Alfalfa Water Use and Crop Coefficients across the Watershed: From Theory to Practice

作者：Samani Zohrab^*; Skaggs Rhonda; Longworth John

来源：Journal of Irrigation and Drainage Engineering, 2013, 139(5): 341-348.

DOI：10.1061/(ASCE)IR.1943-4774.0000549

• Evapotranspiration
• Alfalfa
• Yield

In this study, remote sensing technology and crop production functions were used to compare the theoretical crop coefficient (K-c) and the theoretically optimal or potential crop evapotranspiration (ET) with actual ET for 751 alfalfa fields in the Lower Rio Grande Valley, New Mexico. Results of the remote sensing showed that, although potential alfalfa water use for the year 2008 was 1,451 mm, actual water use at the field level ranged from 386 to 1,241 mm with an average ET of 901 mm for the growing season. Average ET was also calculated using the average yield and published crop production functions. The average ET estimated from average yield using two different crop production functions was between 975-979 mm. Reasons for field-level ET and crop coefficient variability include current irrigation methods and technology, lack of knowledge of irrigation scheduling, limited water supply, interference of harvesting schedule with the irrigation, cultural practices, and economic factors. The results of the study have implications on water rights adjudication and economic return from alfalfa production. The results also reflect the potential for improvement in agricultural productivity and economic return by changing irrigation techniques and agronomic practices. DOI: 10.1061/(ASCE)IR.1943-4774.0000549.

• 出版日期2013-5