soil moisture: managing a limited resource wisely john holman, phd cropping systems agronomist
DESCRIPTION
Winter Wheat Nielsen et al.TRANSCRIPT
Soil Moisture: Managing a Limited Resource Wisely
John Holman, PhD
Cropping Systems Agronomist
How did we get here?
• Fallow not originally part of the Great Plains cropping system
• Fallow stabilized crop yields in wheat-fallow vs. continuous wheat– 30’s, 50’s, and Today
Available Water at Planting (in)0 2 4 6 8 10
Yiel
d (b
u/a)
010203040506070
bu/a = 5.56 + 5.34*inr2 = 0.76
Winter WheatWinter Wheat
Nielsen et al.
What is Plant Available Water?
Soil Textural Class Available Water (in/ft)Coarse Sand 0.25-0.75Fine Sand 0.75-1.00Loamy Sand 1.10-1.20Sandy Loam 1.25-1.40Fine Sandy Loam 1.50-2.00Silt Loam 2.00-2.50Silty Clay Loam 1.80-2.00Silty Clay 1.50-1.70Clay 1.20-1.50
Klocke, N and G. Hergert. 1990. How soil holds water.NebGuide G90-964. University of Nebraska, Lincoln.
PSE = Interval PrecipSWend – SWbeg
PSE – Precipitation Storage Efficiency
• Soil water retained + Precipitation stored during the fallow period
How do you measureWater Use?
Water Use = Soil Water Change+ Precipitation+ Irrigation- Runoff- Deep Percolation
How do you measureWater Use?
Water Use = Soil Water Change+ Precipitation+ Irrigation- Runoff- Deep Percolation
What Factors Affect PSE? Residue am0unt and
orientation, tillage Air temperature, humidity, solar
radiation, wind speed Timing, amount, and form of
precipitation Soil texture, infiltration rate,
existing moisture condition Time between precipitation
events
Effect of Tillage – W-F 1993-1998 (Tribune, KS)
Fallow Method
No-Till 16.0 (6.30) a 23.8 aReducted Till 14.0 (5.51) b 20.9 aConventional Till 8.2 (3.23) c 12.1 b
Source of VariationFallow Method 0.0114
LSD 0.05 1.6 1.7 0.07†Letters within a column represent differences at LSD (0.05)
FallowEfficiency
ANOVA P>F
0.011
cm (in)Accumulation
Percent
Schlegel et al.
Rate of water evap. first 2 days, & during the next 3 to 5 days
Tillage treatmentsMB-plow Sweep-ct Sweep-rt No-till
Rat
e of
wat
er lo
ss (i
nch/
day)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0-2 days after 3-5 days after
Vigil et al. 2012
Average
Fallow Period 1st Summer FWS 2nd Summer Entire Fallow
Prec
ipita
tion
Stor
age
Effic
ienc
y (%
)
0
20
40
60
80
CTNT
P<0.001
P<0.001
P<0.001
P=0.387
Wheat Fallow Systems1996-2006 Akron, CO
Nielsen, et al.
PSE During Fallow in W-F
Precipitation Storage Efficiency
Crop Choice Effect on Surface Residues and Fallow Efficiency
1998-2008
Fallow Method
W-S-F 8.3 (3.25) a 20.1 aW-SF-F 5.3 (2.08) b 12.5 b
Source of VariationFallow Method 0.0346
LSD 0.05 1.6 (1.14) 6.94†Letters within a column represent differences at LSD (0.05)
ANOVA P>F
0.0452
FallowAccumulation Efficiency
cm (in) Percent
Schlegel et al.
Bushland, TX (Unger, 1978)
Wheat Residue (lb/acre)0 2000 4000 6000 8000 10000 12000
Wat
er S
tora
ge (i
n)
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Gra
in S
orgh
um Y
ield
(lb/
a)
1000
1500
2000
2500
3000
3500
4000Water StorageYield
Wheat Residue: Soil water storage & Grain Sorghum Yield
Time of Year: Efficiency from Row-Crop Harvest to
Wheat Seeding (W-S-F)
SWREC-Tribune 2001-2007
Time Period Efficiency
PercentRow-Crop Harvest to July Fallow 28.8July Fallow to Wheat Planting -4.6Row-Crop Harvest to Wheat Planting 21.2
Schlegel et al.
