2019 SWCS International Annual Conference July 28-31, 2019 Pittsburgh, Pennsylvania

1. Development of management zones
for cropping systems in the Lake
Winnipeg basin to improve N and P
application and crop productivity,
and to reduce environmental
impacts
M. Khakbazan, J. Huang, P. Michiels SWCS Meeting
2019, Pittsburgh, PA

2. Study Issue
• Declining water quality and eutrophication of Lake
Winnipeg is a major concern.
• The majority of land in the Lake Winnipeg basin is
used for agriculture.
• Delineating agricultural land into management
zones and managing each according to its needs and
specifications has considerable potential to increase
crop yield and N and P use efficiency, thereby
reducing environmental impacts.

3. Agro-climate zones in Manitoba. Climate in the Uplands area (SW) tends to
have lower rainfall and greater evapotranspiration than the lowlands and gray
wooded zones (John Heard and Rigas Karamanos, 2009. 2009 Proceedings.
https://umanitoba.ca/faculties/afs/agronomists_conf/1437.html)
Previous studies

4. Agro-climatic environment Soil Texture/Drainage
Moist Any texture, poorly drained, Grey wooded soils
Dry
Light or other textured, moderately to poorly drained, grey wooded
soils
Arid Light textured, well drained soils
Table. Agro-climatic environment categories based on agro- climatic zones
and soil characteristics (John Heard and Rigas Karamanos, 2009. 2009
Proceedings.
https://umanitoba.ca/faculties/afs/agronomists_conf/1437.html)
Previous studies

5. CWRS wheat response to N; 147 sites in three agro-climatic environments (John
Heard and Rigas Karamanos, 2009. 2009 Proceedings.
https://umanitoba.ca/faculties/afs/agronomists_conf/1437.html)

6. Screen shot of return $/ac to N for wheat in a dry agro-climatic environment with crop price as a
variable (John Heard and Rigas Karamanos, 2009. 2009 Proceedings.
https://umanitoba.ca/faculties/afs/agronomists_conf/1437.html)
Go to Total Net
Return Below
Expected CWRS Wheat Price
$3.50 $4.00 $4.50 $5.00 $5.50 $6.00 $6.50
Yield
Average Increase Net Return ($/ac.)**
N Rate yield from 0 lb. N* CWRS Wheat:N Price Ratio
(lb./acre) (bu./ac.) (bu./ac.) 7.1 8.1 9.1 10.1 11.1 12.1 13.2
30 34.5 9.0 $16.6 $21.0 $25.5 $30.0 $34.5 $39.0 $43.5
40 37.0 11.4 $20.3 $26.0 $31.7 $37.4 $43.1 $48.9 $54.6
50 39.2 13.6 $23.1 $29.9 $36.7 $43.5 $50.3 $57.2 $64.0
60 41.1 15.6 $24.9 $32.7 $40.5 $48.3 $56.1 $63.9 $71.7
70 42.8 17.3 $25.9 $34.5 $43.2 $51.8 $60.5 $69.1 $77.8
80 44.2 18.7 $26.0 $35.3 $44.7 $54.0 $63.4 $72.7 $82.1
90 45.4 19.9 $25.1 $35.1 $45.0 $54.9 $64.9 $74.8 $84.8
100 46.3 20.8 $23.4 $33.8 $44.1 $54.5 $64.9 $75.3 $85.7
110 47.0 21.4 $20.7 $31.4 $42.1 $52.8 $63.6 $74.3 $85.0
*Yield responses are averages from 67-site years
Current N rate from your soil test report or common practice
**Net Return = (wheat price x yield increase) - (N price x N rate)
Net return in blue represents maximum ± $0.50 for the CWRS Wheat:N Price Ratio range in this table and in Orange
within $1.00 of maximum

