西北寒旱区秸秆颗粒还田对覆膜马铃薯-玉米轮作体系土壤有机碳和作物产量的影响OA

To explore efficient methods of returning straw to film-covered farmland in the cold and ar-id areas of Northwest China,seven treatments were set up:no straw returning(CK),straw granules returning at 6 000 kg·hm-2(KL6000),12 000 kg·hm-2(KL12000),18 000 kg·hm-2(KL18000),and straw crushing returning at 6 000 kg·hm-2(FS6000),12 000 kg·hm-2(FS12000),and 18 000 kg·hm-2(FS18000).The soil volumic mass,farmland fallow efficiency,total organic carbon content,crop yield,and water use efficiency were measured under different returning methods.Furthermore,a systematic analysis of crop yields and farmland soil ecological effects under different returning meth-ods was conducted to provide scientific and technological support for innovating technical models of farmland conservation and productivity enhancement.The results showed that compared with CK,straw returning significantly reduced the soil volumic mass by 5.31%to 16.81%in the current sea-son,and the decrease gradually increased with the increase of returning amount.The improvement in soil volumic mass from crushing returning was slightly better than that from granules returning.The farmland fallow efficiency of straw granules returning to the field was significantly increased by 3.60%to 10.76%compared with CK,and increased by 1.58%to 2.59%compared to the same amount of crushed straw returned(the difference was not significant).The amount of straw returned was positively correlated with the fallow efficiency.Returning straw significantly increased the total organic carbon content in the top soil of farmland during the returning season.The effect of granules returning was better than that of crushing returning.KL6000,KL12000,and KL18000 increased by 5.48%,8.59%,and 10.20%,and 0.92%,1.51%,and 2.40%,respectively,compared with CK and e-quivalent crushing returning.Straw returning significantly improved crop yield and water use efficien-cy.The granular returning method increased crop yield with increasing returning amount during the returning season,while the crushing returning method showed a trend of first increasing and then de-creasing.KL6000,KL12000,and KL18000 increased by 2.91%,16.62%,16.91%,and 2.11%,6.10%,and 9.79%,respectively,compared with CK and the same amount of crushing returning.There was no significant difference between 12 000 kg·hm-2 and 18 000 kg·hm-2.In the second year of returning to the field,the yield difference between different returning methods and returning amounts gradually narrowed.The crop water use efficiency of granules returning in the current season was significantly higher than that of crushing returning by 13.47%,which was not significantly differ-ent from that of CK.The highest water use efficiency was achieved at 12 000 kg·hm-2.In the second year of returning,KL12000,KL18000,and FS18000 were significantly higher than CK.Considering both the straw returning effect and cost comprehensively,returning 12 000 kg·hm-2 of straw gran-ules is recommended for promotion and application as an important technical measure for farmland conservation,stable yield,and increased efficiency in the mulching potato maize rotation system in the cold and arid areas of Northwest China.