不同装袋量下麦秆和毛叶苕子混合腐解特征

Characteristics of mixed decay of wheat straw and hairy vetch under different bagging volumes

掌握不同装袋量下麦秆、毛叶苕子混合的腐解过程,对青海东部农业区秸秆还田和培肥土壤具有重要意义。通过尼龙袋填埋试验,设置物料类型和装袋量两个因素,完全随机组合共9个处理。物料类型设麦秆(W)、毛叶苕子(H)、混合物料(WH)3个水平,装袋量设16、28、44 g 3个水平,研究3种物料类型在不同装袋量下的腐解特征。研究结果表明,各处理下有机物料腐解呈现前期快-中期慢-后期加快的变化规律,至腐解结束,物料类型对累计腐解率有显著影响(P<0.05),麦秆、毛叶苕子、混合物料的累计腐解率平均为45.27%、76.75%、62.25%,表现为毛叶苕子>混合物料>麦秆。装袋量对累计腐解率有显著影响(P<0.05),装袋量分别为16、28、44 g时,平均累计腐解率分别为62.84%、63.32%、58.11%,装袋量28 g下腐解最快。双库指数衰减模型能较好地拟合物料腐解过程中腐解残留率与积温的关系,方程的决定系数均>0.88,预测腐解残留率与实测腐解残留率的MPE、RMSE、nRMSE分别为8%、2.47、7.85%。麦秆、毛叶苕子和混合物料的腐殖化系数平均分别为54.05%、31.32%、41.90%。物料混合显著提高了干物质量的易分解比例(P<0.01),装袋量为16、28、44 g时,混合效应值分别提高了13.27%、15.06%、8.61%,装袋量为28 g时混合效应最高。物料混合显著提高了干物质易分解比例,腐解速率加快。麦秆和毛叶苕子混合能加快物料的腐解,当装袋量为28 g时(相当于麦秆、毛叶苕子还田量分别为5490、3393 kg·hm^(-2))效果最好,该研究结果可为青海东部农业区秸秆还田提供理论和技术指导。

It is important to grasp the decomposition process of wheat straw and hairy vetch mixed under different bag filling amounts for straw return and soil fertilization in the agricultural area of eastern Qinghai.In this study,two factors,material type and bagging volume were set up by nylon bagging experiment with a total of nine treatments in completely randomized combinations.The decomposition characteristics of the three material types at different bagging levels were investigated at three levels.The three material types were straw(W),hairy camelina(H)and their mixed material(WH),and three bagging level were 16,28 and 44 g.The results showed that the decomposition of organic materials under each treatment showed a change pattern of fast in the early stage-slow in the middle stage-and faster in the late stage,and the material type had a significant effect on the cumulative decomposition rate until the end of decomposition(P<0.05),and the cumulative decomposition rates of wheat straw,hairy vetch and mixed materials were 45.27%,76.75%and 62.25%on average,respectively,showing that hairy vetch>mixed materials>straw.The bagging volume had a significant effect on the cumulative decay rate(P<0.05),with the average cumulative decay rates of 62.84%,63.32%and 58.11%at bagging volumes of 16,28 and 44 g,respectively,with the fastest decay at bagging volume of 28 g.The two-bank exponential decay model could better fit the relationship between the decay residue rate and the accumulated temperature during material decay,and the coefficients of determination of the equations were all greater than 0.88.The MPE,RMSE and nRMSE of the predicted and measured decay residue rates were 8%,2.47 and 7.85%,respectively.The average humification coefficients of wheat straw,hairy vetch and mixture were 54.05%,31.32%and 41.90%,respectively.Material mixing significantly increased the percentage of easy decomposition of dry matter mass(P<0.01),and the values of mixing effect increased by 13.27%,15.06%and 8.61%at bagging volumes of 16,28 and 44 g,respectively,with the highest mixing effect at bagging volume of 28 g.The material mixing significantly increased the percentage of dry matter easy to decompose,and the decomposition rate was accelerated.The mixing of wheat straw and hairy vetch accelerated the decomposition of materials,and the best effect was achieved when the bagging volume was 28 g(equivalent to 5490 and 3393 kg·hm^(-2) of wheat straw and hairy vetch returned to the field,respectively).The results could provide theoretical and technical guidance for straw return to the field in the agricultural area of eastern Qinghai.