连续秸秆还田对稻麦轮作农田土壤养分及碳库的影响

Effects of Continuous Straw Returning on Soil Nutrients and Carbon Pool in Rice-wheat Rotation System

为探索苏中地区适宜的秸秆还田量对土壤肥力和产量的影响,本文通过开展大田定位试验,研究了稻麦轮作条件下,不同秸秆还田量对农田土壤养分、碳库以及作物产量的影响。经过连续5季秸秆还田定位试验,结果表明:1不同秸秆还田量能不同程度地增加土壤全氮、有效磷和速效钾含量,且以连续5季75%还田量对土壤养分含量增加效果最为显著,分别比对照提高了3.54%、3.97%和10.28%;2连续5季75%秸秆还田量显著提高了土壤总有机碳含量,而水溶性有机碳和易氧化有机碳含量则以50%和75%还田量表现出明显优势,其对土壤碳素有效率以及碳库管理指数的影响亦是如此;3不同秸秆还田量处理对周年粮食产量均有不同程度的提高,表现为稻麦秸秆均还田>仅稻秸或麦秸还田>稻麦秸秆均不还田,且以连续5季75%还田量影响最为显著,增幅为10.01%。综合考虑,在该地区稻麦轮作条件下,以75%秸秆还田量为宜,可显著提高土壤肥力,增加作物产量。

To explore the influence of suitable amounts of straw returning on soil quality and crop yields for middle region of Jiangsu, a field experiment was conducted to determine the effects of different amounts of straw returning on soil nutrients, carbon pools and crop yields in rice-wheat rotation system. After five-season continuous straw returning, the results showed that： 1） straw returning increased the contents of soil total nitrogen, available phosphorus and rapidly-available potassium, and 75% of five-season continuous straw returning got greatest increases, by 3.54%, 3.97% and 10.28%, respectively. 2） 75% of five-season continuous straw returning significantly increased the contents of soil total organic carbon, while 50% and 75% five-season continuous returning significantly increased the contents of water-soluble organic carbon and easily oxidizable carbon, and the effect was the same on soil available carbon contents and carbon pool management index. 3） Straw returning increased annual crop yield in an order of both rice and wheat straw returning〉only one crop straw returning〉no straw returning. Among them, 75% of five-season continuous straw returning significantly improved the yields, increased by 10.01%. In conclusion, the treatment of 75% of straw returning is most suitable in a rice-wheat rotation system of the study region.