The effects of drought and salinity on KS and RAW managerial coefficients in the efficient water management in maize farms

Abstract

AbstractThis study aimed to investigate the simultaneous effects of drought and salinity on irrigation management coefficients in maize farms. A three-year field research was conducted in the form of a 3 × 3 factorial experiment with a randomized complete block design and three replications from 2020 to 2022 in a maize farm, in Aliabad Fashafoye, Qom province, Iran. The applied treatments included three levels of salinity (S0 = 1.8, S1 = 5.2, and S2 = 8.6 dS/m) and three levels of irrigation (W0 = 100%, W1 = 75%, and W2 = 50% of field capacity). Evapotranspiration stress coefficient (KS) due to W0S1 and W0S2 treatments was (0.975 and 0.934), (0.974 and 0.932), and (0.962 and 0.935) in 2020, 2021, and 2022, respectively. According to the results, KS decreased by increasing the salinity level of irrigation water, so a 1-unit increase in salinity level above the tolerance threshold of the crop to salinity decreased KS by 0.78 and 1.76% for S1 and S2, respectively. Moreover, each percent of volumetric moisture decrease from field capacity decreased KS by 5.9 and 13.3% in W1 and W2, respectively. Also, with the increase in the intensity of the stresses, the readily available water (RAW) of treatments decreased. The sole application of salinity stress decreased the decreasing slope of RAW by 3.2%, while the application of both stresses resulted in the decreasing slopes of 4.9, 5.7, and 7.8% at the salinity levels of S0, S1, and S2, respectively, compared to the control. The findings of this study show that the accurate estimation of crop evapotranspiration and RAW can help to improve the irrigation schedule, and the amount of irrigation water used is less than in non-stress conditions due to the reduction of total evapotranspiration and less water uptake in environmental stresses in maize farms.