7. Screen shot of return $/ac to N for wheat in a dry agro-climatic environment with
urea fertilizer cost as a variable (John Heard and Rigas Karamanos, 2009. 2009
Proceedings. https://umanitoba.ca/faculties/afs/agronomists_conf/1437.html)
Expected N Fertilizer Price
$200 $300 $400 $500 $600 $700 $800
Yield
Increase Net Return ($/ac.)**
N Rate from 0 lb. N* CWRS Wheat:N Price Ratio
(lb./acre) (bu./ac.) 25.3 16.9 12.7 10.1 8.4 7.2 6.3
30 9.0 $38.9 $35.9 $33.0 $30.0 $27.0 $24.1 $21.1
40 11.4 $49.3 $45.3 $41.4 $37.4 $33.5 $29.5 $25.6
50 13.6 $58.3 $53.4 $48.5 $43.5 $38.6 $33.6 $28.7
60 15.6 $66.1 $60.2 $54.3 $48.3 $42.4 $36.5 $30.5
70 17.3 $72.6 $65.7 $58.7 $51.8 $44.9 $38.0 $31.1
80 18.7 $77.7 $69.8 $61.9 $54.0 $46.1 $38.2 $30.3
90 19.9 $81.6 $72.7 $63.8 $54.9 $46.0 $37.2 $28.3
100 20.8 $84.2 $74.3 $64.4 $54.5 $44.7 $34.8 $24.9
110 21.4 $85.5 $74.6 $63.7 $52.8 $42.0 $31.1 $20.2
*Yield responses are averages from 67-site years
Current N rate from your soil test report or common practice
**Net Return = (wheat price x yield increase) - (N price x N rate)
Net return in blue represents maximum ± $0.50 for the CWRS Wheat:N Price Ratio range in this table and in Orange
within $1.00 of maximum

8. • Evaluate management zones based on
climate and soil variability for wheat,
canola, and soybean; identify yield
efficiency gaps among zones; optimize
N and P applications and environmental
benefits.
Objective

9. Methodology
• Data and land management information from
studies in the Lake Winnipeg basin together
with historical yield and fertilizer data (1993-
2018) will be used.
• A productivity index developed by Manitoba
Agriculture (MASC) based on a 10-year moving
average will be used to delineate zones.
• Optimal N and P fertilizer for each zone will be
determined by statistical analysis, actual N and
P application and crop yield will be compared to
optimal scenarios

10. Methodology
• Agronomic, yield, and soil data were also
compiled at a watershed scale from 2006-
2018.
• GIS and Limdep (NLOGIT 4.0)
Econometric Software were used to analyze
the panel data
• Yield =a+bN+cN2+βiXi+λ*Zone + θ*Time

11. 01: Coarser textured soils -
sandy/clay loam; susceptible
to drought because of high
temperatures, high
evapotranspiration and low
precipitation.
02: Clay loam textured
soils; susceptible to
drought because of high
temperatures, high
evapotranspiration and
low precipitation.
04: Carrol, wellwood
and firdale soils and
sandy loam soils;
little frost hazard;
medium drought
hazard.
06: Degraded soil or black soil; frost
hazard varies from slight to significant;
drought is periodic hazard.
05:Sandy loam or
coase sand/clay loam
textured soils; more
frequent occurrence of
drought and hail; frost
is a periodic hazard.
03: Loam to sandy loam textured soils;
susceptible to drought associated with
the Assiniboine River valley and high
evapotranspiration.
16: main risk is excessive moisture; poor
drainage and northern location.
15: Variability in soil types; high
precipitation; yield affected by poor drainage
and lower heat units.
14: Sandy textured soils; excessive moisture
is a hazard because of poor internal drainage.
12: Clay/sandy textured soils
predominate; excellent
temperature; little frost
hazard; main hazard is
excessive moisture and poor
internal drainage in the clay
soil areas.
11: Soils are heterogeneous and influenced
by proximity to lake; main risk is excessive
moisture; internal and external drainage.
10: Coarse/sandy clay loam; soil fertility
varies by soil texture; internal drainage;
higher risk area.
09: .Clay loam or mixture of soil types;
low phosphorus available for plants;
main risk is excessive moisture; severe
and frequent frost damage can occur.
07: Soil texture similar to risk area 6;
salinity; drought is the main risk; frost
damage occurs to a lesser degree.
08: Main risk is excessive moisture in
light textured soils; frost hazard occurs
on the higher higher slopes and
elevations.
Manitoba Risk Areas

14. Soil productivity zones (risk area 5)
B C D E F G H
Nutrientapplication(kgha-1)
0
10
20
30
40
50
60
70
80
90
100
N
P2O5
K2O
S
Soil productivity zones (risk area 5)
B C D E F G HWheatyield(Tonneha-1)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Sample results – Risk area 5

15. Variable Coefficient t-Statistic
N 104.74 2.71
N2 -0.26 -1.16
P 4.80 0.41
K -24.36 -1.41
S -8.27 -0.26
Constant -4117.85 -2.38
Effects of input on wheat yield
Variable Coefficient t-Statistic
N 65.07 1.55
N2 -0.07 -0.30
P -20.85 -1.44
K 38.91 1.58
S -39.71 -1.19
C -368.31 -2.64
D -529.21 -3.49
E -618.93 -4.10
F -614.28 -3.69
G -713.02 -3.97
H -880.37 -3.80
Constant -863.51 -0.42
Effects of input variables and soil
productivity zones on wheat yield
Sample results – Risk area 5

