黄土丘陵区长期施用氮磷肥效应及平衡特征

以１９８３～１９９２年的田间试验结果和室内分析资料为依据，探讨了黄土丘陵区长期施用氮磷肥效应及平衡特征。结果表明：产量对长期施肥反应明显，不同作物在不同土地类型上，均以配施效果好而稳定。作物吸Ｎ，Ｐ量与产量规律一致，但随施肥时间延长，吸Ｎ，Ｐ量呈递减趋势。平衡结果表明：Ｎ，Ｐ配施土壤Ｎ素亏损，川地Ｐ素盈余，有机无机配合，Ｎ素均有盈余。坡地由于水土流失，除ＭＮＰ处理外，土壤Ｐ素均处亏损状态。由此得出，坡地应控制水土流失，提高土壤肥力

The Long Term Application Effects and Balance Characteristics of Nitrogen and Phosphorous in Loessial Hilly Regions

The effects and balance properties of long term nitrogen and phosphorous application in loessial hilly regions are explored in this paper based on field experiments and lab analysis from 1983 to 1992.The result indicates that there is a close correlation between the long term application and yields,and that all crops,planted in any type of soils,have stable yields with effective nitrogen and phosphorous application.The amount of N and P taken up by crops is in conformity with yield production,while the taken up N and P quantity decreases along with an extension of application time.The balance analysis shows that,with a compound application of N and P,there is a lack of nitrogen in soil and a surplus of phosphorous in valley field and that,with a combination of organic and inorganic use,a surplus of nitrogen is obvious.Besides the MNP treatment,there exists a lack of phosphorous on slanting land due to soil and water errosion.It is therefore concluded that there is a need of soil and water control on slanting land for the purpose of improving soil fertility.