Predicting Crop Water Use in the San Joaquin Valley of California Using Remote Sensing
Water Management Research
2010 Annual Report
1a.Objectives (from AD-416)
To develop algorithms relating remotely sensed canopy cover to basal crop coefficients and software for conversion of remote sensing images to crop coefficient maps.
1b.Approach (from AD-416)
Canopy ground cover of various crops from the west side of the San Joaquin Valley will be derived from Landsat and/or other multispectral images collected under acceptably clear weather conditions. Image analyses will be required to process these data. Correlation between the satellite based canopy cover data and basal crop coefficient will be made and algorithms established on crop specific bases. A prototype user interface program will be developed to facilitate the translation of the satellite imagery to canopy cover or crop coefficient maps based on the relationships and algorithms developed in the previous phases of the project. An economic analysis will also be carried out to compare cost and benefit of employing remote sensing for improving crop water use efficiency. Documents Grant with CSU-Seaside.
The agreement was established in support of Objective 1 of the in-house project, and the goal was to develop algorithms relating remotely sensed canopy cover to basal crop coefficients and software for conversion of remote sensing images to crop coefficient maps. The ability to predict crop water demand using remotely sensed canopy information has the potential to account for season-to-season and field-to-field crop variability and to significantly enhance water use efficiency. During this project period, a demonstration system was developed under NASA's Terrestrial Observation and Prediction System (TOPS) to automatically retrieve and pre-process appropriate satellite imagery, calculate vegetation index values, convert to estimates of fractional cover and crop coefficients, and deliver or archive the output maps. The system was intended to eventually support practical irrigation scheduling based on climatic information (as from the California Irrigation Management Information System) for more accurate irrigation water applications that meet crop water requirements. Results will be presented at the 5th National Decennial Irrigation Conference in December 2010 in Phoenix, AZ. The ability to estimate crop evapotranspiration (ET) over large land areas with remotely-sensed data contributes to efficient management decisions by irrigation managers with information to help them schedule irrigation water deliveries and applications. The project is monitored by the ADODR via email and telephone communications, and face-to-face meetings with the cooperator and another ARS scientist at Ft. Collins, CO.