Concluding Thoughts
• Make decisions that will improve precipitation use efficiency:– Good fallow management
• No-till, residue, and weed control– System Intensification
• Can we intensity with cash or forage crops• Flex-cropping: take advantage of opportunities• But efforts need to keep in mind “do no harm”
– Hits on subsequent crops reduce surface residues, etc.
Where do we go from here?
• We know when fallow is inefficient– W-F, no moisture storage during the second
summer fallow period• W-S-F rotation works great when we have rain!
– W-S-F, no moisture storage from July to wheat planting
• Can we grow a short-season spring crop in fallow?– W-S-Flex fallow
• Plant a spring crop when conditions are favorable
• Can we strike a balance?
Western Kansas Flex-Fallow ResultsGarden City, KS
Average Precipitation (1908-2012) = 18.22 inAverage Precipitation (2008-2012) = 15.75 inAverage Precipitation (2010-2012) = 13.33 in
Kansas Annual Precipitation, 1971-2000
Source: K-State Weather Data Library -- www.oznet.ksu.edu/wdl
19.04 in484 mm
24.21 in615 mm
13.87 in352 mm
50.06 in1272 mm
44.89 in1140 mm
39.72 in1009 mm
34.55 in878 mm
29.38 in746 mm
Flex-Fallow Treatments (Cover, Forage, Grain)Season Crop Year Produced
2007 2008 2009 2010 2011Winter 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 x x x x x"" Winter pea/Winter triticale x x x x"" Winter triticale x x x x x"" Winter pea (grain) x x xSpring Spring lentil x x x x x"" Spring lentil/Spring triticale x x x x"" Spring pea x x x x x"" Spring pea/Spring triticale x x x x"" Spring triticale x x x x"" Spring pea (grain) x xOther Chem-fallow x x x x x"" Continuous winter wheat x x x x x
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
Plant Available Water at Wheat Planting:Standing Cover Crop vs Hay
Cover Crop Method
Cover 0.09 a† 5.76 aHay 0.06 b 4.96 b
Source of Variation
LSD 0.05 0.03 0.45†Letters within a column represent differences at LSD 0.05
Plant Available Water (0-6 ft)(in)
<0.0001
Plant Available Water (0-3 in)(in)
ANOVA P>F
<0.001
• Cover >0.8 inches than hay (0-6 ft)
PAW at Wheat Planting-Fallow Method (2008-12)Fallow Method Difference from Fallow
(in)Fallow 7.91 a 0.00Hairy Vetch 6.24 b -1.68S Pea 6.16 b -1.75W Lentil 6.06 bc -1.85S Lentil 5.68 bcd -2.24S Triticale 5.49 bcd -2.43W Pea 5.40 bcd -2.51S Pea/S Triticale 5.24 cde -2.68S Lentil/S Triticale 5.17 cdef -2.75Hairy Vetch/W Triticale 5.15 def -2.76W Pea/W Triticale 4.95 defg -2.97W Lentil/W Triticale 4.49 efg -3.42W Triticale 4.29 fg -3.62Pea (grain) 4.09 gh -3.82W Wheat 3.28 h -4.64LSD 0.05 0.90
Plant Available Water (0-6 ft)(in)
2009-2012 Yield Results
2 good years, 2 very poor yearsCover Crop vs Hay Crop no effect
Economic ResultsNone
VetchVetch/
Trit LentilLentil/
Trit PeaPea/Trit Trit Wheat Lentil
Lentil/Trit Pea
Pea/Trit Trit
Pea, grain Fallow
ExpensesTotal seeding cost $/A 69 48 24 26 37 32 27 21 23 26 40 35 30 40 0
Total hay cost $/A 19 64 17 60 21 65 64 0 19 36 33 41 39 0 0
Grain harvesting $/A 0 0 0 0 0 0 0 30 0 0 0 0 0 30 0
