秸秆还田方式对麦田土壤碳、氮、水动态及小麦产量的影响

为了解不同秸秆还田方式的效果,在田间定位试验的基础上,比较分析了玉米秸秆直接还田(J)、过腹即牛粪还田(F)和发酵后沼液还田(Z)后麦田土壤碳、氮、水和小麦产量的变化。结果表明,三种秸秆还田处理均提高了0~60cm土层土壤有机碳增量(即相对于播前土壤有机碳储量的增加量),在0~20和20~60cm土层三种秸秆还田处理土壤有机碳增量均分别以越冬期和拔节期最高。在越冬期,F和Z处理0~40cm土层的土壤氮含量显著增加,J处理土壤氮含量与不还田对照差异不显著;在拔节期和开花期,三种秸秆还田处理0~20cm土层以及F和J处理20~40cm土层的土壤氮含量均显著增加。秸秆还田提高了土壤保水能力,在开花期,三种秸秆还田处理0~80cm土层的土壤含水量均显著高于对照。在越冬期和拔节期,F和Z处理的干物质积累量和单茎干重与对照差异不显著,但J处理显著降低;三种秸秆还田处理的成熟期干物质积累量和单茎干重均显著增加,以J处理最高。三种秸秆还田处理均显著提高了小麦穗数和产量,其中Z处理增产23.0%。因此,三种秸秆还田方式均能改善土壤质量和提高小麦产量,其中沼液还田综合效应最好。

Effects of Different Straw Returning Methods on Soil Carbon,Nitrogen, Water Dynamics and Yield of Wheat

Based on 6 year field experiments, the effects of different straw returning methods on soil carbon, nitrogen, water and wheat yield were studied. Three kinds of straw returning modes were chosen as returning straw to field directly (J), returning manure to field (F) and returning biogas slurry to field (Z), with no straw returning (CK) as the control group. The results showed that three straw returning treatments all increased organic carbon increment in the 0~60 cm soil layer. The organic carbon increment in 0~20 cm layer was the highest at over-wintering stage, the organic carbon increment in 20~60 cm layer was the highest at jointing stage. At over-wintering stage, F and Z treatments had significantly higher soil nitrogen content in 0~40 cm layer compared to CK, but there was no significant difference in soil nitrogen content between J treatment and CK; at jointing and flowering stages, three straw returning treatments had significantly higher soil nitrogen content in 0~20 cm layer compared to CK. F and J treatments had significantly higher soil nitrogen content in 20~40 cm soil layer. The three straw returning treatments improved soil water-holding capacity at flowering stage, their soil water contents in 0~80 cm layer were significantly higher than that of CK.At the over-wintering stage and jointing stage, F and Z treatments had similar dry matter accumulation and single stem weight to the CK, but J treatment significantly reduced dry matter accumulation and single stem weight compared to CK. At mature period, dry matter accumulation and single stem weight of three straw returning treatments were significantly higher than those of the CK, in which J treatment had the highest dry matter accumulation and single stem weight. Three straw returning treatments significantly increased the spike number and grain yield, and the Z treatment had the highest spike number and grain yield, with grain yield increased by 23% compared to CK. The results above suggested that the three straw returning treatments all improved the soil quality, and increased the grain yield of wheat, and Z treatment (returning biogas slurry to field) had the best combined effect.