Modelling for the
Soil Thematic Strategy:
Assessing Erosion
Control Measures
Erwin Schmid
BOKU / IIASA
workshop at JRC in Ispra, Italy
11th - 12th April 2005
Outline:

6 Fields from the Kocin Farm (SK)

Soil and Crop Management Information

APEX model

List of Alternative Management Practices to
Control Water Erosion

Preliminary Model Results

Discussion
6 Fields from the
Kocin Farm (SK)
Ø rainfall/yr: 540 mm
elevation: 251 m
Field 16527:
size: 50.4 ha
Ø slope: 6.35 %
Field 16528:
size: 121.7 ha
Ø slope: 2.78 %
Field 16529:
size: 30.2 ha
Ø slope: 4.48 %
Field 16553:
size: 41.1 ha
Ø slope: 2.11 %
Field 16555:
size: 78.5 ha
Ø slope: 3.54 %
Field 16556:
size: 22.9 ha
Ø slope: 2.57 %
Soil Properties from Field 16527
s o il la y e r in m
s a n d in %
s ilt in %
c la y in %
b u lk d e n s ity in t/m ³
F ie ld c a p a c ity in m /m
W iltin g P o in t in m /m
o rg C in %
pH
S a tu ra te d C o n d u c tiv ity in m m /h
V o lu m e o f S to n e s in %
S u m o f b a s e s in c m o l/k g
C a tio n e x c h a n g e c a p a c itiy in c m o l/k g
Top
0 .3
8 .0
5 9 .0
3 3 .0
1 .2 7
0 .4 4 3
0 .3 3 7
0 .8 1
6 .7 0
1 .1 5 5
2 .0
1 9 .1 0
1 9 .2 0
Sub1
0 .8
1 0 .4
5 7 .3
3 2 .3
1 .2 8
0 .4 3 3
0 .3 3 1
0 .2 4
6 .2 4
1 .4 3 2
2 .0
2 0 .0 2
2 0 .3 9
Sub2
1 .2
2 3 .8
5 8 .4
1 7 .8
1 .3 9
0 .3 3 7
0 .2 0 2
0 .2 3
7 .3 0
6 .1 4 7
2 .0
1 6 .1 6
1 5 .9 3
Dominant Crop Rotations
Fields
CR1
CR2
CR3
CSIL
ALFA
ALFA
ALFA
WWHT
SBAR
CORN
SBAR
WWHT
SGBT
WWHT
CSIL
SBAR
WWHT
WRAP
WWHT
16555
16553
16528
16529
16556
16527
Crop Management
WWHT
CSIL
ALFA
SBAR
CORN
SGBT
WRAP
Crop Yields in t/ha
mean
std
5.2
1.0
33.7
6.8
6.2
1.4
4.8
1.0
5.0
0.9
52.1
8.3
2.6
0.8
Commercial Fertilizer in kg/ha
N
P2O5
K2O
107
35
30
145
9
17
38
10
5
32
18
19
152
43
63
96
0
0
160
84
50
Legend:
WWHT
CSIL
ALFA
SBAR
Winter Wheat
Corn Silage
Alfalfa
Spring Braley
CORN
SGBT
WRAP
Corn Grain
Sugarbeet
Winter Rape
Manure in t/ha
5% TS
30
40
Agricultural Policy
Environmental eXtender model
optional 7 Water Erosion equations
1. MUST theoretical
2. AOF Onstad-Foster
3. USLE Universial Soil Loss
Equation
4. MUSS Small Watershed MUSLE
5. MUSL Modified USLE
6. MUSI MUSLE with input
parameters
7. RUSLE USLE for steep slopes
>20% i.e.
Management i.e.:
- Buffer Strips
- Grassed Waterways
- Terraces
Evaporation and Transpiration
Rain,
Snow,
Chemicals
APEX
Subsurface
Flow
Surface
Flow
Below Root
Zone
on a daily time step
#
SOILS
OUTLET
LAND USE
#
#
#
DEM
#
#
#
SUB-BASINS
#
APEX
Model
Precipitation in mm
1600
1200
800
400
0
1
8
15
22
29
36
Years
WEATHER
43
50
MANAGEMENT
List of Alternative Management
Practices to Control Water Erosion
1 conventional tillage (i.e.
moldboard plough)
- reference situation
2 contouring
3 reduced tillage (i.e.
shallow disk plough)
4 minimum tillage (except
for root crops, e.g. sugar
beets)
5 winter cover crops
List of Alternative Management
Practices to Control Water Erosion
6 grassed waterways (10% of
field; 50m width)
7 buffer strips (2% of field;
10m width)
8 terraces (i.e. permanent
crops, e.g., vineyards)
9 comb. of management
measures (1);
e.g., contouring, disk
plough & grassed waterway
10 comb. of management
measures (2)
Some Preliminary Modelling
Results for Field # 16527
700
500
in mm
Water
Balance
600
400
300
200
100
conventional tillage
0
1
3
5
precipitation
precipitation: 560 mm
(450 - 680 mm)
runoff
subsurface flow
percolation
100
80
in mm
subsurface flow: <1 mm
9
years
10 year averages:
runoff: 36 mm
(0 - 95 mm)
7
60
40
20
Months
precipitation
runoff
subsurface flow
percolation
DE
C
V
NO
CT
O
SE
P
G
AU
JU
L
JU
N
AY
M
AP
R
AR
M
FE
B
0
JA
N
percolation: 17 mm
(0 - 118 mm)
60
40
in t/ha
Sediment
Transport
50
30
20
10
conventional tillage
0
1
2
3
4
5
10 year average
using MUST:
6
7
8
9
10
Years
5
4
3
2
1
Months
DE
C
V
NO
CT
O
SE
P
G
AU
JU
L
JU
N
AY
M
AP
R
AR
M
FE
B
0
JA
N
in t/ha
sediment yield:
11.4 t/ha
(0 - 54 t/ha)
Carbon in Soil Profile
conventional tillage
62
in t/ha
60
58
56
54
1
2
3
4
5
6
Years
7
8
9
10
30
24
in kg/ha
Nitrogen
Transport
18
12
6
0
conventional tillage
1
2
3
4
5
6
7
8
9
10
Years
Nitrogen in kg/ha/y
sediment
1
sediment
runoff
Months
subsurface flow
DE
C
V
NO
CT
O
SE
P
G
AU
JU
L
JU
N
AY
M
AP
R
AR
0
M
percolation: 1.0 (0 - 8.0)
percolation
2
FE
B
subsurface flow: <0.1
subsurface flow
3
JA
N
runoff: 0.9 (0 - 5.8)
in kg/ha
sediment: 8.0 (0 - 28.5)
runoff
percolation
Crop Yields
conventional tillage
40
35
in t/ha
30
25
20
15
10
5
0
CSIL
SBAR
WWHT
Crops
APEX
OBS
WRAP
Impact Assessment of
Alternative Management
Practices for Field # 16527
Sediment Transport relative to
Conventional Tillage (1)
measure combination (9)
buffer (7)
grassed waterway (6)
cover crops (5)
minimum till (4)
reduced till (3)
contouring (2)
-100
-80
-60
-40
change in %
Field
Outlet
-20
0
Nitrogen in Runoff relative to
Conventional Tillage (1)
measure combination (9)
buffer (7)
grassed waterway (6)
cover crops (5)
minimum till (4)
reduced till (3)
contouring (2)
-100
-80
-60
-40
change in %
Field
Outlet
-20
0
Change of org. Carbon in Soil
Profile after 10 years of simulation
measure combination (9)
buffer (7)
grassed waterway (6)
cover crops (5)
minimum till (4)
reduced till (3)
contouring (2)
conventional (1)
-10
-5
0
5
change over 10 years in %
Field
Filter Area
10
15
Total Crop Production relative to
Conventional Tillage (1)
m e a s u re c o m b in a tio n (9 )
b u ffe r (7 )
g ra s s e d wa te rwa y (6 )
c o v e r c ro p s (5 )
m in im u m till (4 )
re d u c e d till (3 )
c o n to u rin g (2 )
-2 0
-1 5
-1 0
-5
0
5
c h a n g e in %
Note: Total production is the sum of dry matter yields of all crops in the crop
rotation times field area. Reduced field area in (6), (7), and (9) due to
waterways (-10%) and buffer strips (-2%).
Impact Assessment of
Alternative Management
Practices for all 6 Fields
Model Output Presentation with
Output Response Functions
Regression Model (OLS) using Dummy Variables
Y     2 M 2  ,...,  10 M10  
where M2,..., M10 are alternative management practices
that are represented by dummy variables (0,1)
Average Sediment Yields (t/ha)
Variable

