Situation Drought, competition, urban growth, declining ground water levels, and evolving water...
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Situation Drought, competition, urban growth, declining ground water levels, and evolving water laws and policy are contributing to decreasing supplies of irrigation water available to farmers in the semi-arid to arid Western US. Colorado population is expected to increase by 2.8 million by 2030. Greater competition for water is expected resulting in large decreases in irrigated acreage. Along the Front Range of Colorado, irrigated acreage may decrease by 156,000 to 298,000 acres of highly productive cropland by 2030. Farmers are often forced to temporarily or permanently dry-up and fallow previously irrigated land. Abruptly halting irrigated crop production on fields that have been intensively managed results in negative consequences: Residual soil nutrients threaten water quality; weed infestations compete with perennial grass establishment; wind and water erosion can be significant; and compaction and salinity can initially limit the non-irrigated crop and restoration planting choices. Utilizing cover crops may bridge the transition from irrigated production to dryland or grassland production or provide an interim solution to weed and soil management while waiting for irrigation water restoration. Objective Colorado State University Extension is establishing cover crop recommendations for producers who need to assume dryland production or establish grasses into formerly irrigated fields. Summary Results from this work show cover crops provide a viable source of soil cover and residue to reduce erosion, suppress weeds and uptake nutrients for restoration of previously irrigated land. Weed suppression allowed proportionate increases in cover crop biomass with decreases in weed seed and biomass production. The CS grass has shown greater potential to compete with weeds than the WS grass has after a two year cover cropping system. This work has generated much interest from the cooperating farmer and surrounding land owners. Utilizing Cover Crops to Stabilize and Reclaim Previously Irrigated Cropland D. A. Wilson, R. J. Pearson, T. A. Bauder, N. C. Hansen & J. E. Brummer . Future Plans: 2010 season plans include continuation of summer forage cover crops and a second planting of warm and cool season grass mixes in plots where cover crops have reduced nutrient levels and weed pressure. Our primary goal is to provide cover crop recommendations for producers who need to assume dryland production or establish grasses into formerly irrigated fields to mitigate soil erosion, and soil nutrient loss thereby protecting our water resources. Collaboration with area farmers, county extension, NRCS, and conservation districts is expected to increase via additional site trials and/or expansion of current site. Funding Source: USDA-NRCS CIG: Sustainable Cropping Systems for Transition from Full Irrigation To Limited Irrigation and Dryland, Ag Chemical and Ground Water Protection Program (CO Dept of Ag), West Greeley Conservation District Sources: Colorado Department of Local Affairs Demography Section Successful plantings of cover crops are possible in dried-up farmland. Cover crops provide nutrient uptake reducing residual soil N thus lowering NO 3 leaching potential. Site History and Characteristics Location: central Weld County, Colorado. Average annual precipitation: 12.2 in. seasonal Apr – Sep: 9.1 in. Soil Type: Vona Sandy Loam. Last crop was sugar beets in 2005 20 tons manure applied fall 2005 anticipating spring 2006 corn planting. Irrigation well curtailment, mandated by state policy occurred in Spring 2006. Cover crops and grass no-till planted –no High weed infestation