .1
5 /2 5 /8 3
4 -8
■■ 4 .1
5 .9
6 /1 /8 3
2 .9
1 .5
0 .5
5 /1 9 /8 4
5 .7
3-1
4 .4
4 .4
4 .0
4 -6
5 / 3 0 /8 4
8 .1
3 .5
6 .6
-
4 .0
2 .8
2 .8
5 / 1 1 /8 4
1 6 .6
2 8 .8
3 3 .9
5 .0
4 .0
5 .9
5 / 1 2 /8 4
1 9 .8
2 4 -2
2 9 .1
2 .8
3 .0
3 .3
0 .5 8
23
d i a m e te r ( 3 . 9 urn t h i c k ) p o l y e t h y le n e b a g s s e a l e d on one e n d .
S o i l from
t h e l a r g e p l a s t i c b a g s was p l a c e d i n t o t h e t u b u l a r p o l y e t h y le n e b a g s by
c o r r e s p o n d in g d e p th in c r e m e n t so t h a t th e 20—30 cm i n c r e m e n t was i n t r o ­
duced f i r s t ,
fu lly
th e 10—20 cm in c r e m e n t n e x t a n d so o n .
d ro p p e d
B ags w ere
on a h a r d s u r f a c e ( t o c o m p re ss th e d i s t u r b e d s o i l )
s e a l e d when f i l l e d ,
1 9 8 0 ).
Where s lu d g e was
i n j e c t e d , c o r e s a m p le s w ere ta k e n b e tw e e n i n j e c t i o n p a t h s .
w ere c r o p p e d , c o r e s w ere ta k e n fro m b e tw e e n d r i l l ro w s .
im m e d ia te ly
f r o z e n on d ry i c e t o i n h i b i t
d u r i n g t r a n s p o r t a t i o n t o th e l a b o r a t o r y .
w ere
Where s i t e s
The N m in e r a l­
(NM) b a g s w ere th e n e x t r a c t e d fro m th e g ro u n d a t w eekly
v a l s , one p e r r e p l i c a t i o n p e r s i t e i n 1983 a n d 19 8 4 .
w ere
s p lit
and
t h e n i n s e r t e d i n t o th e h o l e s from w h ich th e y o r i g i ­
n a l l y w ere rem oved ( W esterm ann a n d B r o t h e r s ,
iz a tio n
c a re ­
in te r­
E x t r a c t e d NM b a g s
fu rth e r
n itrific a tio n
A t th e l a b o r a t o r y th e NM b a g s
i n t o t h e c o r r e s p o n d in g 10 cm d e p th
in c r e m e n t s ,
d rie d
at
36°C , t h e n a n a ly z e d f o r NO^-N an d NH^-N.
S o il
t e m p e r a tu r e
p r o b e s w ere a s s e m b le d fro m 5 cm p l a s t i c
T h e r m i s to r s (Omega P a r t No.
x
th e
4 4 0 0 5 ) were b e d d e d i n s i l i c o n e - f i l l e d 1 cm
I cm p l a s t i c c o u p lin g m a t e r i a l w ith i n s u l a t e d w ir e s r u n n in g
5 cm t u b in g to th e u p p e r e n d ,
bedded
th e rm is to rs
w ere
tu b in g .
th e en d a t th e s o i l
th ro u g h
su rfa c e .
c e m e n te d i n t o h o l e s d r i l l e d i n t o
th e
The
5
cm
t u b in g a t 1 0 , 20 and 50 cm d e p th s ( d i s t a n c e s ) from th e u p p e r e n d .
Once
th e c e m e n t d r i e d a n d t h e b e d d e d t h e r m i s t o r s w ere s e c u r e th e t u b e s
were
s e a le d
w ith
p ro tru d in g
in s ta lle d
s i l i c o n e c a u lk i n g a t e a c h end w ith th e
fro m
at
th e u p p e r en d o f th e t u b e .
each s it e
th e r m is to r
w ir e s
T e m p e ra tu re p r o b e s
t h e day NM b a g s w ere p la c e d i n t o
th e
were
g ro u n d .
S o i l te m p e r a tu r e r e a d i n g s w ere made c o n c u r r e n t l y w ith NM bag e x t r a c t i o n
24
w i t h a S im pson Model 461 d i g i t a l m u lt im e te r (A p p en d ix T a b le 2 4 ) .
D a ta w ere a n a ly z e d by s te p w is e m u l t i p l e l i n e a r r e g r e s s i o n u s in g th e
maximum
R2 im p ro v e m e n t te c h n iq u e ( S t a t i s t i c a l A n a ly s is S y stem o r
SAS)
on a VAX m odel 1 1 /7 8 0 .
N itr o g e n
w e e k ly
s p e c ie s
a n a ly s e s
of
p ro d u c e d by m i n e r a l i z a t i o n w ere q u a n t i f i e d
s o i l c o n ta i n e d i n NM b a g s
(A p p en d ix
from
T a b le
T o t a l s o f N s p e c i e s by week a n d s o i l d e p th fro m NM b a g s a r e
2 1 ).
sum m arized
i n A p p endix T a b le 2 2 .
D e v e lo p m e n t
of
a p r e d i c t i v e m odel o f f i e l d N m i n e r a l i z a t i o n
from
f i e l d i n c u b a t i o n s r e q u i r e s i n i t i a l d e f i n i t i o n o f v a r i a b l e s in c l u d e d
th e
s e l e c t e d m u l t i p l e r e g r e s s i o n a n a l y s i s ( T a b le 6 ) .
f u r t h e r i d e n t i f y v a r i a b l e s SITE a n d WEEK r e s p e c t i v e l y .
( T a b le
th e
T a b le s 7 and
th e N s p e c i e s ,
In
re g re s s io n
a n a l y s i s c o n s t i t u t e th e sum o f a l l 10 cm in c r e m e n ts by s i t e
(T a b le 1 1 ) .
K je ld a h l
N
i n c r e m e n t s by s i t e
v a lu e s u s e d i n th e
cm.
m u ltip le
T o ta l
of
8
The v a r i a b l e s ,
6 ) r e f l e c t th e t o t a l d e p th o f th e s tu d y p r o f i l e o r 30
case
in
a n d OM l e v e l s u s e d r e s u l t from th e mean
( T a b le 5 ) .
of
10
cm
A ir te m p e r a tu r e was o b t a i n e d from H elena
A i r p o r t c l i m a t o l o g i c a l d a t a su m m aries p u b l i s h e d by th e N a t io n a l Oceano­
g r a p h i c a n d A tm o sp h e ric A d m i n i s t r a t i o n .
la te d
The AIRTC p a r a m e te r was c a l c u ­
a s t h e mean o f t h e maximum d a i l y a i r te m p e r a tu r e f o r th e
6
day
p e r i o d p r e c e d in g a n d th e d ay o f NM b ag e x t r a c t i o n (A p p en d ix T a b le 2 3 ) .
R e s u lts and D is c u s s io n
R e s u lts
( T a b le
d ic tin g
of
th e
maximum R2 m u l t i p l e
lin e a r
re g re s s io n
a n a ly s is
9 ) i n d i c a t e th e in d e p e n d e n t v a r i a b l e s m o st i n f l u e n t i a l i n
N
m i n e r a l i z a t i o n a s m ea su red by t o t a l m in e r a l
N
p re ­
p ro d u c tio n .
25
T a b le 6 .
V a r i a b l e s i n c l u d e d i n th e m u l t i p l e l i n e a r r e g r e s s i o n a n a l y s i s
( l= i n d e p e n d e n t, D = d e p e n d e n t).
V a r ia b l e
Id e n tific a tio n
S ite
Week
T o t a l N03-N 30 cm- '*
T o t a l NH4-N 30 cm-1
,
T o t a l N03-N + MH4-N 30 cm-1
Mean w e e k ly maximum a i r te m p e r a tu r e °C
W eekly s o i l t e m p e r a t u r e a t 10 cm 0 C
W eekly s o i l t e m p e r a t u r e a t 20 cm 0 C
W eekly s o i l t e m p e r a t u r e a t 50 cm 0 C
Mean % o r g a n i c m a t t e r c o n t e n t 30 cm" ^
Mean % t o t a l n i t r o g e n c o n t e n t 30 cm- '*
T a b le ?•
V a r ia b l e
I
I
B
D
D
I
I
I
I
I
I
D e s c r i p t i o n o f in d e p e n d e n t v a r i a b l e SITE u se d i r i t h e m odel.
Id e n tific a tio n *
SITE
*
SITE
WEEK
N03T
NH4T
N03NH4T
AIRTC
SOILT10
S0ILT20
S0ILT50
OM
N
Y ear a n d s i t e
M anagem ent H i s t o r y
1983
H
S lu d g e i n j e c t e d i n t o
fa llo w
1982,
s e e d e d to w i n t e r w h e a t 19 8 2 . .
1983
J
C om m ercial f e r t i l i z e d f a l l o w
s e e d e d t o w i n t e r w h e a t 19 8 2 .
1983
M
W in te r w h e a t 1982, f a l l o w 1983
1984
H
F a llo w 1984
1984
J
F a llo w 1984
1984
M
S lu d g e i n j e c t e d i n t o f a l l o w
s e e d e d t o s p r i n g w h eat 1 9 8 4 .
1983,
1984
R
S lu d g e i n j e c t e d i n t o
fa llo w
s e e d e d t o w in te r w h eat 1 9 8 3 .
1983,
1982,
26
The
s ta tis tic a l
v a ria b le
=
tre a tm e n t
i n t r o d u c e d SITE a s th e
firs t
in d e p e n d e n t
(R^ = 0 .5 0 3 ) , f o llo w e d by WEEK (R^ = 0 .8 0 5 ) , th e n SOILT10
0 .8 2 4 ) ,
OM (R^ = 0 .8 2 5 ) ,
a n d N (R^ = 0 .8 4 2 ) .
T a b le 10 shows
(R^
th e
e q u a t i o n w h ich c o n s t i t u t e s th e " b e s t " 5 in d e p e n d e n t v a r i a b l e m o d el.
T h re e
o f th e 5 in d e p e n d e n t v a r i a b l e s w ere p o s i t i v e l y r e l a t e d to
m i n e r a l i z e d (N03NH4T),'
h o w e v e r,
to th e d e p e n d e n t v a r i a b l e .
to
SOILT10 a n d N w ere n e g a t i v e l y r e l a t e d
T h is n e g a t i v e r e l a t i o n s h i p was p r o b a b ly due
t h e s t a t i s t i c a l m a n i p u la t io n s w h ich i n t e r r e l a t e in d e p e n d e n t
b le s
w i t h i n th e m odel a n d ,
th e re fo re ,
may n o t d e s c r i b e a
v a ria ­
p a rtic u la r
f u n c t i o n a l r e l a t i o n s h i p among v a r i a b l e s .
T a b le 8 .
D e s c r i p t i o n o f in d e p e n d e n t v a r i a b l e WEEK u s e d i n th e m o d e l.
V a r ia b l e
WEEK
SITE
N
J u l i a n Days
,
WEEKS
H
1 4 1 -2 5 7
1 -1 7
J
1 4 1 -2 5 7
1 -1 7
M
1 5 2 -2 5 7
1 -1 6
H
1 4 0 -2 4 9
1 -1 7
J
1 5 1 -2 4 9
1 -1 5
M
1 3 2 -2 4 9
1 -1 8
R
1 3 3 -2 4 9
I -1 8
27
T a b le 9»
R e s u lts o f m u ltip le l i n e a r r e g r e s s io n a n a ly s i s ; F and c o e f­
f i c i e n t o f m u l t i p l e d e t e r m i n a t i o n (R2 ) f o r N03NH4T a s t h e
d e p e n d e n t v a ria b le .