2
3
4
5
6
7
9
Parameter
Estimate
4.14117
-1.75083
-2.43033
-2.94917
-1.31683
-1.86117
-1.66233
-3.46617
in %
100
-42.3
-58.7
-71.2
-31.8
-44.9
-40.1
-83.7
t - probability
< .0001
0.0366
0.0038
0.0005
0.1155
0.0263
0.0471
< .0001
Average org. Carbon
in Soil Profile (t/ha)
Variable

2
3
4
5
6
7
9
Field
Parameter
Estimate
70.48318
0.05286
3.78598
in %
100
+0.1
+5.4
t - probability
< .0001
0.9844
0.2039
4.75454
1.54817
+6.7
+2.2
0.1108
0.6031
-0.03227
-0.03156
-0.1
-0.1
3.95125
+5.6
Filter Area
Parameter
Estimate
in %
t - probability
0.9914
0.9915
12.84499
12.83685
+18.2
+18.2
< .0001
< .0001
0.1849
12.82589
+18.2
< .0001
Average Crop Yields (t/ha)
Variable

2
3
4
5
6
7
9
Parameter
Estimate
6.71183
-0.01683
-0.23817
-0.32600
-0.17683
-0.73193
-0.20039
-0.92123
in %
100
-0.3
-3.5
-4.9
-2.6
-10.9
-3.0
-13.7
t - probability
< .0001
0.9745
0.6509
0.5357
0.7369
0.1647
0.7034
0.0805
Note: Average dry matter yields per hectare. Reduced field areas in (6), (7),
and (9) due to waterways (-10%) and buffer strips (-2%).
Discussion







selection of representative plots across EU25 (project by
end of July)
list of alternative management practices
time length of simulation (short, medium, long-run
impacts)
crucial input information (field size, slopes, crop
management i.e., fertilization, irrigation, tillage, etc.)
grassed waterway and buffer strip design
environmental and economic impacts
model output presentation: surface response functions