稻草还田方式对双季水稻产量和土壤碳库管理指数的影响

Effects of rice straw returning mode on rice grain yield and soil carbon pool management index in double rice-cropping system

采用田间定位试验,设置不施肥(CK)、单施化肥(NPK)、稻草切碎全量还田+化肥(SNPK)和稻草全部烧灰还田+化肥(SINPK)4个处理,研究不同稻草还田方式对双季稻产量和土壤碳素形态、碳库管理指数的影响.结果表明:2010—2011年两年四季的水稻平均产量SNPK与SINPK处理基本持平,但均显著高于NPK处理,增幅为5.7%～7.3%.与NPK和SINPK相比,SNPK能显著提高早稻产量,增幅在3.8%～8.8%.与单施化肥和稻草烧灰还田相比,SNPK提高了土壤不同形态碳素含量和碳库管理指数,总有机碳、活性碳、矿化碳和碳库管理指数分别提高了1.8%～2.0%、5.9%～6.5%、16.0%～41.6%和7.3%～7.8%.土壤碳库管理指数与早、晚稻产量呈显著抛物线关系,相关系数分别为0.999和0.980.SNPK能显著提高翌年早稻产量及土壤不同形态碳素含量和碳库管理指数.

A 2-year field experiment was conducted to study the effects of different rice straw returning modes on the rice grain yield and soil carbon pool management index （CPMI） in a double rice- cropping system. Four treatments were installed, including balanced mineral fertilization （NPK）, NPK plus cut rice straw returning （SNPK）, NPK plus incinerated rice straw returning （SINPK）, and no fertilization （CK）. In treatments SNPK and SINPK, the 2 years average grain yield of early rice and late rice was basically the same, and much higher than that in treatment NPK, with an increment of 5.7%-7.3%. As compared with treatments NPK and SINPK, treatment SNPK increased the grain yield of early rice significantly by 3.8%-8.8%, and enhanced the contents of various soil carbon forms and the soil CPMI, with the soil total organic carbon, active carbon, mineralized carbon contents, and the soil CPMI increased by 1.8%-2.0%, 5.9%-6.5%, 16.0%-41.6%, and 7.3%-7.8%, respectively. There was a significant parabolic correlation between soil CPMI and rice grain yield （r=0.999 and r= 0.980 in early- and late-rice season, respectively）. Treatment SNPK also increased the grain yield, the contents of various soil carbon forms, and the soil CPMI in the next early rice season.