秸秆还田对黄土风沙区土壤微生物、酶活性及作物产量的影响

Effects of Straw Mulching on Soil Microorganism, Enzyme Activity and Crop Yield in Loess Desert

针对内蒙古黄土高原风沙区农作物秸秆利用率低、处置不当和农田土壤生态退化等问题,通过连续2年的田间小区试验,探究了0、3000、6000、12000 kg hm-2不同秸秆还田量对玉米全生育期农田土壤酶活性、微生物动态变化及作物产量的影响。0、3000、6000、12000 kg hm^-2秸秆还田量分别相当于当地单位面积玉米农田年生产秸秆数量的0%、25%、50%和100%。结果表明:秸秆还田后,土壤酶活性、微生物数量及作物产量年际间变化趋势一致。与秸秆不还田处理相比,秸秆还田量25%、50%和100%处理土壤的过氧化氢酶活性提高21.4%、30.9%和16.5%(P<0.05),秸秆还田量25%和50%处理土壤脲酶活性显著提高(P<0.05),而秸秆还田量50%处理土壤蔗糖酶活性提高了26.8%(P<0.05);秸秆还田量25%、50%和100%处理土壤细菌数量分别提高了27.3%、33.7%和28.7%,真菌数量提高了9.3%、13.0%和11.1%,放线菌数量提高了22.3%、31.9%、29.3%。在产量方面,秸秆还田量50%处理的玉米产量显著高于秸秆不还田处理,两年分别增产11.7%和12.1%。综上所述,秸秆还田量25%(3000 kg hm^-2)、50%(6000 kg hm^-2)和100%(12000 kg hm^-2)均可增加土壤酶活性、微生物数量及作物产量,尤其以秸秆还田量50%效果最显著。

In view of the loess plateau in Inner Mongolia crops straw utilization rate is low,the improper disposal and farmland soil ecological degradation and other issues,through two years of field plot test,explores the 0,3000,6000,12000 kg hm-2 straw counters-field measures the whole growth period of corn farmland soil enzyme activity and microorganism dynamic change rule and the influence of crop yield.The mulching capacity of 0,3000,6000 and12000 kg hm^-2 straw is equivalent to 0%,25%,50%and 100%of the annual straw production of corn fields per unit area respectively.The results showed that the change trend of soil enzyme activity,microbial community quantity and yield were consistent in different years.Soil catalase activity of 25%,50%and 100%straw mulching increased by21.4%,30.9%and 16.5%(P<0.05),soil urease activity of 25%and 50%straw mulching increased significantly(P<0.05),and soil sucrase activity of 50%straw mulching increased by 26.8%(P<0.05).The number of bacteria in soil with 25%,50%and 100%straw mulching increased by 27.3%,33.7%and 28.7%respectively,the number of fungi increased by 9.3%,13.0%and 11.1%,and the number of actinomycetes increased by 22.3%,31.9%and 29.3%respectively.In terms of yield,the yield of corn straw returned to the field was significantly higher than that of corn straw not returned to the field,increasing by 11.7%and 12.1%respectively in two years.In summary,25%(3000 kg hm^-2),50%(6000 kg hm^-2)and 100%(12000 kg hm^-2)straw mulching can increase soil enzyme activity,microbial community quantity and crop yield,especially with the most significant effect of 50%mulching.