长期地膜覆盖对棕壤剖面中NH_4^+-N和NO_3^--N动态变化的影响

Effect of Long-term Covering with Plastic Film on NH_4^+-N and NO_3^--N in Depth Profile of Brown Earth

棕壤长期定位试验结果表明,覆膜使表层土壤中NH4+-N含量明显增加,并使各个层次NO3--N含量都有所增加,有效地减少了NO3--N的淋失。研究同时表明施用有机肥和化肥都能提高土壤全氮、碱解氮、NH4+-N、NO3--N含量,而施用单一的氮肥则对土壤碱解氮几乎没有影响。因此,有机肥与无机肥配合施用是培肥覆膜土壤氮素肥力的有效措施。

An experiment was conducted on the loamy brown earth derived from loess -like parent materials near Shenyang Agricultural University during 1987 -2003. The main results showed that the average contents of alkali - hydrolyzable -N（ 1 mol NaOH- N） and total N in all covered treatments increased. The average contents of NH4^＋ -N in the topsoil and the NO3^- - N in all layers were enhanced in all covered treatments. Also in all covered treatments the leaching of NO3^- - N declined. In addition, the application of organic manure could improve the levels of total N, alkali - hydrolyzable - N, NO3^- - N and NH4^＋ - N in the soil. However, the single N treatment had little effect on alkali - hydrolyzable- N. Therefore, more manure should be applied to the soil covered with plastic film so as to improve soll fertility.