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1
Fallow Replacement in Western Kansas
John Holman
Scott Maxwell & Tom Roberts
Cover Crop Benefits
• Improve soil quality
– Increase soil organic matter
– Reduce soil erosion
– Reduce soil compaction
– Increase water infiltration
• Decrease runoff
– Supply nitrogen
• Suppress weeds
• Government programs (EQUIP & CREP)
• Conserve soil moisture?
• Reduce nitrate leaching?
• Impact yield of following crop?
• Improve soil quality
– Increase soil organic matter
– Reduce soil erosion
– Reduce soil compaction
– Increase water infiltration
• Decrease runoff
– Supply nitrogen
• Suppress weeds
• Government programs (EQUIP & CREP)
• Conserve soil moisture?
• Reduce nitrate leaching?
• Impact yield of following crop?
2
b
a
a
aa a
0.5
0.8
1.1
1.4
1.7
2.0
No Cover Crop Late Maturing Soybean Sunn Hemp
Soil O
rgan
ic C
arb
on
(%
)0 to 3 inch soil depth
3 to 6 inch soil depth
a
ab
b
0
2
4
6
8
0 50 100 150 200
Cu
mu
lati
ve
Wate
r In
filt
rati
on
(in
ch)
Time (min)
Sunn Hemp
Late-Maturing Soybean
No Cover Crop
Increase in Soil C
• Claassen- Hesston, KS
– Wheat/Cover-Sorghum,
2002-2010
– Residue: Sun hemp >
Soybean
• Claassen- Hesston, KS
– Wheat/Cover-Sorghum,
2002-2010
– Residue: Sun hemp >
Soybean
• ↑ Soil C (0-3 in)
• ↑ Water infiltration
• = Soil aggregate stability w/N
• = Soil compaction (0-3 in) w/N
• ↑ Soil ag. and comp. wo/N
• ↑ crop yield @ low N rate only
• ↑ Soil C (0-3 in)
• ↑ Water infiltration
• = Soil aggregate stability w/N
• = Soil compaction (0-3 in) w/N
• ↑ Soil ag. and comp. wo/N
• ↑ crop yield @ low N rate only
Fallow Replacement Study
• Initiated in 2006 at KSU-Garden City
• Crop rotations:
– Wheat-Fallow, Wheat-Wheat, & Wheat-Cover Crop/Forage/Grain,
• RCB design, 4 replications, each phase of the rotation present each year
• Plots are 30’ x 135’, 224 plots total, 11 A study
• Measuring:
– Cover crop water use
– Forage yield and nutritive value
– Water storage in seed zone and profile
– Wheat yield, test weight, and protein
– Profitability/loss of including cover crops in rotation
• Initiated in 2006 at KSU-Garden City
• Crop rotations:
– Wheat-Fallow, Wheat-Wheat, & Wheat-Cover Crop/Forage/Grain,
• RCB design, 4 replications, each phase of the rotation present each year
• Plots are 30’ x 135’, 224 plots total, 11 A study
• Measuring:
– Cover crop water use
– Forage yield and nutritive value
– Water storage in seed zone and profile
– Wheat yield, test weight, and protein
– Profitability/loss of including cover crops in rotation
3
Fallow Treatments (Cover, Forage, Grain)
• Fallow and cont. wheat, 16 treatments total • Fallow and cont. wheat, 16 treatments total
Season Cover Crop
2007 2008 2009 2010 2011
Winter Yellow sweet clover x x
"" Yellow sweet clover/Winter triticale x
"" Hairy vetch x x x x x
"" Hairy vetch/Winter triticale x x x x
"" Winter lentil x x x
"" Winter lentil/Winter triticale x x x
"" Winter pea (grain) x x x
"" Winter pea x x x x x
"" Winter pea/Winter triticale x x x x
"" Winter triticale x x x x x
Spring Spring lentil x x x x x
"" Spring lentil/Spring triticale x x x x
"" Spring pea x x x x x
"" Spring pea (grain) x x
"" Spring pea/Spring triticale x x x x
"" Spring triticale x x x x
Year Produced
Cover and Forage Crop Termination
Winter Peas
• Winter terminated ~May 15 (winter triticale heads)
• Spring terminated ~June 1 (spring triticale heads)
