周年秸秆还田对稻麦轮作农田土壤养分、微生物活性及产量的影响

Effects of annual straw returning on soil nutrients, microbial activity and yield in a rice-wheat rotation system

为探索苏中地区适宜的秸秆还田量对土壤肥力和产量的影响,通过开展大田定位试验,研究稻麦轮作条件下不同周年秸秆还田量对农田土壤养分、微生物活性以及作物产量的影响.试验共设计5个处理,分别以25%、50%、75%和100%秸秆还田量为梯度,以秸秆不还田为对照.经过3年定位试验,结果表明:(1)不同秸秆还田量能不同程度地增加土壤养分和有机质含量,土壤全氮、有效磷和有机质以75%还田量最为显著,分别比对照提高了2.61%、6.31%和5.90%,而速效钾含量则以50%还田量最为显著,较对照提高了24.08%;(2)不同秸秆还田量对土壤细菌和放线菌数量均有不同程度的激活,且以50%还田量达到显著水平,分别比对照提高了14.85%和24.58%,而真菌与之不同,除75%还田量处理外均有不同程度的抑制作用;(3)50%和75%还田量显著提高了土壤蔗糖酶和过氧化氢酶活性,而土壤脲酶活性则以50%和100%还田量提升效果显著;(4)周年粮食产量随还田量的增加呈先增加后减少的趋势,以75%还田量增产显著,增幅为10.01%.综合考虑,在该地区稻麦轮作条件下,以50%或75%秸秆还田量为宜,可显著提高土壤肥力,增加作物产量.

Straw returning may have an important effect on soil fertility and crop yields. This research aimed to determine the suitable amounts of straw returning for the rice-wheat rotation system. A three-year field experiment was conducted in a ricewheat rotation farmland in the middle region of Jiangsu Province to understand the effects of different amounts of a nnual straw returning on soil nutrients, microbial activity and crop yields. Five treatments were designed with a gradient of 25%, 50%, 75% and 100% of straw returning, with no-straw returning as the control. The results showed that： 1） All the straw returning treatments increased soil nutrient contents and soil organic matter. Soil total nitrogen, available phosphorus and organic matter contents had the highest level in the straw returning proportion of 75%, which increased by 2.61%, 6.31% and 5.90%, while available potassium content was significantly increased in the straw returning proportion of 50%, which increased by 24.08%, respectively. 2） The soil bacteria and actinomycetes were differently activated by different amounts of straw returning, significantly increased with the treatment of 50% of straw returning, which increased by 14.85% and 24.58%. In contrast, fungi were inhibited in varying degrees except in the treatment of 75%. 3） The treatments of 50% and 75% of straw returning significantly increased the activity of invertase and catalase in soil, while the activity of soil urease was increased remarkably in the treatments of 50% and 100%. 4） The trend of annual crop production firstly increased and then decreased with the increasing amount of straw returning, with its peak of 10.01% improvement in the treatment of 75%. The results indicated that the treatment of 50% or 75% of straw returning can significantly improve the soil fertility and crop yields, therefore should be advocated for the rice-wheat rotation system of Jiangsu.