Effect of moisture stress on alfalfa seed production and plant growth
by Larry Sherman Hicks
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in
Agronomy
Montana State University
© Copyright by Larry Sherman Hicks (1986)
Abstract:
Moisture availability is a primary factor influencing alfalfa (Medicaqo sativa L.) seed yields. The
objective of this study was to evaluate the effect of four applied moisture regimes (non, low, medium,
and high) on alfalfa seed production. Four alfalfa cultivars ('Ladak 65', 'Vernal' , 'Apollo', and 'Thor'),
with differing fall dormancies, were evaluated under a line-source sprinkler irrigation system in 1985 at
Manhattan, Montana.
Cultivars matured in order of their fall dormancy level and with increased irrigation. Total
evapotranspiration (ET) was similar among cultivars and was greatest in the high irrigation regime.
Seasonal ET was similar among cultivars in all irrigation regimes except in the non-irrigated plots.
Patterns of plant available water depletion were similar among cultivars in all irrigation regimes. Root
penetration exhibited patterns similar to cultivar fall dormancy levels with Ladak 65 having the greatest
root penetration. Ladak 65 acheived the greatest heights in all irrigation regimes. Internode length,
biomass, total seed yield, and pure live seed increased with increased ET. A good relationship existed
between increased biomass for increased total and pure live seed yield for all cultivars. Stem number
per plant varied among cultivars with increased biomass. Internode length increased with increased
biomass for all cultivars. Stems per plant, pods per stem, biomass water use efficiency (WUE), seed
WUE, germination, hard seed, and seed weight all varied among cultivars with increased ET. The
relationship between pods per stem and seed yield varied among cultivars. Total viable seed increased
with increased ET for all cultivars except Ladak 65. EFFECT OF MOISTURE STRESS ON ALFALFA
SEED PRODUCTION AND PLANT GROWTH
by
Larry Sherman Hicks
A thesis submitted in partial fulfillment
of the requirements for the degree
of
Master of Science
in
Agronomy
MONTANA STATE UNIVERSITY
Bozeman, Montana
September, 1986
MAW
LIB.
H 3 78
hisasi
C.r-A.
APPROVAL
of a thesis submitted by
Larry Sherman Hicks
This thesis has been read by each member of the thesis
committee and has been found to be satisfactory regarding
content, English usage, format, citation, bibliographic
style, and consistency, and is ready for submission to the
College of Graduate Studies.
W I Cy £ L
Date
<~X/^n/vjy 6('
A l w -- _
Chairperson, Graduate Committee
Approved for the Major Department
Head, Major Department
Approved for the College of Graduate Studies
Date
Graduate Dean
iii
STATEMENT OF PERMISSION TO USE
In presenting this thesis in partial fulfillment of the
requirements
for
a
master's
degree
at
Montana
State
University, I agree that the Library shall make it available
to
borrowers
from
under rules of the Library.
Brief quotations
this thesis are allowable without special
permission,
provided that accurate acknowledgment of source is made.
Permission for extensive quotation from or reproduction
of this thesis may be granted by my major professor,
his absence,
by the Dean of Libraries when,
or
in
in the opinion
of either, the proposed use of the material is for scholarly
purposes.
for
financial
permission.
Signature
Date
Any copying or use of the material in this thesis
gain
shall
not
be
allowed
without
my
V
ACKNOWLEDGMENTS
I
wish
to
express
my sincere
appreciation
to
the
following:
My
parents
for
their encouragement
and
support
in
pursuing an advanced degree.
Jim Bunker for extensive assistance in computer program
data analyses.
Dr.
Ronald H .
friendship,
and
Lockerman for his assistance, guidance,
patience
while
serving
as
my
major
and
Gerald
professor.
Drs.
Loren
Wiesner,
Raymond Ditterline,
Westesen for their advice and friendship while serving on my
graduate committee.
Dr.
D. G.
assistantship
Miller
and
for
financial
arranging
support
my
to
the
research
1985
WSCS
meetings in Moscow, ID.
To
my
contemplate
fellow
the
I
graduate students who
complexity and
inspired
intracacies
of
me
agronomic
research in our many discussions on the subject. Also,
their
indepth
participation
in
the
adventures into the art of trout fishing.
many
to
for
philosophical
Special thanks to
R. Denny Hall.
The
Plant
Montana
Agricultural Experiment Station
and Soil Science Department for support.
and
the
vi
TABLE OF CONTENTS
Page
APPROVAL.........
ii
STATEMENT OF PERMISSION TO USE.......................
ill
VITA.................................................
iv
ACKNOWLEDGMENTS......................................
v
TABLE OF CONTENTS.....................................
LIST OF TABLES.................................
vi
viii
LIST OF FIGURES.......................................
xi
ABSTRACT..............................................
xv
Chapter
I.
II.
INTRODUCTION........... .................... ..
I
LITERATURE REVIEW............................
2
Crop........................................
Botanical Description.......................
Adaptation..................................
Stand Establishment.........................
Harvest................................
Economic Value..............................
Evapotranspiration and Water Use Efficiency..
Moisture Stress on Alfalfa Seed Production...
III.
MATERIALS AND METHODS...............
Site Description............................
Experimental Design.........................
Planting and Establishment..................
Meteorological Observations. .................
Irrigation System. ...........................
Pollination.........
Soil Moisture Determinations............
Root Penetration............................
Evapotranspiration..........................
Growth and Yield Measurements............... '
Water Use Efficiency........................
Seed Quality................................
2
4
5
6
6
8
8
13
19
19
20
21
21
22
23
23
24
24
24
25
26
vii
TABLE OF CONTEMTS-Continued
Page
Statistical Methods.........................
IV.
RESULTS AND DISCUSSION.... ...............
Water Application...................
Environment............
Growing Season.............
Evapotranspiration............
Total Evapotranspiration (ET)............
Seasonal ET..............................
Soil Moisture Depletion...................
Root Penetration.................
Plant Height...........................
Relationship for Internode Length to ET.....
Biomass Yield.......
Relationship for ET to Stem Number per Plant.
Relationship for Stem Number per Plant and
Internode Length to Biomass Yield.........
Total Seed Yield............................
Relationship for Pods per Stem to Seed Yield.
Relationship for Pod Number per Stem to ET...
Pure Live Seed Yield........................
Biomass Effect on Seed Yield................
Biomass Water Use Efficiency. .........
Seed Yield Water Use Efficiency.............
Seed Quality.............................. . .
Germination......... ......... .......... .
Hardseed............
Total Viable Seed (TVS) ....... .......
Seed Weight..................
V.
SUMMARY.............
26
27
27
27
28
29
29
30
34
38
42
46
47
51
52
54
57
58
59
60
65
66
66
66
67
68
71
73
LITERATURE CITED................................
77
APPENDIX ..........................
83
viii
LIST OF TABLES
Table
I.
2
.
3.
4.
5.
6.
7.
8.
9.
Page
Growing season length for each cultivar within
each irrigation treatment in 1985 at the John
Schutter Farm, Manhattan, MT ......... ?.........
28
Regression analyses for the effect of increased
days to maturity and evapotranspiration for all
cultivars in 1985 at the John Schutter Farm,
Manhattan, M T ............. .....................
29
Total evapotranspiration at both locations for
all cultivars at four irrigation regimes in
1985 at the John Schutter Farm, Manhattan, MT...
29
Regression analysis for the effect of increased
ET (cm) on internode length (cm) at both
locations for all cultivars in 1985 at the John
Schutter Farm, Manhattan, MT...................
47
Regression analysis for the effect of increased
ET (cm) on the stem number plant-1 at both
locations for all cultivars in 1985 at the John
Schutter Farm, Manhattan, M T ..................
52
Regression analysis for the effectof stem
number plant
on biomass yield (Mg ha 1) at
both locations for all cultivars in 1985 at the
John Schutter Farm, Manhattan, MT.............
53
Regression analysis for the effect of increased
internode length (cm) on biomass yield (Mg ha )
at both locations for all cultivars in 1985 at
the John Schutter Farm, Manhattan, MT..........
53
Regression analysis for the effect of the pod
number stem
on seed yield at both locations
for all cultivars in 1985 at the John Schutter
Farm, Manhattan, MT............................
58
Regression analysis for the effect of increased
ET (cm) on pods stem
at both locations for
all cultivars in 1985 at the John Schutter Farm,
Manhattan, MT ............ ......................
58
ix
LIST OF TABLES-Continued
Table
10.
11.
12
.
13 .
14 .
15 .
16 .
17.
18.
Page
Regression analysis for the effect of increased
ET on pure live seed (PLS) yield at both
locations for all cultivars in 1985 at the John
Schutter Farm, Manhattan, MT.......... ........
59
Regression analysis for the effect of increased
biomass on pure live seed (PLS) yield for all
cultivars at both locations in 1985 at the John
Schutter Farm, Manhattan, MT.... ............
65
Regression analysis for the effect of increased
ET (cm) on biomass WUE for all cultivars at
both locations in 1985 at the John Schutter
Farm, Manhattan, MT ..................... *.....
65
Regression analysis for the effect of increased
ET (cm) on seed yield WUE for all cultivars at
both locations in 1985 at the John Schutter
Farm, Manhattan, MT.................. .........
66
Regression.analysis for the effect of increased
ET (cm) on percent germination for all cultivars
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT ............................
67
Regression analysis for the effect of increased.
ET (cm) on hardseed percentage for all cultivars
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT............................
68
Regression analysis for the effect of increased
ET (cm) on seed weight (g 1000 seed 1) for
all cultivars at both locations in 1985 at the
John Schutter Farm, Manhattan, MT .............
72
Combined total irrigation amounts (cm) for all
irrigation regimes on both sides of the pipe in
1985 at the John Schutter Farm, Manhattan, MT...
84
Differences in the amount of water used in ET
(cm) and that received through irrigation and
precipitation at both locations for all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT ..................................
84
LIST OF TABLES-Continued
Table
19.
20.
21.
22.
23.
24.
Page
Daily environmental data in 1985 for the John
Schutter Farm, Manhattan M T ....................
84
Biomass yield (Mg ha ) for all cultivars at
both locations in 1985 at the John Schutter
Farm, Manhattan, MT............................
88
Total seed yield (kg ha ^) for all cultivars
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT.........
88
Pure live seed (PLS) yield (kg ha 1) for all
cultivars at both locations in 1985 at the John
Schutter Farm, Manhattan, M T ..................
89
Biomass WUE at four irrigation regimes for all
cultivars at both locations in .1985 at the John
Schutter Farm, Manhattan, MT ..................
89
Percent germination, hard seed, and total viable
seed at both locations for all cultivars in 1985
at the John Schutter Farm, Manhattan, M T .......
90
xi
LIST OF FIGURES
Figure
1.
2.
3.
4.
5.
6.
7.
Page
The effect of time on evapotranspiration (ET)
under non-irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows indicate time of
irrigations...... ..............................
31
The effect of time on evapotranspiration (ET)
under low irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan,' MT. Arrows indicate time of
irrigations....................................
32
The effect of time on evapotranspiration (ET)
under medium irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows indicate time of
irrigations............................. .......
33
The effect of time on evapotranspiration (ET)
under high irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows indicate time of
irrigations................................ .
34
The effect of time on plant available water in
the non-irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan, MT. Arrow indicate time of
irrigations....................................
35
The effect of time on plant available water in
the low irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows indicate time of
irrigations....................................
36
The effect of time on plant available water in
the medium irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows indicate time of
irrigations....................................
37
xii
LIST OF FIGURES-Continued
Page
Figure
8.
9.
10.
11 .
12 .
13 .
14 .
15 .
16.
The effect of time on plant available water in
the high irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows indicate time of
irrigations....................................
38
Root penetration with progression of the season
at location two for all cultivars in the
non-irrigated regime in 1985 at the John
Schutter Farm, Manhattan, M T ...................
39
Root penetration with progression of the season
at location two for all cultivars in the low
irrigated regime in 1985 at the John Schutter
Farm, Manhattan, MT ............................
40
Root penetration with progression of the season
at
location two for all cultivars in the
medium irrigated regime in 1985 at the John
Schutter Farm, Manhattan, M T ...................
41
Root penetration with progression of the season
at location two for all cultivars in the high
irrigated regime in 1985 at the John Schutter
Farm, Manhattan, MT ............................
42
The effect of time on plant height in the nonirrigated
regime at location
two for
all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT ..................................
43
The effect of time plant height in the low
irrigated
regime at location
two for
all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT ..................................
44
The effect of time on plant height in the medium
irrigated
regime at location
two for
all
cultivars in 1985 at the John Schutter Farm,
Manhattan, M T ..................................
45
The effect of time on plant height in the high
irrigated
regime at location
two for
all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT ......... .........................
46
Xiii
LIST OF FIGURES-Continued
Figure
17.
18.
19.
20.
21.
22.
23.
Page
Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low,
medium, high ) on Ladak 65 biomass yield at
both locations in 1985 at the John Schutter
Farm, Manhattan, MT...........................
48
Relationship for increased
evapotranspiration
(ET) at four irrigation levels (non, low,
medium, high) on Vernal biomass yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, M T .................................
49
Relationship for increased
evapotranspiration
(ET) at four irrigation levels (non,
low,
medium, high) on Apollo biomass yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, MT .................................
50
Relationship for increased
evapotranspiration
(ET) at four irrigation levels (non,
low,
medium, high) on Thor biomass yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, M T .......... .......................
51
Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low,
medium, high) on Ladak 65 seed yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, MT ............ .....................
54
Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low,
medium, high) on Vernal seed yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, MT .................................
55
Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low,
medium, high) on Apollo seed yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, M T .................................
56
xiv
I
LIST OF FIGURES-Continued
Figure
24.
25.
26.
27.
28.
29.
30.
31.
Page
Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low,
medium, high) on Thor seed yield at both
locations in 1985 at the John Schutter Farm,
Manhattan, M T ......................... .........
57
Relationship for Ladak 65 biomass yield on total
seed yield under four irrigation levels (non,
low, medium, high) at both locations in 1985 at
the John Schutter Farm, Manhattan, M T ..........
61
Relationship for Thor biomass yield on total
seed
yield under four irrigation levels (non,
low, medium, high) at both locations in 1985 at
the John Schutter Farm, Manhattan, MT ..........
