【摘要】 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。更多还原

【Abstract】 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（1mol NaOH-N） and total N in all covered treatments increased.The average contents of NH⁺₄-N in the topsoil and the NO^-₃-N in all layers were enhanced in all covered treatments.Also in all covered treatments the leaching of NO^-₃-N declined.In addition,the application of organic manure could improve the levels of total N,alkali-hydrolyzable-N,NO^-₃-N and NH⁺₄-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 soil fertility.更多还原