Effect of Different N Management Strategies on Soil Nitrate Leaching in a Wheat-Maize Rotation System in the Piedmont Plain of Taihang Mountain

In order to reduce agricultural pollution caused by the excessive application of nitrogen fertilizer, a field experiment was conducted to investigate the effects of different fertilization strategies on nitrate leaching in 0-100 cm soil layer using nitrate leaching device in a winter wheat-summer maize rotation system on the piedmong plain of Taihang Mountain. The results showed that soil NO₃^--N leaching and accumulation increased with the increasing of nitrogen fertilization. The effects of nitrogen applications on nitrate leaching varied in the 0-100cm soil layer, and the accumulation rate is OPT+N >; FP >; FP-S >; OPT >; OPT-N >; CK. The nitrate mainly existed in 20-40 cm soil layer in wheat season. It appeared mainly in the surface layer and deep layer in maize season. The nitrate accumulation amount in the 0-100cm soil layer have a significant increasing after 3 rotations especially in the 60-100 cm, which indicating that the primary cause of nitrate leaching and accumulation was N fertilization. Compared with other treatments, the OPT significantly increased crop yield, nitrogen use efficiency and partial factor productivity in the 3 years wheat-maize rotations. Considering the economic and ecological benefits, the OPT fertilization strategy is worth to be recommended to farmers.