DF
R e g r e s s io n
E rro r
T o ta l
R2
F
0 .8 4 2
5
112
117
1 1 9.61
I n d e p e n d e n t V a r ia b le
SITE
WEEK
S0ILT10
OM
N
2 5 7 .9 7
2 3 1 .4 5
1 7 .1 2
12.41
1 2 .1 5
The i n c l u s i o n o f a l l
s i t e s i n th e a n a l y s i s p r o v id e d a b ro a d s e l e c ­
t i o n o f p r o d u c t i o n m an ag em en t l e v e l s .
ly
fa llo w e d ,
in je c te d
c ro p p e d
th e
S i t e t r e a t m e n t s in c l u d e d f o r m e r ­
p re v io u s y e a r,
w i t h sew ag e s lu d g e (T a b le ? )•
tr e a tm e n t to each s i t e
c o m m e r c ia lly
fe rtiliz e d ,
an d
The im p o r ta n c e o f th e p r e v io u s
w as a c c o u n te d f o r i n th e m odel b y a s s e s s i n g th e
l e v e l o f m in e r a l N p r e s e n t a t th e tim e o f i n i t i a l s a m p lin g .
in d e x e d i n a s c e n d in g o r d e r a c c o r d in g
to
e a rly
S i t e s w ere
s e a s o n m in e r a l N l e v e l s
(T a b le 1 1 ).
F o r e x a m p l e , s i t e M c o n t a i n e d 14-4 k g m i n e r a l N h a - "* a t
th e i n i t i a l
s a m p lin g w h ile s i t e
u p p e r 30 cm a t t h e i n i t i a l
R h a d 8 2 .2 k g h a - "* m i n e r a l N i n t h e
s a m p lin g .
T hese s i t e s
re p re s e n te d
th e
m inim um a n d maximum m in e r a l N l e v e l s a n d w ere a s s i g n e d in d e x n u m b ers 1
and 7 r e s p e c tiv e ly .
The NM b a g s p r o v i d e d a n i d e a l e n v i r o n m e n t f o r
m e a s u re m e n t o f N m i n e r a l i z a t i o n w i t h i n t h e c ro p p e d f i e l d b e c a u s e p l a n t
r o o t s w e r e u n a b l e t o e x t r a c t m i n e r a l N f r o m t h e NM b a g s .
P re d ic te d
v a lu e s o f N m in e ra liz e d
to a c c o u n t
fo r v a ria tio n
in
m u st i n c l u d e
in itia l
s o il
a n in d e x in g v a r i a b l e
m in e ra l N c o n te n t.
It
is
p ro b a b ly
28 ■
b e c a u s e o f t h e c o n s i d e r a b l e d i f f e r e n c e am o n g m a n a g e m e n t l e v e l s t h a t
SITE was th e m o st i m p o r t a n t in d e p e n d e n t v a r i a b l e i n th e m odel.
T he n e x t v a r i a b l e i n t o t h e m o d e l w as WEEK.
The a d d i t i o n o f t h i s
v a r i a b l e was e x p e c te d b e c a u s e u n d e r optim um c o n d i t i o n s N m i n e r a l i z a t i o n
in c re a s e s
w i t h tim e a s show n i n th e l a b o r a t o r y i n c u b a t i o n s i n C h a p te r
I I I a n d th o s e c o n d u c te d by S ta n f o r d a n d S m ith (1972).
S o i l t e m p e r a t u r e a t th e 10 cm d e p th (S0IL T10) was th e n e x t in d e p e n ­
d e n t v a r i a b l e to e n t e r th e m o d e l.
T e m p e ra tu re i n f l u e n c e s b i o l o g i c a l
a c t i v i t y a n d was t h e r e f o r e c o n s id e r e d i n th e m o d el.
T a b le 1 0 .
M u l t i p l e l i n e a r r e g r e s s i o n e q u a t i o n f o r th e m odel c o n s i d e r ­
i n g N03NH4T a s th e d e p e n d e n t v a r i a b l e .
N MINERALIZED = 5 3 .2 ? + 1 2 .3 6 ( S IT E ) + 4.17(W EEK) - 1.25(S0IL T 10)
+ 4 1 .8 0 ( 0 M ) -
T a b le 1 1 .
9 9 1 .7 4 (B )
S t r a t i f i c a t i o n o f S IT E b y i n i t i a l m i n e r a l n i t r o g e n l e v e l s
f o r d e p e n d e n t v a r i a b l e s N03NH4T an d M03T.
INDEX NUMBER
N03NH4T
14.4
2 6 .2
2 7 .8
2 8 .6
3 8 .5
8 2 .2
9 4 -2
N03T
4 .9
1 3 .2
1 4 .8
1 8 .2
2 8 .3
7 3 .1
7 9 .3
N03NH4T SITE/IEAR
1
2
3
4
5
6
7
M
H
J
J
H
R
M
83
84
84
83
83
84
84
N03T
1
2 .
3
4
5
6
7
SITE/YEAR
M
H
J
J
H
R
M
83
84
83
84
83
84
84
29
At
th is
p o i n t t h e m odel c o n t a i n s 5 in d e p e n d e n t v a r i a b l e s
c o n s i­
d e r e d v e r y i m p o r t a n t i n p r e d i c t i n g t o t a l m in e r a l N p r o d u c t i o n o v e r
15
to
18 week s tu d y p e r i o d .
in c lu d e d
A d d i t i o n a l in d e p e n d e n t
i n s u b s e q u e n t m o d e ls ,
m o d e l 's a b i l i t y
h o w e v e r,
v a ria b le s
th e im p ro v e m e n t i n
th e
w ere
o r th e
to a c c o u n t f o r th e v a r i a b i l i t y i n N m i n e r a l i z a t i o n
was
s m a ll.
The " b e s t " 6 v a r i a b l e m odel in c l u d e d AIRTC (R2 = 0 .8 4 2 ) .
The
maximum
R2
and
th is
o c c u re d
SIT E ,
WEEK,
t e c h n i q u e a ll o w s f o r in d e p e n d e n t v a r i a b l e r e p la c e m e n t
i n t h e b e s t 7 v a r i a b l e m odel w h ich
SOILT10,
S0IL T 20,
e v e n tu a lly
in c lu d e d
S0IL T 50, OM, a n d N (R2 = 0 .8 4 2 ) .
" b e s t " 8 v a r i a b l e m odel a d d e d AIRTC (R2 = 0 .8 4 3 ) .
O v e r a ll
The
d iffe re n c e
b e tw e e n t h e s e l e c t e d 5 v a r i a b l e m odel a n d th e 8 v a r i a b l e m odel i n te r m s
o f R2 was 0.0 0 1 o r 0.1% .
The i n c l u s i o n o f t h e a d d i t i o n a l v a r i a b l e s was
n o t n e c e s s a r y to e n h a n c e t h e m o d e l.
84%
of
th e
The 5 v a r i a b l e m odel a c c o u n ts f o r
v a r i a b i l i t y i n t o t a l m in e r a l N
p ro d u c tio n
and
in c lu d e s
in d e p e n d e n t v a r i a b l e s known t o i n f l u e n c e th e r a t e o f N m i n e r a l i z a t i o n .
Ammonium
(NH4T)
a c c e p t a b l e m o d e l.
p ro d u ct
in
a s t h e d e p e n d e n t v a r i a b l e d id n o t
re s u lt
in
an
T h is was e x p e c te d s i n c e ammonium i s a n i n t e r m e d i a t e
th e f o r m a ti o n o f n i t r a t e d u r i n g m i n e r a l i z a t i o n
and
t h e r e f o r e be th e l e a s t c o n s i s t e n t c o n s t i t u e n t i n th e p r o c e s s .
w ould
The b e s t
8 v a r i a b l e m odel had a n R2 o f 0 .3 1 0 (A p p e n d ix T a b le 2 5 ) .
The
a lo n g
p ra c tic a lity
o f m e a s u rin g n i t r a t e
(W03T) a n d ammonium
w ith o r g a n i c m a t t e r (OM) a n d K j e l d a h l n i t r o g e n (N) e a r l y i n
s p r i n g to e s t a b l i s h th e s i t e c l a s s i s l i m i t e d .
tio n a l
(MH4T)
a p p ro a c h
to
p re d ic tin g N m in e ra liz a tio n
A second,
was
more
th e
fu n c ­
e s ta b lis h e d
by
s im p ly a r r a n g i n g th e s i t e c l a s s by th e l e v e l o f n i t r a t e i n th e u p p e r 30
cm
of
t h e s o i l (T a b le 1 1 ) .
)
N ote t h a t t h e change i n s i t e
in d e x
from
30
t h a t o f N03NH4T i s m in im a l, t h a t i s ,
The
m odel c o n s i d e r i n g N03T a s t h e d e p e n d e n t v a r i a b l e a n d th e
c o m i ta n t
firs t
s i t e J 84 s w itc h e d w ith s i t e J 83«
re a rra n g e m e n t
o f s i t e in d e x ( T a b le 12) e n t e r s
in d e p e n d e n t v a r i a b l e
i n T a b le 1 3 .
It
th e
seem s
as
th e
(R2 = 0 .5 9 7 ) a n d WEEK (R2 = 0 .8 3 1 ) a s shown
A d d itio n a l in d e p e n d e n t v a r i a b le s a r e e n te r e d f i n a l l y p ro ­
d u c in g a " b e s t " 8 v a r i a b l e m odel w ith a n R2 o f 0 .8 6 2 .
b e tw e e n
SITE
con­
2 a n d 8 v a r i a b l e m o d els i n te r m s o f
l o g i c a l t o s e l e c t th e 2 v a r i a b l e m odel
r2
The
d iffe re n c e
i s 0 .031 o r
when
3.1% .
th e
o b je c tiv e
M u lt i p le l i n e a r r e g r e s s i o n e q u a t i o n f o r th e m odel
in g N03T a s t h e d e p e n d e n t v a r i a b l e .
c o n s id e r­
i s t o p r o v id e a f u n c t i o n a l m o d el.
T a b le 1 2 .
N MINERALIZED = - 1 8 .6 ? + 1 1 .7 5 (SIT E ) + 3 .1 5 (WEEK)
T a b le 1 3 .
R e s u lts o f m u ltip le l in e a r r e g r e s s io n a n a ly s is ;
F and c o e f­
f i c i e n t o f m u l t i p l e d e t e r m i n a t i o n (R2 ) f o r N03T a s th e
dependent v a ria b le .
DF
R e g r e s s io n
E rro r
T o ta l
2
115
117
R2
0 .8 3 1
F
2 8 3 .4 7
I n d e p e n d e n t V a r ia b le
SITE
WEEK
3 7 6 .1 2
1 5 9 .6 9
31
T h is
fu n c tio n a l
a p p ro a c h a l s o p r o v id e d a 2 v a r i a b l e m odel
u s in g
th e
same s i t e in d e x a s t h a t o f t h e N03hH4T m odel (T a b le 14) a n d p ro d u c e d an
of
0 .8 2 7 ( T a b le 15) •
m o d els
The o v e r a l l s i g n i f i c a n c e o f th e 2
v a ria b le
i s th e s i m p l i c i t y w i t h w h ich t h e m o d els a c c o u n t f o r 84% o f
th e
v a r i a b i l i t y i n p r e d i c t i n g e i t h e r t o t a l m in e r a l N o r t o t a l n i t r a t e M i n
th e s u r f a c e 30 cm.
The
pendent
at
2 v a r i a b l e m odel p r e s e n t s a s t r a i g h t f o r w a r d lo o k a t th e
v a r i a b l e s deemed m o st i m p o r ta n t i n p r e d i c t i n g D m i n e r a l i z a t i o n
th is lo c a tio n .
