“A timer or other pump control should be installed to terminate water at the time decided upon. A basic irrigation scheduling method (example, checkbook method) should be applied to determine when irrigation is needed.”

In addition to the basic IWM system, an intermediate system may also add management strategies that can assist in providing water to the field in a more timely and effective manner, Rodrigue says.

“These could include polypipe hole sizing methods to create better irrigation distribution uniformity, multiple side inlets in flood irrigation to get water to individual components, surge/cutback methods to reduce tailwater, and furrow diking to increase irrigation application efficiency and maximize the benefit of rainfall during the growing season.”

An advanced IWM system, he says, could include soil moisture monitoring and advanced irrigation scheduling methods. “Soil moisture measurement can be used to assist in determining irrigation scheduling and the effectiveness of each irrigation.”

The following principles should be applied for various crop growth stages, Rodrigue says.

·  The volume of water needed for each irrigation should be based on plant available water-holding capacity of the soil for the crop rooting depth (see websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx), management-allowed soil water depletion, and irrigation efficiency.

·  The irrigation frequency should be based on the volume of irrigation water needed and/or available, the rate of crop evapotranspiration, and effective precipitation (this is extremely difficult to evaluate without soil moisture monitoring).

·  The application rate should be based on the volume of water to be applied, the frequency of irrigation applications, soil infiltration and permeability characteristics, and the capacity of the irrigation system.