Forecasting methods for the total evapotranspiration of fodder crops in arid conditions of Kalmykia

Abstract

In 1995-2015, in the dry steppe and semi-desert zones of the Caspian lowland, a series of experimental studies were conducted on brown and light chestnut soils to establish the total evapotranspiration of annual fodder crops using irrigated arable land. Four different methods were studied; the water balance method was used as a control one. The temperature coefficients of the total water consumption, as well as the coefficients of an air humidity deficit combined with the scale of biological time of vegetation were determined. Specified coefficients of water consumption were determined; they were differentiated depending on different conditions of mineral nutrition and the planned yield. For production conditions, biological and mathematical models of dependence have been developed in order to determine an optimal water regime in the arid zone. Based on the obtained experimental data, the convergence of the calculated values obtained by the bioclimatic and water balance methods was achieved. The planned crop yield was produced.