The v a r i a b l e SITE i s d i r e c t l y r e l a t e d
m in e r a l N c o n t e n t i n th e u p p e r 30 cm.
v a ria b le
s o il
to
in itia l
W ith th e a d d i t i o n o f tim e i n th e
WEEK th e m odel i s e s s e n t i a l l y c o m p le te .
For t h i s p a r tic u la r
t h i s m odel c o u ld be u s e d to p r e d i c t g ro w in g s e a s o n W m i n e r a l i z a ­
tio n q u ite a c c u r a te ly .
is
in d e ­
The d e t e r m i n a t i o n o f n i t r a t e i n t h e u p p e r 30 cm
r e a l l y th e o n ly m e a su re m e n t n e e d e d t o a s c e r t a i n t h e m in e r a l N
p ro ­
d u c t i o n a t a p a r t i c u l a r tim e .
F u r t h e r m a n i p u la t io n o f th e d a ta to r e p l a c e SITE w ith th e a c t u a l
m i n e r a l i z e d i n tim e w ould a ll o w f o r f i e l d
lo c a tio n s .
S im ila rly ,
th e
in c lu s io n
N
t e s t i n g o f th e m odel i n o t h e r
o f a n e q u a ti o n d e s c r i b i n g
th e
te m p o r a l s o i l w a te r l o s s w ould e n h a n c e t h e a c c u r a c y o f t h e m o d el.
T a b le 14«
M u l t i p l e l i n e a r r e g r e s s i o n e q u a t i o n f o r th e m odel
in g N03T a s t h e d e p e n d e n t v a r i a b l e .
N MINERALIZED = - 1 8 .2 9 + 1 1 .7 5 (SIT E ) + 3 . OS(WEEK)
c o n s id e r­
■
I
32
T a b le 1 5 .
R e s u lts o f m u ltip le l i n e a r r e g r e s s io n a n a ly s is ; F and c o e f­
f i c i e n t o f m u l t i p l e d e t e r m i n a t i o n (R2 ) f o r N03NH4T a s t h e
d e p e n d e n t v a ria b le .
DF
R e g r e s s io n
E rro r
T o ta l
R2
'2
115
117
0 .8 2 7
F
2 7 5 .4 8
XJ->
I n d e p e n d e n t V a r ia b le
SITE
WEEK
3 6 4 .6 1
1 4 9 .5 7
The o b j e c t i v e s o f th e s tu d y w ere s u c c e s s f u l l y a d d r e s s e d .
m in e ra liz a tio n
w as q u a n t i f i e d
in
t h e f i e l d u n d e r n o n i r r ! g a t e d c o n d i­
t i o n s u s i n g t h e m e th o d o f W e s te rm a n n a n d C r o t h e r s ( 1 9 8 0 ) .
tio n a l
m odel o f f i e l d
N itr o g e n
N m in e ra liz a tio n
T he f u n c ­
in c lu d e d v a r i a b le s id e n tif y in g
a n in d e x o f i n i t i a l g ro w in g s e a s o n m i n e r a l N s t a t u s (SITE) a n d tim e ~ o f
i n c u b a t i o n ( WEEK).
D e v e lo p m e n t o f th e f u n c t i o n a l m o d el p r o v id e d a
u s e f u l t o o l f o r t h e p r e d i c t i o n o f g r o w i n g s e a s o n m i n e r a l N.
d e v e l o p m e n t o f t h e m o d e l w o u ld e n h a n c e i t s
F u rth e r
u se by a g r o n o m is ts f o r
p r e d i c ti n g m in e ra l N p ro d u c tio n th e re b y in c r e a s in g p r e c is io n o f f e r t i ­
l i z e r N re c o m m e n d a tio n s .
)
33
CHAPTER V
GENERAL CONCLUSIONS
The
o b je c tiv e s
s e le c te d
o f th e s tu d y w ere t o q u a n t i f y N m i n e r a l i z a t i o n
M ontana s o i l s by f i e l d a n d l a b o r a t o r y
in c u b a tio n
of
te c h n iq u e s
w i t h d e v e lo p m e n t o f p r e d i c t i v e m o d els fro m f i e l d a n d l a b o r a t o r y d a t a .
L a b o r a to r y i n c u b a t i o n s r e v e a l e d th e l i n e a r r e l a t i o n s h i p o f N m in e r s
a l i z a t i o n w ith tim e .
m akes
fa ll
s o il
q u e s tio n a b le .
th e
n a tu ra l
C o n s id e r a b le m in e r a l N was p ro d u c e d a t O0C w h ich
s a m p lin g f o r s p r i n g c r o p N
fe rtiliz e r
The N m i n e r a l i z a t i o n d e t e c t e d a t 0°C was p r o b a b ly due to
s e le c tiv e
p r o c e s s e s f o r m ic r o b e s t h a t
p r o l i f e r a t e u n d e r c o ld M ontana s o i l c o n d i t i o n s .
tio n
in
th e
la b o ra to ry .
th e
fie ld
s u rv iv e
N itr o g e n
The m odel d e v e lo p e d t o p r e d i c t N
l a b o r a t o r y e x p e r im e n t in c l u d e d a n
s o i l t e m p e r a t u r e a t 10 cm.
d ic te d
10
exceed
1 4 » 1°C .
1983 a n d 1984«
4-4% OM.
e q u a ti o n
m in e ra liz a tio n
th a t
More
p re d ic te d
M ontana w h ic h
i n th e f i e l d s tu d y a t E a s t H e le n a ,
d id
M ontana
The l a b o r a t o r y m odel was fo u n d to be l i n e a r from
p re­
not
s o il
in
1.8%
A p p ro x im a te ly 20 kg N h a - ”' was m i n e r a l i z e d f o r e a c h p e r ­
OM a s p r e d i c t e d by th e c o m p u te r m odel when r u n f o r
p e rio d .
in c u b a te d
T h e se te m p e r a t u r e s w ere c o n s i d e r a b l y lo w e r th a n
m e a su re d
and
m in e ra liz a ­
The s o i l te m p e r a tu r e e q u a t i o n
cm s o i l te m p e r a t u r e s f o r M o c c a s in ,
te m p e ra tu re s
cent
can
was r e l a t e d t o t e m p e r a tu r e and CM c o n t e n t o f th e s o i l s
fro m
to
r e q u ir e m e n ts
m in e ra liz e d
m o d e lin g p e r i o d was e x te n d e d .
th e
61
day
N was p r e d i c t e d when th e d u r a t i o n
of
th e
T h is c o u ld be o f p a r t i c u l a r c o n se q u e n c e
34
u n d er i r r i g a t e d c o n d itio n s .
R e s u lts
of
th e
f i e l d i n c u b a t i o n s p ro d u c e d
a n o th e r
m odel
w hich
r e l i e d on a n in d e x o f e a r l y s e a s o n m in e r a l N c o n t e n t i n t h e u p p e r 30 cm
o f th e s o i l p r o f i l e a n d tim e i n w eeks.
C o n s id e r in g s e v e n s i t e y e a r s o f
d a t a th e m odel a c c o u n te d f o r 83% o f th e v a r i a b i l i t y i n N m i n e r a l i z a t i o n
u n d e r th e e x p e r i m e n t a l c o n d i t i o n s .
is
r e a l i z e d when c o n s i d e r i n g th e m in im a l m e a s u re m e n ts r e q u i r e d to
th e
an
The p r a c t i c a l i t y o f t h e f i e l d m odel
m o d e l.
D e te r m in a tio n o f e a r l y s e a s o n s o i l n i t r a t e N to 30 cm a n d
e s t i m a t e o f m i n e r a l i z a t i o n tim e a r e t h e o n ly m e a su re m e n ts
u n d e r th e e x p e r i m e n t a l c o n d i t i o n s .
te m p o r a l
u se
s o il
re q u ire d
I n c lu s io n o f an e q u a tio n d e s c r ib in g
w a te r l o s s a n d c o n tin u e d e x p e r i m e n t a t i o n
on
d iffe rin g
s o i l s a t s e v e r a l l o c a t i o n s w ould e n h a n c e a n d v a l i d a t e th e f i e l d m o d el.
The
w h ich
two m o d e ls w ere d e v e lo p e d u n d e r e n t i r e l y d i f f e r e n t
may
p re d ic t
some d o u b t .a s to th e a b i l i t y o f
s im ila r r e s u l ts .
la b o ra to ry
th o s e
in te rje c t
s tu d y
c o n d itio n s
th e
m o d els
The te m p e r a tu r e e q u a ti o n s e l e c t e d
fo r
to
th e
p r e d i c t e d s o i l te m p e r a t u r e s c o n s i d e r a b l y lo w e r
th a n
m e a su re d a t th e E a s t H e le n a f i e l d l o c a t i o n a t t h e same d e p th
in
1983 a n d 1 9 8 4 .
The
Amesha
two m o d e ls w ere c o n t r a s t e d
(1.8%
c o lle c te d
d r y la n d
CM)
m a t h e m a t ic a ll y .
th e
h ig h
S a p p in g to n -
b u lk s o i l sam ple u s e d i n th e l a b o r a t o r y
s tu d y
fro m s i t e H f o l l o w i n g h a r v e s t o f a 4700 kh h a- '* (7 0
w i n t e r w h e a t c ro p i n 1983.
A ssum ing t h a t l i t t l e
a n d ab o v e n o rm a l
was
b u s h e l)
Y i e ld s w ere ab o v e a v e r a g e on
D ie h l R anch i n 1983 due t o optim um f e r t i l i t y
ta tio n .
The
th e
p re c ip i­
m in e r a l N re m a in e d i n t h e s o i l f o ll o w i n g
y i e l d i n g c ro p a n d t h a t some N was m i n e r a l i z e d b e tw e e n
p o s t­
h a r v e s t sa m p le c o l l e c t i o n i n 1983 and e s t a b l i s h m e n t o f th e f i e l d e x p e r ­
35
im e n t
in
n itra te
th e f a llo w e d H s i t e i n 1984»
l e v e l w ould be lo w .
h a -1
w ere
1984
th e re b y
th e i n i t i a l
or
e a rly
season
As n o te d i n T a b le 1 1 , 1 3 .2 kg o f n i t r a t e W
m e a su re d i n th e e a r l y s e a s o n sam p le to 30 cm a t s i t e
i n d e x in g
t h i s a s s i t e SITE 2 .
C o n s id e r in g a
H
12
in
WEEK
p e r i o d f o r .N m i n e r a l i z a t i o n , th e same a s t h a t o f th e l a b o r a t o r y in c u b a ­
tio n ,
th e
f i e l d m odel p r e d i c t e d 4 2 . 2 kg N h a -1 a s n i t r a t e N w ould
m in e ra liz e d .
week
The
l a b o r a t o r y m odel p r e d i c t e d 4 6 .7 kg h a -1 f o r th e
p e r i o d a s t o t a l m in e r a l N w h ich i n c l u d e d n i t r i t e
( T a b le
and
4 )•
th a t
R e a liz in g t h a t l i t t l e
ammonium a n d n i t r i t e - N
t h e s e two i n t e r m e d i a t e s w ould be s u b t r a c t e d from
p r e d i c t e d b y th e l a b o r a t o r y m o d el,
in g ly
and
s im ila r
am ount
be
12
ammonium-N
a re
p resen t
th e
v a lu e
th e two m o d e ls p r e d i c t e d a s u r p r i s ­
o f m i n e r a l i z e d N.
The d i f f e r e n c e
b e tw e en
th e
p r e d i c t i o n s , n o t c o u n ti n g ammonium o r n i t r i t e , was o n ly 4 - 5 kg N ha- "'.
