长期地膜覆盖及不同施肥处理对棕壤无机氮和氮素矿化率的影响

长期地膜覆盖对土壤许多理化性质产生较大影响，但对无机氮和氮素矿化率的影响却鲜有报道。本文重点研究沈阳农业大学棕壤定位实验站（1987年开始）内长期地膜覆盖及不同施肥处理下土壤无机氮和氮素矿化率在整个生长季内的变化情况。结果表明，长期的地膜覆盖可以增加NO2^--N的积累，并抑制NO3^--N的迁移，但对NH4^＋—N的含量则影响不大；而且覆膜促进了土壤有机氮索的矿化，从而加速了NH4^＋-N和NO3^--N的释放进释．研究结果同时表明有机肥与无机肥配合施用比单一施用有机肥更能促进土壤的N素矿化。

Effect of Long-Term Plastic Film Mulching and Fertilization on Inorganic N Distribution and Organic N Mineralization in Brown Earth

This experiment was conducted on the loamy brown earth derived from loess-like parent materials at Shenyang Agricultural University during 1987~2003.The main results showed that the NO~-_3-N has been accumulated in the long-term plastic film mulching treatments.And the net N-mineralization rates in all covered treatments have increased.Also covering with plastic film can improve the content of NH~ _4-N and NO~-_3-N.In addition,the application of organic materials with inorganic fertilizers could improve the levels of net N-mineralization rates in soil.