62
Relationship for Vernal biomass yield on total
seed yield under four irrigation levels (non,
low, medium, high) at both locations in 1985 at
the John Schutter Farm, Manhattan, M T ..........
63
Relationship for Apollo biomass yield on total
seed yield under four irrigation levels (non,
low, medium, high) at both locations in 1985 at
the John Schutter Farm, Manhattan, MT..........
64
Relationship for increased evapotranspiration
(ET) on total viable seed percent for Vernal
at four irrigation levels (non, low, medium,
high) at both locations in 1985 at the John
Schutter Farm, Manhattan, M T ...................
69
Relationship for increased
evapotranspiration
(ET) on total viable seed percent for Apollo at
four irrigation levels (non, low, medium, high)
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT ............................
70
Relationship for increased evapotranspiration
(ET) on total viable seed percent for Thor
at four irrigation levels (non, low, medium,
high) at both locations in 1985 at the John
Schutter Farm, Manhattan, M T ...................
71
XV
ABSTRACT
Moisture availability is a primary factor influencing
alfalfa (Medicaqo sativa L .) seed yields. The objective of
this study was to evaluate the effect of four applied
moisture regimes (non, low, medium, and high) on alfalfa
seed
production.
Four alfalfa cultivars (1Ladak 65',
1Vernal1,
1Apollo.1,
and 'Thor'), with differing fall
dormancies, were evaluated under a line-source sprinkler
irrigation system in 1985 at Manhattan, Montana.
Cultivars matured in order of their fall dormancy level
and with increased irrigation. Total evapotranspiration (ET)
was similar among cultivars and was greatest in the high
irrigation regime. Seasonal ET was similar among cultivars
in all irrigation regimes except in the non-irrigated plots.
Patterns of plant available water depletion were similar
among cultivars in all irrigation regimes. Root penetration
exhibited patterns similar to cultivar fall dormancy levels
with Ladak 65 having the greatest root penetration. Ladak 65
acheived the greatest heights in all irrigation regimes.
Internode length, biomass, total seed yield, and pure live
seed increased with increased ET. A good relationship
existed between increased biomass for increased total and
pure live seed yield for all cultivars. Stem number per
plant
varied among cultivars with increased
biomass.
Internode length increased with increased biomass for all
cultivars. Stems per plant, pods per stem, biomass water
use efficiency (WUE), seed WUE, germination, hard seed, and
seed weight all varied among cultivars with increased ET.
The relationship between pods per stem and seed yield varied
among cultivars. Total viable seed increased with increased
ET for all cultivars except Ladak 65.
I
CHAPTER I
INTRODUCTION
The
first
annual
report
of
the
Montana
Farmers
Institute in 1902 indicated that alfalfa was introduced into
Montana
around 1880.
The date it was first cultivated
for
seed in the state is unknown.
Prior
to
World
War
II,
most of
produced
in the United States came from
Montana,
Utah,
were
the
alfalfa
Kansas,
Oklahoma,
and South Dakota. Although large
harvested,
average
yields
were
seed
acreages
usually
. below
H O kg ha ^ . Seed yields have increased dramatically in most
areas
since the advent of
germplasm,
cultural
efficient
practices.
approximately
Irrigation
production
and
135
kg
selective
pollinator
However,
pesticides,
utilization,
Montana
and
still
averages
management.
alfalfa
Soil moisture may
limiting factor in achieving desirable alfalfa seed
Improved
better
ha-1.
is an important component in
crop
improved
seed
be
a
yields.
irrigation management practices may be required to
maximize alfalfa seed production.
This study was
initiated
to evaluate the effects of varying levels of moisture stress
on the seed yield of
four alfalfa cultivars.
2
CHAPTER II
LITERATURE REVIEW
Crop
Alfalfa
(Medicaqo
domesticated
forage.
alfalfa
been
has
Phylogenetic
sativa L .),
is
Bolton et al.
the
indicate
known
(1972) reported
used as a forage crop
studies
oldest
for
southwestern
3300
Asia
that
years.
as
the
probable origin for alfalfa. Alfalfa became more diverse as
it spread from northeast Persia to other parts of the world.
Bolton
et al.
(1972) reported that alfalfa was brought
to
South America by the Spaniards in the 16th century.
The
first recorded production of alfalfa in the United
States was in Georgia in 1736.
the
acid
However, it did not tolerate
soils and humid climate
(Martin
et
al.,
1976;
Bolton et al., 1972). Introduction into California from Peru
in
1841
and from Chile in 1850 secured alfalfa's place
the United States (Martin et al.,
1976).
Alfalfa was
in
well
adapted to the sunny, dry climate and irrigated soils of the
southwest
and rapidly spread to neighboring states (Hendry,
1923). Introduction of a winter hardy alfalfa into Minnesota
by
Windelin Grimm during the mid 1880's
further
increased
alfalfa's range of utilization (Martin et al., 1976).
3
The
exact date alfalfa was introduced into Montana
is
unknown. Communications by W.B. Harlan indicate that alfalfa
was
seeded
in
(Alexander,
rancher,
the late 1800's in
1961).
is
J .D .
the
0 1Donnell,
Bitterroot
a
Valley
Yellowstone Valley
reported to have grown alfalfa in 1884
(Mont.
Farmers Inst., 1902).
Alfalfa
has world-wide distribution.
However,
it
is
largely confined to the temperate regions of the world.
The
United
the
States,
Argentina,
leading producers,
(Bolton
et
al.,
and
the Soviet Union
are
accounting for 70% of the world
1972).
The combined acreage
acreage
of
France,
Italy, Canada, and Australia account for another 20%.
Wisconsin,
leading
and
Iowa,
California
and
alfalfa hay producing states in the
Johnson,
1983).
Montana
alfalfa
hay production (Pratt
Fergus,
Beaverhead,
and
production
hectares
U .S .
are
(Clampet
and
Lies,
in
1984) . Madison,
Gallatin counties are the leading
1984). Total 1983 hay
in Montana was 2,441,275 metric tons on
(Pratt and Lies,
the
ranks Ilth in the nation
producers in Montana (Pratt and Lies,
3,203
Minnesota
1984).
473,481
An average of 6,944
and
kg ha 1 of alfalfa hay were produced on 246,048 ha of
irrigated
land
and
227,433
ha
of
non-irrigated
land,
respectively.
The
United
States
produced 46,330
metric
tons
of
alfalfa seed in 1980 with California, Idaho, Washington, and
Nevada
being the leading seed producing states (Clampet and
4
Johnson,
the
1981).
Montana and South Dakota are ranked 8th in
U.S., each producing approximately I,905 metric tons of
alfalfa seed (Clampet and Johnson, 1981). Average seed yield
for Montana in 1980 was 134.4 kg ha-1 (Clampet and
1981).
Average
U.S.
produced 582 kg ha
yield was 267 kg ha""1 and
Johnson,
California
(Clampet and Johnson, 1981).
Botanical Description
Alfalfa is an herbaceous perennial legume that may live
20
years or longer in dry climates (Martin et
Flowers
are
shades
of
1979).
Seed
born on loose racemes and vary in
purple
pods
have
one to five
1979).
followed
alternate,
1976).
third
of
Approximatly
a
margin
this
et
and
al.,
contain
leaf,
cotyledons,
with
subsequent
trifoliolate leaves (Martin et
leaflets
the
from
kidney-shaped seeds (Ditterline et
unifoliolate
pinnately,
projection
al.,
one
Oblong
of
spirals
Alfalfa seedlings emerge with two
by
1976).
color
to yellow or white (bitterline
several yellowish-green,
al.,
ai.,
are sharply toothed on
and
the
mid-rib
tip
the
terminates
(Martin
et
al.,
upper
with
al.,
the
1976).
48% of the plant may be leaves (Kiesselbach et
1934). Stems arise from a fleshy crown and may grow to
height
of
one
meter,
with 5 to
25
stems
per
plant
(Ditterline et al., 1976).
Alfalfa
rhizomatous,
has four general root
and
types;
tap,
creeping (Smoliak and Bjorge,
branched,
1981).
An
5
alfalfa tap-root system may penetrate the soil in excess
nine meters (Martin et al.,
that
1976).
of
Carlson (1925) reported
all alfalfa cultivars develop branched root systems in
compacted
soil,
while
taproots predominate ■ under
porous
is the most commonly grown
alfalfa
conditions.
Medicago sativa L .
(Clement,
1962).
However,
yellow-flowered
alfalfa
(M.
falcata
L .) is sometimes regarded as a subspecies of common
alfalfa
(Clement
yellow flowers,
1962).
M^
falcata is
distinguished
by
sickle-shaped pods, decumbent growth habit,
low-set branched crowns, and branched roots (Clement, 1962).
Adaptation
Alfalfa
is
conditions.
adapted
Accord
to
(1972)
a
wide
range
reported
that
of
yellow-flowered
alfalfa
has survived temperatures below -62° C ,
alfalfa
has
Deep
survived
loam
soils
temperatures
in
climatic
excess
with porous subsoils
are
and
common
of 54.5°C.
best
for
alfalfa production (Martin et al., 1976). Smoliak and Bjorge
(1981)
reported
waterlogging,
,that alfalfa does not
or
poor
tolerate
internal soil drainage
flooding,
during
the
growing season.
Alfalfa grows on most soils in semi-arid regions except
those
tables
with
either
(Martin
tolerance.
high alkaline salts
et al.,
1976).
or
shallow
Alfalfa has moderate
According to. Richards (1969),
water
salt
alfalfa tolerates
6
an EC of 8 mmhos cm * before a 50% stand reduction occurs.
Alfalfa is very sensitive to soil acidity less than
6.0.
(Smoliak and Bjorge,
pH
1981 ). However, it may be grown
on acid soils with lime amendments.
(Martin et al.,
1976).
Alfalfa is relatively drought tolerant, but responds well to
irrigation.
Stand Establishment
Good
seedbed
preparation is the key to alfalfa
stand
establishment. Cultivated soils should be packed to obtain a
firm
seedbed
direct
(Ditterline et al.,
drilled
into
cereal
1979).
grain
Alfalfa may
stubble
with
be
minimum
tillage. Seeding depth is commonly 6 to 12 mm in heavy soils
and slightly deeper on light soils (Martin et al., 1976).
Wiesner (1982) reported that seeding rates for
seed
Wide
production
row
in Montana range from .6 to 2.0 kg
X..
■
spacings out-yield dense stands
for
production.
Irrigated
range
61
from
alfalfa
to
and
92
respectively (Wiesner,
dryland
and
1982).
122
to
alfalfa
244
ha
seed
row
spacings
in
Montana,
cm
Additionally, 25-35 cm plant
spacing within the row is important for maximum seed yields.
Harvest
Alfalfa
seed production in many areas is a
of hay production (Smith,
by-product
1972). Seed is harvested when hay
is not needed or when a good seed set occurs (Smith, 1972).
a
'
7
Seed
production is best on vigorous
excessive
soil moisture,
highest
(Smith,
seed
1972).
yields
However,
and fertility can induce
delay and/or prolong flowering ,
production
plants.
lodging,
and result in poor
nectar
Tysdal (1946) reported that the
were
obtained
from
upright
plants
growing in widely spaced rows.
Seed
are usually ready for harvest 60 days after
flowering,
(Smith
when
1972;
combined
or
2/3 to 3/4 of the pods (curls)
Wiesner,
1982).
swathed
then
Seed
crops
combined
peak
are
are
brown
directly
(Wiesner,
1982).
Shattering losses are proportional to the amount of handling
during
harvest (Smith,
plant
defoliation
popularity
alfalfa
seed
harvest
in
combined
(Wiesner,
decreased
wind-row
rows
with
a
Direct combining
desiccant
spray
as a method of reducing handling
harvested
1982).
1981).
(Smith,
1981).
Most
is
gaining
losses
during
alfalfa
Montana is sprayed with desiccant and
1982).
losses
Direct
from wind
combining
and
rain
seed
direct
provides
(Wiesner,
The crop must be swathed and allowed to dry in wind­
if desiccants are not used (Wiesner,
should
following
be
1982).
done early in the morning when a
heavy
Swathing
dew
is
present to prevent seed loss (Wiesner, 1982).
Alfalfa
seed
should be at approximatly
before combining (Wiesner,
be
13%
moisture
1982). Additionally, seed should
checked often in storage for heating when combined at
high moisture content.
a
8
Economic Value
Alfalfa
seed in the United States averaged $0.54 kg-1 in
1980 (Clampet and Johnson,
1981).
Additionally, total U.S.
alfalfa
seed production in 1980 was valued at $115,000,000.
Montana
producers
alfalfa
seed
received an average of
$0.34
and $3,440,000 for a state total
kg-1
for
(Pratt
and
Lies, 1981).
Evapotranspiration
(ET) and Water Use Efficiency
(WUE)
Evaporation (E), transpiration (T), and water use efficiency
(WUE)
and
are important alfalfa production components.
Stewart
Hagan (1969) reported that the physiological nature
of
alfalfa manifested through seasonal fall storage followed by
spring
retrieval of photosynthates alters the yield
relationship
Smeal
into a convex function.
(1984)
relationship
reported
that a
However,
highly
to
Arnold
significant
existed between alfalfa dry matter
ET
and
linear
production
and ET.
Precipitation,
temperature,
Hagan,
humidity,
1969).
measurements
exerted
irrigation,
and
Rosenberg
were
minimal
wind
(1969)
solar
affect ET
reported
obtained from well watered
canopy resistance.
Well
radiation,,
(Stewart
that
and
best
crops
watered
ET
which
alfalfa
demonstrated little resistance to ET and consumed as much or
more
water
than
Rosenberg, 1969).
other crops (Blad
and
Rosenberg,
1974;
9
Rosenberg
(1969)
reported
ET
rates
25%
higher
in
alfalfa than native pasture grown under the same conditions.
Sharrett
et
al.
significantly
(1983)
higher
in
reported
that
irrigated than
ET
dryland
Lower
available soil water in dryland alfalfa
lower
leaf
canopy
water potential,
rates
alfalfa.
resulted
which reduced ET
temperatures (CT) during the day.
were
and
in
raised
Early morning
ET
and CT did not differ appreciably between irrigated and nonirrigated
(1984)
and
alfalfa (Sharrett et al.,
reported
that
period
1983).