16. Wheat yield and total monthly precipitation during crop
growing season (May to Sep.) in risk area 5 in Manitoba
Year
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
Averageprecipitation(mm/month)
0
20
40
60
80
100
Wheatyield(kgha
-1
)
0
1000
2000
3000
4000
5000
Precipitation
Wheat yield
y = 89.944x + 1829.6
R² = 0.7831

17. Variable Coefficient t-Statistic
2001 -677.08 -6.07
2002 -526.82 -4.93
2004 186.13 1.74
2005 -708.23 -6.49
2006 -365.13 -3.30
2007 -349.88 -3.15
2008 446.46 3.72
2009 788.90 6.43
2010 350.41 2.76
2011 -281.73 -1.90
2012 80.81 0.54
2013 1077.68 7.38
2014 801.78 4.85
2015 705.63 4.17
2016 448.48 2.68
2017 1484.55 8.44
2018 1272.55 6.11
Constant 4860.07 4.22
Variable Coefficient t-Statistic
N -25.38 -1.02
N2 0.16 1.17
P -1.94 -0.19
K -10.37 -0.81
S -28.45 -1.91
C -278.30 -4.32
D -453.05 -6.12
E -536.67 -7.26
F -680.17 -8.35
G -773.96 -8.55
H -1093.84 -8.05
1993 -1577.40 -12.83
1994 -1064.20 -8.64
1995 -1291.13 -9.63
1996 -570.20 -4.74
1997 -932.61 -8.30
1998 -519.50 -4.36
1999 -594.41 -5.39
2000 -196.68 -1.81
Effects of input variables, soil productivity zones and time
on wheat yield (kg ha-1)

19. Effects of input variables, zones, and years on wheat yield
(Zone 5D and year 2013 were assumed as bases)
Results at the STC watershed scale
Inputs Estimate fixed effects Estimate fixed effects
Variables Coefficient t-stat Zone Coefficient t-stat Year Coefficient t-stat
N 28.18 5.99 5D 2006 -580.82 -5.46
N2 -0.09 -5.20 5E -152.33 -3.70 2007 -697.69 -5.73
P -1.11 -0.65 12E -109.76 -1.74 2008 -7.11 -0.07
K 3.65 2.46 2009 241.31 2.27
S 7.62 3.33 2010 68.37 0.72
Res Cov 327.12 2.39 2011 -1035.10 -11.29
Constant 1620.72 5.19 2012 41.67 0.44
2014 419.08 4.49
2015 283.95 2.83
2016 -191.27 -2.03
2017 173.46 1.44

20. Effects of input variables, zones, and years on wheat net
return (Zone 5D and year 2013 were assumed as bases)
Inputs Estimate fixed effects Estimate fixed effects
Variables Coefficient t-ratio Zone Coefficient t-ratio Year Coefficient t-ratio
N 5.12 5.07 5D 2006 -89.29 -3.91
N2 -0.02 -5.41 5E -33.38 -3.79 2007 -118.67 -4.54
P -1.34 -3.66 12E -22.99 -1.70 2008 23.93 1.10
K 0.30 0.94 2009 70.19 3.07
S 0.75 1.54 2010 75.73 3.69
Res Cov 155.87 5.30 2011 -231.27 -10.72
Constant -40.59 -0.60 2012 5.12 0.25
2014 146.38 7.32
2015 113.65 5.27
2016 17.35 0.86
2017 83.44 3.24

21. Conclusions
• Both spatial (zone) and temporal (time) variability
had effects on crop productivity, but temporal
trends had the greater effect.
AT STC Watershed Scale:
• Excessive moisture (i.e., 2011), drought (i.e.,
2006), or severe weather (i.e., 2007, 2012) have
caused significant crop production losses in
Manitoba.
• NR losses were $40 yr-1 ha-1 for wheat.

22. • Additionally, conservation tillage had positive
effects on crop yield and economics.
• Conservation tillage could increase NR of wheat by
$73 ha-1.
• BMPs like “tile drainage or retention ponds” that
reduce the negative effect of temporal trends
should be investigated in Manitoba.
Results at the STC watershed scale

23. Acknowledgements
• Agriculture and Agri-Food Canada (AAFC) Growing
Forward for providing financial support
• Deerwood Soil and Water Management Association for
collecting data
• Manitoba Agriculture Service Corporation for providing
crop yield and N fertilizer data
• Canola Council of Canada for providing financial support
• Northeast Agricultural Research Foundation for the data
from Melfort, Saskatchewan
• We also greatly acknowledge technical contributions
from the Lake Winnipeg Watershed Project team.