two years following irrigation well curtailment. This is a typical scene in many formerly irrigated fields due to their abandonment. Planting Sequence 2009 2010 Plans Plot 1 rep 1 Barley Tritica le S. Sudan Plant S. Sudan 2 Sorghum Tritica le Millet Tritical e S. Sudan Plant Cool Season Grass 3 S. Sudan Winter Wheat Sorghum Pubescen t Wheat Grass Cool Season Grass Monitor Grass Production 4 Fallow Winter Wheat S. Sudan Plant S. Sudan 5 Millet Fallow S. Sudan Warm Season Grass Monitor Grass Production Crop harvest occurred when individual crops approached maturity. Samples were analyzed for total N to determine nitrogen uptake. Biomass production was influenced by timing and amount of precipitation events. Grasses were mowed once on 21-Aug-09. Cover Crop & Grass Biomass Production Transect data was collected at full crop canopy prior to harvest. Trend illustrated by plots shows increases in cover crop and residue ground cover with decreases in weed population and incidence of bare soil. Triticale Harv Triticale Gly W. Wheat Harv W. Wheat Gly Fallow 66 52 65 34 0 28 39 34 46 63 6 2 0 0 2 0 7 1 20 35 2008 Spring Cover Crop Transect Data (% incidence) R = residue W = weed B = bare ground C = cover Hay Millet Sorghum Sudan 40 74 99 15 12 1 17 6 0 28 8 0 2008 Fall Cover Crop Transect Data (% incidence) Residue Weeds Bare Ground Cover Sorghum Sudan Fallow Hay Millet 49 27 0 42 26 47 57 41 10 16 15 15 15 10 28 2 2007 Cover Crop Transect Data (% incidence) R = residue W = weed B = bare ground C = cover Ground Cover, Residue and Weed Suppression Sudan Cool Season Grass Warm Season Grass 77% 44% 12% 7% 14% 20% 12% 11% 39% 4% 31% 29% 2009 Fall Cover Transect Data (% incidence) C = cover B = bare ground W = weed R = residue 3-A pr -08 16- Apr-08 28-May-08 9-J un -08 2-J ul -08 25- Jul-08 6-A u g -08 18- Aug-08 31- Aug-08 8-S ep -08 12- Sep-08 0.00 1.00 2.00 3.00 4.00 0.24 0.45 0.30 1.03 0.34 0.55 1.75 3.05 0.33 0.18 1.30 2008 Precipitation (inches) Seasonal totals: 2008 = 9.5 inches 2009 = 9.0 inches Precipitation 4/2 7/2009 5/3/2 009 5/2 5/2009 6/7 /2 009 6/1 1/ 2009 6/2 1/ 2009 7/2/2009 7/2 2 / 2009 7/2 7/ 2009 8/6/2009 8/16/ 2009 9/1 2/ 2009 9/2 5/ 2009 0 0.5 1 1.5 2 0.08 0.05 0.37 0.09 1.14 0.02 0.96000000000 0001 0.56 0.3 0.08000000000 00001 0.02999999999 99998 0.3 0.18 0.42 1.2 1.04 0.05 0.42 0.07 0.54 0.1 0.04 0.36 0.37 0.05 0.18 2009 Precipitation (inches) Warm Season Grass Cool Season Grass S. Sudan 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 0.13 0.36 6.74 2009 Biomass Yield adjusted tons/acre (18% moisture) tons/acre Surface horizon (0-1 ft) NO 3 -N reductions occurred. Nitrogen uptake occurred accounting for some of these reductions,NO 3 -N leaching is also possible due to rainfall events in 2008 and coarse textured soil. Nitrogen uptake is greater in higher yielding crops in terms of biomass production. Soil Nitrate Uptake and Removal Barley->Triticale->S. Sudan Sorghum->Triticale->Millet->S. Sudan S. Sudan->W. Wheat->Sorghum-> CS Grass Fallow->W. Wheat->S. Sudan Millet->Fallow->S. Sudan->WS Grass Barley->Triticale->S. Sudan Sorghum->W. Wheat->Sorghum->CS Grass Fallow->W. Wheat->S. Sudan Millet->Fallow->S. Sudan->WS Grass S. Sudan->Triticale->Millet->S. Sudan 0 50 100 150 200 250 224 156 74 174 161 201 76 134 145 187 2008-2009 Total N Plant Uptake Lbs/Acre Three Year Cropping Sequence Barley->Triticale->S. Sudan S. Sudan->W. Wheat->Sorghum-> CS Grass Millet->Fallow->S. Sudan->WS Grass Sorghum->W. Wheat->Sorghum->CS Grass Millet->Fallow->S. Sudan->WS Grass 0 50 100 150 200 250 198 147 107 127 122 154 203 91 113 111 106 45 34 18 52 12 10 27 31 17 151 58 44 33 14 4 40 9 23 9 2007 -2009 NO3+-N 0-1 ft soil depth 2009 2008 2007 Lbs/Acre Three Year Cropping Sequence Plot 4: 25SEP09 S. Sudan Harvest. 