Jabbar et
that ET increased from morning to
leaf water potential decreased during
in
alfalfa
with
adequate
soil
al.
mid-day
this
time
moisture.
Low
temperatures may induce strong canopy resistance which leads
to
lower
ET
rates than
are
possible
under
atmospheric
conditions at that time. (Rosenberg, 1969).
Alfalfa
al.,
ET rates depend upon growth
1958),
plant
height
factors
such
(Stewart
and
when
as degree of ground
Hagan,
alfalfa
1969).
was
regrowth (Stewart and
cover
ET
(1969)
cultivars.
et
Wit
reported
(1958),
that
ET
and
increased
1969).
reported
rates
ET
plant
decreased
harvested
Hagan,
and
rates
Additionally,
higher ET rates were observed in taller plants.
Hagan
(Peck
atmospheric demand, soil moisture regimes, and
significantly
during
stage,
Stewart and
differed
differences
among
between
'Grimm', a winterhardy cultivar, and 'Hairy Peruvian', which
is
adapted to hot climates.
Alfalfa
ET
reached
maximum
10
rates in late spring and declined as summer advanced.
Soil moisture content exhibits an important role in the
ET rate. Stewart and Hagan (1969) reported that ET increased
markedly above reference treatments as soil moisture regimes
increased
in
wetness up to but not
including
saturation.
Alfalfa growth and ET decreased when approximatly 80% of the
available
soil
moisture was depleted (Stewart
and
Hagan,
1969).
Most net radiation is used in ET when soil moisture
available
and
crop
cover shades the
ground
(Tanner
is
and
Lemon, 1962). Jabbar et al. (1984) reported that ET patterns
followed
the
patterns of solar
radiation.
Net
radiation
provided energy sufficient to evaporate 7mm of water per day
on
clear
summer
days in Nebraska (Rosenberg
and
Shashi,
1978). Tanner and Lemon (1962) reported that alfalfa may use
more energy than is supplied by radiant energy. This usually
occurs
in
(Rosenberg,
the
spring
1969).
when alfalfa
Advected
sensible
is
growing
heat
actively
provides
the
additional energy consumed in the ET process (Rosenberg
and
Shashi, 1978; Tanner and Lemon, 1962).
Irrigation
in the western states is limited
to.areas surrounded by dryland
primarily
or desert. Advected sensible
heat is a major source of energy consumed when ET occurs
alfalfa
under
dry
conditions
(Rosenberg,
1969).
Approximately 20 to 40% of the energy for ET in alfalfa
be
supplied by advected sensible heat (Blad and
in
may
Rosenberg,
11
.1974).
Rosenberg and Shashi (1978) reported that ET values
rarely exceed 12 mm in alfalfa. Evapotranspiration values in
alfalfa
14.22
during
a drought in Nebraska ranged from
4.75
to
mm of water per day and exceeded IOmm per day on one-
third of the days.
Total ET should include nocturnal ET. Rosenberg (1969)
reported
that
nocturnal ET is common
during
the
alfalfa
growing season. This is due to strong temperature inversions
which
result
Nocturnal
summer.
total
in
ET
was
Nocturnal
a downward delivery
of
greatest
and
ET
in spring
sensible
heat.
lowest
during
has accounted for 20% of
the
daily
water consumption in alfalfa with as much as I mm
of
water, per night being transpired.
Jabbar
et al.
(1984) reported that transpiration
may
equal ET in alfalfa when the canopy covers the soil surface.
However,
wide
this is doubtful
row-spacing.
transpiration
Tanner
in alfalfa grown for seed due to
and Lemon (1962)
reported
that
is influenced by both plant and soil factors.
Plant factors include leaf area,
root proliferation,
type and physiological age (Tanner and
Lemon,
1962).
plant
Soil
factors affecting evaporation include soil moisture content,
soil
Lemon,
water
moisture suction,
1962).
and
The plant is the major area of resistance to
transmission
resistance
and water transmission (Tanner
becoming
in
the
the. soil-plant
major area only
wilting point (Jabbar et al., 1984).
system
near
with
the
soil
plant
12
Soil water content is crucial in transpiration. Gardner
and Ehlig (1963) reported that transpiration rates should be
proportional to available soil water content at wilting. The
lower
at
limits of water available for transpiration may occur
suctions above -1.5 MPa.
that
transpiration
is
Ogata et al.
determined
conditions following irrigation.
gradients
as
soil
(1960)
largely
reported
by
weather
However, increased suction
moisture becomes depleted
lead
to
a
continuous decreasing transpiration rate. Gardener and Ehlig
(1963)
reported
that the transpiration rate
increased
as
soil water increased in alfalfa.
Alfalfa
under
production per unit of water use
low
evaporative
conditions
is
(Stewart
greatest
and
Hagan,
1969). Additionally, yield per unit of water use declined as
ET
rate increased with seasonal progression from summer
fall.
In
New
Mexico,
peak
water-use of
0.96
cm
to
day-1
occurred during late June and July (Arnold and Smeal, 1985).
Stewart
and
Hagan (1969) reported a
between
evaporation
pan data and alfalfa
under good field conditions.
linearly
with
decreased
as
conditions
quality
al.,
yield
(Gomez
was
correlation
yield
produced
Alfalfa forage yield increased
et
al.,
increased with
(Stewart and Hagan,
1985;
nitrogen
ET
positive
1985).
ET
1969)..
However,
under
good
Conversely,
generally lower with high ET rates
WUE
field
forage
(Gomez
et
Jensen et al., 1985) . Additionally, whole plant
percentage
decreased linearly with ET
(Gomez
et
13
al.,
1985).
Water
temperate regions
use
efficiency is less
in
arid
than
at high temperatures with sufficient soil
moisture.
Moisture Stress on Alfalfa Seed Production .
Alfalfa
This
is
seed
yield may vary with time
and
due to the interaction between plant
location.
factors
and
soil moisture availability (Goldman and Dovrat, 1980). Blinn
(1910)
reported that proper soil moisture is important
alfalfa seed production.
and
Soil moisture suction between -0.2
-0.8 MPa produced optimum alfalfa seed yields when
soil was kept continuously moist and
not
irrigation
water
applied during heavy bloom (Taylor et al.,
contrast,
alfalfa forage
optimum.
Forage yield
water
the
was
1959).
In
such
an
yields did not exhibit
increased with increased amounts of
as soil moisture suction decreased to field
(Mayernak et al.,
for
capacity
1985; Taylor et al., 1959). Additionally,
irrigation throughout the season increased forage yield over
irrigation supplied early in the season.
Moisture
growth
stress
(Rahman,
decreased
soil
wilting point.
greatly affected
1973).
moisture
Growth
before
Naylor et al.
decreased in forage yield,
was
alfalfa
greatly
reaching
vegetative
reduced
the
(1985) reported that
acid detergent fiber,
by
permanent
alfalfa
cell wall
content, lignin, cellulose, and hemicellulose, and increased
in leaf and ash percentage as water stress increased. Pandey
14
et
al.
(1984)
water decreased
(Vigna
reported
in cowpea
radiata L .),
(Arachis
hypogaea
that
harvest
index declined as
(Vigna unguiculata L .), mungbean
soybean (Glycine max L .),
and
peanut
L .) suggesting that seed yield was
sensitive to moisture stress than total plant yield.
more
Taylor
et al. (1959) reported that alfalfa seed yields were reduced
if soil moisture was reduced to -1.5 MPa before harvest.
Alfalfa
obtain
plants
maximum
must
yields
be mature to fill seed
(Yamada
et
al.,
pods
1973).
to
However,
vegetative growth must be suppressed to promote flowering in
alfalfa.
Suppression
formation
of
vegetative
alfalfa seed more than
growth (Fuelleman,
on
of
plants
that
grew
vulgaris
L. )
moisture
near
favored
increased
the
vegetative
1934). Alter (1920) reported that stress
alfalfa is neededI to force seed
reported
growth
setting.
heaviest alfalfa seed yields
slowly.
seed
the
Similar to alfalfa,
Blinn
(1910)
resulted
good beet
yields were obtained
by
minimum requirement
for
keeping
plant
when
(Beta
soi I
growth
(Blinn, 1910).
The amount of soil moisture at flowering and during pod
maturation is important for good alfalfa seed yields (Willis
and Bopp,
alfalfa
during
reported
by
1910;
Martin,
1915;
Hollowell,
1929). Reduced
seed yields were observed if plants were
the bloom stage (Taylor et
al.,
1959).
that highest seed yields in alfalfa were
irrigated
They
also
obtained
maintaining continuous soil moisture from the initiation
15
of
spring
(1980)
growth
reported
until
flowering.
Goldman
that 80 mm of applied water
and
Dovrat
reduced
yields when conditions favored vegetative growth.
seed
Yamada et
al.
(1973) reported that 122 cm of water was needed to fill
the
soil profile and insure good alfalfa seed yields on dry
California soils.
(replenishment
Cohen et al.
(1972) reported
irrigation
of soil moisture) timing and amount markedly
affected alfalfa flower intensity. Moderate rates of applied
water
(90
mm), before flowering in alfalfa did
seed
yield;
however,
to
affect
seed yields decreased at high
(150 mm) (Goldman and Dovrat,
applied
not
1980).
dry soils at mid-flowering
alfalfa seed y i e l d s b u t ,
rates
Moderate water rates
markedly
increased
seed yield was less affected
by
water applied after flowering (Goldman and Dovrat, 1980).
Taylor et al. (1959) concluded that there is an optimum
soil
moisture for maximum alfalfa seed
yields.
Extremely
dry or wet soil may affect the proper functioning of flowers
for
alfalfa
seed production.
alfalfa
was
Dovrat,
1980).
response
prolonged
Tysdal
Flowering and seed
under wet conditions
(1946)
reported no
of four alfalfa cultivars to three
set
(Goldman
difference
soil
in
and
in
moisture
regimes (high, medium, and low).
Martin
is
usually
(1915) reported that alfalfa seed crop
due
to an excess or an insufficiency
moisture
during pod maturation.
reported
that
wet
or flooded
Thompson and Fick
conditions
reduce
failure
of
soil
(1981)
alfalfa
16
forage
yields
growth
was
flooding
and decrease stand
in
alfalfa.
Root
inhibited and top growth was reduced 50%
at 34° C .
periods
life
of
However,
alfalfa may
after
tolerate
flooding at lower temperatures.
longer
Tysdal
(1946)
reported that alfalfa lodged and produced two to five
less
seed yield with more shrivelled seed under
irrigation.
times
excessive
Forty-percent soil moisture resulted in greater
seed
yield and more seed per 100 grams of fresh weight than
from
alfalfa
plants grown at 20 or 30%
soil
moisture
in
contributed
to
greenhouse experiments.
Lack
of
suppressed
second
al.
sufficient
alfalfa
year
seed
subsoil moisture
yield during
the
first
and/or
of production (Yamada et al., 1973). Taylor et
(1959) reported that maximum alfalfa seed yields may be
obtained
if
mean soil moisture suction is not
allowed
to
exceed -0.2 MPa.
Soil
Pandey
moisture stress may affect seed yield components.
et
al.
development,
contribute
(1946)
seed
all
ovule
to
reported
raceme,
(1984)
reported
number
per
that
pod,
high seed yields in
that
fresh weight,
flowers per plant,
flower
and
grain
and
seed
filling
legumes. TysdaI
number
of
stems and seed per
pods
per
plant,
100
weight and grams of seed per 100 grams of fresh weight
increased from low (20%) to
high (40%) soil
moisture.
The number of racemes per plant was highest in medium
soil
pod
moisture
in greenhouse grown alfalfa.
Alfalfa
(30%)
seed
17
yield under field conditions was consistently higher in
low
compared
row
to
high moisture regimes at three
spacings (Tysdal,
produced
the
1946).
most
different
Additionally, high moisture plots
seed.
Moisture
interactions
were
attributed to differential affects of irrigation timing.
Moderate
moisture
which
temperature,
low
humidity,
below optimum produced alfalfa
was
reserves
conducive
content
1945).
and
vegetative
to the storage of high
(Grandfield,
carbohydrate
among
air
growth
organic
The range of
with change in water
soil
root
variation
supply
in
differs
species and also at various stages of growth within a
species
(Rahman,
1973).
A
wide
range
of
carbohydrate
variation was demonstrated in alfalfa at preflower,
end
of
flowering, and fruiting stages (Rahman, 1973).
The
rate
accumulation
of
total
in roots,
nonstructural
carbohydrate
followed by a period of
depletion,
was much greater in plants under moisture stress than plants
grown with unlimited soil moisture (Grandfield,
et
al.,
1972).
positively
1945;
Dovrat et al.,
al.,
stem,
per
stem,
carbohydrates
levels
were
1969).
High alfalfa root and
crown
reserves produced more stems and buds (Willard
1934),
more
(Dobrenz
root
correlated with alfalfa seed yields (Grandfield,
carbohydrate
et
High
1945; Cohen
seed
larger quantities of seed,
per pod,
and Massengale,
and a higher
1966),
more pods
percent
pod
per
set
greater number of racemes
and more pods per raceme (Dovrat et
al.,
1969)
18
than plants with low carbohydrate reserves. However, Dobrenz
and
per
Massengale (1966) reported that the number
stem
were
carbohydrate
reported
consistently
negatively
fractions in the roots.
that
stored root
with alfalfa seed weight.
structural
carbohydrates
vegetative
growth.
pod
high
racemes
correlated
Cohen et
carbohydrates
correlated
of
al.
with
(1972)
were positively
Total available
became limited due
to
non-
increased
This resulted in a lower percentage
of
set in alfalfa plants with high flowering intensity
at
soil moisture levels (Cohen et
al.,
1972).
Cultural
practices designed to increase carbohydrate root reserves in
alfalfa
yields.
during the growing season may maximize alfalfa seed
19
CHAPTER III
MATERIALS AND METHODS
Moisture
plant
growth.
growth
the
stress
The
affects vegetative
and
effects of moisture stress
reproductive
on
alfalfa
and seed yield components were evaluated in 1985
John
Schutter
Farm,
Manhattan,
MT.
Four
on
alfalfa
cultivars of varying fall dormancy levels (Ladak 65, Vernal,
Apollo,
and
Thor) were utilized,
with Ladak 65 being
the
most dormant.