W ith a d d i t i o n a l e x p e r i m e n t a t i o n ,
th e
m o d els
a b ility
b o t h i n th e f i e l d a n d l a b o r a t o r y ,
d e v e lo p e d s h o u ld p r o v id e s i g n i f i c a n t
im p ro v e m e n t
in
our
t o p r e d i c t m in e r a l N p r o d u c t i o n o f f i e l d s o i l s t h e r e b y m axim iz­
in g f e r t i l i z e r M e f f ic ie n c y .
36
REFERENCES CITED
37
REFERENCES CITED
B ow er, C. A ., R e i t e m e i e r , R. F . , a n d M. F ire m a n . 1 9 5 2 . E xchange­
a b le c a tio n a n a ly s i s o f s a li n e and a l k a l i s o i l s .
S o i l S c i . 7 3 :2 5 1 -
261.
B re m n e r, J . M. 1 9 6 5 . T o t a l n i t r o g e n .
S o il A n a ly s is .
A g ro n . 9 :1 1 7 1 -1 1 7 5 .
I n C.A . B la c k ( e d . ) M ethods o f
Am. S o c . A g r o n ., M a d iso n , WI
C assm an, K. G ., a n d D. N. M unns. 1 9 8 0 . N itr o g e n m i n e r a l i z a t i o n a s
a f f e c te d by s o i l m o is tu re ,
t e m p e r a t u r e , a n d d e p th .
S o il S c i. Soc.
Am. J . 4 4 :1 2 3 3 -1 2 3 7 .
E l - H a r i s , M. K ., V. L . C o c h ra n , L. F . E l l i o t , a n d D. F . B e z d ic e k . 1 9 83.
E ffe c t of tilla g e ,
c r o p p in g , an d f e r t i l i z e r m anagem ent on s o i l
n itro g e n m in e ra liz a tio n p o te n tia l.
S o i l S c i . S o c . Am. J . 4 7 :1 1 5 7 1161.
Eno,
C. F . ,
I 9 6 0 . N i t r a t e p r o d u c t i o n i n th e f i e l d by i n c u b a t i n g th e
s o i l in p o ly e th y le n e b a g s.
S o i l S c i . S o c . Am. P r o c . 2 4 :2 7 7 -2 7 8 .
L e g g , J . O ., F . W. C h i c h e s t e r , G. S t a n f o r d , and W. H. DeM ar. 1 9 7 1 .
I n c o r p o r a t i o n . o f ^ j j - t a g g e d m in e r a l n i t r o g e n i n t o s t a b l e fo rm s o f
s o i l o r g a n i c n i t r o g e n . S o i l S c i . S o c . Am. P r o c . 3 5 :2 7 3 - 2 7 6 .
M e ik le , R. W., a n d T. R. T readw ay.
1979.
e s tim a te ly s o i l te m p e ra tu re s . S o il S c i .
A m a th e m a tic a l m ethod f o r
1 2 8 :2 2 6 -2 4 2 .
O ls e n , S . R ., D. V. C o le , F . S . W a ta n a b e , a n d L . A. D ean. 19 5 4 . E s t i ­
m a tio n o f a v a i l a b l e p h o s p h o ru s i n s o i l s by e x t r a c t i o n w i t h sodium
b ic a rb o n a te .
USDA C i r c u l a r No. 9 3 9 .
R ic h a r d s ,
L . A .,
( e d ) . 1 9 5 4 . D ia g n o s is a n d im p ro v e m e n t o f s a l i n e an d
a lk a li s o ils .
U. S . S a l i n i t y L a b o r a t o r y , USDA H andbook No, 60.
S im s, J . R. a n d V. A. H aby. 1970. S i m p l i f i e d c o l o r i m e t r i c d e te r m in a ­
t i o n o f s o i l o r g a n i c m a t t e r . S o i l S c i . 1 1 2 :1 3 7 -1 4 1 .
S m ith , S . J . , L . B. Y oung, a n d G. E. M i l l e r .
19 7 7 . E v a l u a t i o n o f s o i l
n i t r o g e n m i n e r a l i z a t i o n p o t e n t i a l s u n d e r m o d if ie d f i e l d c o n d i t i o n s .
S o i l S c i . S o c . Am. J . 4 1 :7 4 -7 6
S ta n fo rd ,
G ., M. H. F r e r e , a n d D. H. S c h w a n in g e r. 1 9 7 3 . T e m p e ra tu re
c o e f f ic ie n t o f s o i l n itro g e n m in e r a liz a tio n .
S o i l S c i . 1 1 5 :3 2 1 323.
38
S ta n fo rd ,
G. a n d J . Hanway.
1955.
P r e d ic tin g n itro g e n f e r t i l i z e r
n e e d s o f Iow a s o i l s :
II.
A s i m p l i f i e d te c h n iq u e f o r d e te r m in in g
r e l a t i v e n i t r a t e p ro d u c tio n in s o i l s .
S o i l S c i . S o c . Am. P r o c .
1 9 :7 4 - 7 7 .
S t a n f o r d , G ., a n d S . J . S m ith . 1 9 7 2 . . N itr o g e n m i n e r a l i z a t i o n p o te n ­
tia ls of s o ils .
S o i l S c i . S o c . Am. P r o c . 3 6 :4 6 5 -4 7 2 .
T y l e r , K. B ., F . E. B r o a d b e n t, and G. N. H i l l .
1 9 5 9 . Low—te m p e r a tu r e
e ffe c ts
on n i t r i f i c a t i o n
in fo u r C a lifo rn ia
s o ils .
S o il S c i.
8 7 :1 2 3 - 1 2 9 .
W e ste rm a n n , D. T . , a n d S . E. C r o t h e r s . 1 9 8 0 . M e a s u rin g s o i l n i t r o g e n
m i n e r a l i z a t i o n u n d e r f i e l d c o n d i t i o n s . A g ro n . J .
7 2 :1 0 0 9 -1 0 1 2 .
39
APPENDIX
40
A p p en d ix T a b le 1 6 .
P h y s i c a l a n d c h e m ic a l c h a r a c t e r i s t i c s o f f i v e Mon­
ta n a s o i l s .
S e rie s
D e p th
H o riz o n
OM
E
B rid g e r
A
B
C
0 -1 5
1 5 -4 5
4 5 -9 6
1 0 .0
2 .2
1 .0
C
—% —
5 .£ 0
1 .2 8
0 .5 9
Bozeman
A
0 -1 5
4 .4
2 .5 5
0 .2 2
1 1 .6
7 .8
cl
W illia m s
A
B
C
0 -1 5
1 5 -4 3
4 3 -1 0 2
2 .6
1 .5
1 .0
1 .5 1
0 .8 5
0 .5 5
0 .1 5
0 .1 0
0 .0 7
1 0 .1
8 .5
7 .9
6 .6
8 .0
8.4
cl
A
B
C -
0 -1 5
.1 5 -4 8
4 8 -1 2 2
2 .4
2 .0
1 .0
1 .3 9
1 .1 8
0 .5 9
0 .1 6
0 .1 4
0 .0 9
8 .7
8.4
6 .5
7 .7
8 .3
8 .5
C
' 0 -1 5
15-23
2 3 -1 2 2
1 .8
1 .4
0 .8
1 .0 4
0.8 1
0 .4 9
0 .1 1
0 .0 9
0 .0 5
9 .5
9 .0
9 .8
8 .3
8 .5
9 .0
cl
sol
scl
—
S cobey
S a p p in g to n
Amesha
A
B
C
C:N
pH
0 .4 8
0 .1 3
0 .0 8
12.1
9 .8
7 .4
7 .0
6 .7
7 .7
I
cl
s ic l
T e x tu re
C
C
C
C
41
A p p e n d ix T a b le 1 7 .
Sum m arized l a b o r a t o r y i n c u b a t i o n d a ta by s o i l h o r i ­
zon a t O0C ( n = 5 ) .
Week
S o il
B rid g e r
A
A
B
C
S a p p in g to n A
Amesha
B
C
2
4
6
8
g~1 - 0 .0
1.7
0 .2
10
12
0 .0
1 .8
0 .4
0 .0
0 .5
0 .1
NO2-N
NO3-N
NHJ-N
7 .3
1 0 .5
4 .1
0 .0
5 .9
1 .5
0 .0
2 .8
' 0 .4
T o ta l
21.. 9
7 .4
3 .2
1 .9
2 .2
0 .6
NO2 -N
NO3-N
NH4-N
3 .8
2 7 .0
0 .2
0 .0
8 .0
0 .2
0 .0
3 .8
0.4
0 .0
2 .8
0 .3
0 .0
2 .9
0 .4
0 .0
2 .1
0 .1
T o ta l
T o ta l
3 1 .0
8 .2
4 ,2
3 .1
3 .3
2 .2
5 2 .0
NO2-N
NO3-N
NH4-N
0 .0
0 .0
4 .9
0 .0
0 .0
3 .0
0 .0
0 .0
0.4
0 .0
0 .4
1 .7
0 .0
0 .2
1 .3
0 .0
0 .0
0 .6
T o ta l
T o ta l
4 .9
3 .0
0.4
2 .1
1 .5
0 .6
1 2 .5
NO2-N
NO3-N
NH4-N
0 .3
2 .9
2 .6
0 .1
0 .0
1 .0
0 .0
0 .0
0 .0
0 .0
0 .0
1 .1
0 .0 '
0 .0
0 .9
0 .0
0 .0
0 .2
T o ta l
T o ta l
5 .8
1.1
O
O
Bozeman
H o riz o n
1 .1
0 .9
0 .2
= . ■ 9 .1
NO2-N
NO3-N
NH4-N
0 .4
4 .4
0 .0
0 .0
1 .6
0 .2
0 .0
0 .6
0 .3
0 .0
0 .5
0 .1
0 .0
0.9
0 .2
0 .0
0 .3
0 .0
T o ta l
T o ta l
4.8
1 .8
0 .9
0 .6
1 .1
0 .3
NO2-N
NO3-N
NH4-N
0 .1
0 .0
2 .8
0 .0
0 .0
1 .0
0 .0
0 .0
1 .7
0 .0
0 .0
0 .9
0 .0
0 .0
1 .6
0 .0
0 .0
0 .7
T o ta l
2 .9
1 .0
1 .7
0 .9
1 .6
0 .7
NO2-N
NO3-N
NH4 -N
0 .0
0 .9
1 .5
0 .1
0 .0
1 .0
0 .0
0 .0
0 .2
0 .0
0 .0
0 .9
0 .0
0 .0
0 .8
0 .0
0 .0
0 .3
T o ta l
2 .4
1 .1
0 .2
0 .9
0 .8
. 0 .3
T o ta l
=
=
3 7 .2
9 .5
T o ta l
='
8 .8
T o ta l
=
5 .7
42
A p p en d ix T a b le 1 7 .
C o n tin u e d .