• Plots split: ½ hayed & ½ sprayed out and left standing
• Winter terminated ~May 15 (winter triticale heads)
• Spring terminated ~June 1 (spring triticale heads)
• Plots split: ½ hayed & ½ sprayed out and left standing
4
2008-2010, Crop Biomass
• Winter lentil: 2009-2010• Winter lentil: 2009-2010
531
15071760 1984
2341
370 489 694
4318 4383 4392 4503
0
1000
2000
3000
4000
5000
6000
7000
Len
til
Pea
Len
til/
Tri
tica
le
Tri
tica
le
Pea
/Tri
tica
le
Len
til
Ha
iry
vet
ch
Pea
Len
til/
Tri
tica
le
Tri
tica
le
Ha
iry
vet
ch/T
riti
cale
Pea
/Tri
tica
le
Spring Winter
Fo
rag
e Y
ield
(lb
s/A
DM
)
2008-2010, Crop Biomass Average
• Winter triticale yield > spring triticale
• Legumes: spring yield > winter: winter injury
– Spring pea > winter pea
– Winter lentil = spring lentil
– Hairy vetch 1 year winter kill
• Winter triticale yield > spring triticale
• Legumes: spring yield > winter: winter injury
– Spring pea > winter pea
– Winter lentil = spring lentil
– Hairy vetch 1 year winter kill
1625
2735
2028
4406
1019
518
0
1000
2000
3000
4000
5000
6000
Spring Winter Spring Winter Spring Winter
All Cover Crop Treatments Triticale Treatments only Legume Treatments only
Fora
ge
Yie
ld (
lbs/
A)
100%
Dry
Matt
er
5
Residue or Forage Value?Residue or Forage Value?
Crude Protein (CP)
• Microbial protein and amino acid production
• > 13% “premium” nutritive value
• Alfalfa 18-24% CP
• Microbial protein and amino acid production
• > 13% “premium” nutritive value
• Alfalfa 18-24% CP
Cover Crop CP
15 16 1619 19
2326
1719 19 19
22
0
5
10
15
20
25
30
Pe
a/T
riti
cale
Ha
iry
ve
tch
/Tri
tic
ale
Tri
tic
ale
Le
ntil/T
riti
cale
Le
nti
l
Pea
Ve
tch
Tri
tic
ale
Pe
a/T
riti
cale
Le
ntil/T
riti
cale
Pea
Le
nti
l
Winter Spring
CP
(%
) D
ry M
att
er
6
Total Digestible Nutrients (TDN)
• Energy available
• Alfalfa 61-67% TDN
• Energy available
• Alfalfa 61-67% TDN
Cover Crop TDN
63 63 64 64 64
67
70
6163 63
6667
565860626466687072
Tri
tic
ale
Ha
iry
ve
tch
/Tri
tic
ale
Pe
a/T
riti
ca
le
Ve
tch
Len
til/T
riti
ca
le
Pe
a
Len
til
Tri
tic
ale
Pe
a
Pe
a/T
riti
ca
le
Len
til/T
riti
ca
le
Len
til
Winter Spring
TD
N (
%)
Dry
Ma
tte
r
Cover and Forage Crop
Impact on Winter Wheat
Cover and Forage Crop
Impact on Winter Wheat
7
Wheat Following High Residue, 2007
Following vetchFollowing vetch
Following triticaleFollowing triticale
Wheat Following Low Residue, 2007
Following fallowFollowing fallow
Following lentilFollowing lentil
8
Western KS Moisture Results• Fallow storage, 20-30% effective
• Growing cover crop used moisture
– Improves storage and may improve stand establishment
• Fallow storage, 20-30% effective
• Growing cover crop used moisture
– Improves storage and may improve stand establishment
2008 Yield Results
• Hail week prior to harvest
• Only visual difference was cont. wheat
• Hail week prior to harvest
• Only visual difference was cont. wheat
2008 Winter Wheat Yield following 2007 Cover Crops
13
21 21 22 22 22 23 2426
21 21 21 23 24 22
0
5
10
15
20
25
30
Wh
ea
t
Ye
llo
w s
we
et
clo
ve
r
Tri
tic
ale
Ye
llo
w s
we
et
clo
ve
r/T
ritic
ale
Pea
/Tri
tic
ale
Pe
a (
gra
in)
Hair
y
ve
tch
/Tri
tic
ale
Ve
tch
Pe
a
Pea
/Tri
tic
ale
Tri
tic
ale
Le
nti
l
Pe
a
Le
nti
l/T
ritic
ale
Fallo
w
Winter Spring None
Win
ter
Wh
ea
t Y
ield
(b
u/A
13
.5%
)
9
2009 Winter Wheat Yield following 2008 Cover Crops
57h
74g 76fg 77efg 78efg 81dcef86abc 87abc
79defg83bcde 85abcd
89ab 90a83bcde
0
10
20
30
40
