| Keeping and improving soil quality is not only a material base for achieving agricultural sustainable development, but also a sill for ensuring food safety in our county. In view of the fact that the negatr e effect of soil quality degradation on global food safety , environmental quality and health of man and animal is increasing serious, studies on mechanism of soil quality evolution and soil degradation have become one of hot questions in soil science home and abroad. In our country, studies on soil quality and soil degradation mainly collected on paddy soil in Taihu and red soil in south, next to phaeozem and Chao soil, studies on other soils were very poor. Purple soil was peculiar soil resource in our country, but research of purple soil quality evolution was comparatively short, from seeing prese it studies, focusing on soil and water loss of purple soil papule sloping fields resulting from soil degradation, relatively being lack of research on effect of agronomic measures on purple soil quality, but almost being vacancy in the fact of purple paddy soil quality. Long-term located experiment is the important method and mean to studying regular of soil quality evolution. The tendency of soil quality evolution cannot get only depending on short-term experiment, because the effect of every factor in system on soil fertilizer was the result of long-term accumulation. The accurate result was gained difficultly without long-term and strict located experiment. Therefore, taking "national long-term monitor base for purple soil fertility and fertilizer efficiency" as research platform, the paper used the way combining fixed-site trials in field, simulation experiment, investigat research with analysis in lab to system study on purple soil fertility evolution, productivity sustainability and purple soil acidification.The paper studied spatial and temporal changes of purple soil fertility through using monitor data getting by long-term located experiment and historical .eserved soil samples, clarified the change of purple soil fertility under long-term located application fertilizer with time through analyzing soil organic matter, nutrient(N, P, K)content and soil physical properties yearly, cleared spatial change of soil nutrient fertility under long-term located application fertilizer through analyzing the tenth-year nutrient (N, P, K) content in soil profile, which will be fundatmentals for increasing soil quality and guaranteeing purple soil resource to sustainable utilize. At the same time, through crop yield data accumulating in long-term located trials, the paper researched the change tendency of crop yield and the productivity' sustainability of purple soil, made clear of productivity change tendency and sustainability of purple soil under different application fertilizer systems, explicited main restricted factor to impart on purple soil productivity, put forward management measure to keep and improve system productivity, which will be data for agricultural sustainable development in purple soil district. The paper still studied purple soil acidification present situation influencing factors and development tendency through combining investigate research, simulation experiment and located experiment in field. The main aim is to supply theory for cultivating and increasing purple soil quality, guaranteeing sustainable utilization of purple soil resource, keeping the virtuous circle of ecological system, establishing sustainable development agricultural product system. The main experimental result as follows:The result of 10-year located trials showed that NPK and combined application with NPK and organic manure can maintain and improve purple soil fertility. Compared with before experiment, organic matter aid total N content increased, total P and available P raised, available K kept basicbalance in plow layer soil. After 10-year located trials, purple soil supply capacity with N, P, K nutrient and fertility were decreasing year by year, soil nutrient appeared the trends of non-equilibrium in N...
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