Week
6
NO3-N
MHj-N
1 .8
7 .9
0 .1
0 .0
2.4
0 .2
0 .0
1 .2
0 .4
T o ta l
9 .8
2 .6
1 .6
NO2-N
NO^-N
NHj-N
0 .1
0 .7
1 .3
0.0
0.0
1.4
- T o ta l
2 .1
NO2-N
NO3-N
NHj-N
10
12
0 .0
1 .1
0.3
0 .0
0 .3
0 .1
1 .1
1.4
0 .4
0 .0
0 .0
1 .2
0 .0
0 .7
1 .0
0 .0
0 .0
1.4
0 .0
0 .1
0 .6
1.4
1 .2
1 .7
■ 1.4
0 .7
0 .0
0 .0
0 .1
0.0
0.0
1.2
0 .0
0 .0
0.4
0 .0
0 .0
0.3
0 .0
0 .0
1 .5
0 .0
0 .0
0 .1
T o ta l
0 .1
1.2
0.4
0.3
1 .5
0 .1
=
A
NOp-N
NOj —N
NHj-N
0 .0
0 .0
2 .2
0.0
3 .3
0 .4
0 .0
1 .4
0 .0
0 .0
1.5
1 .3
0 .0
1 .0
1 .5
0 .0
1 .8
0 .0
'
T o ta l
2 .2
3 .7
1.4
2 .8
2 .5
1 .8
NO2-N
NO3-N
NH4-N
0 .2
0 .0
0 .7
0 .0
0 .0
1.4
0 .0
0 .0
1 .0
0 .0
0 .0
1 .1
0 .0
0 .0
■ 1 .3
0 .0
0 .0
0 .7
T o ta l
O'. 9
1.4
I *0
1 .1
1 .3
■ 0 .7
C
NO2-N
NO3-N
NH4-N
0 .0
0 .3
0 .2
0 .0
0.5
0 .6
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
. 0 .0
0 .0
T o ta l
0 .5
1 .1
0 .0
0 .0
0 .0
0 .0
1 6 .9
T o ta l
=
8 .5
T o ta l
3 .6
T o ta l
■Vf
B
=
T o ta l
ii
C
T o ta l
o\
^ I
4
A
B
W illia m s
2
Il
S cobey
H o riz o n
I
I O O^ CM
CO
. . .
v -O O O
bO
S o il
T o ta l
=
1 .6
43
A p p en d ix T a b le 1 8 .
Sum m arized l a b o r a t o r y i n c u b a t i o n d a ta by s o i l h o r i ­
zon a t 14°C ( n = 5 ) .
Week
H o riz o n
A
B
C
S a p p in g to n
Amesha
A
B
C
6
NO2-N
NO3-N
NH4-N
0 .0
3 1 .3
0 .0
0 .0
5 .7
0 .1
0 .0
4 -2
0 .4
8
g_1 - 0 .0
2 .8
0 .1
T o ta l
31.3
5 .8
4.6
2 .9
2 .9
2 .2
NO2-N
NO3-N
NH4-N
0 .0
4 7 .1
0 .0
0 .0
9 .0
0 .1
0 .0
7 .4
0 .3
0 .0
5 .9
0 .1
0 .0
5 .8
0 .2
5 .9
■ 0 .0
T o ta l
4 7 .1
9 .1
7 .7
6 .0
6 .0
5 .9
NO2-N
NO3-N
NH4-N
0 .5
4.6
3 .4
0 .0
4.6
0 .0
0 .0 .
2 .1
0 .0
1 .9
0 .3
0 .0
2 .0
0 .1
0 .0
1 .3
0 .0
T o ta l
8 .5
4.6
2 .1
2 .2
2 .1
1 .3
0 .5
NO2-M
NO3-N ■ 3 .6
NH4-N
0 .9
0 .0
3.6
0 .0
0 .0
1 .6
0 .0
0 .0
1 .5
0 .3
0 .0
1 .7
0 .0
0 .0
1 .0
0 .0
T o ta l
T o ta l
5 .0
3.6
1 .6
1 .8
1 .7
1 .0
1 4 .7
NO2-N
NO3-N
NH4-N
0 .2
7 .5
0 .0
0 .0
3 .3
0 .1
0 .0
3 .1
0 .5
0 .0
2 .5
0 .0
0 .0
2 .7
0 .2
0 .0
2 .2
0 .0
T o ta l
T o ta l
7 .7
3 .4
3 .6
2 .5
. 2 .9
2 .2
NO2-N
NO3-N
NH4-N
0 .8
6 .2
0 .0
0 .0
7.5
0 .0
0 .0
6 .1
0 .0
0 .0
6 .1
0 .0
0 .0
4 .5
0 .0
0 .0
2 .0
0 .0
T o ta l
T o ta l
7 .0
7.5
6 .1
6 .1
4.5
2 .0
3 3 .2
NO2-N
NO3-N
NH4-N
0 .0
1 .1
1 .4
0 .1
0.9
0 .2
0 .0
1 .0
0 .0
1 .1
0 .6
0 .0
1 .0
0 .0
0 .0
0 .4
0 .0
T o ta l
T o ta l
2 .5
1 .2
1 .0
1 .7
1 .0
10
12
0 .0
2.7
0 .2
0 .0
2 .2
0 .0
T o ta l
=
4 9 .7
0
0
B rid g e r
A
4
0
0
Bo zeman
2
0
0
S o il
.
0 .4
T o ta l
=
8 1 .8
T o ta l
=
=
=
2 0 .8
2 2 .3
7 .8
44
A p p en d ix T a b le 1 8 .
C o n tin u e d .
Week
S o il
S cobey
H o riz o n
A
B
C
A
B
C
4
6
8
10
12
0.0
g~1 - NO^-N
NO3 -N
NH^-N
0.0
14.4
3.2
0.5
0.0
2.5
0.2
2.4
0 .0
0.0
4.1
0.2
0.2
0.0
2.2
0.1
T o ta l
14.4
4-3
3.7
2.7
2 .6
2.3
NOp-N
-MO-z—N
NH^-N
0.2
8.5
0.0
0.0
0.0
0.0
5.9
4.6
2 .8
0.0
0.0
0.0
4.9
0.0
0.0
8.4
0.0
0.0
- T o ta l
8.7
8.4
5.9
4.9
4^6
2.8
NO2-N
NO3 - N
NH^-N
0 .0
0.7
0.0
0.0
0.0
4.9
4.9
0 .0
0.0
0 .0
0.0
0.0
3.5
0.0
0.0
1.7
0.0
T o ta l
0.7
1.7
4.9
4.9
3.5
2.0
0.0
'
T o ta l
=
30.0
T o ta l
=
35.3
2 .0
NOp-N
0.0
0.0
0.0
0.0 ■
0.0
NO-z-N
NH^-N
1 4 .0
0 .0
6 .6
0 .0
4 -0
0 .0
3 .3
0.6
3 .4
0.2
0 .0
3.0
0.0
T o ta l
14.0
6 .6
4.0
3 .9
3.6
3.0
NO2-N
NO3-N
NH4-N
0 .6
3 .8
0 .0
0 .0
5 .5
0 .0
0 .0
'5 . 7
' 0 .0
0.0
5 .4
0.0
0.0
4.1
0.0
■0 . 0
1.6
0.0
T o ta l
4.4
5 .5
5 .7
5 .4
4.1
1.6
NO2-N
NO3-N
NH4-N
0.5
2 .6
0 .0
0 .0
2 .9
0 .0
O
O
W illia m s
2
4.5
0.0
0.0
4 .3
0.0
0.0
3.2
0.0
0.0
1.5
0.0
T o ta l
3 .1
2 .9
4 .5
4 .3
3.2
1.5
T o ta l
=
17.7
T o ta l
=
3 5 .1
T o ta l
=
2 6 .7
T o ta l
=
1 9 .5
45
A p p en d ix T a b le 1 9 .
Sum m arized l a b o r a t o r y i n c u b a t i o n d a ta by s o i l h o r i ­
zon a t 2 8 ° c ( n = 5 ) .
Week
S o il
Bozeman
B rid g e r
H o riz o n
A
A
B
S a p p in g to n A
Amasha
B
S cobey
A
B
2
4
6
8
0 .0
7 .2
0 .2
0 .0
7 .0
0 .0
TO
12
NO2-N
NO3-N
NH^j-N
0 .8
4 4 -8
0 .0
0 .0
1 5 .9
0 .0
0 .0
7 .5
0 .2
g"1 - 0 .0
7 .7
0 .1
T o ta l
4 5 .6
' 1 5 .9
7 .7
7 .8
7 -4
7 .0
NO2-N
NO3-N
NH4-N
1 .0
7 8 .8
0 .4
0 .0
2 8 .5
0 .1
0 .0
1 8 .3
0 .3
0 .0
2 2 .1
0 .1
0 .0
2 5 .1
0 .3
0 .0
3 8 .6
0 .2
T o ta l
T o ta l
8 0 .2
2 8 .6
1 8 .6
2 2 .2
2 5 .4
3 8 .8
= 2 1 3 .8
NO2-N
NO3-N
NH4-N
0 .0
•1 5 .7
1 .3
0 .0
7.6
0 .0
0 .0
3.0
0 .0
0 .0
6 .1
0 .0
0 .0
5 .2
0 .5
0 .0
4.2
0 .0
T o ta l
T o ta l
1 7 .0
7.6
3.0 .
6 .1
5 .7
4.2
NO2-N
NO3-N
NH4-N
0 .1
1 7 .2
0 .1
0 .0
9 .6
0 .0
0 .0
7.3
0.4
0 .0
6 .1
0 .0
0 .0
4 .5
0 .1
0 .0
4.2
0 .1
T o ta l
T o ta l
1 7 .4
9 .6
7.7
6 .1
4.6
4.3
' 4 9 .7
NO2-N
NO3-N
NH4-N
0 .1
1 5 .2
0 .0
0 .0
3.7
0 .5
0 .0
5.1
0 .0
0 .0
3 .0
0 .0
0 .0
2.5
1 .7
0 .0
1 .9
0 .0
T o ta l
T o ta l
1 5 .3
4 .2
5 .1
3 .0
4 -2
1 .9
3 3 .7
NO2-N
NO3-N
NH4-N
0 .0
2 2 .0
0 .0
0 .0
1 0 .3
0 .0
0 .0
6.5
0.3
0 .0
5 .9
0 .0
0 .0
.4 . 3
0 .2
0 .0
4 .2
0 .0
T o ta l
T o ta l
2 2 .0
1 0 .3
6 .8
5.-9
4 .5
4.2
5 3 .2
NO2-N
NO3-N
NH4-N
0 .0
1 8 .5
0 .0
0 .0
2 .9
0 .0
0 .0
6 .2
0 .0
0 .0
3 .0
0 .0
0 .0
2 .1
0 .5
■ 0 .0
1.4
0 .0
T o ta l
T o ta l
1 8 .5
2 .9
6 .2
3 .0
2 .6
1.4
34*6
T o ta l
=
=
9 1 .4
4 3 .6
46
A p p en d ix T a b le 1 9 .
C o n tin u e d .
Week
S o il
H o riz o n
2
4
6
NO2-N
NO3-N
NH^-N
0.0
4-2
0 .1
0.0
3.2
0.0
0.0
4.6
0.0
T o ta l
4-3
3.2
NOo-N
MO-^—N
NHj-N
0.0
2 6 .5
0 .0
T o ta l
12
----0.0
2.5
0.0
0.0
2.3
0.5
0.0
1.6
0.0
4.6
2.5
2.8
1.6
0.0
7 .5
0 .0
0.0
4 .7
0 .0
0.0
5 .8
0 .0
0.0
5 .1
0 .6
0.0
4 -0
0 .0
2 6 .5
7 .5
4 -7
5 .8
5 .7
4 .0
NO2-N
0 .3
NO3-N ■ 1 0 .8
NHj-N
0 .0
4 .0
0 .0
0 .0
2 .0
0 .0
0 .0
5 .1
0 .0
0 .0
4 -4
0 .7
0 .0
3 .6
0 .0
T o ta l
1 1 .1
4 .0
2 .0
5 .1
5 .1
3 .6
NO^--N
NO-^-N
NHj-N
0 .1
2 .1
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
0 .0
T o ta l
2 .2
0 .0
0 .0
0 .0
0 .0
0 .0
g
S co b ey
W illia m s
C
A
B
O
O
C
8
10
-1
T o ta l
=.
19.0
T o ta l
=
5 4 -2
T o ta l
=
3 0 -9
T o ta l
=
2 .2
47
A p p e n d ix T a b le 2 0 .
L i s t i n g o f n i t r o g e n m i n e r a l i z a t i o n c o m p u te r m o d el.
