Modelling the relationships between the yield and evapotranspiration of maize under salinity stress and nitrogen deficiency

Abstract

Understanding the intraseasonal sensitivity of crop evapotranspiration (ET) to stresses allows for accurate modelling of crop yield. In this research, the effects of water salinity stress and soil nitrogen deficiency on evapotranspiration (in the growth stages) and maize yield in 2017 and 2018 were investigated.Four treatments of saline water levels of 0.5 (S 0 ), 2.1 (S 1 ), 3.5 (S 2 ) and 5.7 (S 3 ) dS m À1 were combined with four nitrogen fertilization levels of 100% (N 0 ), 75% (N 1 ), 50% (N 2 ) and 25% (N 3 ). The maize ET amounts from the S 0 N 0 to S 3 N 3 treatments decreased from 80 to 55 mm (in the initial stage), 202 to 129 mm (in development), 127 to 80 mm (in the mid) and 14.5 to 10.5 mm (in the late). The dry biomass yield of maize from the S 0 N 0 to S 3 N 3 treatments was equal to 15.3 to 9.23 t.ha À1 . The relative yield of maize was modelled by the additive models of Blank, Stewart and Singh and the multipliable models of Jensen, Rao and Minhas. The results showed that the Stewart and Jensen models were selected as the optimal models. By using the optimal models, the relative yield of maize can be modelled based on the evapotranspiration rate (in the growth stages) under salinity stress and nitrogen deficiency.