Impacts of fertilizer practices on environmental risk of nitrate in semiarid farmlands in the Loess Plateau of China

Abstract

The lack of understanding of nitrate dynamics in soil profiles of semiarid regions hampers the assessment of the environmental risks associated with nitrate. A long-term field experiment established in the Loess Plateau of Northwest China in 1984 was used to investigate the seasonal dynamics of water and nitrate contents in the soil profile (0-300 cm) under bare fallow and continuous winter wheat (Triticum aestivum L.) with various fertilizer treatments. For treatments without mineral N input (i.e., no fertilizer, farmyard manure alone, and with P fertilizer), the amount of nitrate accumulated in the soil profile (52-120 kg N ha , the average for June, August, February and April) was signifi..