Program RGG4
Nitrogen Mineralization Model
1020 From Laboratory Incubation Data
1030 IBM-PC1 04-24-85
1040 :
1050 DIM TN(50),KPP(SO)
1060 ' Enter Start and Ending Date
1070 CLS : PRINT
1080 INPUT "Enter Starting Julian Date: ";D1
1090 INPUT "Enter Ending Julian Date : ";D2
1100 :
2000 ' Start Computation Loop
2010 ' starting,1 ending and step S OM's times 10
2020 OM1=18 : 0H2=44 : OH3=2
2030 FOR I=Dl TO 02
2040
'Generate soil temperature in Celsius
2050
T=30.5-(.40t'l)+(.00939'(l"2))-(.0000417"(1*3))+(3.22E-08*(l"4))
2060
T=(T-32)‘.55556
2070
FOR J=OHl TO 0H2 STEP 0H3
2080
'NHlN is daily kg N, TN(J) is total kg at each I
2090
NHIN=(.28"(J/10))+(.03*T)-.25
2100
TN(J)=TNfJ)+NHIN
NEXT J
2110
2120 NEXT I
2130 :
2140 ' Calculate Kg N/l OM
2150 FOR J=ONl TO 0H2 STEP 0M3
2160
KPP(J)=TN(J)/(J/10)
2170
KA=KAFKPP(J)
2180 NEXT J
2190 KA=KA/(((0H2-0H1)/0M3)+1)
1000
1010
2200
2210
4000
4010
4020
4030
4040
4050
4060
4070
4080
4090
4100
4110
4120
4130
4140
4150
4160
4170
4180
4190
4200
4210
4220
4230
4240
4250
:
:
' Screen Output
CLS
PRINT
PRINT TAB(IO)!"NITROGEN MINERALIZATION"
PRINT TAB(IO);"DAY ";Dl;n THROUGH ";D2
PRINT : PRINT
PRINT "
IOM
Kg N/ha
Kg N/l OH"
PRINT "
FOR J=OMl T0UTT2 STEPUfTT"
PRINT USING "
#.
##.##";J/10;TN(J);KPP(J)
NEXT J
A$="AVERAGE Kg per I OH = "
PRINT : PRINT USING "
I ##.ff ;A$;KA
:
' Printer Output
LPRINT TAB(S)!"NITROGEN MINERALIZATION MODEL"
LPRTNT TAB(15);"RGG3"
LPRINT ■
LPRINT TAB(S);"DAY ";01;" THROUGH ";02
LPRINT : LPRINT
LPRlNT " IOM
KG N/HA
KG N/l OM
LPRINT "
"
FOR J=OMl TOUIT2 S T E P D H LPRINT USING " §.#
###.#
##.##";J/10;TN(J);KPP(J)
NEXT J
LPRINT : LPRINT USING " & ##.## ";A$;KA
48
A p p en d ix T a b le 2 1 .
N itr o g e n m i n e r a l i z a t i o n d a ta from f i e l d i n c u b a t i o n s
by 10 cm d e p th in c r e m e n t s ( n = 3 ) •
D e p th (cm)
NH4-N
S ite
1983
J u l i a n D a te
H
H
H
H
H
H
H
H
142
152
159
166
173
180
187
194
H
H
H
H
0 -1 0
NO3 --N
1 0 -2 0
2 0 -3 0
0 -10
-1
1 0 -2 0
2 0 -3 0
4 -0
5 .1
5 .4
3 .4
8 .0
3 .4
4 -9 .
2 .7
3 .0
4 .6
4« 6
4 .5
5 .1
3 .6
5 .4
2 .5
3 .1
3 .6
4 -5
3 .2
5 .4
3 .6
3 .9
2 .2
3 .0
5 .5
6.4
8 .3
6 .3
6 .8
1 1 .9
13 .1
7 .9
7 .6
9 .4
1 0 .0
9 .5
1 0 .7
1 5 .0
1 4 -3
1 7 .4
1 4 -4
14.6
1 4 .1
1 6 .7
1 4 .6
2 4 .9
2 0 .7
201
208
215
222
4 .9
4 .2
5 .7
8 .5
4 .2
4 -5
5 .5
8 .0
4 .6
6 .0
5 .5
7 .9
1 3 .0
1 5 .3
2 2 .8
2 0 .7
1 6 .5
1 3 .4
2 0 .4
1 8 .2
2 1 .3
2 0 .7
2 1 .5
2 1 .0
H
H
H
H
H
229
236
243
250
257
4 .2
4 .8 .
4 .8
6 .3
5 .1
4 -3
3 .6
6 .3
5 .8
4 .8
7 .1
6 .0
4 ,9
4 .8
4 -5
2 1 .6
3 2 .8
2 7 .0
2 2 .9
2 7 .9
1 9 .2
2 1 .7
2 4 .7
1 8 .5
2 2 .6
2 0 .7
2 1 .6
1 9 .8
1 7 .7
2 2 .9
J
J
J
J
141
152
159
166
5 .2
7 .1
6 .8
5 .7
4 .5
5 .8
5 .7
4 .5
4 .2
4 .2
5 .1
3 .6
4.8
8 .6
1 0 .1
9 .7
4 .1
7 .9
9 .8
9 .5
5 .8
8 .9
1 0 .9
1 1 .3
J
J
J
J
173
180
187
194
8 .2
6 .6
8 .6
3 .7
6 .7
5 .5
6 .7
2 .7
5 .7
5 .2
6 .0
2 .2
8 .9
1 0 .4
1 8 .5
2 1 .2
8 .8
1 0 .7
1 5 .2
1 5 .9
9 .1
1 1 .0
14.0
1 3 .9
J
J
J
J
201
208
215
222
6 .0
5 .8
9 .8
9 .5
5 .7
5 .1
7 .4
9 .2
3 .7
4 -5
7 .3
7 .3
1 8 .3
2 2 .9
3 2 .2
2 8 .2
1 1 .9
17 .1
2 2 .3
2 1 .6
1 5 .0
1 4 .9
17 .1
1 5 .9
J
J
J
J
J
229
. 236
243
250
257
5 .1
5 .2
7 .6
5 .4
7 .6
4.8
6 .6
6 .2
5 .7
6.4
4 -6
' 5 .2
6 .0
4 .2
5 .1
2 9 .2
3 4 .6
2 3 .5
4 0 .4
3 3 .8
2 2 .3
'2 1 .7
1 8 .5
2 6 .5
2 7 .3
1 7 .6
1 2 .8
1 5 .2
1 7 .7
2 1 .6
.
49
A p p en d ix T a b le 2 1 .
C o n tin u e d .
D e p th (cm)
M
M
M
M
152
159
166
.173
3 .6
5 .5
4 -5
5 .8
M
M
10-20
2 0 -3 0
2.7
4.8
3 .9
5.8
3 .3
4.8
3 .6
5 .1
S S
NO
180
187
194
201
4 .0
5 .5
2 .7
4 -9
4.2
5.5
2.2
5.2
4 .0
4 .3
2 .2
5 .1
S S S S
• 0 -1 0
R
S ite
1983
J u l i a n D ate
208
215
222
229
4 -5
6 .3
7 .4
6.4
1.9
7.7
7.1
6 .0
M
M
M
M
236
243
250
257
5 .8
7 .9
6 .6
7 .6
5 .7
7 .0
7 .6
5 .5
0 -1 0
h a - 1 ----3 .0
7 .7
6 .7
3 .4
N
1 0 -2 0
2 0 -3 0
1 .5
7 .3
6 .6
3 .3
0 .4
7 .3
5 .8
3 .0
3 .3
4 .2 .
4.6
4 .8
3 .1
4 .5
4 -3
4 -2
3 .3
4 -2
4 .3
3 .1
1 .9
7 -4
7 .0
6.4
4 .0
1 1 .6
7 .3
1 3 .7
4 -3
8 .9
7 .1
1 0 .3
2 .8
8 .2
4 .8
9 .1
4.8
8 .9
7 .4
6 .6
8 .2
2 3 .2
1 9 .7
7 -3
8 .2
13 .1
1 4 .3
1 2 .7
6 .1
9 .8
8 .5
1 7 .0
50
A p p en d ix T a b le 2 1 .
C o n tin u e d .
D e p th (cm)
K't
NH4-N
-N
S ite
1984
J u l i a n D ate
0 -1 0
1 0 -2 0
20-30
H
H
H
144
151
158
1 .6
2 .4
4 .2
0 .9
1 .6
3 .3
0 ,7
1 .0
3 .1
H
H
H
H
165
172
179
186
2 .4
3 .1
6 .2
6 .7
1 .8
3 .1
4.8
6 .2
2 .2
2 .7
5 .1
6.4
5 .8
5 .5
7 -4
4 .3
6 .3
5 .2
6 .8
4.8
8 .0
6 .8
6.1
3 .9
H
H
H
H
193 .
200
207
214
4 -2
3 .6
6.4
3 .6
3 .6
3 .0
5 .5
3 .3
3 .4
3 .1
5 .4
. 3 .3
1 0 .0
9 .7
2 0 .3
1 3 .6
7 .6
1 0 .9
1 9 .8
16.4
8 .8
9 .4
9 .4
1 5 .0
H
H
H
H
H
221
228
235
242
249
4 .9
4 -5
3 .7
7 .3
2 3 .7
4.6
5 .2
4 -2
6 .1
1 4 .9
4 .3
4 .9
3 .3
7 .0
1 8 .9
2 0 .4
1 6 .7
1 7 .9
4 0 .7
2 9 .2
1 5 .8
1 6 .8
1 8 .0
2 4 .7 '
2 5 .0
1 3 .7
1 3 .8
1 8 .5
2 1 .7
2 2 .3
J
J
J
J
151
158
165
172
4 .0
5 .5
4 .3
3 .1
2 .8
4 .2
2 .7
3 .1
2 .7
3 .4
2 .6
3 .1
8 .1
13.1
1 4 .9
10.1
3 .6
1 1 .0
1 0 .9
1 0 .4
6 .7
1 5 .0
1 3 .0
1 1 .3
J
J
J
J
179
186
193
200
6 .0
7 .7
5 .2
6 .7
6 .7
7 .3
3 .9
4 .5
5 .7 .
6 .2
4 .0
4.6
1 2 .2
1 5 .2
1 4 .1
1 4 .6
8 .9
1 2 .4
1 1 .3
1 1 .9
1 0 .4
1 1 .5
1 5 .5
1 4 .0
J
J
J
J
207
214
221
228
6.4
5 .8
5 .2
6 .8
6.4
3 .9
3 .9
6 .0
4.6
4*0
4 .2
4.8
2 3 .8
2 1 .5
1 7 .9
2 1 .3
2 0 .4
1 3 .4
1 9 .5
1 7 .3
2 1 .2
J
J
J
235
6 .0
9 .1
1 3 .6
3 .2
6 .8
9 .2
2 .8
7 .7
9 .4
2 2 .2
2 0 .9
2 2 .3
2 2 .6
2 3 .2
2 2 .5
2 5 .9
2 6 .7
3 3 .2
242
249
•
.
0 -1 0
1 0 -2 0
h a - 1 -------4 .2
5 .2
1 .2
2 .2
5 .2
4 .9
'
2 0 -3 0
5 .7
1 .5
6 .7
1 4 .0
2 0 .3
2 1 .2
51
A p p en d ix T a b le 2 1 .
C o n tin u e d .
|
i
a i
O I
M !