Site Description
The
experiment
was
established
in 1984
on
previously cropped to barley (Hordeum vulgare L.).
was a Manhattan very fine,
Typic
Calciborolls).
replication ^
cm
to
site
The soil
sandy-loam (coarse-loamy, mixed,
Composite soil samples of five
cores
were taken on 15 May at O to -30 and 30 to
determine
analyzed
a
initial
soil
fertility.
Samples
60
were
by standard soil test methods in the Montana State
University Soil and Plant Testing Laboratory. The cumulative
analyses indicated the presence of 140,
ha-1
of
electrical
N,
P,
and
K,
conductivity
effervescence,
256,
respectively.
(EC)
of
0.7
The
and 2216,
kg
soil
an
mmhos,
had
medium
and pH and organic matter content at 0 to 30
20
and 30 to 60 cm of 8.4,
Bulk
densities
8.7 and 1.64, 0.62 %, respectively.
at 20 cm increments from 0 to 400
cm
were
1.32,
1.30, 1.29, 1.33, 1.30, 1.33, 1.40, 1.36, 1.34, 1.39,
1.39,
1.36,
1.37,
1.35, 1.40, 1.41, 1.41, 1.43, 1.44, and
1.45, respectively.
Additional
Samples
were
soil
samples were taken on
analyzed
as
in
indicated the presence of 76,
1984.
83,
2
June
Cumulative
1985.
analyses
1597, and 73, kg ha-1 of
N, P , K, S , and 0.3, 52.1, 5.4 c mol kg-1 of Na, 1/2 Ca, and
1/2 Mg, respectively.
Experimental Design
A
design
a
modified
randomized
block,
split-block
was utilized with two replications on either side of
line-source irrigation
treatments
(2.4
x
irrigated,
low,
medium
angles
complete
from
irrigation
the
system.
4.8 m)
of
and
Four
main
increasing
irrigation
moisture
high) were applied
line-source
on
both
sides.
at
right
Main
plot
treatments were fixed due to the systematics of
J-
the
(non-
line-source
system,
and
"
could
not
.
be
tested
statistically by analysis of variance (ANOVA) (Hanks et al.,
1980).
However,
angles
to the pipe to afford a valid
for
cultivar
interactions.
the
cultivars
differences
Main
and
were randomized
at
statistical
irrigation
plot effects were analyzed
regression as described by Hanks et al. (1980).
by
right
analysis
cultivar
by
linear
21
Planting and Establishment
The
experimental site was preplant
incorporated
with
EPTC (S-ethyl dipropylthiocarbamate) at 0.77 I ha-1 on 4 May
1984 and roller packed
planted
on 18 June
Seed were
1984 with a coneseed planter to a depth
Seeding rate was 60 seeds meter-1 of linear
of 13 mm
Eight
to insure a firm seedbed.
row
plots
utilized
Wiesner
spacings
produced
with
sixty-one
(1982)
the
cm
row
spacings
reported that 61 to
best
yields
row.
92
were
cm
row
irrigation
under
in
Montana. Commercial granular Rhizobium inoculum specific for
alfalfa was added to the seed prior to planting.
The experimental area was irrigated uniformly
immediately
after
irrigations
(6.5
planting followed by four
mm)
until
full
(13- mm)
day
interval
emergence. Subsequent
/
irrigations
(13
mm)
during the
applied at 14 day intervals.
applied
were
establishment
approximately
to
25
one
cm
plant
in
were
Five centimeters of water were
late in the fall to fill the soil
thinned
year
profile.
every 30 cm when
height.
Plots
were
they
Plants
were
hand-weeded
throughout the growing season when necessary.
Meteorological Observations
Precipitation,
with
standard
(Appendix,
temperature, and humidity were measured
weather
instruments
and
recorded
daily
Table 18). Evaporation was recorded by measuring
daily water loss from No. I wash tubs as described by Bauder
22
et al. (1982) (Appendix, Table 18).
Irrigation System
Irrigation
sprinkler
al.
treatments were applied with a
system
(1976).
similar to the one described by Hanks
Model 25 sprinklers with
Bird
Sprinkler Manufacturing Co.,
were
utilized.
379.5
rate
line-source
The
4 mm nozzles
Glendora
,
system was operated at
(Rain
California)
approximately
kP.a producing a 15 m wetting radius and
of 0.34 I s 1 per sprinkler head.
a
discharge
The main irrigation
line consisted of 7.6 cm aluminium pipe with hook and
couplings.
Sprinklers
were
et
placed on 2.5 x 60
cm
latch
risers
spaced 4.6 m apart.
In
1985,
insufficient
only
water
two
as
irrigations were applied
a
result
of
drought.
due
to
Additional
irrigations were originally planned.
Evaporative losses from evaporation pans in the
irrigation
Cumulative
regime
were
used
use (Bauder et al.,
water
were
June
placed
season.
1985
evaporated.
each
schedule
irrigations.
evaporation from pans is a good estimate of crop
water
growing
to
medium
in the pans at the
approximately
Collection
applied water.
Fifteen
centimeters
initiation
of
of
the
Irrigations were applied on 17 May and
when
subplot
1982).
at
15
cm
of
water
20
were
cups were placed in the
center
of
canopy level to determine the
amount
of
Irrigations were applied when wind speed was
23
less
than
8 kmph and at successive
intervals
to
control
runoff.
Pollination
Alfalfa
leafcutter
(Fabriscus),
bees
are
were
the
production
bees,
Meqachile
rotundata
used as pollinators. Alfalfa leafcutter
most reliable pollinator
for
in northern regions (Hobbs 1973).
alfalfa
Eight
seed
liters
(25,000 larva) of leafcutter bees and four loose grooved bee
boards
were placed.in a shelter facing southeast on 30 June
1985. Buckwheat
(Faqopyrum
saqittatum L .) was planted in
12 m rows at both ends of the field on 18 May and I June
to
provide bee nesting material.
Soil Moisture Determinations
Soil
moisture determinations were made with a
probe (Cambell,
Neutron
neutron
Model 503DR Hydroprobe) at 20 cm intervals.
probe access tubes (1120 160 psi PVC pipe with a 43
mm internal diameter) were placed 400 cm deep in the
of
each plot on 4 April 1985 .
taken
on
Additional
24
Initial probe readings were
April 1985 and at 14
measurements
center
to
21
day
intervals.
were taken prior to and
24
hours
after each irrigation.
Plant
available water (PAW) in 1985 was the difference
between the soil moisture content and the permanent
wilting
point (PWP). PWP was 9.5, 8.5, 6.8, 6.0, 5.8, 5.9, 6.2, 6.3,
24
6.4,
5.9,
8.2,
at 20 centimeter increments from 0 to 400 centimeters.
PWP
values were determined by pressure plate extractions at.
-1.5
MPa.
6.1, 6.6, 6.1, 6.2, 6.4, 6.7, 6.8, 7.1, 7.9, and
Plant
available water was calculated at
20
cm
intervals to 400 cm on one side of the pipe (location two).
Root Penetration
Root
penetration was determined by depletion of PAW at
20 cm increments. Water depletion in the lower soil profile
was
attributed to root penetration
reduction
in
plant
available
when a 5 %
water
or
occurred
greater
between
observation dates.
Evapotranspiration
Evapotranspiration
(ET) consist of crop
and soil surface evaporation.
transpiration
Seasonal ET was determined at
location two for each treatment by the equation:
moisture
soil
Total
both
ET =
soil
content at planting + precipitation + irrigation -
moisture content at the following measurement
ET was the cummulative of seasonal ET
locations.
period.
calculated
at
Total ET was used to evaluate plant growth
and yield parameters.
Growth and Yield Measurements
Plant
height was measured in location two a t . ten
day
intervals from 4 April until 24 July 1985. Measurements were
25
terminated
when
the non-irrigated plants attained
maximum
height and the high irrigated plants lodged.
Two
square
harvested
black
meters adjacent to the access
tubes
were
when 2/3 to 3/4 of the seed pods turned brown
in color.
Smith (1972) and Wiesner
(1982)
to
reported
highest seed yields when 2/3 to 3/4 of the pods are brown to
black.
per
stem
Harvest
measurements consisted of number of
harvested area,
—
I
■
,
basal stems plant-1,
number
plants
of
pods
length of the third internode from the crown, total
biomass, and seed yield. Basal stems plant-1, number of pods
stem-1,
and
third
determined by
internode
random
length from the
selection of
ten stems
crown
were
within
the
harvest area.
Plants were initially processed through a Vogel rubberroller
three
thresher
for straw removal.
Seed were
removed
successive runs through a resilient tapered
(Hannaford
"Seedmaster",
by
thresher
Model MkII) and cleaned
with
an
Oregon "Continuous" seed-blower.
Water Use Efficiency
Water
production
use efficiency (WUE) was used to determine
of
a
given yield component per unit
of
the
water
consumed by evapotranspiration. WUE determinations were made
for
total biomass and seed yield for each
each irrigation regime.
cultivar
within
26
Seed Quality
Seed
from
determinations
all
was
cultivars
open
utilized
pollinated.
for
quality
Consequently,
seed
utilized in quality determinations were not genetically pure
within each cultivar.
A
seed
Precision Divider (Garnet MFG Co.) was used to reduce
samples
quality
four
to
a 5 to 10
g
representative
sample
for
analyses.
Germination was determined by
utilizing
replications
of 50 seeds which were placed
on
blotters
moist
in standard germination boxes in a 20*C germinatof
for 7 days.
Number of germinated, dead + abnormal, and hard
seeds were determined.
Seed weight was determined by
using
four replications of 1,000 seeds from each sample.
Pure
percent
live
total
seed
viable
(PLS) was
calculated
seed by total seed
by
multipling
yield
for
each
cultivar within each irrigation regime.
Statistical Methods
Data
were
analyzed
with the Plant and
Discovery computer system and the M.S.U.
Soil
Science
Computing
Service
Vax780 using SAS. Main plot effects were analyzed by
regression.
Figures
were
constructed using
the
linear
graphics
package Tellagraf on the M.S.U. CP-6 main frame computer.
27
CHAPTER IV
RESULTS AND DISCUSSION
Water Application
A
water
line-source
application
conditions.
the
irrigation
system
on both sides of the
pipe
identical
under
Table
16).
Variable
application was attributed to above ground
side-hill
slope.
wind
Variable water application between
resulted in variations in evapotranspiration (ET),
and
ideal
Differential water application between sides of
pipe occurred in 1985 (Appendix,
water
produces
seed yield.
and
sides
biomass,
Experimental results in 1985 are presented
as two locations because of differential water application.
Environment
Environmental
Growing
season
data are given in
precipitation
drought conditions.
Appendix,
Table
was limited in 1985
due
Total growing season precipitation
19.
to
was
140 mm. Most of the precipitation occurred in May and August
with 71 and 40.5 mm,
highest
with
respectively.
a
respectively.
mean
Humidity
high
July temperatures
and low
of
296 and
20°
were
C.,
was highest in August and the early
part of September. Evaporative demand was highest in May and
decreased throughout the growing season.
I
28
Growing Season
Maximum growing season length from initial green-up
late
March
I).
until harvest in September was 157 days
in
(Table
Plants matured in sequential order from the %on to high
irrigation
regime.
Regression
analysis indicated
a
good
relationship
between increased days to
maturity
I
.
increased evapotranspiration for all cultivars (Table
In
general
cultivars. matured,in relation
to
their
and
2).
fall
dormancy level with Ladak 65 maturing first.
Table
I. Growing season length for each cultivar within
each irrigation treatment in 1985 at the John
Schutter Farm, Manhattan, MT.
•
Harvest Date
Total Days
Cultivar .
\Ladak 65
Non-Irr.
Low
Medium
High
8/6
8/9
8/19
8/29
127
130
140
150
Vernal
Non-Irr.
Low
Medium
' High
8/6
8/13
8/29
9/5
. 127
134
150
157
. Apollo
Non-Irr.
Low
Medium
High
8/13
8/26
9/5
9/5
134
147
157
157
Thor
Non-Irr.
Low
Medium
High
8/13
8/26
9/5
9/5
134
147
157
157
29
Table
2. Regression analyses for the effect of increased
days to maturity and evapotranspiration for all
cultivars in 1985 at both locations at the John
Schutter Farm, Manhattan, MT.
Cultivar
Intercept
-1,388
-997
-1,226
-1,375
Ladak 65
Vernal
Apollo
Thor
Slope
13.6
10.3
11.4
12.4
Prob.
R2
0.90
0.95
0.87
0.83
0.0003
0.0001
0.0007
0.0017
Evapotranspiration
Total Evapotranspiration (ET).
Total ET was similar
at
both locations for each cultivar except in the non-irr!gated
regimes (Table 3).
Differences were attributed to
variable
water application resulting from winds and side-hill slope.
Table
3. Total evapotranspiration at both locations for all
cultivars at four irrigation regimes in 1985 at
the John Schutter Farm, Manhattan, MT.
Cultivar
Evapotranspiration (mm)
Irrigation Regime
Medium
Non-Irr.
Low
High
Location I
Ladak 65
Vernal
Apollo
Thor
258
268
291
280
393
401
423
428
526
509
509
510
645
639
609
634
Location 2
Ladak 65
Vernal
Apollo
Thor
362
345
340
335
419
406
418
401
580
543
540
539
626
639
635
668
30
Total
ET
was
greatest in the high
irrigated
These results agree with reports by Sharrett et
plots.
al.
(1983)
and Stewart and Hagan (1969).
Total
ET was greater in all treatments than the
precipitation
This
and irrigation in 1985 (Appendix,
may be attributed to a fall irrigation in
total
Table 17).
1984
which
filled the soil profile. Water use above the added crop year
moisture
depths
indicated
depletion of stored moisture
in the soil profile.
at
lower
Deep root penetration could be
responsible for the additional moisture consumed in ET.
Total
ET from one season may indicate
potential
soil
moisture levels needed to produce a crop the next year. This
information
could
be
useful in irrigation
management
to
insure maximum yields in succeeding years.
Water
consumption
an irrigation regime.
as
much
among cultivars was similar
However, growing season length varied
as 13 days among cultivars
treatment
(Table
within
I).
This
within
an
irrigation
would indicate that
the
same
amount of water was needed to produce a seed crop regardless
of the cultivar or length of time to mature the crop.
