ET Data
What is ET Data?
Evapotranspiration data can be of value to you whether you're irrigating corn or watering your bluegrass lawn. Evapotranspiration is a term that was coined to describe the water use of growing crops. It might be easier to think of it in terms of two component words--evaporation and transpiration. Many times evapotranspiration is referred to simply as ET.
The amount of ET that occurs is influenced by climatic factors, farming practices, stage of crop growth, and other factors. ET for a well-watered corn crop in northwestern Kansas can range from 17 inches to 27 inches due to yearly climatic differences. Precipitation can also vary widely from year-to-year and is often not uniformly distributed across the growing season as needed. These climatic variations emphasize the need to schedule irrigation based on crop needs.
While all this may sound rather complicated, the procedure for irrigation scheduling is really rather simple. The scheduling procedure is just like balancing a checkbook. The withdrawals are the ET values. Deposits are rainfall and/or irrigation amounts. The balance is the amount of water remaining in the soil. Irrigation scheduling publications are available from your local county extension office. They will provide a step by step procedure for setting up your water budget account.
Farmers and homeowners alike can benefit from irrigation scheduling using ET values. Evapotranspiration may be a mouthful to say but don't let that prevent you from taking a bite out of your irrigation water usage. Irrigation scheduling software are available at the Kansas Mobile Irrigation Lab.
General Information for Using ET
Simple irrigation scheduling software Kiscorn
More advanced KANSCHED irrigation scheduling software
Alfalfa-based Penman Crop Coefficients for Western Kansas (A discussion in PDF format)
Excel file containing the Crop Coefficients Do not use these crop coefficients with Penman-Monteith or other short grass-based ET equations!!!
Sunflower Kc values for modifying Alfalfa-based ETr values in Excel File Uploaded January 2011
Clear day solar radiation calculator This program can be used to calculate the maximum solar radiation on a given day of the year for a specific latitude. Uploaded May 25, 2009.