[目的]研究紫云英(Astragalus sinicus L。)与氮肥不同配施比例下土壤养分含量变化及水稻对养分的吸收利用特征，为南方稻区紫云英与化学氮肥的合理利用提供理论依据。[方法]在水稻-紫云英轮作体系下，设常规施肥为对照处理(100N%，CF)、2个氮肥用量水平下(80N%、60N%)4个紫云英翻压量(15、22。5、30、37。5 t hm-2)处理，总共 9个处理。在水稻收获期，测定土壤pH、有机质、全氮、有效磷、速效钾养分含量、水稻氮磷钾养分吸收量，通过偏最小二乘法路径模型(PLS-PM)对不同指标进行相关性分析。[结果]在 80%N和 60%N水平下，当紫云英翻压量达到 22。5 t hm-2 及以上时，能显著提高土壤有效磷的含量，提升幅度分别为 5。08%～7。46%和 5。40%～12。38%，且对土壤速效钾含量有一定提升作用。在两种氮水平下，当紫云英翻压量分别达到 22。5 t hm-2 和 30 t hm-2 以上时，能显著提高水稻地上部全磷、全钾养分吸收量，并能维持水稻产量不下降。相关性分析显示，紫云英翻压量和施氮肥水平分别与土壤速效养分含量和土壤全氮含量具有极显著的正相关关系，且与水稻地上部养分吸收量和水稻产量均为显著正相关。[结论]紫云英翻压对土壤有机质、全氮含量具有正效应，且能显著提高土壤有效磷和速效钾含量，进而提高水稻地上部养分吸收量及其产量。施氮肥水平则主要显著影响土壤全氮的含量，从而提高水稻地上部养分吸收量及其产量。在皖南稻区，减施 20%化学氮肥，紫云英翻压量为 22。5 t hm-2 以上，以及减施 40%化学氮肥，紫云英翻压量为30 t hm-2 以上时，可保持水稻稳产。
Effects of Different Returned Amounts of Chinese Milk Vetch and Nitrogen Application Levels on Soil Fertility,Rice Nutrient Uptake and Yield in the Rice Area of Southern Anhui Province
[Objective]The aims were to study the changes of soil nutrient content and nutrient uptake and utilization characteristics of rice under different matching ratios of Chinese milk vetch(Astragalus sinicus L.)and nitrogen fertilizer,which could provide a theoretical basis for the rational use of zoysia and chemical nitrogen fertilization in southern rice areas.[Method]Under the rice-purslane crop rotation system,the treatments were designated,regular fertilization(CF)as control,and four gradients of purslane tillage(15,22.5,30,37.5 t hm-2)at two levels of N fertilizer(80N%,60N%),for a total of 9 treatments.During the rice harvesting period,soil pH,organic matter,total nitrogen,available phosphorus,available potassium,uptake of nitrogen,phosphorus and potassium and yield of rice were determined using conventional methods.Correlation analysis of different indicators was performed by partial least squares path model(PLS-PM).[Result]The results showed that the soil available phosphorus contents significantly increased by 5.08%-7.46%and 5.40%-12.38%at 80%N and 60%N levels when the amounts of Chinese milk vetch was tilled at 22.5 t hm-2 and above,respectively.The soil organic matter and available potassium content was inevitably increased.At the same time,the above-ground P2O5 and K2O uptakes of rice could be significantly increased when the Chinese milk vetch returned amount reached above 22.5 t hm-2 and 30 t hm-2 at both N levels,respectively.Overall both improved phosphorus and potassium fertilizer uptake rates and were able to maintain rice yields without decreasing.Correlation analysis showed that the amount of Chinese milk vetch and the level of nitrogen fertilizer application had a highly significant positive correlation on soil available nutrient content,total nitrogen,aboveground nutrient uptake and rice yield,respectively.[Conclusion]The return to soil of Chinese milk vetch could significantly affect the soil organic matter,total nitrogen,available phosphorus,available potassium,above-ground nutrient uptake and yield of rice.The level of nitrogen fertilizer application mainly affected the content of soil total nitrogen and thus the above-ground nutrient uptake and yield of rice.The yield of rice could be maintained when 20%chemical nitrogen fertilizer is reduced after the amount of zoysia tilling is 22.5 t hm-2 or more in this area,and the rice yield could also be kept when 40%chemical nitrogen fertilizer is reduced after the amount of zoysia tilling is 30 t hm-2 or more.
Chinese milk vetchNitrogen fertilizerRice yieldSoil fertility
NETL
NSTL
万方数据
