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Irrigation Water Management

Irrigation Water Management

by Kelly J. Klausmeyer, Agricultural Engineer
Natural Resources Conservation Service
Hays, Kansas

Irrigation water management is the act of timing and regulating irrigation water application in a way that will satisfy the water requirement of the crop without wasting water, energy, and plant nutrients or degrading the soil resource. This involves applying water according to crop needs in amounts that can be held in the soil and at rates consistent with the intake characteristics of the soil.

A primary objective in the field of irrigation water management is to give irrigators an understanding of conservation irrigation principles. This is done by showing them how they can judge the effectiveness of their own irrigation practices, make good water management decisions, or recognize the need to make adjustments in existing systems or to install new systems. The net result of proper irrigation water management typically:

  • Prevents excessive use of water
  • Minimizes pumping costs
  • Prevents excessive soil erosion
  • Reduces labor
  • Maintains or improves quality of groundwater and downstream surface water
  • Increases crop biomass yield and product quality

Irrigation scheduling is the part of proper irrigation water management that involves the decision of when to irrigate and how much water to apply. Scheduling tools provide information that irrigation decision makers can use to develop irrigation strategies for each field on the farm. Such strategies may be based on long-term data that represents average conditions or may be developed as the season progresses, using real-time information and short-time predictions. In both cases, information about the crop, soil, climate, irrigation system, water deliveries, and management objectives must be considered to tailor irrigation scheduling procedures to a specific irrigation decision maker and field condition. An irrigation scheduling tool needs only be accurate enough to make the decision when and how much to irrigate.

Modern scheduling is based on soil-water balance or crop-water balance for one or more points in the field. By measuring existing and estimating future soil-water content or by monitoring crop-water stress level, irrigation water can be applied before damaging crop stress occurs. Scheduling irrigation involves forecasting of crop water use rates to anticipate future water needs.

Computerized irrigation scheduling allows the storage and transfer of data, easy access to data, and calculations using the most advanced and complex methods for predicting crop evapotranspiration. Many computer software programs are available to assist in scheduling irrigations. In Kansas, software available from the Kansas State Research and Extension is typically used. The software (called KanSched) is used by the Natural Resources Conservation Service (NRCS) to document irrigation water management under the Environmental Quality Incentives Program.

To learn more about irrigation water management or natural resources conservation, please contact your local NRCS office or conservation district office located at your local county USDA Service Center. The office is located at your local U.S. Department of Agriculture (USDA) Service Center (listed in the telephone book under United States Government or on the internet at offices.usda.gov). More information is also available on the Kansas Web site at www.ks.nrcs.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider and employer.

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