50
60
70
80
90
100
Wh
eat
Clo
ver/
Tri
tica
le
Pea
(g
rain
)
Tri
tica
le
Pea
/Tri
tica
le
Ha
iry
Vetc
h/T
riti
ca
le
Hair
y V
etc
h
Pe
a
Le
nti
l/T
riti
ca
le
Pea
/Tri
tica
le
Tri
tica
le
Len
til
Pe
a
Fa
llo
w
Winter Spring None
Win
ter
Wh
eat
Yie
ld (b
u/A
13.5
%)
2009 Yield Results
• Only visual difference was cont. wheat
• No effect of residue management treatment
• Only visual difference was cont. wheat
• No effect of residue management treatment
2010 Winter Wheat Yield following 2009 Cover Crops
72a 70ab70ab 68abc68bcd 70ab 67bcde67bcde66bcde66bcde 66cde65cde 64de63e
43f
0
10
20
30
40
50
60
70
80
Wh
ea
t
Tri
tic
ale
Pe
a/T
riti
ca
le
Pe
a (
gra
in)
Ha
iry
Ve
tch
/Tri
tic
ale
Le
nti
l/T
riti
ca
le
Pe
a
Le
nti
l
Ha
iry
Ve
tch
Pe
a/T
riti
ca
le
Le
nti
l/T
riti
ca
le
Pe
a
Tri
tic
ale
Le
nti
l
Fa
llo
w
Winter Spring None
Win
ter
Wh
ea
t Y
ield
(b
u/A
13
.5%
)
2010 Yield Results
• Only visual difference was cont. wheat
• Cover yielded 2.9 bu/A more than hay
• Only visual difference was cont. wheat
• Cover yielded 2.9 bu/A more than hay
10
2011 Yield Results
• Very dry year, marginal wheat stands• No effect of residue management treatment• On average spring forage reduced yield 3 bu/A
• Very dry year, marginal wheat stands• No effect of residue management treatment• On average spring forage reduced yield 3 bu/A
2009-2011 Yield Results
• 2 good years, 1 very poor year• No effect of residue management treatment• Winter triticale, grain pea, and cont. ww yields less
• 2 good years, 1 very poor year• No effect of residue management treatment• Winter triticale, grain pea, and cont. ww yields less
11
Field Pea Yields
• Austrian winter pea (2006-2011): too much injury
• Spring pea (2010-2011): 30-35 bu/A
• Feed pea: $4.50/bu (60 lbs/bu)
– 10 bu/A wheat yield reduction
– ~$13/A profit, with 10 bu/A wheat reduction
– Additional $45/A profit compared to chem-fallow
Western KS Preliminary ResultsNone
Vetch Vetch/Trit Lentil Lentil/Trit Pea Pea/Trit Trit Lentil Lentil/Trit Pea Pea/Trit Trit Fallow
Expenses
Drill $/A 11 11 11 11 11 11 11 11 11 11 11 11 0Seed lb/A 25 30 100 63 30 120 76 0Seed $/lb 2.3 0.4 0.3 0.2 0.4 0.2 0.2 0Total seed cost $/A 56 35 12 13 25 20 14 11 14 28 23 17 0Total drilling cost $/A 67 46 23 24 36 30 25 21 25 38 33 28 0
Swath $/A 10 10 10 10 10 10 10 10 10 10 10 10 0Bale & Stack $/ton 16 16 16 16 16 16 16 16 16 16 16 16 0Total hay cost $/A 15 49 14 49 17 50 49 15 26 24 31 28 0
Spray application $/A 5 5 5 5 5 5 5 5 5 5 5 5 5RT3, $/A 3 3 3 3 3 3 3 3 3 3 3 3 32,4-D, $/A 3 3 3 3 3 3 3 3 3 3 3 3 3Applications/A 3 3 3 3 3 3 3 3 3 3 3 3 4Total spray cost $/A 34 34 34 34 34 34 34 34 34 34 34 34 46
Total Expense (cover) 101 80 57 58 70 65 59 55 59 73 67 62 46Total Expense (hay) 116 130 71 107 86 115 109 71 85 96 99 90 46
Returns
Yield ton/A 0.3 2.4 0.2 2.4 0.4 2.5 2.4 0.3 1.0 0.8 1.3 1.1 0.0Price $/ton 91 91 91 91 91 91 91 91 91 91 91 91 0Yield Return $/A 25 221 19 217 35 226 220 27 88 76 118 100 0
N Return lb/A 40 40 40 40 40 40 0 40 40 40 40 0 0N value $/lb N 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5N Return $/A 20 20 20 20 20 20 0 20 20 20 20 0 0
Soil benefits $/ANet Return (cover) -81 -60 -37 -38 -50 -45 -59 -35 -39 -53 -47 -62 -46Net Return (hay) -91 66 -52 85 -52 86 87 -44 -9 -21 7 -3 -46
*Assumption: N contribution from legume 0 when hayed, 50 lbs of N add for winter triticale, and 25 lbs of N add for spring triticale.
