集约化种植条件下典型潮土区土壤氮素的演变特征

通过对集约化种植制度下黄淮海平原7个典型潮土区土壤N素的调查,结合第二次全国土壤普查资料,对20年来潮土N素含量、分布及其演变特征进行了全面的分析和评价.结果表明:土壤N素较20年前有所积累,其中全N含量除个别地区有所下降外,其他地区都呈上升趋势,增幅在0 ～ 56.54% 之间;各地土壤碱解N含量普遍上升,增幅在2.03% ～ 81.52%之间.但总体上典型潮土区N素水平依然较低,其中,92% 以上面积的土壤全N含量低于1 g/kg,90% 以上面积的土壤碱解N含量集中在30 ～ 90 mg/kg之间,都处于偏低及以下水平.

Changes of soil nitrogen under intensive crop production in typical fluvo-aquic soil regions

To evaluate soil nitrogen levels and their distributions and changes under the intensive crop production in fluvo-aquic soils in China during the late two decades, a comprehensive survey was conducted in seven typical fluvo-aquic soil regions in Huanghuaihai plain. The results showed the accumulation of soil nitrogen, soil total nitrogen content increased by 0-56.54% in most of fluvo-aquic soil regions, and soil hydraulic nitrogen increased by 2.03%-81.52% in all of fluvo-aquic soil survey sites. However, soil nitrogen generally was at lower level according to the grade criteria of soil nutrient, above 92% and 90% of the fluvo-aquic soil areas were under 1 g/kg for total nitrogen and 30-90 mg/kg for hydraulic nitrogen respectively.