D ep th (cm)
Nh4-M
-N
S ite
1984
J u l i a n D ate
0 -1 0
1 0 -2 0
2 0 -3 0
0 -1 0
-I
1 0 -2 0
2 0 -3 0
M
M
M
137
144
151
2 .8
2 .4
2 .4
3 .0
1 .3
1 .8
2 .2
1 .2
1 .2
17.4
2 0 .9
1 2 .5
2 7 .4
2 9 .8
2 2 .3
2 5 .9
3 2 .8
2 5 .9
M
M
M
M
158
165
172
179
5 .8
3 .0
4 -9
5 .2
4 -2
2 .1
5 .4
. 5 .1
3 .0
2 .2
4 .9
3 .9
2 9 .3
2 6 .8
26 .1
2 3 .8
3 7 .1
2 8 .2
2 7 .0
2 8 .3
4 0 .4
3 3 .5
3 0 .8
3 0 .8
M
M
M
M
186
193
200
207
5 .2
4 .8
5 .8
7 .1
4 .3
3 .7
■ 7 .8
6 .7
1 0 .6
4 .9
5 .1
6 .1
2 6 .7
3 4 .6
2 1 .7
4 1 .4
2 6 .4
2 6 .7
2 5 .5
2 7 .7
2 6 .7
3 1 .9
3 3 .5
3 2 .3
M
M
M
M
214
221
228
. 235
4 .0
7 .9
4.6
3 .0
3 .7
5 .7
4 .0
2 .7
3 .7
6 .0
4 -0
2 .7
3 7 .4
42.2
4 3 .8
6 9 .7
3 2 .3
3 0 .7
3 1 .9
3 4 -0
3 2 .6
3 3 .2
3 5 .9
3 3 .2
M
M
242
249
8 .6
1 4 .4
9 .7
1 5 .6
5 .7
1 4 .4
5 3 .9
5 4 .4
3 4 .9
4 4 -2
3 4 .9
4 9 .3
R
R
R
R
133
137
144
151
2 .8
1 .6
1 .5
2 .4
3 .0
2 .1
1 .8
2 .2
3 .3
3 .0 •
1 .6
2 .2
1 9 .8
1 5 .5
2 4 .7
2 9 .9
2 4 .1
2 5 .0
2 6 .8
3 9 .3
2 9 .2
2 8 .8
3 3 .4
3 3 .7
R
R
R
R
158
165
172
179
3 .6
3 .7
5 .7
4 .3
4 .3
3 .6
4 .9
4 .5
3 .7
3 .6
5 .1
4 .3
2 3 .2
2 0 .9
2 5 .0
2 4 .1
3 6 .1
3 0 .2
2 8 .6
2 6 .8
4 3 .7
3 6 .1
3 3 .5
3 0 .8
R
R
R
R
186
193
200
207
4 .9
3 .1
3 .6
6 .6
4.6
3 .1
3 .4
5 .5
4 -2
3 .7
3 .9
4 .0
2 5 .8
2 8 .6
3 0 .7
3 0 .7
2 9 .8
3 2 .0
3 3 .8
2 1 .2
3 2 .9
3 1 .1
2 9 .9
3 2 .5
R
R
R
R
214
221
228
235
3 .9
4.8
3 .6
3 .1
3 .9
4.6
3 .9
2 .1
4.6
4.6
3 .6
2 .9
2 7 .6
3 7 .7
4 0 .5
3 7 .1
3 1 .6
3 5 .6
3 5 .2
3 1 .0
3 3 .2
3 1 .0
3 0 .1
2 8 .0
R
R
242
249
6 .2
1 0 .7
7 .9
1 1 .8
9 .1
1 4 .4
3 4 .4
3 4 -4
3 7 .5
3 4 .3
3 0 .2
3 5 .5
■
52
A p p en d ix T a b le 2 2 .
N itr o g e n m i n e r a l i z a t i o n d a t a from f i e l d i n c u b a t i o n s
by 10 cm d e p th i n c r e m e n t s ( n = 3 ) , t o t a l o f NH^-N and
NO-j-N.
T o t a l M in e r a l N
1983
J u l i a n D ate
0 -1 0
S ite H
S ite J
D e p th (cm)
D e p th (cm)
1 0 -2 0
2 0 -3 0
Un- 1
0 -1 0
1 0 -2 0
2 0 -3 0
'141
152
159
166
173
7 .0
1 0 .6
1 1 .8
1 1 .7
1 4 .3
1 0 .9
1 2 .2
1 4 -0
1 4 .5
1 4 .6
2 0 .5
1 8 .0
1 9 .1
1 7 .3
2 2 .1
1 0 .0
1 5 .7
1 6 .9
1 5 .4
1 7 .1
8 .6
1 3 .7
1 5 .5
14.0
1 5 .5
1 0 .0
13.1
1 6 .0
1 4 .9
14.8
180
187
194
201
208
1 0 .2
1 6 .8
1 5 .8
1 7 .9
1 9 .5
1 4 .3
2 0 .4
1 6 .8
2 0 .7
1 7 .9
1 8 .2
2 8 .8
2 2 .9
2 5 .9
2 6 .7
1 7 .0
2 7 .1
2 4 .9
2 4 .3
2 8 .7
1 6 .2
2 1 .9
1 6 .6
1 7 .6
2 2 .2
1 6 .2
2 0 .0
16.1
1 8 .7
1 9 .4
215
222
229
236
243
2 8 .5
2 9 .2
2 5 .8
3 7 .6
3 1 .8
2 5 .9
2 6 .2
2 3 .5
2 5 .3
3 1 .0
2 7 .0
2 8 .9
2 7 .8
2 7 .6
2 4 -7
42.0
3 7 .7
3 4 .3
3 9 .8
3 1 .1
2 9 .7
3 0 .8
2 7 .1
2 8 .3
2 4 .7
2 4 .4
2 3 .2
2 2 .2
1 8 .0
2 1 .2
250
257
2 9 .2
2 3 .0
2 4 .3
2 7 .4
2 2 .5
2 7 .4
4 5 .8
4 1 .4
3 2 .2
3 3 .7
2 1 .9
2 6 .7
S ite M
152
159
166
173
180
187
194
201
6 .6
1 3 .2
1 1 .2
9 .2
7 .3
9 .7
7 .3
9 .7
4 .2
1 2 .1
1 0 .5
9 .1
7 .3
1 0 .0
6 .5
9 .4
3 .7
1 2 .1
9 .4
8 .1
7 .3
8 .5
6 .5
8 .2
208
215
222
229
236
243
250
257
8 .5
1 7 .9
1 4 .7
2 0 .1
14 -0
3 1 .1
2 1 .3
1 4 .9
6 .2
1 6 .6
1 4 -2
1 6 .3
1 3 .9
2 0 .1
2 1 .9
1 8 .2
4 -7
1 5 .6
1 1 .8
1 5 .5
1 0 .9
1 8 .7
1 5 .9
2 3 .6
53
A p p en d ix T a b le 2 2 .
C o n tin u e d .
T o t a l M in e ra l E
D e p th (cm)
D e p th (cm)
0 -1 0
1 0 -2 0
140
144
151
158
165
172
179
186
1 0 .0
5 .8
3 .6
9 .1
8 .2
8 .6
1 3 .6
1 1 .0
7 .1
6 .1
3 .8
8 .5
8 .1
8 .3
1 1 .6
1 1 .0
193
200
207
214
14.2
1 3 .3
2 6 .7
1 7 .2
1 1 .2
1 3 .9
2 5 .3
- 1 9 .7
2 5 .3
2 1 .2
2 1 .6
4 8 .0
5 2 .9
2 0 .4
2 2 .0
2 2 .2
3 0 .8
3 9 .9
221
228
235
242 .
249
,
2 0 -3 0
- - - -Kg
8 .9
6 .4
2 .5
9 .8
1 0 .2
9 .5
1 1 .2
1 0 .3
?
O
S ite J
1 0 -2 0
2 0 -3 0
1 2 .1
1 8 .6
1 9 .2
1 3 .2
1 8 .2
2 2 .9
6.4
1 5 .2
1 1 .6
1 3 .5
1 5 .6
1 9 .7
9 .4
1 8 .4
1 5 .6
1 4 .4
1 6 .1
1 7 .7
1 2 .2
1 2 .5
1 4 .8
1 8 .3
1 9 .3
2 1 .3
3 0 .2
2 7 .3
1 5 .2
16.4
2 6 .8
1 7 .3
1 9 .5
1 8 .6
2 5 .8
1 8 .0
1 8 .0
1 8 .7
2 1 .8
2 8 .7
2 3 .1
28 .1
2 8 .2
3 0 .0
3 5 .9
2 3 .4
2 3 .3
2 5 .8
3 0 .0
3 1 .7
2 4 .5
2 6 .0
2 8 .7
3 4 .4
42.6
4 1 .2
r5
I
1984
J u l i a n D ate
S ite H
S ite M
S ite R
132
133
137
144
151
158
165
172
179
2 1 .4
3 3 .8
3 9 .6
2 0 .2
2 3 .3
1 4 .9
3 5 .1
2 9 .8
,3 1 .0
2 9 .0
3 0 .4
3 1 .1
2 4 .1
4 1 -3
3 0 .3
3 2 .4
3 3 .4
2 8 .1
3 4 .0
2 7 .1
4 3 .7
3 5 .7
3 5 .7
3 4 -7
2 2 .6
17.1
2 6 .2
3 2 .3
2 6 .8
24.6
3 0 .7
2 8 .4
2 7 .1
2 7 .1
2 8 .6
4 1 .5
4 0 .4
3 3 .8
3 3 .5
3 1 .3
3 2 .5
3 1 .8
3 5 .0
3 5 .9
4 7 .4
3 9 .7
3 8 .6
3 5 .1
186
193
200
207
214
221
228
235
242
249
3 1 .9
3 9 -4
2 7 .5
4 8 .5
4 1 -4
5 0 .1
4 8 .4
7 2 .7
6 2 .5
6 8 .8
3 0 .7
3 0 .4
3 3 .3
3 4 -4
3 6 .0
3 6 .4
3 5 .9
3 6 .7
44.6
5 9 .8
3 7 .3
3 6 .8
3 8 .6
3 8 .4
3 6 .3
3 9 .2
3 9 .9
3 5 .9
40.6
6 3 .7
30.-7
3 1 .7
3 4 .3
3 7 .3
3 1 .5
4 2 .5
4 4 .1
40.2
.4 0 . 6
4 5 .1
3 4 -4
3 5 .1
3 7 .2
2 6 .7
3 5 .5
40.2
3 9 .1
3 3 .1
3 5 .4
4 6 .1
3 7 .1
3 4 .8
3 4 .8
3 6 .5
3 7 .8
3 5 .6
3 3 .7
3 0 .9
3 9 .3
4 9 .9
.
54
A p p en d ix T a b le 2 3 .
Summary o f mean w e e k ly a i r
te m p e r a t u r e s
(AIRTC)
d e r i v e d from H e le n a A i r p o r t c l i m a t o l o g i c a l d a ta f o r ■
1983 a n d 1984 by J u l i a n D a t e .
1983
J u l i a n D ate
SITE
AIRTC
1983
J u l i a n D ate
141
152
159
166
173
H
H
H
H
H
1 7 .8
2 6 .1
2 2 .7
2 1 .7
2 0 .9
141
152
159
166
173
J
J
J
J
J
1 7 .8
2 6 .1
2 2 .7
2 1 .7
2 0 .9
180
187
194
201
208
H
H
H
H
H
24.6
2 4 .3
2 7 .4
2 4 -9
2 8 .1
180
187
194
201
208
J
J '
J
J
J
24.6
2 4 .3
2 7 .4
2 4 .9
2 8 .1
215
222
229
236
243
H
H
H
H
H
3 1 .1
3 2 .9
2 9 .0
2 6 .0
2 9 .7
215
222
229
236
243
J
J
J
J
J
31 .1
3 2 .9
2 9 .0
2 6 .0
2 9 .7
250
257
H
H
2 4 .4
2 0 .6
250
257
J
J
2 4 -4
2 0 .6
152
159
166
173
180
M
M
M
M
M
2 5 .3
2 2 .7
2 1 .7
2 0 .9
24.6
187
194
201
208
215
M
M
M
M
M
2 4 .3
2 7 -4
2 4 .9
2 8 .1
3 1 .1
222
229
236
243
M
M
M
M
3 2 .9
2 9 .0
2 6 .0
2 9 .7
250
257
M
M
2 4 .4
2 0 .6
.