Winter Spring
12
COVER CROPS REDUCE SOIL LOSS IN RUNOFF
a
ab
abb
b
0.0
0.5
1.0
1.5
2.0
2.5
Fallow Winter Lentil
Spring Triticale
Spring Pea Winter Triticale
Se
dim
en
t L
os
s (M
g h
a-1
)
COVER CROPS REDUCE THE SOIL’S SUSCEPTIBILITY TO WIND EROSION
a
ab
abc
bc
bc
bc
bc
c
c
c
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Winter Triticale (Hayed)
Fallow (Control)
Winter Lentil (Cover)
Spring Pea (Cover)
Spring Triticale (Hayed)
Winter Triticale (Cover)
Spring Triticale (Cover)
Spring Lentil (Cover)
Spring Pea (Grain)
Continuous Winter Wheat
Wind Erodible Fraction (Aggregates <0.84 mm)
13
Western KS Cool-Season Crops
• Legume
– Clover: biennial-slow growth, seed cost ($25/A)
– Vetch: hard seed, cattle-photosensitization and muscle problems, winter injury, seed cost ($50/A)
– Peas (W & S): winter injury, fair yield, seed cost ($25/A)
– Lentils (W & S): hardy, low yield, seed cost ($11/A)
• Non-legume
– Triticale (W & S): hardy, high yield, seed cost ($15/A)
• Mixtures
– Legumes survive better, high yield, some N fixing, reduce seed cost
• Legume
– Clover: biennial-slow growth, seed cost ($25/A)
– Vetch: hard seed, cattle-photosensitization and muscle problems, winter injury, seed cost ($50/A)
– Peas (W & S): winter injury, fair yield, seed cost ($25/A)
– Lentils (W & S): hardy, low yield, seed cost ($11/A)
• Non-legume
– Triticale (W & S): hardy, high yield, seed cost ($15/A)
• Mixtures
– Legumes survive better, high yield, some N fixing, reduce seed cost
Future Direction
• Wheat-grain sorghum-(fallow/fallow replacement)
• Spring oats compared to triticale
• Radishes and turnips: large taproot-reduce soil compaction?
• Cocktail mixes?
• Wheat-grain sorghum-(fallow/fallow replacement)
• Spring oats compared to triticale
• Radishes and turnips: large taproot-reduce soil compaction?
• Cocktail mixes?
Crop Hay Cover Grain
Spring pea x x x
Spring pea/Spring Oat x x
Spring pea/Spring Triticale x x
Spring Oat x x
Spring Triticale x x
Daikon radish & Shogoin turnip x
Cocktail mix x
(oat, triticale, pea, buckwheat, radish and turnip)
Fallow
14
• Planted 8/30/10
• Harvested 10/14/10
• Size of plants w/ competition
• Planted 8/30/10
• Harvested 10/14/10
• Size of plants w/ competition
• Planted 8/30/10
• Harvested 12/2/10
• Size of plants wo/ competition
• Planted 8/30/10
• Harvested 12/2/10
• Size of plants wo/ competition
Daikon Radish
• Planted 8/30/10
• Harvested 12/2/10
• Planted 8/30/10
• Harvested 12/2/10
• 2/18/11• 2/18/11
Soil depth (in) Soil penetrometer (psi)
1 132
2 244
3 320
4 386
5 468
6 493
7 473
8 493
9 453
10 437
11 442
12 437
15
Mixtures?