6.74 Tons/Acre. Plot 4: 8MAY09 Winter Wheat residue from 2008 crop. S. Sudan residue on right and Sorghum residue on left. Plot 4: 8JUN09 S. Sudan, no- till seeded 22JUN09. Plot 4: 25AUG09 S. Sudan growth following late July rain. Plot 3: 9SEP09 Cool Season Grass establishment after two years of cover crop. Plot 5: 9SEP09 Warm Season Grass establishment after two years of cover crop. Grass Species: Warm Season Grass : PBSI Native Sandyland Mix which consisted of: 10% Little Blue Stem, 5% Indian Rice Grass, 10% Sideoats Grama, 10% Sand Lovegrass, 20% Prairie Sandreed, 20% Switchgrass, and 5% Sand Bluestem. Cool Season Grass: Pubescent Wheat Grass. Tr iticale Forage Winter W heat Trit icale Residue Ha y Mille t Sorg hum S. S udan 0.00 1.00 2.00 3.00 4.00 5.00 6.00 1.28 1.43 0.94 0.74 2.04 5.38 2008 Biomass Yield adjusted tons/acre (18% moisture) tons/acre
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Transcript of Situation Drought, competition, urban growth, declining ground water levels, and evolving water...
SituationDrought, competition, urban growth, declining ground water levels, and
evolving water laws and policy are contributing to decreasing supplies of irrigation water available to farmers in the semi-arid to arid Western US.
Colorado population is expected to increase by 2.8 million by 2030. Greater competition for water is expected resulting in large decreases in irrigated acreage.
Along the Front Range of Colorado, irrigated acreage may decrease by 156,000 to 298,000 acres of highly productive cropland by 2030.
Farmers are often forced to temporarily or permanently dry-up and fallow
previously irrigated land.
Abruptly halting irrigated crop production on fields that have been intensively managed results in negative consequences: Residual soil nutrients threaten water quality; weed infestations compete with perennial grass establishment; wind and water erosion can be significant; and compaction and salinity can initially limit the non-irrigated crop and restoration planting choices.
Utilizing cover crops may bridge the transition from irrigated production to dryland or grassland production or provide an interim solution to weed and soil management while waiting for irrigation water restoration.
Objective
Colorado State University Extension is establishing cover crop recommendations for producers who need to assume dryland production or establish grasses into formerly irrigated fields.
SummaryResults from this work show cover crops provide a viable source of soil cover and residue to reduce erosion, suppress weeds and uptake
nutrients for restoration of previously irrigated land. Weed suppression allowed proportionate increases in cover crop biomass with decreases in weed seed and biomass production. The CS grass has shown greater potential to compete with weeds than the WS grass has after a two
year cover cropping system. This work has generated much interest from the cooperating farmer and surrounding land owners.
Utilizing Cover Crops to Stabilize and Reclaim Previously Irrigated Cropland
D. A. Wilson, R. J. Pearson, T. A. Bauder, N. C. Hansen & J. E. Brummer
.
Future Plans:2010 season plans include continuation of summer forage
cover crops and a second planting of warm and cool season grass mixes in plots where cover crops have reduced nutrient levels and weed pressure.
Our primary goal is to provide cover crop recommendations for producers who need to assume dryland production or establish grasses into formerly irrigated fields to mitigate soil erosion, and soil nutrient loss thereby protecting our water resources.
Collaboration with area farmers, county extension, NRCS, and conservation districts is expected to increase via additional site trials and/or expansion of current site.