Seasonal ET.
for
location
among
Seasonal ET moisture data were
collected
two to determine if differential ET
cultivars
within
each
irrigation
occurred
regime.
All
cultivate exhibited similar seasonal ET patterns within each
irrigation
season
regime (Fig.
under
I,
non-irrigation.
2,
3,
These
4) except during
cultivar
mid­
variations
31
(Figure
I) may have resulted from either non-uniform canopy
cover or variable plant density.
N O N -IR R
A LADAK 65
X VERNAL
140-
H THOR
<
too­
19
26
16
23
30
14
JUNE
Figure
28
ls
4
25
AUGUST
I. The effect of time on evapotranspiration (ET)
under non-irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan,
MT.
Arrows
indicate
time
of
irrigations.
Rosenberg
rates
21
were
and Shashi (1978) reported that
alfalfa
maximal in late spring and declined
as
ET
summer
advanced. Our experiment exhibited similar results.
Seasonal
plants
A
ET may be used to monitor crop water
use
as
make transitional changes in growth and development.
seasonal ET model may have potential in
the
development
of more efficient irrigation management practices.
32
L O W -IR R
A LADAK 65
X VERNAL
□ APOLLO
H THOR
120 -
<
100-
19
MAY
Figure
26
JUNE
16
23
30
JULY
21
28
16
25
AUGUST
2. The effect of time on evapotranspiration (ET)
under low irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan,
MT. Arrows
indicate
time
of
irrigations.
33
M E D IU M -IR R
A LADAK 65_____
X VERNAL
□ APOLLO
H THOR
19
26
16
23
30
14
21
26
4
18
25
AUGUST
Figure
3. The effect of time on evapotranspiration (ET)
under medium irrigation at location two for all
cultivars in
1985 at the John Schutter Farm,
Manhattan,
MT.
Arrows
indicate
time
of
irrigations.
34
H IG H -IR R
A LADAK 65
160 -
X VERNAL
D APOLLO
H THOR
19
26
16
23
30
14
21
28
4
18
23
AUGUST
Figure
4. The effect of time on evapotranspiration (ET)
under high irrigation at location two for all
cultivars in 1985 at the John Schutter Farm,
Manhattan,
MT.
Arrows
indicate
time
of
irrigations.
Soil Moisture Depletion
Irrigations
varying
degrees
replenished
within
each
plant
available
treatment
(Fig.
water
to
5,
7,
6,
8). However, irrigations applied in 1985 were not sufficient
to
maintain
resulting
plant
1985
the
season
in a net decrease in stored soil moisture in
irrigation regimes.
in
available water throughout
all
Additional irrigations were not applied
due to drought conditions.
Ladak 65 had equal
or
35
lower PAW than the other cultivars in all irrigation regimes
at the initiation
the
least
season
of the season. Additionally, Ladak 65 had
amount of PAW in all irrigation regimes
progressed.
penetration
or
This
may be the result
extraction
of
soil
of
moisture
as
deep
at
the
root
greater
tensions.
N O N -IR R
A LADAK 65
X VERNAL
D APOLLO
H THOR
20
27
APRIL
Figure
4
11
18
25
I
JUNE
JULY
AUGUST
SEPTEMBER
5. The effect of time on plant available water in
the non-irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan,
MT.
Arrows
indicate
time
of
irrigations.
The slight increase in plant available water at the end
of
the season for Apollo and Thor may be attributed to late
season precipitation in the non-irrigated plots (Figure
5).
36
Late
season precipitation may also account for the leveling
off of PAW depletion in the low irrigated plots (Figure
Stabilization
6).
of PAW depletion at the end of the season
by
Thor in the medium irrigation (Figure 7) and Ladak 65 in the
high
irrigation
treatments (Figure 8) may indicate
either
the onset of dormancy or complete senescence.
L O W -IR R
A LADAK 65
X VERNAL
O APOLLO
H THOR
20 ~ ■—
20
i
27
APRIL
Figure
4
11
18
25
I
JUNE
15
22
2*
6
JULY
13
20
27
3
10
17
AUGUST
24
31
7
SEPTEMBER
6. The effect of time on plant available water in
the low irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan,
MT.
Arrows
indicate
time
of
irrigations.
Plant
available
water is a good indicator
of
stored
soil moisture. It may be used to determine irrigation timing
and rate of application needed to produce a specified amount
37
of crop growth.
determine
A
fall
Plant available water data might be used to
whether a fall or spring irrigation is desirable.
irrigation would be most benefical if PAW was
low
and irrigation cost were minimal.
M E D IU M -IR R
6 LADAK 65
X VERNAL
□ APOLLO
H THOR
2 0 4 — I— r
20
27
APRIL
Figure
4
11
18
25
I
JUNE
8
15
22
2»
6
JULY
13
20
27
3
10
AUGUST
n
24
31
7
SEPTEMBER
7. The effect of time on plant available water in
the medium irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan,
MT.
Arrows
indicate
time
of
irrigations.
38
H IG H -IR R
A LADAK 65
X VERNAL
D APOLLO
H THOR
20
27
4
11
18
25
Figure
15
22
2*
6
JULY
APRIL
11
20
27
I
10
AUGUST
17
24
11
7
SEPTEMBER
8. The effect of time on plant available water in
the high irrigated regime for all cultivars at
location two in 1985 at the John Schutter Farm,
Manhattan, MT. Arrows
indicate
time
of
irrigations.
Root Penetration
Ladak
65 had the deepest root penetration from 4
to harvest at all irrigation levels (Fig.
with
the exception of Vernal,
9,
10,
11,
July
12)
in the non-irrigated regime,
where the roots of both penetrated to 340 cm.
39
N O N -IR R
A LADAK 65
X VERNAL
D APOLLO
H THOR
290330370-
AUGUST
Figure
9. Root penetration with progression of the season
at location two for all cultivars in the nonirrigated regime in 1985 at the John Schutter
Farm, Manhattan, MT.
Root growth of Thor was slower than the other cultivars
during the early portion of the season in the low
plots
(Figure
10).
irrigated
Apollo root penetration stabilized
at
approximately 260 cm by the end of the growing season in the
medium irrigated plots (Figure 11).
In
general,
higher irrigation regimes had deeper root
penetration as a result of a longer growing season. However,
on
8 August root penetration for all cultivars in the
irrigated
regime
was
deepest
or
equal
to
the
nonother
40
irrigation
regimes.
penetration
of
irrigated
deeper
and
plots.
under
moisture.
any
cultivar
These
dry
However,
onset
Ladak
65
at
had
the
360
deepest
cm
in
the
data suggest that roots
conditions
in
order
to
root
medium
penetrate
extract
soil
dry conditions result in early maturity
of dormancy resulting in less time
for
maximum
root growth.
L O W -IR R
A LADAK 65
130-
X VERNAL
□ APOLLO
H THOR
250290330370-
JUNE
AUGUST
Figure 10. Root penetration with progression of the season
at location two for all cultivars in the low
irrigated regime in 1985 at the John Schutter
Farm, Manhattan, MT.
41
M ED IU W -IR R
A LADAK 65
130170-
X VERNAL
D APOLLO
H THOR
210 250290330370-
AUGUST
Figure 11. Root penetration with progression of the season
at location two for all cultivars in the medium
irrigated
regime in 1985
at the John Schutter
Farm, Manhattan, MT.
42
H IG H -IR R
A LADAK 65
X VERNAL
D APOLLO
B THOR
290330370-
AUGUST
JUNE
Figure 12. Root penetration with progression of the season
at location two for all cultivars in the high
irrigated regime in 1985 at the John Schutter
Farm, Manhattan, MT.
Ladak
65
is known to be a good forage producer
under
dryland conditions,
this may be the result of its deep root
penetration.
data would suggest that
These
deeper
rooted
cultivars would be better dryland producers because of their
ability to obtain deep stored soil moisture.
Plant Height
All
cultivars achieved minimum and maximum heights
the non and high irrigation regimes,
in
respectively. Ladak 65
43
achieved greater heights than the other cultivars under
all
irrigation regimes (Fig. 13, 14, 15, 16,). However, seasonal
ET patterns (Fig. I, 2, 3, 4) for all cultivars were similar
within
each irrigation treatment.
These data suggest
that
Ladak 65 was more efficient in converting water consumed
ET
into
stem
growth.
This physiological trait
may
in
have
potential use in promoting greater forage and seed yield.
N O N -IR R
IZZl LADAK 65
100 -
a
ra
VERNAL
APOLLO
THOR
MAY
JU N E
JULY
Figure 13. The effect of time on plant height in the nonirrigated
regime at location two
for
all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT.
44
120
110100-
L O W -IR R
EZl LADAK 65
□
VERNAL
C S APOLLO
90
E
u
X
O
LJ
THOR
-PR
8070-
/s;
60 -
','H
X
t—
Z
<
%
Af .
;1 :';S|
%
50-
■fk
40
30-
II I% I
%
20-
10zV
0
25
5
MAY
Cf / #
'A zS /,
KSi /Li
25
4
JUNE
24
Ef
=S1
/s/'' zS
Ms'A
4
JULY
Figure 14. The effect of time
on plant
height in the low
irrigated
regime
at
location
two
for a ] I
cultivars
in
1985 at the John
Schutter
Farm,
Manhattan, MT.
45
M E D IU M -IR R
IZZl
GD
ED
ED
LADAK 65
VERNAL
APOLLO
THOR
JUNE
Figure 15. The effect of time on
plant height in the medium
irrigated
regime
at
location
two
for
all
cultivars
in
1985 at the
John
Schutter
Farm,
Manhattan, MT.
46
H IG H -IR R
EZl LADAK 65
100E
a
VERNAL
C a APOLLO
THOR
80-
Figure 16. The effect of time on plant height in the high
irrigated
regime
at location two for
all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT.
Relationship for Internode Length to ET
All
between
65,
cultivars
had
a
positive
linear
relationship
increased ET on internode length (Table
Apollo,
4 ).
Ladak
and Thor exhibited a good relationship between
increased ET and internode length.
Vernal exhibited a poor
2
as indicated by its low R . Apollo and Thor
relationship
exhibited the greatest increase in internode length for each
centimeter
of
water consumed in
ET.
Increased
internode
47
length
of
Apollo
and Thor could be the
result
of
their
Flemish genetic background and lower fall dormancy level.
Table 4.
Regression analysis for the effect of increased ET
(cm) on internode length (cm) at both locations
for all cultivars in 1.985 at the John Schutter
Farm, Manhattan, MT.
Intercept
Cultivar
1.96
3.00
0.52
0.19
Ladak 65
Vernal
Apollo
Thor
Prob.
Slope
0.0008
0.04
0.0005
0.0002
0.06
0.05
0.12
0.12
R2
0.87
0.55
0.89
0.91
Biomass Yield
All
cultivars
exhibited
a
linear
between increased ET and total biomass.
have
reported
that
Yields increased 45,
Several researchers
alfalfa forage yields
increased ET (Gomez et al.,
46,
1985;
relationship
increased
Mayernak et al.,
with
1985).
40, and 42 % from the non to high
irrigation regime for Ladak 65 (Fig.
17), Vernal (Fig. 18),
Apollo (Fig. 19), and Thor (Fig. 20), respectively. Ladak 65
had
the
irrigation
20) .
greatest
average
biomass
yield
regime and Thor had the least
in
the
high
(Appendix,
Table
48
LADAK 65
A LOC I
D LOC 2
Y = 1.51 + 0.016X
R = 0 .8 3
ET (mm)
Figure 17. Relationship for
increased
evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high)
on
Ladak
65
biomass
yield
at
both
locations in 1985 at the John Schutter Farm,
Manhattan, MT.
49
VERNAL
A LOC I
D LOC 2
1.2 + 0.016X
ET (mm)
Figure 18. Relationship for
increased
evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high) on Vernal biomass yield at both locations
in 1985 at the John Schutter F a r m , Manhattan, MT.
50
A P O LLO
A LOC I
□ LOC 2
Y = 2.1 + 0.015X
ET
(m m )
Figure 19. Relationship
for
increased
evapotranspiration
(ET) at four irrigation levels (non, low, m e d i u m ,
high)
on Apollo biomass yield at both
locations
in 1985 at the John Schutter Farm, Manhattan, MT.
51
THOR
A LOC I
D
LOC 2
Y = 3 .3 + 0.013X
ET (mm)
Figure 20. Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high) on Thor biomass yield at both locations in
1985 at the John Schutter Farm, Manhattan, MT.
Relationship for ET to Stem Number per Plant
Cultivars varied in stem number plant-1 to increased ET
(Table
5).
between
stem
exhibited
ET.
Vernal
number
and Apollo had a negative
plant 1 and ET.
Ladak
relationship
65
no relationship between stem number
Genetic
influenced
variations.
by
background
and
physiological
environment
may be
responsible
and
Thor
plant-1
and
traits
as
for
these
52
Highest
regime
(Appendix,
plant *
These
seed
yields occurred in the
Table 21).
However,
high
irrigation
basal stem
number
decreased for Vernal and Apollo with increased
ET.
data suggest that stems for these cultivars increased
in size and branched with increased irrigation.
Grandfield (1945) and Cohen et al. (1972) reported
alfalfa
plants
nonstructual
under
stress
had
high
levels
of
carbohydrates. Willard et al. (1934)
that
total
reported
that high root and crown carbohydrate reserves produced more
stems.
These previous reports would explain the high number
of stems plant
Table
in the non-irrigated plots.
5. Regression analysis for the effect of increased ET
(cm) on stem number plant
at both locations for
all cultivars in 1985 at the John Schutter Farm,
Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
28.46
35.08
30.34
19.05
Slope
Prob.
-0.09
-0.26
-0.20
0.02
NS
0.0001
0.02
NS
R2
0.22
0.94
0.65
0.03
Relationship for Stem Number per Plant
and Internode Length to Biomass Yield
Cultivars
varied
in relationship
to
increased
stem
number per plant and biomass yield (Table 6). Vernal had the
best
fit
and
Ladak
decrease
with the greatest probability followed by
65.
in
The negative relationships
resulted
the number of stems plant-1 with a
Apollo
in
a
subsequent
increase in total biomass with increased ET (Figures 17, 18,
53
19,
20). Consequently, these data suggest that the stems in
the
high
possible
irrigation regime
greater
irrigated
may have been
larger
with
leaf area than stems in the low and
regimes.
