秸秆还田对稻麦轮作农田活性有机碳组分含量、酶活性及产量的短期效应

Short-term influence of straw return on the contents of soil organic carbon fractions,enzyme activities and crop yields in rice-wheat rotation farmland

【目的】秸秆还田作为一种有效的秸秆处理方式不仅能够提高土壤肥力,增加作物产量,还可以缓解农田生态压力。研究稻麦轮作系统下不同秸秆还田量对土壤活性有机碳库、酶活性和作物产量的短期影响,可为提出适宜当地生产的秸秆还田量提供理论依据。【方法】利用稻麦轮作农田定位试验进行了研究。采用随机区组设计,设7个处理,以稻麦季秸秆均不还田为对照处理(CK),6个不同秸秆还田量处理。测定了秸秆还田后土壤活性有机碳库和土壤酶活性的变化,稻麦产量以及三者之间的相关关系。【结果】1)与秸秆不还田处理相比,试验范围内的秸秆还田量能在一定程度上提高土壤活性碳组分的含量和土壤酶活性,并能增加水稻和小麦的产量及其构成因素;2)土壤总有机碳和微生物生物量碳的含量随着秸秆还田量增加,增幅呈先增大后减小的趋势,以连续两季50%秸秆还田量处理下显著较高,而水溶性有机碳、活性有机碳含量和碳库管理指数在连续两季25%秸秆还田量处理下最高;3)相比秸秆不还田处理,连续两季25%秸秆还田量对土壤脲酶、过氧化氢酶和蔗糖酶活性的影响均最显著;4)水稻和小麦的产量均为在连续两季25%和50%秸秆还田量处理下增产较显著,与秸秆不还田相比,水稻增产达9.0%,小麦增产达11.45%;5)土壤碳库、土壤酶活性以及水稻和小麦产量之间均存在显著相关。【结论】在本试验条件下,连续两季25%和50%秸秆还田量表现出显著提高土壤碳汇能力和增加作物产量的优势。

【Objectives】Straw return is an effective way to recycle straw resources,improve soil fertility and increase crop yields. The amount of straw return affects the soil labile organic carbon pool,soil enzyme activity and crop yields in different extent,so it is meaningful to study the suitable straw returning amount for best yield and soil fertility efficiencies. 【Methods】A field trail with a random block design was carried out in rice- wheat rotation farmland with three replicates. There were totally seven treatments in the trail: non- straw return in both rice and wheat season( CK),25%,50%,75% and 100% of total straw from previous crop returned in rice or wheat season,and 100% of straw returned only in rice or wheat season. Both the rice and wheat yields were investigated and the soil labile organic carbon pool and enzyme activity were measured. 【Results】1) Compared to the CK,straw return could improve the contents of soil labile organic carbon fractions and soil enzyme activities,and increase both yields and their components of rice and wheat. 2) The highest soil total organic carbon( TOC) andmicrobial biomass carbon( MBC) contents are turned out with the straw return proportion of 50% in both rice and wheat seasons,and the highest soil dissolved organic carbon( DOC),labile organic carbon( LOC) and carbon pool management index( CPMI) are in proportion of consecutive 25%. 3) The consecutive 25% of total rice and wheat straw return induces the most significantly soil urease,catalase and sucrase activities. 4) Both the yields of rice and wheat in the treatments of consecutive 25% and 50% of rice and wheat straw return are significantly higher than in CK,with the increases of 9. 0% and 11. 45%,respectively. 5) The correlations among soil carbon pool,soil enzyme activities and the crop yields are significant. 【Conclusions】Under the condition of this experiment,the consecutive returning of 25% and 50% of the rice and wheat straw could significantly increase soil carbon sink capacity,and improve the crop yields in short term.