ETcrop is a simple application for estimating the evapotranspiration demand of common agricultural crops.
The application was develop in an effort to help water managers and producers to quickly estimate the water needs of
How it works
Crop evapotranspiration is estimated as the product between daily reference evapotranspiration
and a crop coefficient. Reference evapotranspiration is computed using a mass-transfer model and the
crop coefficient is approximated using green canopy cover. Recent research studies are consistently showing
that canopy cover can be effectively used as a proxy to track crop growth and crop coefficients.
The ETcrop web-app was built on concepts described in the following peer-reviewed studies:
Patrignani, A. and Ochsner, T.E., 2015. Canopeo: A powerful new tool for measuring fractional green canopy cover. Agronomy Journal, 107(6), pp.2312-2320.
Trout, T.J. and DeJonge, K.C., 2018. Crop water use and crop coefficients of maize in the great plains. Journal of Irrigation and Drainage Engineering, 144(6), p.04018009.
Muhammad, M.K.I., Nashwan, M.S., Shahid, S., Ismail, T.B., Song, Y.H. and Chung, E.S., 2019. Evaluation of empirical reference evapotranspiration models using compromise programming: a case study of Peninsular Malaysia. Sustainability, 11(16), p.4267.
Dalton, J., 1802. Experimental essays on the constitution of mixed gases. Manchester Literary and Philosophical Society Memo, 5, pp.535-602.
Step 1: Just wait a second or two until the web-app has fully loaded the weather information for your location.
Step 2: Take a downward-facing image of the crop. Make sure you keep the camera lens at least 2 or 3 feet from the top of the canopy.
Step 3: The web-app will automatically compute the reference evapotranspiration, green canopy cover, crop coefficient, and crop evapotranspiration.
The resulting crop evapotranspiration in mm/day gives you an estimate of the current crop water needs.
The ETcrop value can be used to assist you with irrigation . To provide you with more information ETcrop also reports the date, time, and geographic coordinates of each picture.
The accuracy of the location depends on the GPS onboard of your mobile device.