SITE
AIRTC
55
A p p en d ix T a b le 2 3 .
C o n tin u e d .
1984
J u l i a n D ate
SITE
AIRTC
1984
J u l i a n D a te
140
144
151
158
165
H
H
H
H
H
2 1 .5
1 6 .9
21.2
18.4
1 7 .5
151
158
165
J
J
J
21.2
18.4
1 7 -5
172
179
186
193
200
H
H
H ■
H
H
24.2
25.0
29.0
2 9 .5
3 0 .9
172
179
186
193
200
J
J
J
J
J
24.2
2 5 .0
2 9 .0
2 9 .5
3 0 .9
. 207
214
221
228
235
H
H
H
H
H
2 8 .6
3 0 .1
30.6
3 2 .1
2 9 .9
207
214
221 .
228
235
J
J
J
J
2 8 .6
30 .1
30.6
32.1
2 9 .9
242
249
H
H
2 8 .3
2 4 .1
242
249
J
J
2 8 .3
2 4 .1
132
137
144
151
158
165
M
M
M
M
M
M
1 8 .0
2 1 .5
1 9 .0
2 1 .2
18.4
1 7 .5
133
137
144
151
158
165
R
R
R
R
R
R
1 7 .5
2 1 .7
1 9 .0
2 1 .2
18.4
1 7 .5
172
179
186
193
200
M
M
M
M
M
24.2
' 2 5 .0
2 9 .0
2 9 .5
3 0 .9
172
179
186
193
200
R
R
R
R
R
24.2
25.0
29.0
2 9 .5
3 0 .9
207
214
221
228
235
'M
M
M
M
M
2 8 .6
3 0 .1
3 0 .6
3 2. 1
2 9 .9
207
214
221 .
228
235
R
R
R
R
R
2 8 .6
3 0 .1
30.6
3 2 .1
2 9 .9
242
249
M
M
2 8 .3
2 4 .1
242
249
R
R
2 8 .3
24.1
■
SITE
AIRTC
On
56
A pp en d ix T a b le 2 4 .
Summary
o f w e e k ly s o i l
te m p e ra tu re s
( S0ILT10 ,
SOILT2 0 , S0ILT50) m e a su re d a t e a c h s i t e i n 1983 and
1984 by J u l i a n D a t e .
1983
J u l i a n D ate
S ite
. SOILT10
S0ILT20
S0ILT50
H
H
H
H
H
141
152
159 '
166
173
1 9 .0
2 3 .0
2 4 .5
1 5 .0
2 2 .0
1 3 .0
2 0 .0
1 8 .5
1 4 .0
1 5 .5
9 .0
1 6 .0
1 6 .0
1 4 .0
■ 1 3 .0
H
H
H
H
H
180
187
194
201
208
1 6 .0
2 5 .0
24.0
2 0 .0
1 9 .5
1 5 .5
2 0 .5
1 8 .5
1 8 .5
1 9 .0
1 5 .0
1 5 .0
1 6 .0
1 6 .0
1 8 .0
H
H
H
H
H
215
222
229
236
245
2 8 .0
2 1 .0
2 5 .0
2 2 .0
2 2 .0
2 1 .0
2 1 .0
2 0 .5
1 8 .0
1 9 .0
1 9 .0
2 0 .5
1 9 -0
1 8 .0
1 7 .0
H
H
250
257
2 0 .5
14.0
1 6 .0
1 3 .0
1 5 .5
1 4 .5
J
J
J
J
J
141
152
159
166
175
1 9 .0
2 1 .0
24.0
1 5 .0
2 3 .0
1 3 .0
1 8 .0
1 8 .0
1 3 .5 '
1 5 .5
8 .5
1 4 .0
14.0
1 3 .0
1 2 .5
J
J
J
J
J
180
187
194
201
208
1 7 .0
2 4 .5
2 5 .0
2 2 .0
2 0 .0
1 5 .0
2 1 .0
1 9 .0
1 8 .0
1 9 .0
1 4 .5
1 5 .0
1 5 .5
1 6 .0
1 8 .0
J
J
J
J
J
215
222
229
236
245
2 9 .0
2 3 .0
2 8 .0
2 5 .0
2 6 .0
2 2 .0
2 1 .0
2 1 .0
1 8 .0
2 0 .0
1 9 .0
1 9 .5
1 9 .0
1 6 .5
1 6 .5
J
J
250
257
2 3 .0
1 6 .0
1 7 .0
14.0
1 5 .0
1 3 .0
’
57
A p p en d ix T a b le 2 4 .
S ite
C o n tin u e d .
1983
J u l i a n D ate
S0ILT10
S0ILT20
S0ILT50
M
M
M
M
M
152
' 159
166
173
180
2 0 .5
2 4 .0
1 6 .0
2 1 .0
1 6 .5
1 8 .5
1 9 .0
1 4 .5
1 6 .0
1 6 .0
1 5 .0
1 6 .0
1 4 .0
1 3 .0
1 5 .5
M
M
M
M
M
187
194
201
208
215
24.Q
2 6 .0
2 2 .0
1 9 .0
2 4 .0
2 1 .0
2 0 .0
2 0 .0
1 8 .5
2 0 .5
1 6 .0
1 6 .0
1 7 .0
1 9 .0
1 9 .5
M.
M
M
M
M
222
229
236
243
250
2 0 .5
2 4 .5
2 2 .5
2 5 .0
2 0 .5
2 1 .0
2 0 .5
1 9 .0
2 0 .5
1 6 .5
2 0 .5
1 9 .5
1 8 .0
1 8 .0
1 6 .0
M
257
1 3 .5
1 4 .0
1 5 .0
S ite
1984
J u l i a n D ate
SOILTTO
S0ILT50
H
H
H
H
H
140
144
151
158
165
1 4 .0
1 0 .0
1 8 .0
1 1 .0
1 2 .0
SOILT20
-------- 0 C --------1 2 .0
1 1 .0
1 5 .0
1 2 .0
1 1 .5
H
H‘
H
H
H
1-72
179
186
193
200
1 6 .0
1 6 .0
1 9 .5
2 3 .0
2 2 .0
1 5 .0
1 6 .0
1 9 .0
2 0 .0
2 2 .0
1 4 .0
1 5 .5
1 7 .0
1 9 .0
2 0 .0
H
H
H
H
H
207
214
221
228
235
2 2 .5
2 0 .5
2 2 .0
1 9 .5
1 7 .0
2 0 .0
2 0 .0
2 0 .0
1 9 .5
1 8 .0
1 9 .0
1 9 .5
1 9 .5
1 9 .0
1 9 .5
H
H
242
249
1 5 .5
1 4 .5
1 6 .0
1 4 .0
1 7 .5
1 6 .0
1 0 .0
1 0 .0
1 1 .5
1 2 .5
1 1 .5
58
A p p en d ix T a b le 2 4 .
C o n tin u e d .
1984
J u l i a n D ate
S0ILT10
S0ILT20
S0ILT50
151
158
165
172
1.79
186
1 8 .0
1 2 .5
1 4 .0
1 7 .5
1 4 .0
2 1 .0
1 4 .0
1 2 .5
1 2 .0
1 6 .0
. 1 7 .0
1 9 .0
9 .0
1 0 .5
1 0 .0
1 3 .0
1 3 .5
1 5 .5
J
J
J
J
J
193
200
207
214
221
2 4 .0
2 2 .5
2 4 .0
2 2 .5
2 4 .0
2 0 .0
2 1 .0
2 0 .0
2 0 .0
1 9 .5
1 6 .0
1 7 .0
1 6 .0
1 7 .0
1 7 .0
J
J
J
J
228
235
242
249
2 1 .0
1 7 .0
1 5 .5
1 4 .5
1 9 .0
1 8 .0
1 6 .0
1 4 .0
1 7 .0
1 9 .5
1 7 .5
1 6 .0
M
M
M
M
M
132
137
144
151
158
1 6 .0
1 0 .0
1 1 .0
2 0 .0
1 0 .0
1 5 .0
1 1 .0
1 3 .0
1 8 .0
1 3 .0
1 3 .5
1 0 .5
1 1 .0
1 2 .5
1 3 .0
M
M
M
M
M
165
172
179
186
193
1 2 .0
1 5 .0
1 7 .0
1 9 .0
2 2 .5
1 3 .0
1 6 .0
1 7 .0
1 9 .0
1 9 .5
1 2 .0
1 4 .5
1 5 .0
1 6 .0
1 6 .5
M
M
M
M
M
200
,207
214
221
228
2 1 .0
2 1 .0
2 2 .5
2 2 .0
2 5 .0
2 2 .0
2 1 .0
2 1 .0
2 1 .0
2 1 .0
1 9 .0
1 7 .5
1 8 .0
1 9 .0
2 0 .0
M
M
M
235
242
249
1 7 .0
1 5 .5 '
1 4 .5
1 8 .0
1 6 .0
1 4 .0
1 9 .5
1 7 .5
1 6 .0
S ite
J
J
J
J
J
J
■
'
59
A p p en d ix T a b le 24«
C o n tin u e d .
S ite
1984
J u l i a n D ate
S0ILT10
S0ILT20
S0ILT50
R
R
R
R
R
133
137
144
151
158
1 6 .0
1 0 .0
1 1 .0
1 9 .0
1 0 .0
1 2 .5
1 0 .0
1 2 .0
1 6 .0
1 1 .5
9 .0
1 1 .0
1 1 .0
1 2 .0
1 2 .0
R
R
R
R
R
165
172
179
186
193
1 1 .5
1 4 .5
1 6 .0
1 8 .0
2 3 .0
1 1 .5
1 4 -0
1 6 .0
1 7 .0
1 9 .0
1 1 .0
1 3 .5
1 4 .0
1 5 .5
1 6 .0 ■
R
R
R
R
R
200
207
214
221
228
1 9 .5
2 1 .0
2 2 .0
2 3 .0
2 7 .0
2 1 .0
2 0 .0
1 9 .0
1 9 .0
2 3 .0
1 8 .5
1 7 .5
1 8 .0
1 8 .0
2 1 .5
R
R
R
235
242
249
1 8 .0
1 6 .0
1 4 .0
1 6 .5
1 4 .0
1 2 .0
1 6 .0
1 5 .0
1 3 .0
'
60
A p p endix T a b le 2 5 .
M u lt i p le l i n e a r r e g r e s s i o n m odel w i t h NH4.T a s
d ep en d en t v a r ia b le , " b e s t" 8 v a r ia b le s .
DF
R e g r e s s io n
E rro r
T o ta l
V a r ia b l e
In te rc e p t
SITE
WEEK
AIRTC
SOILT10
S0ILT20
S0ILT50
OM
N
8
109
117
b V alu e
1 9 .5 7
0 .0 4
0 .8 4
- 0 .1 5
0 .11
- 0 .4 8
0 .2 5
9 .8 6
- 1 9 5 .8 7 ,
R2
0 .3 1 0
F
6 .1 3
S ta n d a r d E r r o r
0 .3 7 3
0 .2 0 4
0 .3 3 6
0 .3 0 1
0 .7 2 9
0 .6 5 5
5 .4 8 5
1 3 1 .5 8 2
0.0 1
1 6 .81
0 .2 0
0 .1 4
0 .4 3
' 0 .1 4
3 .2 3
2 .2 2
th e
MONTANA STATE UNIVERSITY LIBRARIES
D378
021*5
cop. 2