Funding Source: USDA-NRCS CIG: Sustainable Cropping Systems for Transition from Full Irrigation To Limited Irrigation and Dryland,
Ag Chemical and Ground Water Protection Program (CO Dept of Ag),
West Greeley Conservation District
Sources:
Colorado Department of Local Affairs Demography Section
Colorado's Decision Support Systems and Basin Roundtable/Basin Advisor input
Successful plantings of cover crops are possible in dried-up farmland. Cover crops
provide nutrient uptake reducing residual soil N thus lowering NO3 leaching potential.
Site History and Characteristics
Location: central Weld County, Colorado.
Average annual precipitation: 12.2 in. seasonal Apr – Sep: 9.1 in.
Soil Type: Vona Sandy Loam.
Last crop was sugar beets in 2005
20 tons manure applied fall 2005 anticipating spring 2006 corn planting.
Irrigation well curtailment, mandated by state policy occurred in Spring 2006.
Cover crops and grass no-till planted –no tillage occurring with project.
High weed infestation two years following irrigation well curtailment. This is a typical
scene in many formerly irrigated fields due to their abandonment.
Planting Sequence 2009 2010PlansPlot
1
rep 1
Barley Triticale S. Sudan Plant S. Sudan
2 Sorghum Triticale Millet Triticale S. Sudan Plant Cool Season Grass
3 S. Sudan Winter Wheat Sorghum
PubescentWheat Grass
Cool Season Grass
Monitor Grass Production
4 Fallow Winter Wheat
S. Sudan Plant S. Sudan
5 Millet Fallow S. Sudan Warm
Season Grass
Monitor Grass Production
Crop harvest occurred when individual crops approached maturity.Samples were analyzed for total N to determine nitrogen uptake.Biomass production was influenced by timing and amount of precipitation events.Grasses were mowed once on 21-Aug-09.
Cover Crop & Grass Biomass Production
Transect data was collected at full crop canopy prior to harvest.Trend illustrated by plots shows increases in cover crop and residue ground cover with decreases in weed population and incidence of bare soil.
Triticale Harv Triticale Gly W. Wheat Harv W. Wheat Gly Fallow
6652
65
34
0
2839
34
46
63
62
0
0
2
0 7 1
2035
2008 Spring Cover Crop Transect Data(% incidence)
R = residue W = weed B = bare ground C = cover
Hay Millet Sorghum Sudan
40
74
9915
12
1
17
6
0
28
80
2008 Fall Cover Crop Transect Data(% incidence)
Residue Weeds Bare Ground Cover
Sorghum Sudan Fallow Hay Millet
49
27
0
42
26
47
57
41
10 16
15
1515 10
28
2
2007 Cover Crop Transect Data(% incidence)
R = residue W = weed B = bare ground C = cover
Ground Cover, Residue and Weed Suppression
SudanCool Season GrassWarm Season Grass
77%
44%
12%
7%
14%
20%
12%
11%
39%
4%
31%29%
2009 Fall Cover Transect Data (% incidence)
C = cover B = bare ground W = weed R = residue
3-Apr-0
8
13-A
pr-08
23-A
pr-08
3-M
ay-0
8
13-M
ay-0
8
23-M
ay-0
8
2-Ju
n-08
12-J
un-08
22-J
un-08
2-Ju
l-08
12-J
ul-08
22-J
ul-08
1-Aug-0
8
11-A
ug-08
21-A
ug-08
31-A
ug-08
10-S
ep-0
80.00
1.00
2.00
3.00
4.00
0.240.45 0.30
1.03
0.340.55
1.75
3.05
0.330.18
1.30
2008 Precipitation(inches)
Seasonal totals: 2008 = 9.5 inches2009 = 9.0 inches
Precipitation
27-A
pr-09
7-M
ay-0
9
17-M
ay-0
9
27-M
ay-0
9
6-Ju
n-09
16-J
un-09
26-J
un-09
6-Ju
l-09
16-J
ul-09
26-J
ul-09
5-Aug-0
9
15-A
ug-09
25-A
ug-09
4-Sep
-09
14-S
ep-0
9
24-S
ep-0
9
4-Oct
-09
0
0.5
1
1.5
2
0.080.05
0.37
0.09
1.14
0.02
0.960000000000001
0.56
0.30.0800000000000001
0.0299999999999998
0.30.18
0.42
1.21.04
0.05
0.42
0.07
0.54
0.1 0.04
0.36 0.37
0.050.18
2009 Precipitation (inches)
Warm Season Grass Cool Season Grass S. Sudan0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0.13 0.36
6.74
2009 Biomass Yieldadjusted tons/acre (18% moisture)
ton
s/a
cre
Surface horizon (0-1 ft) NO3-N reductions occurred.Nitrogen uptake occurred accounting for some of these reductions,NO3-N leaching is
also possible due to rainfall events in 2008 and coarse textured soil.Nitrogen uptake is greater in higher yielding crops in terms of biomass production.
