Consumptive-use coefficients currently used for determining irrigation requirements and water rights in New Mexico have been imported from other states for most crops because of lack of measurements made in the State. This condition exists also for most of the states because of the great expense incurred to make measurements for all crops in any one state.

A major objective of this project is to enlarge the store of consumptive use (evapotranspiration) information in New Mexico by making additional consumptive-use measurements for selected crops in the State and to extract consumptive-use data from earlier irrigation research projects in which soil moisture depletion measurements have been made for scheduling irrigations.

The specific objectives of the project are:

1. to determine the quantity and rate of moisture depletion by consumptive use throughout the growing season of selected crops grown in San Juan and Dona Ana Counties, New Mexico;
2. to determine the relationship between consumptive use of water by selected crops and pan evaporation; and
3. to determine the accuracy of coefficients used presently in the Blaney-Criddle method and modifications of coefficients that may be needed to compute consumptive use by this method for conditions in New Mexico.

PROJECT NO. A-043-NMEX