Fallow spray cost $/A 36 36 36 36 36 36 36 36 36 36 36 36 36 36 48
In-crop spray cost $/A 0 0 0 0 0 0 0 11 0 0 0 0 0 11 0Total Expense (cover) 104 83 60 61 73 68 63 - 59 62 76 71 66 - -Total Expense (hay) 123 148 77 121 94 133 126 - 78 98 109 111 104 - -Total Expense (grain) - - - - - - - 98 - - - - - 117 48
ReturnsYield ton/A or bu/A 0.2 2.2 0.2 2.0 0.3 2.2 2.2 33.0 0.3 1.0 0.8 1.2 1.1 14.0 0.0Price $/ton or $/bu 110 110 110 110 110 110 110 7 110 110 110 110 110 7 0Yield Return $/A 25 240 17 219 36 243 238 216 30 105 93 130 121 92 0
N Return $/A 20 20 20 20 20 20 0 0 20 20 20 20 0 0 0
Impact on wheat bu/A -4 -9 -2 -9 -6 -12 -9 -22 -3 -7 -6 -8 -5 -12 0Impact on wheat $/A -26 -59 -13 -59 -39 -78 -59 -144 -20 -46 -39 -52 -33 -78 0
Net Return (cover) -111 -122 -53 -100 -92 -126 -121 - -58 -88 -95 -103 -98 - -Net Return (hay) -124 9 -73 14 -97 7 28 - -68 -51 -55 -47 -29 - -Net Return (grain) - - - - - - - -46 - - - - - -38 -48Net Return (alt vs fallow) -76 56 -25 61 -50 55 75 2 -20 -3 -8 1 19 10
*Assumption: N contribution from legume 0 when hayed, 50 lbs N add for winter trit, and 25 lbs N add for spring trit.
Winter Spring
Economic Results Summary
Return Winter Spring None
VetchVetch/Trit Lentil
Lentil/Trit Pea
Pea/Trit Trit Wheat Lentil
Lentil/Trit Pea
Pea/Trit Trit
Pea, grain Fallow
Cover crop -111 -122 -53 -100 -92-
126 -121 - -58 -88 -95-
103 -98 - -
Hay -124 9 -73 14 -97 7 28 - -68 -51 -55 -47 -29 - -
Grain only - - - - - - - -46 - - - - - -38 -48
Best alternative -76 56 -25 61 -50 55 75 2 -20 -3 -8 1 19 10
Fallow costs $48/AReturns include any reduction of following wheat yieldWinter and spring triticale hay, grain peas, cont. wheat
New Study (W-S-F)Spring oat versus triticale?
Radish or turnip planted with wheat ?
Clover planted with sorghum?
Cocktail mixes?Crop Hay Cover GrainFallowSpring pea xSpring pea/Spring oat x xSpring pea/Spring triticale x xSpring oat x xSpring triticale xYellow sweet clover (planted with sorghum) x xDaikon radish (planted with wheat) xShogoin turnip (planted with wheat) xCocktail mix x x (oat, triticale, pea, buckwheat, forage brassica & forage radish)
PAW at Wheat Planting-Fallow Method (2012-13)Fallow Method Difference from Fallow
(in)Fallow 6.38 a 0.00Spring Pea (grain) 3.26 b -3.12Spring Pea 3.04 b -3.34Spring Oat 2.77 bc -3.61Spring Pea/Triticale 2.61 bc -3.77Spring Triticale 2.04 bc -4.33Spring Peat/Oat 2.03 bc -4.35Cocktail* 1.95 bc -4.42Safflower 1.11 c -5.27LSD 0.05 1.90*Cocktail (oat, triticale, pea, buckwheat, forage brassica, & forage radish)
Plant Available Water (0-6 ft)(in)
ResultsImpact on wheat yield and profitability
– Depends on wheat yield potential
– Wet years little to no impact on yield (yield ≥ 70 bu/A)
– Dry years
– 2011: dry year (WF yielded 23 bu/A)
– Spring crops < 3 bu & winter crops < 6 bu
– 2012: second dry year (WF yielded 32 bu/A)
– Spring crops < 23 bu & winter crops < 24 bu
– “Average” year?
– IF you knew you were going to be in a drought W-F best
– What is the best choice long-term?
– How much weight do you put on a record drought year?
