节水条件下土壤氮素的环境影响效应研究

土壤无机氮素的损失主要是铵氮的挥发损失和硝氮的反硝化和淋失.土壤水分和氮素含量的增加,都将增加氮肥淋失的潜在威胁,如处置不当,获得高产可能需要以环境的污染为代价.节水条件下土壤无机氮素的损失量有所减少,但是氮素利用效率也同时受到了土壤水分状况的限制.探讨了作物产量、氮素损失和农业生产要素(水分、氮素)实际投入量之间的关系,建立了节水条件下土壤氮素损失和环境评价概念型模型,通过在北京水利科学研究所永乐店灌溉试验站3年的试验资料对模型进行了参数求解及校验.

Effects of soil mineral nitrogen on the environment under water-saving irrigation conditions

Mineral nitrogen losses in dryland involve ammonia volatilization,nitrate leaching and denitrification.The objective of this paper is to investigate the relationship between soil mineral losses and soil moisture as well as mineral nitrogen content under water-saving irrigation conditions.The field experiments were carried out in a field with winter wheat and corn for three years.Based on the observations of field experiments and the analysis of relationship among initial soil mineral nitrogen content,irrigation amount,fertilizer supply,and mineral nitrogen losses,a conceptual model is developed to estimate soil mineral nitrogen losses and evaluate the impact of irrigation water and fertilizer N input on the environment.The results show that crop grain yield increased with the increased nitrogen losses.Nitrogen use efficiency is also limited by soil water content under water-saving irrigation conditions.