Crop‐Water Production Function Model for Saline Irrigation Waters

TLDR

Crop‑water production functions link crop yield to seasonal water application and are essential for optimizing irrigation management. The study develops a model to compute crop‑water production functions for saline irrigation waters. The model combines yield–evapotranspiration, yield–root‑zone salinity, and salinity–leaching fraction relationships, permits growth‑based evapotranspiration adjustments, and was applied to tall fescue at various salinity levels, with computed leaching fractions and yields compared to published experimental values. Computed yields closely matched measured yields, while agreement for leaching fractions was less satisfactory.

Abstract

Abstract The relationship between crop yield and seasonal amount of applied water (crop‐water production function) is required to determine optimum irrigation management. A model is developed for the computation of crop‐water production functions with saline irrigation waters. The model combines three relationships: yield and evapotranspiration, yield and average root zone salinity, and average root zone salinity and leaching fraction. The model allows plant growth adjustment, and therefore evapotranspiration adjustment, to root zone salinity. Crop‐water production functions were computed for tall fescue ( Festuca elatior arundinacea L.) for various levels of salinity in the irrigation water. A comparison was made between calculated and published experimentally measured values of leaching fractions and yields of tall fescue grown under conditions of various irrigation water salinities, water application quantities and applied water frequencies. Calculated and measured yields were in good agreement considering the usual degree of variability of field data. Agreement between calculated and measured leaching fractions was not as good as for yields.