Thor exhibited no relationship
a
non-
between
stem number plant-1 and biomass yield.
Table
6. Regression analysis for the effect of stem number
plant
on biomass yield (Mg ha 1) at
both
locations for all cultivars in 1985 at the John
Schutter Farm, Manhattan, MT.
Cultivar
Intercept
25.15
23.00
20.56
-I .65
Ladak 65
Vernal
Apollo
Thor
Slope
R2
Prob
-0.65
-0.62
-0.54
0.55
0.06
0.0002
0.02
NS
0.47
0.92
0.60
0.18
Internode length contributes to plant height and taller
plants
may
have greater biological
demonstrated
a
positive
linear
yield.
response
All
for
cultivars
increased
internode length on increased biomass (Table 7) .
Table
7. Regression analysis for the effect of increased
internode length (cm) on biomass yield (Mg ha )
at both locations for all cultivars in 1985 at the
John Schutter Farm, Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
-2.91
0.60
3.05
4.06
Slope
2.63
1.49
1.03
0.85
Irrigation or other cultural practice,
Prob.
0.003
0.10 ■
0.03
0.02
that result
increased internode length may increase biomass
R2
0.79
0.39
0.55
0.65
in
production.
54
Ladak
for,
65
had the greatest amount a
variability
accounted
followed by Thor, Apollo, and Vernal, respectively.
Total Seed Yield
Ladak 65 had a curvalinear response for increased ET on
seed yield (Fig.
and Thor (Fig.
seed yield.
Thor
21).
Vernal (Fig.
22), Apollo (Fig. 23),
24) had linear responses for increased ET to
Seed yield for Ladak 65,
increased 60,
69,
66,
Vernal,
Apollo,
and
and 64 % from the non to high
irrigated plots, respectively.
LADAK 65
1800-
A LOC I
□ L0C 2
SZ
1600-
Y = 1530 - 3.64X + 0 .0 0 6 X
1400-
1000 -
ET (mm)
Figure 21. Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high) on Ladak 65 seed yield at both locations in
1985 at the John Schutter Farm, Manhattan, MT.
55
Greatest
seed
yields
occurred
under
the
higher
irrigation
regimes. Plants in the higher irrigation regimes
maintained
their flowers longer and had a longer
duration.
These
results
are in agreement
with
flowering
those
of
Goldman and Dovrat (1980).
2000
VERNAL
1 8 00-
A LOC I
D LOC 2
1600-
Y = 5 9 8 + 1.86X
1200-
1000 -
ET (mm)
Figure 22. Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high) on Vernal seed yield at both locations in
1985 at the John Schutter Farm, Manhattan, MT.
Both irrigations in 1985 were applied before flowering.
Taylor et al.
(1959) and Goldman and Dovrat (1980) reported
that irrigation during flowering decreased seed yields.
56
Taylor et al.
were
obtained
Results
from
(1959) reported that optimum seed yields
when the soil was kept
this
continuously
experiment agreed with
Taylor
moist.
et
al.
(1959) .
2000
APOLLO
1800-
A LOC I
□ LOC 2
1600-
Y = 269 + 2.55X
1400-
1200 -
1000-
ET (mm)
Figure 23. Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high) on Apollo seed yield at both locations in
1985 at the John Schutter Farm, Manhattan, MT.
Many
soil
researchers agree that insufficient or
excessive
moisture is not condusive to high alfalfa seed
(Willis
and Bopp,
Tysdal,
1946; Taylor, 1959; Goldman and Dovrat, 1980). Seed
yield
1910;
Martin,
1915;
Hollowell,
yields
in this experiment would indicate that
optimum
1929;
soil
57
moisture
conditions occurred in the high irrigation regime.
However,
only
two
irrigations
occurring
before bloom.
were
Subsequently,
applied
the
with
soil
both
profile
contained sufficient moisture to mature the crop.
2000
THOR
1800-
A LOC I
D LOC 2
1600-
Y = 370 + 1.93X
R = 0 .8 4
1400-
1200 -
1000 -
ET (mm)
Figure 24. Relationship for increased evapotranspiration
(ET) at four irrigation levels (non, low, medium,
high) on Thor seed yield at both locations in
1985 at the John Schutter Farm, Manhattan, MT.
Relationship for Pods Per Stem to Seed Yield
Pod
some
number stem ^ is a good indicator of seed yield in
crops.
Thor
was the only cultivar that
exhibited
relationship between pods stem-1 and seed yield (Table 8).
a
58
Pod
yield
number
stem *
was not a good estimate
in this experiment.
variation
and
observation
for
seed
of
stem
This may be the result
the size of the pods on
the
stems.
Visual
at harvest indicated a large variation in
stem
and pod size. Larger pods had more seed pod-1. .
Table
8. Regression analysis for the effect of the pod
number stem
on.seed yield at both locations
for all cultivars in 1985 at the John Schutter
Farm, Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
1504
234
367
368
Slope
Prob.
-0.93
7.68
7.99
6.42
R2
NS
NS
NS
0.05
0.02
0.17
0.20
0.51
Relationship for Pod Number Per Stem to ET
Large variation among cultivars occurred for
ET
on
pod number per stem (Table 9).
exhibited
number
per
increase
Table
no
relationship
stem.
increased
Ladak 65 and
between increased
Vernal and Thor had
a
ET
Apollo
and
positive
pod
linear
in the number of pods per stem with increased
ET.
9. Regression analysis for the effect of increased ET
(cm) on pods stem
at both locations for all
cultivars in 1985 at the John Schutter Farm,
Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
244.59
121.45
105.52
43.19
Slope
-1.39
0.76
0.69
2.10
Prob. .
NS
0.08
NS
0.003
R2
0.16
0.43
0.22
0.80
59
Variation
differences
or
in pod number may be attributed to
cultivar
in their response to reproductive growth
possibly
differential
pollinator
habit
visitation
among
Pure live seed (PLS) yield is the percent total
viable
cultivars.
Pure Live Seed Yield
seed
multiplied by total seed yield and is an estimate of a
seed
crops quality and value.
Differences occurred between
increased ET and PLS and total seed yield for all cultivars.
All
cultivars had a good relationship between increased
and PLS (Table 10).
while
Vernal,
ET
Ladak 65 had a curvalinear relationship
Apollo,
and Thor had linear
relationships.
Relative to the other cultivars. Vernal yielded the most PLS
in
the
greatest
non
PLS
and
medium treatments while
yield
in the low and
high
Apollo
had
irrigated
the
plots
(Appendix, Table 22).
Table 10. Regression analysis for the effect of increased ET
on pure live seed (PLS) yield at both locations
for all cultivars in 19.85 at the John Schutter
Farm, Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
Slope
1331
-3.75*
0.006**
2.013
2.831
2.085
354
-50
155
Prob.
0.003
0.003
0.0001
0.001
* (X) ** (X2) Ladak 65 had a quadratic
for increased ET on PLS yield.
R2
0.90
0.79
0.96
0.84
response
60
As
values,
good
or
better relationship,
as indicated by
2
existed between increased ET on PLS (Table 10) than
for increased ET on total seed yield (Figures
24).
R
21,
22,
23,
High total seed yields were not necessarily indicative
of high levels of PLS in this experiment.
Biomass Effect On Seed Yield
Biomass Effect on Total Seed Yield. Good relationships
existed
between increased
Ladak 65 (Fig.
Apollo (Fig.
for
25),
28).
biomass and total seed yield for
Thor (Fig.
26), Vernal (Fig. 27), and
Ladak 65 demonstrated the best
response
increased biomass on total seed yield followed by Thor,
Vernal
and
Apollo.
production potential.
Larger plants may have a
higher
seed
61
2000-
LADAK 65
A LOC I
1800-
□ L0C 2
Y = IOB + 132X
1600-
MOO-
1200 -
1000 -
BIOMASS (Mg ha1)
Figure 25. Relationship for Ladak 65 biomass yield on total
seed yield
under four irrigation
levels
(non,
low,
medium, high) at both locations in 1985 at
the John Schutter F a r m , Manhattan, MT.
62
2000-
THOR
A LOC I
1800 -
□ L0C 2
Y = - 7 8 + 148x
1600 -
R = 0 .9 2
UOO-
1200 -
1000-
BIOMASS (Mg ha1)
Figure 26. Relationship for Thor biomass yield on total seed
yield
under
four
irrigation
levels (non, low,
medium high) at
both locations in 1985
at
the
John Schutter Farm, Manhattan, MT.
63
2000-
VERNAL
A LOC I
1 8 00-
D LOC 2
Y = 4 4 0 + 112X
1600-
R = 0 .8 5
1400-
1200 -
1000-
BIOMASS (Mg h a1)
Figure 27. Relationship for Vernal
seed yield under four
low,
medium,
high) at
the John Schutter Farm,
biomass
yield
on
total
irrigation
levels
(non,
both locations in 1985 at
Manhattan, MT.
64
APOLLO
2000 -
A LOC I
D LOC 2
1800-
Y = 245 + 132X
1600-
1 4 00-
1000-
BIOMASS (Mg hd1)
Figure 28. Relationship for Apollo biomass yield on total
seed
yield under four irrigation levels (non,
low, medium, high) at both locations in 1985 at
the John Schutter Farm, Manhattan, MT.
Biomass
cultivars
biomass
had
and
relationship
increased
Effect
a
PLS
on Pure Live
Seed
positive relationship
yield (Table
between
increased
11).
Yield
(PLS). All
between
increased
There
was
a
biomass to
PLS
than
biomass to total seed yield (Figures 25,
better
for
26, 27,
28). However, the increase was slight for Vernal and Apollo.
Results
sampling
from
this experiment would indicate
that
biomass
may have potential use as an indicator for alfalfa
PLS yields.
65
Table 11. Regression analysis for the effect of increased
biomass on pure live seed (PLS) yield for all
cultivars at both locations in 1985 at the John
Schutter Farm, Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
Slope
Prob.
-2.9
213.6
-87.0
-332.8
106.6
121.8
147.2
160 .I
0.0001
0.0004
0.003
0.0002
R2
0.95
0.89
0.78
0.92
Biomass Water Use Efficiency
Biomass
WUE was generally lower in the high irrigation
regime (Appendix,
Table 23). Water use efficiency (WUE) for
biomass (Table 12) varied among cultivars. Thor was the only
cultivar that demonstrated a relationship between
ET
and
biomass
WUE.
All cultivars had a
negative
indicating a reduction in WUE with increasing
Ladak
data
65,
Vernal,
increased
ET.
However,
and Apollo were non-significant.
agree with reports from Stewart and Hagan
slope
(1969)
These
who
indicated that WUE declined as ET increased in alfalfa.
Table 12. Regression analysis for the effect of increased ET
(cm) on biomass WUE for all cultivars at both
locations in 1985 at the John Schutter Farm,
Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
25.5
22.5
25.8
26.8
Slope
-0.012
-0.007
-0.012
-0.015
Prob.
NS
NS
NS
0.02
R2
0.29
0.26
0.34
0.63
66
Seed Yield Water Use Efficiency
All
cultivars
had a reduction in seed yield WUE
increased ET (Table 13).
with
Vernal, Apollo, and Thor exhibited
relationships between increased ET and seed yield WUE.
o
However, R values were low indicating that other factors in
addition
to ET
contributed to seed
yield
WUE.
Ladak
65
exhibited no relationship.
Table 13. Regression analysis for the effect of increased ET
(cm) on seed yield WUE for all cultivars at both
locations in 1985 at the John Schutter Farm,
Manhattan, MT.
Cultivar
Intercept
Ladak 65
Vernal
Apollo
Thor
Both
biomass
potential
for
Slope
3.81
4.49
3.70
3.57
and
seed
-0.002
-0.003
-0.001
-0.002
yield
use in irrigation
WUE
Prob.
. R2
NS
0.04
0.06
0.06
data
management.
0.36
0.54
0.47
0.48
may
have
Higher
seed
yields due to increased irrigation may not be economical
some
cases
due to increased cost of water application
in
and
decreased plant efficiency.
Seed Quality
Germination.
Seed quality is a critical factor in
the
production of alfalfa seed. Germination percent varied among
cultivars
Regression
within irrigation regimes (Appendix,
analyses
indicated
differences
Table
in
24).
the
67
relationship
for increased ET to germination percent
among
cultivars (Table 14).
Table 14. Regression analysis for the effect of increased ET
(cm) on percent germination for all cultivars at
both locations in 1985 at the John Schutter Farm,
Manhattan, MT.
Cultivar
Intercept
Ladak 65
Vernal
Apollo
Thor
Ladak
Slope
3.1
4.9
15.7
8.9
Prob.
0.19
0.12
-0.03
0.12
0.01
NS
NS
0.07
65 and Thor had a linear response
germination
to
R2
0.66
0.28
0.04
0.44
for increased
increased ET with respective
increases
of
0.19 and 0.12 % for each centimeter of ET. However, much of
the
variability was not accounted for with increased ET
on
germination percentage. No association existed for increased
ET and germination for Vernal and Apollo.
Hardseed.
(Appendix,
Percent
Table
24).
hardseed
varied
Ladak .65
and
among
cultivars
Apollo
had
good
relationships between ET and hard-seededness as indicated by
the probabilities and R 2 values,
no
relationship
(Table 15).
while Vernal and Thor
Ladak 65 hardseed
decreased
with increased ET while Apollo
increased
with increased ET.
decreased
0.14
,
centimeter of ET.
and
suspected
to
percentage
hardseed
content
Percent hardseed for Ladak 65
Apollo increased 0.20
%
for
each
Temperature directly affects the rate and
amount of water lost through ET.
is
had
effect
the
Additionally,
development
of
temperature
hardseed.
68
Controlled
environment
determine
if
studies
hardseed
among
should,
be. conducted
cultivars
is
to
due
to
environmental influence. genetic inheritance, or both.
Table 15. Regression analysis for the effect of increased ET
(cm) oh hardseed percentage for all cultiyars at
both locations in 1985 at the John Schutter Farm,
Manhattan, MT.
Cultivar
Intercept
Slope
Prob
67.7
72.4
48.5
64.6
-0.14
0.14
0.49
0.20
0.01
NS
0.001
NS
Ladak 65
Vernal
Apollo
Thor
Viable
Seed
(TVS).
