Crop selection and irrigation scheduling decision tools for limited ...
Crop selection and irrigation scheduling decision tools for limited ...
Crop selection and irrigation scheduling decision tools for limited ...
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Limited Irrigation Management Decision Tools<br />
Norman Klocke, Kansas State University<br />
Water <strong>and</strong> the Future<br />
of Kansas Conference<br />
September 30, 2011<br />
Topeka, Kansas<br />
Klocke‐
Collaborators<br />
• Loyd Stone, Soil Physics, KSU, Manhattan<br />
• Troy Dumler, Ag Economist, KSU, Garden City<br />
• Steven Briggeman, Sprout Software, KC, MO<br />
• Dale Bolton, Data Processing, KSU, Garden City<br />
This research was supported in part by the Ogallala Aquifer<br />
Program, a consortium between USDA‐Agricultural Research<br />
Service, Kansas State University, Texas AgriLife Research, Texas<br />
AgriLife Extension Service, Texas Tech University, <strong>and</strong> West Texas<br />
A&M University.<br />
Klocke‐
Questions <strong>for</strong> Limited* Irrigation Management<br />
Using Economic Return<br />
• Which Combination of <strong>Crop</strong>s to Plant?<br />
• What are Optimum Irrigation Schedules?<br />
*Limited Irrigation = Restricted Water Supply by<br />
Irrigation System Capacity or Public Policy<br />
Klocke‐
• Evaluate an array crop rotations <strong>and</strong> water<br />
allocations<br />
• Net return = (<strong>Crop</strong> price X <strong>Crop</strong> Yield) –<br />
(Production Costs) – (Irrigation Costs)<br />
• Income risk analysis
<strong>Crop</strong>s <strong>for</strong><br />
Rotations<br />
Alfalfa<br />
Corn<br />
Grain Sorghum<br />
Soybean<br />
Wheat<br />
Sunflower<br />
Fallow<br />
L<strong>and</strong> Splits –Predetermined<br />
100%<br />
50% ‐ 50%<br />
75% ‐ 25%<br />
33% ‐ 33% ‐ 33%<br />
50% ‐ 25% ‐ 25%<br />
25% ‐ 25% ‐ 25% ‐ 25%<br />
Klocke
<strong>Crop</strong> Water Allocator<br />
Relative Yield vs. Net Irrigation For Corn<br />
Klocke<br />
Net Return = Rel. Yield X Max. Yield X Price – Operating Costs
<strong>Crop</strong>ping <strong>for</strong> 2012??<br />
• All wheat <strong>for</strong> 2012 (least risk ?)<br />
– Need to irrigate fall 2011<br />
– Borrow 2012 water <strong>for</strong> fall 2011<br />
• Wheat‐Corn <strong>for</strong> 2012<br />
– Need to irrigate wheat fall 2011<br />
– Borrow 2012 water <strong>for</strong> fall 2011?<br />
• Fall‐winter fallow then corn/sorghum in 2012<br />
• Fall‐winter fallow then all corn in 2012 (most risk ?)<br />
Klocke
<strong>Crop</strong>ping <strong>for</strong> 2012?<br />
Assumptions <strong>for</strong> 2011/2012 <strong>Crop</strong> Selections<br />
Rainfall 11"‐2011 11"‐2012<br />
Well 400 gpm 2200 hrs. pumping<br />
Irrigation in 2012=13 inches total<br />
Wheat is irrigated in Fall 2011<br />
Prices<br />
$6/bu‐corn; $8/bu‐wheat; $4/bu‐sorg.<br />
Klocke
<strong>Crop</strong>ping <strong>for</strong> 2012?<br />
<strong>Crop</strong><br />
Irrigation<br />
Yield<br />
(bu/ac)<br />
Net<br />
Return<br />
Klocke<br />
All Wheat 13" 55 $162/ac<br />
Wheat/Corn 5"/20" 21/203 $341/ac<br />
Corn/Sorghum 20"/5" 203/42 $302/ac<br />
All Corn 13" 128 $338/ac<br />
Net Return = Price X Yield – Operating Costs
Forecasting Irrigation Schedule<br />
By Economic Return<br />
Pre‐Growing Season Irrigation?<br />
Date of First Irrigation During the Growing Season?<br />
Irrigation Frequency?<br />
Irrigation System Capacity<br />
M<strong>and</strong>ated Annual Irrigation<br />
Predetermined Irrigation Schedule?<br />
Date of Last Irrigation During the Growing Season?<br />
Klocke‐
Reference ET<br />
Kansas Water Budget<br />
Maximum ET<br />
Soil Water Balance<br />
Actual ET<br />
Available SW<br />
Effective ET<br />
Yield<br />
Klocke
Corn –<br />
Results <strong>for</strong> Available SW = 30%, 50%, 70%<br />
Oct. 1 Relative Net<br />
ASW Yield Return ET Drain<br />
(%) (%) ($/ac) (in) (in)<br />
30 70 350 20.5 0.2<br />
50 75 410 21.4 0.9<br />
70 78 430 21.8 2.4<br />
Annual Irrigation = 12 inches between May 20 & Aug 20<br />
Annual Precipitation = 16 inches<br />
Klocke‐
Income Risk from 80%, 50%, 20%<br />
Rainfall Probabilities‐Corn<br />
Annual Relative Net<br />
Precip. Yield Return ET Drain<br />
(mm) (%) ($/ac) (in) (in)<br />
12 56 120 18.7 0<br />
16 70 350 20.5 0.2<br />
19 76 420 21.5 1.0<br />
30% ASW on October 1<br />
Annual Irrigation = 12 inches between May 20 & Aug 20<br />
Klocke‐
Effectiveness of Pre‐Season Irrigation<br />
Klocke‐<br />
Oct. 1 GS NGS Rel. Net<br />
ASW Irr. Irr. Yield Return Drain.<br />
(%) (in) (in) (%) ($/ac) (in)<br />
30 12 0 70 350 0.2<br />
30 9 3 70 350 0.5<br />
70 12 0 80 450 2.0<br />
70 9 3 75 400 2.9<br />
Pre‐season Irrigation on March 1, March 15, April 1<br />
NGS = Non‐Growing Season<br />
GS = Growing Season<br />
Annual Precipitation = 16 inches
Summary<br />
User Acceptance – Computer Literate<br />
Producers<br />
<strong>Crop</strong> Consultants<br />
Water Policy Agencies<br />
Irrigation Specialists<br />
Educators<br />
Training Needs<br />
CWA – 1 hour<br />
CYP – 2 hour<br />
Klocke‐
Download CWA <strong>and</strong> CYP at:<br />
www.mobile<strong>irrigation</strong>lab.com<br />
Klocke‐
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