Learn how to optimize the available water for crop production

January 20, 2013

If you missed the December UNL Extension program on developing a deficit irrigation strategy, all the sessions have now been posted online.

When water is limited, how do you determine which strategy will maximize profits. What should you plant to optimize available water? How many acres should be irrigated? How much water should be applied? If allocations are pooled for multiple fields, how much should be applied to each field? How should multi-year supplies be allocated across years? If water supplies can be traded, what is the value of the water? These and many more questions are analyzed using the UNL Water Optimizer and presented in these sessions.

The program explores Nebraska’s unique water availability — annual precipitation ranges from 16 inches at Scottsbluff to 32 inches near Lincoln — and looks at how to develop a deficit irrigation strategy best suited to your operation. (Deficit irrigation is when less than the optimal amount of irrigation water is applied.)

Since few years are average, speakers also address how to adjust irrigation plans mid-season for current conditions.

While the workshop primarily covers water management from a producer’s perspective, the research tools and results also would be useful for evaluating water policy alternatives.

The program was held at the Monsanto Water Utilization Learning Center near Gothenburg.

Online Presentations

All the sessions are available at right or in a larger view on YouTube (linked below).

• Crop Response to Water with Gary Hergert, UNL Extension Soil Quality Specialist, Panhandle REC (28 minutes). This segment looks at cropping systems in the Panhandle and how they are affected by different irrigation application levels. Deficit irrigation and plant population strategies are discussed.
   
• Deficit Irrigation with Derrel Martin, UNL Extension Irrigation Specialist (36 minutes) (36 minutes).  As irrigation is limited or restricted in most of Nebraska,  many growers will need to consider deficit irrigation. Deficit irrigation research trials have shown that reducing irrigation application by 50% resulted in just an 11% yield loss.
   
• Implementing Plans with Derrel Martin, UNL Extension Irrigation Specialist (17 minutes). If the current growing season is drier than expected, be sure to use your entire allocation and to apply water during critical growth stages. Learn how to use the Water Optimizer tool during the planning process.
   
• Multiple Fields and Multiple Years with Ray Supalla, retired UNL Extension Agricultural Economist  (33 minutes). Water Optimizer looks at the economic feasibility of transferring water from one field to another and the economic incentive of possibly trading water.
   
• Plans for Single Fields and Single Year with Ray Supalla, retired UNL Extension Agricultural Economist  (26 minutes). Calculates economic returns of various irrigated and dryland cropping options. The presentation gives a summary of several cropping option scenarios.
   
• Predicting Yield and Economics with Derrel Martin, UNL Extension Irrigation Specialist (42 minutes). Water Optimizer helps growers decide what crop they should grow and how much water to apply. Growers may need to decide if they should irrigate the whole field at a lower irrigation level or fully irrigate a part of the field and leave a portion dryland. Optimizer can calculate the net return for many different scenarios.
   
• System Capacity and Other Issues with Derrel Martin, UNL Extension Irrigation Specialist (26 minutes). This segment looks at how we can use historical rainfall data as a decision aid tool for this year's decisions. It discusses the irrigation system capacity needed to avoid crop stress.

Water Optimizer — A Decision-aid Tool for Producers

Water Optimizer is a decision support suite of programs developed by University of Nebraska-Lincoln Extension to help crop producers with limited irrigation water. It can help identify the cropping strategy and irrigation amount to optimize profit when water supplies are short.

Water Optimizer has been tested and used by growers for several years and now supports all 93 Nebraska counties. The Excel programs are free and available in four options:

• Single Field/Single Year Model
• Multi Field/Single Year Model
• Multi Year/Single Field Model
• Water Optimizer Budget Calculator

Chuck Burr
Extension Water/Cropping Systems Extension Educator