秸秆不同还田方式对紫色土微生物量碳、氮、磷及可溶性有机质的影响

以广泛分布于西南丘陵区的紫色土为研究对象,通过田间微区试验,研究了油菜/玉米轮作下秸秆不同还田方式对紫色土微生物量碳、氮、磷和可溶性有机质的影响,以期为秸秆在农业生产上的综合利用提供理论依据。结果表明:秸秆直接还田(CS)、生物质炭还田(BC)、秸秆+促腐剂还田(CSD)和秸秆1∶1配施生物质炭还田(CSB)均有效提高土壤微生物量碳(SMBC)、氮(SMBN)、磷(SMBP)含量,其中以CSD处理的微生物量碳、磷最高,分别比CK(单施化肥)增加了46.32%,94.09%;CSB处理的微生物量氮最高,其次为CSD处理,分别达到了104.47,104.14mg/kg。对土壤可溶性有机质而言,除BC处理外,其他秸秆还田处理下土壤可溶性有机碳(DOC)提高了63.26%~189.46%,其中CSD处理最高,达72.74mg/kg;与CK处理相比,秸秆不同还田方式显著降低了土壤可溶性有机氮(DON)含量,但4种处理的土壤可溶性有机磷(DOP)均有提高,特别是CSD处理对土壤可溶性有机磷的提高效果最佳。与CK处理相比,秸秆不同还田方式降低了土壤DON/TN,但有效提高了SMBC/SOC(除BC处理),其中CS和CSD处理的提高效果显著,同时CSD处理的DOC/SOC和SMBN/TN值最高,分别达到了0.49%和7.66%。秸秆不同还田方式能有效提高作物产量,与CK处理相比,各处理的油菜和玉米产量分别提高了3.37%~7.01%和1.49%~3.92%,其中以CSD处理的增产效果最佳。因此,油菜/玉米轮作下西南丘陵山区紫色土最优的秸秆还田方式为秸秆+促腐剂还田,该还田方式下活性有机质含量最高,有利于提高土壤生产力。

Effects of Different Straw Returning Methods on Soil Microbial Biomass Carbon, Nitrogen, Phosphorus and Soluble Organic Matter in Purple Soil

In order to explore the effects of different straw returning methods on microbial biomass carbon,nitrogen,phosphorus and soluble organic matter under rape/corn rotation system,field experiments were conducted on the purple soil,which was widely distributed in southwestern hilly region of China.This study was expected to contribute to the comprehensive and rational utilization of straw.The results showed that straw directly returning (CS),biochar returning (BC),straw with transformation proinoter returning (CSD),equivalent straw and biochar returning (CSB) could all effectively increase the contents of soil microbial biomass carbon,nitrogen and phosphorus.The contents of soil microbial biomass carbon and phosphorus in CSD treatment were the highest,which were 46.32％ and 94.09％ higher than CK (single chemical fertilizer).Microbial biomass nitrogen content in CSB treatment was the highest followed by CSD treatment,which reached 104.47 mg/kg and 104.14 mg/kg,respectively.Except BC treatment,other treatments improved soluble organic carbon content by 63.26％～189.46％,and the value of CSD treatment was most distinct,reaching 72.74 mg/kg.Four straw returning treatments decreased the content of soil soluble organic nitrogen (DON) comparing with CK,while the content of soil soluble organic phosphorus (DOP) increased,especially CSD treatment had the best effect on the improvement of soil soluble organic phosphorus.Compared with CK,straw returning reduced the DON/TN,but effectively increased the SMBC/SOC (except BC treatment),CS and CSD treatments had more expressive performance.DOC/SOC and SMBN/TN in CSD treatment were the highest,which reached 0.49 ％ and 7.66 ％,respectively.Compared with CK,all straw returning treatments could increase the yields of rape and maize by 3.37％～7.01％ and 1.49％～3.92％,respectively.CSD treatment was the best among four treatments.The best straw returning method under rape/corn rotation system in purple soil of southwestern hilly region was straw with transformation promoter returning,which had the highest active organic matter and was beneficial to increase soil productivity.