ResultsSpring triticale forage
– 4 years of no yield impact & 1 year yield reduced
– 2008, 2009, 2010, & 2011 no impact
– 2012 -24 bu
– On average wheat yield -2.5 to 5 bu/A (range: +2 to -24)
– 1 ton forage @ $110/ton
– Net $19 to 36/A more than chem-fallow long-term
– Net $54/A more than chem-fallow without 2012
– Break-even yield reduction of 7.5 bu/A @ $7.00/bu
– Wheat-fallow yield potential of <25 bu requires fallow
ConclusionIt is only sustainable if it is profitable
– Graze it, bale it, or combine it!
– No difference if grown as forage or cover
Good fallow management
– No-till, residue, and weed control
High seed cost, offsets N contribution- grow own seed
– More economical to apply N
Select fallow replacement crop adapted to region
Terminate cover crop prior to June 1 for winter wheat
– Check with your insurance provider
If moisture is available then intensify rotation, otherwise fallow (flex-fallow)
Harvesting crop as forage or grain in place of fallow can increase profitability
Reducing Fallow and Tillage in Dryland Cropping Systems
Alan SchlegelSouthwest Research-Extension Center – Tribune, Kansas
Troy DumlerFormer Ag Economist, Research-Extension Center – Garden City, Kansas
Objectives
Determine effect of long-term tillage practices (1991-2012) in a wheat-sorghum-fallow rotation on:
- Soil water - Grain yield Alan Schlegel
Southwest Research-Extension Center – Tribune, Kansas
WSF rotationConventional tillage
Reduced tillage
No-till
WSF, Tribune
0
5
10
15
20
Prec
ip.,
inch
1991 1994 1997 2000 2003 2006 2009
Year
In-Season Precipitation - Sorghum
WSF, Tribune
Weed control during fallow
Tillage Chemical
- - - - # of operations - - - -
CT 4-5 0
RT 2-3 2
NT 0 4
1991-2000
Weed control during fallow
Tillage Chemical
- - - - # of operations - - - -
CT 4-5 0
RT 4-5 (W) 4 (S)
NT 0 4
2001 thru current
Available Soil Water at Wheat Planting
0
2
4
6
8
10
CT RT NTTillage
ASW
, inc
h
WSF, Tribune, 1991-2010
WSF, Tribune
Tribune Wheat Yields in WSF Rotation
NT vs CT: 22%> 1991-2000 & 61%> 2001-2010.
NT vs RT: 9%> 1991-2000 & 32%> 2001-2010.
Available Soil Water at Sorghum Planting
012345678
CT RT NTTillage
ASW
, inc
h
WSF, Tribune, 1991-2010
WSF, Tribune
Tribune Sorghum Yields in WSF Rotation
NT vs CT: 71%> 1991-2000 & 256%> 2001-2010.
NT vs RT: 10%> 1991-2000 & 119%> 2001-2010.
Summary (2001-2010)
Available soil water at planting: 1.5 inches greater with RT/NT than CT.
Grain yield: wheat: NT 50% greater than CT 30% greater than RT
sorghum: NT ~3X greater than CT ~2X greater than RT
TRIBUNE 1974-2004Y = -27.3 + 3.78X
n = 253 r2 = 0.638 RMSE = 10.7 P<0.0001
WATER SUPPLY: ASW + PRECIP. (in.)0 5 10 15 20 25 30
WH
EA
T G
RA
IN
(bu/
acre
)
0
20
40
60
80
100
CONVENTIONAL TILLAGEY = -19.9 + 3.24X
n = 75 r2 = 0.651 RMSE = 8.84 P<0.0001
WIN
TER
WH
EA
T G
RA
IN
(bu/
acre
)
0
20
40
60
80
100TRIBUNE1974-2004
A
NO TILLAGEY = -56.4 + 5.20X
n = 64 r2 = 0.831 RMSE = 8.79 P<0.0001
WATER SUPPLY: ASW + PRECIP. (in.)4 8 12 16 20 24 28
0
20
40
60
80
100
B
TRIBUNE 1973-2003Y = -35.9 + 6.70X
n = 142 r2 = 0.595 RMSE = 21.7 P<0.0001
WATER SUPPLY: ASW + PRECIP. (in.)0 5 10 15 20 25
SO
RG
HU
M G
RA
IN
(bu/
acre
)
0
20
40
60
80
100
120
140
160
180
CONVENTIONAL TILLAGEY = -20.9 + 5.22X
n = 59 r2 = 0.409 RMSE = 22.11 P<0.0001
SO
RG
HU
M G
RA
IN
(bu/
acre
)
0
20
40
60
80
100
120
140
160
180TRIBUNE1973-2003
A
NO TILLAGEY = -46.0 + 7.45X
n = 28 r2 = 0.834 RMSE = 14.94 P<0.0001
WATER SUPPLY: ASW + PRECIP. (in.)0 4 8 12 16 20 24
0
20
40
60
80
100
120
140
160
180
B
Cost of Production
Tillage Wheat Sorghum
CT $82.09 $98.76
RT $82.88 $117.19
NT $98.72 $120.46
* Input costs do not include harvest costs which vary with yield.
