Non-radial technical efficiency measurement of irrigation water relative to other inputs used in Arkansas rice production

Abstract

Groundwater from the Mississippi River Valley alluvial aquifer is an essential resource for agricultural irrigation in Arkansas, but groundwater from this valuable resource is being withdrawn more rapidly than aquifer recharge in many parts of the state. Rice accounts for a significant portion of groundwater withdrawn from the aquifer. Rice is also a high-cost crop relative to other field crops. This study uses data envelopment analysis and non-radial technical efficiency to evaluate irrigation water efficiency along with the efficiency of other key rice production inputs using data from 142 rice fields enrolled in the University of Arkansas Rice Research Verification Program (RRVP). The study also evaluates the impacts of management practices on input use efficiency using fractional regression. This study differs from most other studies that focus specifically on irrigation water efficiency in that efficiencies of other related rice inputs are also evaluated. We found irrigation water was overused on average by 37.3 % across the 142 fields, with 60 fields (42.3 % of all fields evaluated) over-applying irrigation water by over 50 %. Other rice inputs identified as highly inefficient included herbicides, diesel, and labor, which were overused on average by 46.4 %, 54.6 %, and 58.9 %, respectively, across the 142 fields. Results of the fractional regression analysis revealed management practices significantly improving irrigation water efficiency also significantly improved diesel and labor efficiency as well as overall field efficiency.