随着人口、资源和环境之间的矛盾日趋尖锐,中国耕地土壤肥力及其变化日益为世人所关注。本文利用最近20年东北地区的吉林和黑龙江省,华北地区的北京市和河北省以及长江下游地区的江苏和浙江省的15个县市180个样本点的土壤数据资料,分析了20世纪80年代以来东部地区农业土壤肥力的演变趋势。结果表明,从总体上看,东部地区除土壤速效钾下降和酸碱性有所退化外,农业土壤的有机质、全氮和速效磷平均含量都增加了。在空间分布上,土壤肥力的变化趋势存在明显差异。长江下游和华北地区的平均肥力提高,东北地区下降。另外,除华北地区的土壤酸碱性有改善外,长江下游和东北地区土壤都存在酸化倾向。

With the intensified pressure of population increase on natural resources and the environment in China, changes in soil quality, especially in soil fertility, have become the focus of increasing world wide concern The aim of this paper is to try to precisely judge the new changing trend in soil fertility and quality in China for the sake of providing scientific basis for decision making to policy makers Data used in this article is from the second national soil census conducted in 1982 1986 and the follow up soil survey based on the sample plots of the soil census done by Nanjing Institute of Soil Science in 2000 Five soil chemical indicators-organic matter total nitrogen, effective phosphorus, effective potassium, and pH value, with close relation to the crops growth, are selected as the primary analytical variables of soil fertility In this paper, agricultural soil fertility and quality changes from the early 1980s to 2000 were described by using data from 3 regions in China-the Northeast, the North China Plain and the middle and lower reaches of the Yangtze River-covering 180 sample plots in 15 counties of 6 provincesin.The principle for sample plot and data selection in the study is that soil fertility indicators mentioned above should be recorded both in the early 1980s and 2000 on sample plot basis Meanwhile, soil sampling season and analytical methods of soil experiments in the two periods should be basically the same so as to guarantee data from each plot of the two periods one to one correspondence and comparably in agreement. This is one of the reasons accountable for the more reliable and more convincing analysis and conclusions of the present paper than other similar studies The results show that, on average, soil organic matter, total nitrogen and effective phosphorus content have been increased since rural reform in China, although soil effective potassium and pH value degraded From the perspective of spatial distribution, however, there exist significant variations in soil fertility and quality The average soil fertility rose in North China and the middle and lower Yangtze River basin, and dropped in Northeast China Additionally, with the exception of North China, which saw an improvement in soil pH value, acidification tendency was observed in the middle and lower reaches of the Yangtze River and Northeast China.