Total
R2
0.70
0.37
0.88
0.30
viable
seed
indicative of the amount of seed capable of germination.
is
the
summation of germination percentage
Vernal (Fig.
linear
29),
and
is
It
hardseed.
Apollo (Fig. 30), and Thor (Fig. 31) had
responses for increased ET on TVS with
the
highest
percentage TVS occurring in the high irrigation regime.
Ladak 65 exhibited no relationship between increased ET
and
TVS with TVS ranging from 71 to 77 %
regimes.
to
94
among
irrigation
Average TVS ranged from 83 to 95, 76 to 93, and 80
%
(Appendix,
practices
for
Vernal,
Table
that
23).
Apollo,
and
Thor,
respectively
These data indicate that irrigation
increase seed yield may
also
benefit
production of high quality seed for some cultivars.
the
69
VERNAL
A LDC I
□ LDC 2
9= 4 4 0 + 112X
ET (mm)
Figure 29. Relationship for increased evapotranspiration
(ET) on total viable seed percent for Vernal at
four irrigation levels (non, low, medium, high)
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT.
Tysdal (1946) reported a higher incidence of shrivelled
seed
under
excessive
irrigation.
Seed
yield
experiment
would suggest that irrigation and soil
conditions
met
the optimum requirements for
yield and were not excessive.
seed
yield may also relate to optimum levels of
this
moisture
high
seed
quality.
in
alfalfa
This optimum level
high
for
seed
70
APOLLO
A LOC I
□ LOC 2
Y = 64.2 + 0.047X
ET (mm)
Figure 30. Relationship for increased evapotranspiration
(ET) on total viable seed percent for Apollo at
four irrigation levels (non, low, medium, high)
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT.
Industry
produced
experiment
personal
under
are
dryland
report highest quality
conditions.
seed
Results
in direct contrast with those
being
from
reported
this
by
industry. This could be the result of differences in harvest
and
seed
cleaning
procedures.
warranted in this area.
Additional
research
is
71
THOR
A LOC I
M .
90-
□ LOC 2
D
Y = 7 3 .0 + 0 .0 3 2 X
ET (mm)
Figure 31. Relationship for increased evapotranspiration
(ET) on total viable seed percent for Thor at
four irrigation levels (non, low, medium, high)
at both locations in 1985 at the John Schutter
Farm, Manhattan, MT.
Seed Weight. Seed with high test weights are associated
with
larger
and
more vigorous seed in
some
crops.
Seed
weight varied among cultivars. Increased ET had no effect on
seed
weight for Ladak 65 and Thor (Table
Apollo
16).
Vernal
and
exhibited an increase in seed weight of 4 mg cm 1 of
increased ET (Table 16).
Variations
result
of
both
among
cultivar
seed weights
differences in seed size
may
and/or
be
the
density.
72
Further investigations are warranted in this area.
No
trends between seed weight and other quality
were observed.
good
Seed weight in alfalfa
is not necessarily a
quality indicator due to variability among
Additional
tests
cultivars.
research is warranted before seed weight
should
be used as a seed quality test in alfalfa.
.Table 16. Regression analysis for the effect of increased ET
(cm) on seed weight (g 1000 seed ) for all
cultivars at both locations in 1985 at the John
Schutter Farm, Manhattan, MT.
Cultivar
Ladak 65
Vernal
Apollo
Thor
Intercept
Slope
1.658
1.569
1.632
1.711
0.001.
0.004
0.004
0.002
Prob.
NS
0.02
0.01
NS
R2
0.12
0.6
0.71
0.24
73
CHAPTER V
SUMMARY
Large
growth,
variability
yield,
and
existed among
cultivars
for
most
quality parameters measured. Many
of
these differences may have resulted from genetic differences
among cultivars.
resulting
in
cultivar.
Good
production
Additionally,
alfalfa is cross pollinated
a large diversity among individuals within
pollination
research.
High
is critical for
temperatures and
existed during the growing season in 1985.
were
alfalfa
low
a
seed
humidity
These conditions
conducive to extensive leafcutter bee
activity
which
resulted in good pollination and high seed yields.
No
yield
relationship
and
between fall dormancy level and
quality were observed.
However,
both
rate
maturity and root penetration exhibited a relationship
fall dormancy.
coincided
Cultivar height in
with
fall dormancy
seed
of
with
the non-irrigated regime
levels.
The
most
dormant
cultivar, Ladak 65, was tallest in all irrigation regimes.
Total ET increased with increased irrigation indicating
that
alfalfa
transpiration
has a low resistance to
when
sufficient
transpire large amounts of water.
water
biomass
is
loss
through
present
to
74
Seasonal
ET
was
similar among
cultivars
initiation of senescence which indicated that
traits
involved
until
the
physiological
in water conductance and movement did
not
differ among cultivars until the on-set of senescence.
Variations
in
stem
number
plant ^
irrigation regimes among cultivars.
existed
across
All cultivars exhibited
an increase in internode length with increased ET.
Total
biomass
increased
with increased
ET
cultivars. Ladak 65 produced the greatest amount
in
the high irrigation regime.
for
all
of biomass
Ladak 65 is predominantly a
dryland cultivar. However, it respond well to irrigation and
out
yields many cultivars in a
internode
one-cut
system.
Increased
length directly contributed to total biomass. The
stem number plant-1 decreased with increased biomass for all
cultivars except Thor.
Total seed yield among cultivars exhibited differential
relationships
to
increased
cultivars, Ladak
irrigated
65
ET.
Relative
produced the most
to
seed
in
the
other
the
non-
plots while Apollo produced the most seed in
the
high irrigated plots.
Pure
live
seed yields differed from total seed
for all cultivars at all irrigation regimes. Some
produced
large
amounts of total seed, but did
yield
cultivars
not.produce
high amounts of PLS.
_.
Pods
this
stem
experiment.
was not a good indicator of seed yield
in
Increased ET differentially affected pods
75
stem
— I
among
cultivars.
Vernal
and
Thor
pods
stem
— I
increased with increased ET.
Total
and PLS yields increased with increased biomass.
These data suggest that management
increased
biomass
practice directed toward
may increase seed
yield
under
similar
condition as existed in this experiment.
Biomass
all
WUE with increased ET was non-significant
cultivars
increased
ET
except Thor.
which
for
Seed yield WUE decreased
under high cost
of
with
irrigation
would
result in decreased economic returns at some point.
Germination
cultivars.
Total
and
percentages
viable seed increased with
except for Ladak 65.
most
hardseed
varied
among
increased
ET
High levels of irrigation produced the
seed and total viable seed.
Large
variation
existed
among cultivars in seed weight.
Much
stress
is
Greatest
of the literature indicates
that some degree
needed to force alfalfa to flower and set
yield
occurred
in
plots
receiving
of
seed.
the
most
irrigation. Apparently, irrigation and soil moisture content
in
1985 were near the optimum requirement for high
alfalfa
seed yields. Plant stress was not apparent in the medium and
high
irrigation
moisture
regimes
because
in the soil profile.
of
sufficient
Contrary to some
stored
literature
plant stress was not a contributing factor in flowering
seed
set in the medium and high irrigation
regimes.
and
These
results would suggest that alfalfa flowering and seed set is
76
not
necessarily controlled by plant stress.
Day length may
control flowering when moisture is not a limiting factor.
Several factors should be considered before high levels
of irrigation are recommended. Increased irrigation resulted
in
extremely
medium
Plants
lodged
in
the
and high irrigation treatments. Lodged plants often
contribute
levels
tall plants in 1985.
to reduced seed yields.
produced
the
greatest
While
high
amount of
irrigation
seed, they
also
delayed maturity. Late season rains or early snow fall could
result
in low quality and potential
seed
loss.
Flowering intensity was greatest in the high irrigation
regime.
However,
a
decreased
in
late
season
mean
temperatures may reduce leafcutter bee activity. Late season
pollination
seed
at
may result in a
harvest.
High
higher percentage of
irrigation in the
immature
spring
may
be
utilized as a tool to coincide peak flowering and leafcutter
bee activity.
The most important attribute of alfalfa is the ability
to
produce
large
Traditionally,
quantities of highly
alfalfa
palatable
breeding has placed major
forage.
emphasis
on the production of high forage yielding cultivars via pest
resistance and more rapid
seed
yield
and
regrowth potential. Consequently,
quality characteristics
have
little attention. Hopefully, alfalfa seed yield
research
will
be
considered
cultivars in the future.
when
developing
been
given
and quality
improved
77
LITERATURE CITED
■;
78
LITERATURE CITED
Accord, C . R . 1972. Alfalfa pasture pay good net returns. In
Proceedings
of twenty-third annual
Montana
Nutrition
Conference. Montana Agr. Exp. Sta. Research Report 16.
Alexander, M. 1961. Introductions to Soil Microbiology. John
Wiley and Sons. New York.
Alter; J . C . 1920. Alfalfa seed growing and the weather.
Utah Agr. Exp. Sta. Bull. 171.
Arnold, R . N., and D . Smeal. 1985. Water-use production,
functions
and
consumptive-use curves of
alfalfa
in
northwestern New Mexico. Abstracts. Western Soc. of Crop
Sci. and Soil Sci. joint meeting.
Blad, B . L., and N. J . Rosenberg. 1974. Evapotranspiration
in the East Central Great Plains. Agron. J . 66:248-252.
Blinn,
154.
P.
K.
1910. Alfalfa studies. Colo. Exp. Sta. Bull.
Bolton, J . L., B . P . Golpen, and H . Boenziger. 1972. World
distribution and historical developments.In Alfalfa Science
and Technology. Edited by C . H . Hansen. Chapter I. Agron.
Monograph 15. Am. Soc. of Agron.
Bauder, J . W., L . D . King, and G . L . Westesen. 1982.
Scheduling irrigation with evaporation pans. Cooperative
Extension Services. Montana State University, Bozeman, MT.
Bull. 1262.
Carlson, F. A. 1925. The effect of soil structure on the
character of alfalfa root systems. J. Am. Soc. Agron.
17:336-335.
Clampet,
G.
L. ,
Statistics.
USDA.
Washington D . C.
and
U.
E . Johnson. 1981. Agricultural
S. Government Printing Office,
Clampet,
G.
L. ,
Statistics.
USDA.
Washington D . C .
and
U.
E.
S.
Johnson. 1983. Agricultural
Government Printing Office,
Clement, W. M. Jr. 1962. Chromosome numbers and taxonomic
relationships in Medicaqo. Crop Sci. 2:25-28.
79
Cohen, Y., H . Bielorai, and A. Dovrat. 1972. Effect of
timing of irrigation on total nonstructural carbohydrate
level in roots and on seed yield of alfalfa. Crop Sci.
12:634-636.
Ditterline, R. L., C. S . Copper, L . E . Wiesner, J. R. Sims,
and V. R. Stewart. 1979. Growing alfalfa in Montana. Montana
Agr. Exp. Sta. Bull. 684.
Dobrenz, A. K., and M. A. Massengale.
1966. Change in
carbohydrates in alfalfa roots during the period of floral
initiation and seed development. Crop Sci. 6:604-607.
Dovrat, A., D . Levanon, and M. Waldman. 1969. Effect of
plant spacing on components of seed yield in alfalfa. Crop
Sci. 9:33-34.
Fuelleman, R . F. 1934. Water utilization and other factors
influencing the fruiting of alfalfa. Univ. of Wisconsin.
Thesis.
Gardner, W. R., and C . F . Ehlig. 1963. The influence of soil
water on transpiration by plants. J . Geophys. Res., 68:57195724.
Goldman, A., and A. Dovrat. 1980. Irrigation regime and
honey bee activity as related to seed yield in alfalfa.
Agron. J. 27:961-965.
Gomez, J. F., D . G . Lugg, and T . W. Sammis. 1985. Alfalfa
yield and quality at different evapotranspiration levels.
Abstracts. Western Soc. of Crop Sci. and Soil Sci. joint
meetings.
Grandfield, C . 0. 1945. Alfalfa seed production as affected
by organic reserves, air, temperature, humidity and soil
moisture. J . Agric. Res. 70:123-132.
Hanks, R . J., J . Keller, V. P . Rasmussen, and G . D . Wilson.
1976.
Line
source sprinkler for continuous
variable
irrigation-crop studies. Soil Sci. Soc. Am. J . 40(3):426429.
Hanks, R. J., D . V. Sisson, R. L . Hurst, and K. G . Hubbars.
1980.
Statistical analysis of results from irrigation
experiments using the line-source sprinkler system. Soil
Sci. Soc. of Am. 44(4):886-887.
Hendry, G . W. 1923.
Agron. 15:171-176.
Alfalfa in history.
J.
Am. Soc. of
80
Hobbs, G . A. 1973. Alfalfa leafcutter bees for pollinating
alfalfa in western Canada. Agriculture Canada. Publication
1495.
Hollowell, E . A. 1929. Influence of atmospheric and soil
moisture upon seed setting in clover. J . Agr. Res. 39:229247.
Jabbar, A. S ;, D . G . Lugg, T . W. Sammis, and L . W. Gay.
1984. A field study of plant resistance to water flow in
alfalfa. Agron. J. 76:765-769.
Jensen. E . H., C . N. Mahannah, W. W. Miller, and J. J . Read.
1985. Effect of four irrigation regimes on quality of
alfalfa hay: Abstracts. Western Soc. of Crop Sci. And Soil
Sci. joint meetings.
Kiesselbachf T . A., A. Anderson, and J . C . Russel. 1934.
Subsoil moisture and crop production. J . Am. Soc. Agron.
26:422-442.
Martin, J . N. 1915. Relation of moisture to seed production
in alfalfa. Iowa Agric Exp. Bull. 23
Martin,
J . H., W. H. Leonard, and D . L. Stamp. 1976.
Principles of Field Crop Production. Macmillan Publishing
Co., Inc. New York.
(
Mayernak, J . W., C . G . Currier, and B . A. Melton. 1985.
Irrigation management for maximizing alfalfa, forage yield
with deficient levels of water. Abstracts. Western Soc. of
Crop Sci. and Soil Sci. joint meetings.
Montana Farmers Institute First Annual Report. 1902.
Naylor,
C . H., D . J . Undersander, and N . A. Cole. 1985.
Effect of water stress on alfalfa composition. Abstracts.
