Moisture supply for winter wheat plantings after bare fallow and bastard fallow under arid conditions

From 1972 to 2015, stocks of productive moisture were determined in the 1-m-deep soil layer during different periods of plant growth and development at Prikumsk Experimental and Selection Station in a six-course rotation: bare fallow–winter wheat–winter wheat–corn to green fodder–winter wheat–spring barley. Analysis of moisture supply for crops in the arid area showed that bare fallows provide the emergence of seedlings in 62% of years, while repeated winter wheat plantings yield seedlings in 22.8% of years. As the amount of autumn precipitation increased, the relative productivity advantage of winter wheat after bare fallow decreased from 99.4 to 43.2%. By spring, the stocks of productive moisture were 37.7% higher and the productivity was 73.5%, or 1.75 t/ha, higher after bare fallow than after bastard fallow.