Evapotranspiration (Et) Resources
Crop Water Use by Plant Growth Stage
These charts can be used with readings from an ETgage® or other ET reference. To use the chart, first identify the change in the ET rate across the horizontal row and then identify the current growth stage in the left column. Follow the two columns to the point where they intersect to identify the ET rate to use in your irrigation scheduling. When planning irrigation, account for soil moisture, precipitation, weather conditions, and the ET rate for growth stage of your crop.
See maps of daily and weekly evapotranspiration below.
Estimating Growth Stage
Each of the Crop Growth Stage Charts listed above also includes illustrations of the growth stages. For more detailed information, see these resources:
- How a Corn Plant Develops, a photo-illustrated identification guide for the reproductive and vegetative growth stages; published by Iowa State University.
- Soybean Growth and Management Quick Guide, a photo-illustrated identification guide for the vegetative and reproductive stages of soybean; published by North Dakota State University.
Other ET Resources
Using Modified Atmometers (ETgage) for Irrigation Management, NebGuide G1579
This NebGuide describes the atmometer (evapotranspiration gage) and explains how it can be used for irrigation scheduling. Examples are provided to show how information collected with an atmometer can be used to estimate crop water use for corn and soybean.
Maps of Potential Evapotranspiration Rates for the High Plains Region