Western Soc. of Crop Sci. and Soil Sci. joint meetings.
Ogata,
G., L . A. Richards, and W. R. Gardner.
1960.
Transpiration of alfalfa determined from soil water content
changes. Soil Science,89:179-182.
Pandey, R. K., W. A. T . Herrera, and J . W. Pendleton. 1984,
Drought response of grain legumes under an irrigation
gradient: I . Yield and components. Agron. J . 76:549-553.
Peck, N. H., M. T . Vittern, and R. D . Miller. 1958.
Evapotranspiration rates of alfalfa and vegetable crops.
Agron. J . 50:109-112.
81
Pratt, L . H .,
and C . R . Lies. 1981 . Montana Agriculture I
Statistics. Vol. 18.
and C .
Pratt, L . J.
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Rahman, A . E . 1973.
Phyton. 15:67-86.
R . Lies. 1984 . Montana Agricultural
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Richards, L . A. 1969. Diagnosis and Improvement of Saline
and Alkali Soils. USDA, Agriculture Handbook No. 60.
Rosenberg,
N.
J.
1969.
Seasonal
patterns
in
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Plains. Agron J . 6:879-886.
Rosenberg,
N.
J.,
and
B.
Shashi.
1978.
Extreme
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S . B . Idso, and D .G .
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Smoliak, S., and M . Bjorge. 1981. Alberta Forage Manual.
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82
Tysdal, H . M . 1946. Influence of tripping, soil moisture,
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Landbouwk. Onderz. No. 64-6:88.
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Yamada, H., D . W. Henderson, R. J . Miller, and R. M. Hoover.
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Irrigation
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APPENDIX
84
Table 17. Combined total irrigation amounts (cm) for all
irrigation regimes both sides of the pipe in 1985
at the John Schutter Farm, Manhattan, MT.
Irr. Treatment
NON
0
LOW
7.36
MEDIUM
HIGH
HIGH
MEDIUM
LOW
18.95
31.4
30.6
21.66
10.99
NON
1.12
* Additionally, 14.0 cm of precipitation accummulated during
the growing season.
Table 18. Differences in the amount of water used in ET (cm)
and that received through
irrigation
and
precipitation at both locations for all cultivars
in 1985 at the John Schutter Farm, Manhattan, MT.
----------------- Cultivar ---------------Irr. Regime
Ladak 65
Vernal
Apollo
Thor
Location I.
Non- Irr.
Low
Medium
High
11.8
18.7
19.4
19.2
12.8
18.1
17.7
18.4
15.1
21 .I
18.6
15.6
14.0
21.3
17.9
18.2
Location 2.
Non-Irr.
Low
Medium
High
21.2
9.6
23.0
17.4
19.3
15.8
18.3
19.3
18.8
17.3
17.3
18.7
18.4
14.3
16.5
22.6
Table 19. Daily environmental data in 1985
Schutter Farm, Manhattan MT.
Date
4/25
4/26
4/27
4/28
4/29
4/30
Precip
(mm)
0.0
0.0
0.0
0.0
0.0
0.0
TEMPERATURE
High Low Mean
-- C----8
-I
4
14
8
11
22
7
14
26
8
17
18
4
11
22
4
13
for
the
HUMIDITY
High
Low
---- %— —
62
23
62
18
28
16
39
14
66
30
59
19
John
Evap
(mm)
—
—
—
—
—
—
85
Table 19.
O
O
April
totals
(c o n ti n ue d)
----------- means
18
5
12
53
20
—
18
19
12
6
8
14
17
14
15
8
3
4
8
13
13
10
9
13
12
14
16
17
17
17
14
13
13
12
12
6
13
means
12
65
42
66
66
52
48
50
64
65
66
67
58
52
64
50
50
64
64
62
66
67
67
66
68
70
74
76
74
70
66
68
14
18
32
16
14
20
16
14
22
40
38
20
14
17
23
28
31
16
17
26
19
20
23
22
39
50
37
31
31
42
21
10.0
6.0
4.0
9.5
7.5
5.0
9.5
12.0
9.0
3.0
I .0
6.0
4.0
6.0
10.0
8.5
8.0
8.0
7.0
4.5
5.5
7.0
8.5
5.0
3.0
0.0
4.0
2.0
5.0
6.0
9.0
63
25
193.5
10
10
13
14
15
19
19
14
14
12
12
19
16
70
70
72
74
74
73
50
62
58
50
68
68
68
47
46
34
49
36
28
20
23
20
20
26
17
26
0.0
2.0
5.5
1.0
1.5
6.5
5.0
10.0
13.0
7.0
7.5
7.0
6.0
5/1
5/2
5/3
5/4
5/5
5/6
5/7
5/8
5/9
5/10
5/11
5/12
5/13
5/14
5/15
5/16
5/17
5/18
5/19
5/20
5/21
5/22
5/23
5/24
5/25
5/26
5/27
5/28
5/29
5/30
5/31
May
totals
0.0
0.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
3.0
10.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
14.0
18.0
20.0
0.0
0.0
4.0
0.0
0.0
25
26
23
13
15
21
27
24
22
13
9
9
17
21
21
18
17
23
24
23
26
26
27
27
22
16
19
19
20
11
20
10
11
0
-I
0
7
7
4
7
3
-4
-I
-I
4
4
I
I
3
4
6
6
8
7
7
6
9
8
4
4
I
5
71.0
20
4
6/1
6/2
6/3
6/4
6/5
6/6
6/7
6/8
6/9
6/10
6/11
6/12
6/13
12.0
0.0
0.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
13
13
18
17
21
24
29
21
21
20
19
27
24
7
7
7
10
9
14
9
6
7
4
5
10
8
86
Table 19.
6/14
6/15
6/16
6/17
6/18
6/19
6/20
6/21
6/22
6/23
6/24
6/25
6/26
6/27
6/28
6/29
6/30
June
totals
7/1
7/2
7/3
7/4
7/5
7/6
7/7
7/8
7/9
7/10
7/11
7/12
7/13
7/14
7/15
7/16
7/17
7/18
7/19
7/20
7/21
7/22
7/23
7/24
7/25
7/26
7/27
7/28
7/29
7/30
(con ti nu e d)
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4.0
0.0
0.0
0.0
0.0
T
0.0
17
0.0
0.0
0.0
0.0
0.0
0.0
2.0
0.0
0.0
0.0
0.0
1.0
0.0
0.0
0.0
0.0
I .5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
3.5
3.0
23
27
24
23
24
32
29
24
28
30
9
12
19
26
27
28
30
8
8
3
6
8
10
6
7
9
4
6
I
2
9
11
8
9
23
8
32
29
33
33
35
33
31
26
32
32
28
24
28
26
30
28
23
26
29
30
32
32
27
28
29
32
31
28
16
19
9
11
10
11
13
16
11
10
13
17
12
9
9
11
11
10
10
10
10
12
11
16
9
8
9
14
11
12
8
9
16
18
14
15
16
21
18
16
19
17
7
7
10
18
19
18
19
means
15
68
68
55
50
68
64
66
68
66
69
72
66
68
70
64
68
67
31
22
24
27
23
17
20
26
16
16
48
42
26
24
30
30
19
4.5
6.5
7.5
10.0
7.0
11.0
12.0
6.0
11.0
7.0
0.5
3.0
4.0
7.0
4.0
3.0
6.0
66
28
182.0
20
20
21
22
24
25
21
18
22
25
20
17
19
19
21
19
17
18
20
21
22
24
18
18
19
23
21
20
12
14
67
66
74
72
70
68
74
74
71
70
80
74
73
70
69
78
80
82
78
77
76
76
74
79
75
76
68
59
80
80
22
34
22
28
18
27
36
31
28
32
42
50
20
13
31
38
48
40
30
25
20
26
43
28
30
26
27
36
80
58
5.0
9.0
9.5
4.5
8.0
9.0
4.5
5.0
5.0
5.0
2.0
3.0
5.0
5.0
6.0
3.5
I .5
2.0
4.0
6.0
9.5
7.0
3.0
8.0
4.5
10.0
6.0
5.5
0.0
2.0
87
Table 19.
(con ti nu e d)
0.0
24
10
17
80
40
3.5
11.0
29
11
20
74
33
162.0
0.0
0.0
9.5
3.0
I .5
0.0
0.0
0.0
0.0
10.5
0.0
2
0.0
0.0
0.0
1.0
0.0
0.0
0.0
12.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0
0.0
0.0
0.0
32
21
23
29
22
27
32
20
23
21
13
16
16
16
21
26
16
23
28
25
26
19
21
23
28
31
28
27
27
28
29
12
9
8
11
8
9
12
6
4
7
7
6
3
3
8
6
I
7
8
6
8
8
3
6
8
11
11
9
9
9
12
22
15
15
20
15
18
22
13
14
14
10
11
9
9
14
16
8
15
18
16
17
13
12
14
18
21
20
18
18
19
20
79
78
80
79
79
81
78
71
72
72
75
76
80
77
75
75
74
75
76
77
76
74
76
74
75
72
76
80
76
56
49
17
45
43
22
48
30
20
28
22
31
62
43
38
32
21
44
27
24
30
23
40
27
27
22
26
31
36
29
24
17
35
8.0
3.5
0.0
2.0
1.0
4.5
4.0
7.0
5.0
0.0
3.0
1.5
3.0
2.5
2.5
2.0
6.0
8.0
5.0
3.0
6.0
5.0
6.0
6.0
7.0
8.0
4.0
5.0
1.0
5.0
7.0
40.5
24
8
16
75
31
131.5
0.0
9/1
0.0
9/2
.5
9/3
9/4
0.0
0.0
9/5
0.0
9/6
0.0
9/7
9/8
0.0
0.0
9/9
0.0
9/10
Septemb er
totals
5.0
31
19
14
17
22
23
25
23
7
15
10
3
9
7
8
12
6
3
4
7
74
78
78
76
76
75
86
84
82
82
44
50
29
34
28
38
84
62
69
55
5.0
3.0
2.0
3.0
6.0
0.0
—
—
79
49
7/31
July
totals
8/1
8/2
8/3
8/4
8/5
8/6
8/7
8/8
8/9
8/10
8/11
8/12
8/13
8/14
8/15
8/16
8/17
8/18
8/19
8/20
8/21
8/22
8/23
8/24
8/25
8/26
8/27
8/28
8/29
8/30
8/31
August
totals
20
21
11
12
12
15
18
16
13
6
11
-- means-14
7
—
19.0
88
Table 19.
(con ti nu e d)
Growing
season
totals 140.0
—
22
5
15
63
31
688 . 5
Represents data not available.
Table 20. Biomass yield (Mg ha
for all cultivars at both
locations in 1985 at the John Schutter Farm,
Manhattan, MT.
U L U . Li - L V a r
Irr. Regime
Ladak 65
Vernal
Apollo
Thor
Location I.
Non-Irr.
Low
Medium
High
6.71
7.44
8.12
12.54
5.80
7.57
10.62
10.08
7.41
7.67
10.04
10.16
6.51
9.53
10.33
10.96
Location 2.
Non-Irr.
Low
Medium
High
7.25
8.42
10.76
13.05
6.39
7.63
10.51
12.60
6.75
9.16
9.71
13.54
6.28
9.26
9.65
11.30
Table 21. Total seed yield (kg ha 1) for all cultivars at
both locations in 1985 at the John Schutter Farm,
Manhattan, MT.
v LU . l J V a r
Irr . Regime
Ladak 65
Vernal
Apollo
Thor
Location I .
Non-Irr.
Low
Medium
High
984
993
I ,286
1,706
1,109
1,357
1,625
1,590
928
1,411
1,533
1,730
878
1,366
1,356
1,699
Location 2.
Non-Irr.
Low
Medium
High
1,160
1,139
1,544
1,891
957
1,399
1,764
1,730
1,110
1,459
1,688
1,904
899
1,243
1,257
1,581
89
Table 22. Pure live seed (PLS) yield (kg ha 1) for all
cultivars at both locations in 1985 at the John
Schutter Farm, Manhattan, MT.
---------------- Cultivar -------------Irr. Regime
Ladak 65
Location I.
Non-Irr.
Low
Medium
High
728
715
926
1,297
Location 2.
Non-Irr.
Low
Medium
High
835
843
1,096
1,456
Vernal
921
1,194
1,495
1,447
814
1,259
1,605
1,644
Apollo
Thor
724
1,199
1,378
1,609
710
1,202
1,220
1,597
844
I ,269
1,485
1,752
719
1,131
1,106
1,470
Table 23. Biomass WUE at four irrigation regimes for all
cultivars at both locations in 1985 at the
John Schutter Farm, Manhattan, MT.
Irr. Regime
Ladak 65
Vernal
Location I.
Non-Irr.
Low
Medium
High
26
19
15
19
22
19
21
16
25
18
20
17
23
22
20
17
Location 2.
Non-Irr.
Low
Medium
High
20
20
19
21
19
19
19
20
20
22
18
21
19
23
18
17
Apollo
Thor
90
Table 24. Percent germination, hardseed, and total viable
seed at both locations for all cultivars in 1985
at the John Schutter Farm, Manhattan, MT.
Germ.
Hard Seed
- % -
Location I.
Ladak 65
Non-Irr.
Low
Medium
High
Vernal
Non-Irr.
Low
Medium
High
Apollo
Non-Irr.
Low
Medium
High
Thor
Non-Irr.
Low
Medium
High
Location 2.
Ladak 65
Non-Irr.
Low
Medium
High
Vernal
Non-Irr.
Low
Medium
High
Apollo
Non-Irr.
Low
Medium
High
Thor
Non-Irr.
Low
Medium
High
Total Viable
•
9
12
13
16
65
60
59
60
74
72
72
76
5
10
13
9
78
78
79
82
83
88
92
91
16
15
17
12
62
70
73
81
78
85
90
93
14
11
16
15
67
79
74
79
81
88
90
94
8
12
11
18
64
62
60
59
72
74
71
77
13
9
11
15
72
81
80
80
85
90
81
95
13
14
14
15
63
73
74
77
76
87
88
92
12
13
18
17
68
78
70
76
80
91
88
93
MONTANA STATE U NIVERSITY LIBRARIES
stks N378.H529
Effect of moisture stress on alfalfa see
RL
3 1762 00513959 5
2