油菜·小麦秸秆在稻田土壤中腐解及养分释放特征

目的]探明川东北丘陵区油菜、小麦秸秆在稻田土壤中腐解及养分释放特征,为水稻合理栽培提供理论依据。方法]采用尼龙网袋法,以油菜荚壳、油菜茎秆、油菜蔸部和小麦秸秆为试验材料,研究这4种材料在土壤中腐解及养分释放特征。结果]4种秸秆材料腐解速率均呈现先快后慢,从大到小依次为油菜荚壳、小麦秸秆、油菜茎秆、油菜蔸部,还埋10 d累积腐解率在29.20%~51.70%,还埋100 d累积腐解率在43.50%~75.80%;不同秸秆材料养分释放速率亦表现为先快后慢,还埋20 d各材料的碳、氮、磷、钾释放率均在30.00%以上,其中钾素释放速度最快(平均达98.70%),还埋100 d累积释放率从大到小依次为钾(99.10%)、磷(60.60%)、氮(58.40%)、碳(58.00%)。结论]生产上应根据秸秆腐解规律及养分释放规律制订合理的水稻栽培管理措施。

Decomposition and Nutrient Release Characteristics of Rapeseed and Wheat Straws Incorporated into Paddy Soil

Objective] This study aims to explore the decomposition and nutrient release characteristics of rapeseed and wheat straws incorpo-rated into paddy soil in the hilly area of northeast Sichuan Province.Method] With rapeseed pod shell, stem, root and wheat straw as materi-als, the decomposition and nutrient release characteristics were studied by method of nylon net bag incorporated into paddy soil . Result] The decomposition rates of 4 materials were much faster at the beginning stage than the end of the experiment , and rapeseed pod shell decomposed fastest, followed by wheat straw, rapeseed stem and rapeseed root.After 10 days of incorporation, the cumulative decomposition rates of the four straws were between 29.20% to 51.70% while those were between 43.50% to 75.80% after 100 days of incorporation.The nutrient re-lease rate also had been found to be much faster at the beginning stage than the end.After 20 days of incorporation, the release rates of nutri-ent (C, N, P, K) for all the straws were more than 30.00%, and the release rate of K was the highest (an average of 98.70%).After 100 days of incorporation, the sequence of nutrient release rates for all the straws were K (99.10%), P(60.60%), N(58.40%), C (58.00%).Conclusion] It is necessary to make reasonable management measures for rice cultivation on the basis of crop straw decomposi-tion characteristics and nutrient release.