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为探讨西南山区水稻-油菜轮作模式下秸秆还田对作物产量和土壤氮素固持能力的影响,于2013-2015年在洱海流域稻油轮作农田中设置空白处理(CK)、单施化肥(CF)、化肥+玉米秸秆(CFMS)以及化肥+蚕豆秸秆(CFBS)4个处理,测定分析了作物产量、土壤微生物量及土壤理化性质等关键指标。结果表明,与CF处理相比,秸秆还田提高水稻、油菜产量及其地上部含氮量,增加氮素有效输出。不同处理土壤微生物量碳、氮质量分数存在差异,其大小顺序为:CFMS>CFBS>CF>CK。与土壤碳氮比相比,土壤微生物熵和微生物量C/N对秸秆还田做出快速响应,秸秆还田提高土壤微生物熵,降低微生物量C/N。此外,秸秆还田显著降低油菜收获后的土壤硝态氮残留(P<0.05),与CF相比,玉米秸秆和蚕豆秸秆还田分别使土壤硝态氮残留量减少11.6%~55.0%和13.7%~52.3%。可见,中国西南山区稻油轮作模式下秸秆还田能提高作物产量和含氮量,增强土壤微生物氮素固持能力,有效降低土壤氮素流失风险,且玉米秸秆在增产、固氮方面的作用优于蚕豆秸秆。结果可为提高西南山区水稻、油菜产量,增强土壤氮素固持能力,降低土壤氮素流失风险提供参考。
In order to investigate the effects of straw return on crop yield and soil nitrogen holding capacity under the mode of rice-canola rotation in southwest mountainous area, blank treatment (CK) was set up in paddy-rice rotation farmland in Erhai Lake from 2013 to 2015, ), Chemical fertilizer + corn stover (CFMS) and chemical fertilizer + fava bean stalk (CFBS). The key indicators such as crop yield, soil microbial biomass and soil physical and chemical properties were analyzed. The results showed that compared with the CF treatment, straw returning increased the yield of rice and rapeseed and the aboveground nitrogen content, and increased the effective output of nitrogen. The differences of soil microbial biomass C and N between different treatments were as follows: CFMS> CFBS> CF> CK. Compared with soil C and N, soil microbial entropy and microbial biomass C / N respond quickly to straw returning. Straw returning increased soil microbial entropy and decreased microbial biomass C / N. In addition, straw returning significantly reduced residual nitrate nitrogen in rapeseed after harvest (P <0.05). Compared with CF, corn stover and fava bean residue decreased soil nitrate nitrogen residue by 11.6% -55.0% and 13.7% respectively % ~ 52.3%. It can be seen that straw return to paddy field in southwest China can increase crop yield and nitrogen content, increase soil nitrogen holding capacity and reduce the risk of soil nitrogen loss effectively. Moreover, the effect of corn straw on yield increase and nitrogen fixation is superior to Broad bean straw. The results could provide reference for improving the yield of rice and rapeseed in the mountainous area of southwest China, enhancing soil nitrogen holding ability and reducing the risk of soil nitrogen loss.