免耕和稻草还田对稻田土壤肥力和水稻产量的影响

为了明确稻草还田和免耕等保护性耕作措施对土壤肥力和水稻产量的影响,自2008年于广西大学农学院科研基地进行长期定位试验,设置免耕（NT）、免耕+稻草覆盖还田（NT-SMR）、常规耕作+稻草覆盖还田（CT-SMR）、常规耕作（CT）和常规耕作+稻草翻压还田（CT-SR）5个处理,于2018年水稻成熟期测定产量,水稻收获后分层（0~5、5~10和10~20cm）测定土壤肥力。结果表明,稻田不同土层肥力指标均存在显著性差异,总体上表现为0~5、5~10和10~20cm土层的有机碳、全氮、碱解氮、有效磷和速效钾含量依次下降。NT-SMR处理显著提高了0~5cm土层的有机碳、全氮、碱解氮和有效磷含量,但降低了土壤速效钾含量。在5~10和10~20cm土层,稻草还田处理的有机碳、全氮、碱解氮、有效磷和速效钾含量均优于无稻草还田处理。水稻产量与土壤肥力呈显著正相关。2016年CT-SR处理水稻产量在早季分别比NT和CT处理显著提高了8.52%和7.99%,在晚季分别显著提高了12.12%和7.55%;2018年NT-SMR处理的水稻产量在早季分别比NT和CT处理显著提高了17.78%和10.30%,在晚季分别显著提高了13.88%和19.39%。因此,免耕和稻草还田能明显提高稻田耕作层土壤肥力,增加稻谷产量。

Effects of No-Tillage and Straw Returning on Soil Fertility and Rice Yield in Farmland

To determine the effects of conservation tillage such as straw returning and no-tillage on soil fertility and rice yield, the long-term positioning test has been carried out in the research base of Guangxi University of agriculture from 2008, and five treatments, no tillage (NT), no tillage and straw mulching returning (NT-SMR), conventional tillage and straw mulching returning (CT-SMR), conventional tillage (CT), conventional tillage and straw returning (CT-SR), were set up. The rice yield had been measured in 2018 at the maturity stage, after harvesting, the soil fertility was measured in layers (0-5, 5-10, 10-20cm). The results showed that there were significant differences in the soil fertility indexes at different levels of paddy fields, which showed that the contents of soil organic carbon, total nitrogen, available nitrogen, available phosphorus and available potassium decreased successively in 0-5, 5-10 and 10-20cm soil layers. NT-SMR significantly increased the contents of soil organic carbon, total nitrogen, available nitrogen and available phosphorus in the 0-5cm soil layer, but decreased the content of available potassium. In 5-10 and 10-20cm soil layers, the contents of soil organic carbon, total nitrogen, available nitrogen, available phosphorus and available potassium in straw returning treatment was better than that in straw free returning treatment. There was a significant positive correlation between rice yield and soil fertility. In 2016, the rice yield of CT-SR treatment was significantly increased by 8.52% and 7.99% compared with NT and CT treatment in early season, and by 12.12% and 7.55% in late season; In 2018, the rice yield of NT-SMR treatment was significantly increased by 17.78% and 10.30% compared with NT and CT treatment in early season, and by 13.88% and 19.39% in late season. Therefore, no-tillage and straw returning can significantly improve soil fertility and increase rice yield.