Interannual Variation in Long-Term Center Pivot–Irrigated Maize Evapotranspiration and Various Water Productivity Response Indices. I: Grain Yield, Actual and Basal Evapotranspiration, Irrigation-Yield Production Functions, Evapotranspiration-Yield Production Functions, and Yield Response Factors

Abstract

Quantification of crop response to the amount of water applied, available, or used is important for decision making to ensure effective, profitable, conservative agricultural production. However, these variables and responses may have interannual attributes and long-term research has rarely quantified interannual variations of irrigation-yield production functions (IYPF), evapotranspiration-yield production functions (ETYPF), and yield response factors (Ky). This long-term research measured grain yield, actual crop evapotranspiration (ETa), increase in ETa attributable to various irrigation levels, basal evapotranspiration (ETb; ET required to establish grain yield), IYPF, ETYPF, and seasonal Ky for maize (