Sorghum Costs
MiloCT CT CT RT RT RT NT NT NT
Rate Price Total Rate Price Total Rate Price TotalSeed 3 2.87 8.61 3 2.87 8.61 3 2.87 8.61Fertilizer
N 45 0.24 10.80 50 0.39 19.50 55 0.39 21.45P 20 0.44 8.80 22 0.44 9.68 25 0.44 11.00
HerbicideBiceplite II Mag 1.5 13.43 20.15 1.5 13.43 20.15 1.5 13.43 20.15RT3 0 0.40 0.00 22 0.20 4.40 22 0.20 4.402,4-D 0 0.20 0.00 2 3.10 6.20 2 3.10 6.20Atrazine 0 2.62 0.00 51 0.15 7.65 51 0.15 7.65Glyphosate 0.00 32 0.12 3.84 32 0.12 3.84Glyphosate 0.00 32 0.12 3.84 32 0.12 3.84Glyphosate 0.00 0.00 0.00herb 0.00 0.00 0.00herb 0.00 0.00 0.00herb 0.00 0.00 0.00
MachinerySweep 3 7.42 22.26 0 7.42 0.00 0 7.42 0.00NH3 appl 1 10.55 10.55 0 10.55 0.00 0 10.55 0.00D/L Fert 0 4.75 0.00 1 4.75 4.75 1 4.75 4.75Herbicide 1 4.98 4.98 3 4.98 14.94 3 4.98 14.94Plant 1 12.61 12.61 1 13.63 13.63 1 13.63 13.63
Total 98.76 117.19 120.46
Wheat Costs
WheatCT CT CT RT RT RT NT NT NT
Rate Price Total Rate Price Total Rate Price TotalSeed 50 0.13 6.50 50 0.13 6.50 50 0.13 6.50Fertilizer
N 40 0.24 9.60 45 0.24 10.80 50 0.39 19.50P 15 0.44 6.60 17 0.44 7.48 20 0.44 8.80
HerbicideAlly 0.1 13.21 1.32 0.1 13.21 1.32 0.1 13.21 1.32Banvel 4 0.43 1.72 4 0.43 1.72 4 0.43 1.72RT3 0 0.20 0.00 16.5 0.20 3.30 16.5 0.20 3.302,4-D 0 3.10 0.00 1 3.10 3.10 1 3.10 3.10Glyphosate 0.00 0.00 32 0.12 3.84Glyphosate 0.00 0.00 32 0.12 3.84Glyphosate 0.00 0.00 32 0.12 3.84herb 0.00 0.00 0.00herb 0.00 0.00 0.00herb 0.00 0.00 0.00
MachinerySweep 4 7.42 29.68 2 7.42 14.84 0 0.00 0.00NH3 appl 1 10.55 10.55 1 10.55 10.55 0 10.55 0.00D/L Fert 0 4.75 0.00 0 4.75 0.00 1 4.75 4.75Herbicide 1 4.98 4.98 2 4.98 9.96 5 4.98 24.90Plant 1 11.14 11.14 1 13.31 13.31 1 13.31 13.31
Total 82.09 82.88 98.72
Tribune Tillage Study
2010-2011 market year average price ($5.50, $4.85) and costs.
Questions?