• A lot of interest in mixtures
• Some species more competitive
• Select a mixture based on need, more is not necessarily better
– Spring forage: legume improving N content of forage and N fixation, and grass for high biomass (ex: spring pea and oat)
– Spring cover crop: large taproot may help soil quality, legume for N fixation, and large biomass crop (ex: daikon radish, spring pea, and triticale)
– Summer grazing: large taproot for soil quality and grazing, legume, and high biomass (ex: turnip, cowpea, sorghum sudangrass)
• A lot of interest in mixtures
• Some species more competitive
• Select a mixture based on need, more is not necessarily better
– Spring forage: legume improving N content of forage and N fixation, and grass for high biomass (ex: spring pea and oat)
– Spring cover crop: large taproot may help soil quality, legume for N fixation, and large biomass crop (ex: daikon radish, spring pea, and triticale)
– Summer grazing: large taproot for soil quality and grazing, legume, and high biomass (ex: turnip, cowpea, sorghum sudangrass)
Eastern KS: Cover Crop Study
• Cover crop-grain sorghum rotation 3 site yrs (Manhattan & Hutchinson)
• Cover crop biomass
• Cover crop-grain sorghum rotation 3 site yrs (Manhattan & Hutchinson)
• Cover crop biomass
16
Eastern KS: Cover Crop Study
• Grain sorghum yield correlated to N in cover crop
• Correlation to flag leaf N, R2 = 0.79
• Grain sorghum yield correlated to N in cover crop
• Correlation to flag leaf N, R2 = 0.79
Western KS Results
• Impact on wheat yield and profitability?
– In wet years little to no impact on yield
– In drought years all treatments reduced yield except some of the spring crops
– On average spring crops reduced yield (3 bu/A)
– 1 ton forage @ $100/ton: net $40/A more than chem-fallow
vs.
– 3 bu/A @ $8.00/bu: $24.00/A
– Averaged across years:
– Cont. WW reduced yield 37% (25% more total than W-F)
– Winter triticale reduced yield 9% or 5.5 bu/A
– Grain pea reduce yield 11% or 7 bu/A (11 bu/A less in drought)
– No difference between cover or hay
• Impact on wheat yield and profitability?
– In wet years little to no impact on yield
– In drought years all treatments reduced yield except some of the spring crops
– On average spring crops reduced yield (3 bu/A)
– 1 ton forage @ $100/ton: net $40/A more than chem-fallow
vs.
– 3 bu/A @ $8.00/bu: $24.00/A
– Averaged across years:
– Cont. WW reduced yield 37% (25% more total than W-F)
– Winter triticale reduced yield 9% or 5.5 bu/A
– Grain pea reduce yield 11% or 7 bu/A (11 bu/A less in drought)
– No difference between cover or hay
17
Western KS Results
• Bale it, Graze it, or Combine it!
• High seed cost, offsets N contribution- grow own seed
– More economical to apply N
• Select fallow replacement crop adapted to region
– Winter hardiness
– Many proposed cover crops will not perform
• Terminate cover crop prior to June 1 for wheat
• If moisture is available consider double-crop after wheat
• Harvesting crop as forage or grain increased profitability
• Bale it, Graze it, or Combine it!
• High seed cost, offsets N contribution- grow own seed
– More economical to apply N
• Select fallow replacement crop adapted to region
– Winter hardiness
– Many proposed cover crops will not perform
• Terminate cover crop prior to June 1 for wheat
• If moisture is available consider double-crop after wheat
• Harvesting crop as forage or grain increased profitability
Questions?
18
Cover Crops
pea clover vetch
hairy vetch & triticale lentil pea
Planting Spring Crops in the Fall
Spring triticaleSpring triticale Winter triticaleWinter triticale
• Plant a mixture of spring and winter crops for more fall grazing
• Plant a spring crop in the fall for feed in a drought
• Plant a mixture of spring and winter crops for more fall grazing
• Plant a spring crop in the fall for feed in a drought
19
Eastern KS: Cover Crop Study
• Cover crop N accumulation• Cover crop N accumulation
Western KS Warm-Season Crops• Legume
– Oilseed: guar and soybean
– Forage: cowpea, lablab, mungbean, pigeon pea, soybean
– Cover: sunhemp (toxic to cattle)
• Brassicas
– Soil & Cover: turnip, radish, and Ethiopian cabbage
• Grasses
– Forage: forage sorghum, sorghum sudangrass, millet
• Drought, Weeds & Rabbits (2011)
– Best: turnip, radish, guar, cowpea, lablab, Ethiopian cabbage, and grasses