Nitrate leaching in an irrigated wheat-maize rotation field in the North China Plain

Abstract

Soil water deep drainage and nitrate (NO3-) leaching losses below the root zone were investigated in a 1 ha wheat-maize rotation field under traditional agricultural management that local farmers generally follow in the North China Plain, using the soil water balance method and NO 3-N concentration in suction samples. Water drainage, and NO 3-N distribution and leaching losses exhibited pronounced spatial and temporal variability. Soil water deep drainage and NO3-N leaching loss mostly occurred during the summer maize growing season (rainy season), which coincided with irrigations and significant rainfall. On average, soil water deep drainage was 39 and 90 mm in the 1998/1999 and 1999/2000 c..