Soil Nitrate Uptake and Removal
Barley->Triticale->S. Sudan
Sorghum->Triticale->Millet->S. Sudan
S. Sudan->W. Wheat->Sorghum-> CS Grass
Fallow->W. Wheat->S. Sudan
Millet->Fallow->S. Sudan->WS Grass
Barley->Triticale->S. Sudan
Sorghum->W. Wheat->Sorghum->CS Grass
Fallow->W. Wheat->S. Sudan
Millet->Fallow->S. Sudan->WS Grass
S. Sudan->Triticale->Millet->S. Sudan
0 50 100 150 200 250
224
156
74
174
161
201
76
134
145
187
2008-2009 Total N Plant Uptake
Lbs/Acre
Th
ree
Yea
r C
rop
pin
g S
equ
ence
Barley->Triticale->S. Sudan
Sorghum->Triticale->Millet->S. Sudan
S. Sudan->W. Wheat->Sorghum-> CS Grass
Fallow->W. Wheat->Sudan
Millet->Fallow->S. Sudan->WS Grass
Barley->Triticale->S. Sudan
Sorghum->W. Wheat->Sorghum->CS Grass
Fallow->W. Wheat->S. Sudan
Millet->Fallow->S. Sudan->WS Grass
S. Sudan->Triticale->Millet->S. Sudan
0 50 100 150 200 250
198
147
107
127
122
154
203
91
113
111
106
45
34
18
52
12
10
27
31
17
151
58
44
33
14
4
40
9
23
9
2007 -2009 NO3+-N0-1 ft soil depth
2009
2008
2007
Lbs/Acre
Th
ree
Yea
r C
rop
pin
g S
equ
ence
Plot 4:
25SEP09 S. Sudan Harvest. 6.74 Tons/Acre.
Plot 4:8MAY09
Winter Wheat residue from 2008 crop.
S. Sudan residue on right and Sorghum residue on left.
Plot 4:8JUN09
S. Sudan, no-till seeded 22JUN09.
Plot 4:25AUG09
S. Sudan growth following late July rain.
Plot 3: 9SEP09Cool Season Grass
establishment after two years of cover crop.
Plot 5: 9SEP09Warm Season Grass
establishment after two years of cover crop.
Grass Species:Warm Season Grass: PBSI Native Sandyland Mix which
consisted of: 10% Little Blue Stem, 5% Indian Rice Grass, 10% Sideoats Grama, 10% Sand Lovegrass, 20% Prairie Sandreed, 20% Switchgrass, and 5% Sand Bluestem.
Cool Season Grass: Pubescent Wheat Grass.
Triticale Forage
Winter Wheat
Triticale Residue
Hay Millet Sorghum S. Sudan0.00
1.00
2.00
3.00
4.00
5.00
6.00
1.28 1.430.94 0.74
2.04
5.38
2008 Biomass Yieldadjusted tons/acre (18% moisture)
ton
s/a
cre
