黄河三角洲盐碱地毛叶苕子不同还田方式下腐解及养分释放特征

Characteristics of decomposition and nutrient release of Vicia villosa under different returning methods in saline alkali land of the Yellow River Delta

绿肥在盐碱地土壤结构改良和地力提升上具有独特优势,但在黄河三角洲地区的相关研究较缺乏。通过种植试验和尼龙网袋模拟腐解试验,探究毛叶苕子作绿肥的养分供应能力以及在免耕覆盖和翻压2种还田方式下的腐解、养分释放特征,以期为其合理利用提供参考。结果表明,黄河三角洲盐碱地种植毛叶苕子还田可以在较大程度上提供后茬玉米所需的氮、钾,但磷供应较少。2种还田方式均表现为前期腐解和养分释放速率快,后期腐解和养分释放速率明显降低的趋势,养分累积释放率为钾>氮>碳>磷。至还田81 d,覆盖还田和翻压还田的腐解率分别为53.7%和74.8%,碳、氮、磷、钾释放率分别为75.6%~81.0%、77.1%~81.2%、59.8%~63.2%、80.1%~93.8%。与免耕覆盖还田相比,翻压还田的累积腐解率和前期的腐解速率显著较高。2种还田方式的养分释放水平相当,但覆盖还田下各养分的快速释放期均短于翻压还田,持续供应养分能力更好。从保护土壤墒情和减少能源消耗的角度,毛叶苕子免耕覆盖还田具有一定优势,但可能受后期降雨、风等自然条件的影响更大,需要综合考虑和进一步的验证。

Green manure has unique advantages in improving soil structure and fertility in saline alkali land,but such research is absent in the Yellow River Delta.To provide references for its rational utilization,through planting experiments and nylon net bag simulated decomposition experiments,the nutrient supply capacity of Vicia villosa as green manure and the decomposition and nutrient release characteristics of the no-till mulching and rolling back methods were investigated.The results showed that the return of V.villosa to the field in the saline alkali areas of the Yellow River Delta could provide a greater proportion of the nitrogen and potassium nutrients required by the subsequent maize crop,but less of the phosphorus.Under 2 returning methods,the decomposition and nutrient release rates were both fast in the early stage then significantly decreased in the late stage,and the nutrient accumulation and release rate was potassium>nitrogen>carbon>phosphorus.By 81 d,the decomposition rates of straw mulching treatment and soil coverage treatment were 53.7%and 74.8%,respectively,and the release rates of carbon,nitrogen,phosphorus and potassium were 75.6%~81.0%,77.1%~81.2%,59.8%~63.2%and 80.1%~93.8%,respectively.Compared with soil coverage treatment,the cumulative decomposition rate and early decomposition rate under straw mulching treatment were significantly higher.The nutrient release levels of the two returning methods were nearly the same,but the rapid release period of each nutrient under soil coverage treatment was shorter than that under straw mulching treatment,indicating its better ability to sustainable nutrient supply.From the perspective of protecting soil moisture and reducing energy consumption,soil coverage returning method has certain advantages,but it may be more affected by later rainfall,wind and other natural conditions,which needs comprehensive consideration and further verification.