秸秆还田对盐碱地土壤物理性质、酶活性及油葵产量的影响

针对宁夏银北盐碱地区存在的土壤板结、通气性差、结构不良等问题,建立秸秆还田1 a、2 a与未还田试验,研究不同处理对土壤物理性质、酶活性及油葵产量的影响。结果表明:秸秆还田可显著降低土壤体积质量,还田2 a处理可降低体积质量6.04%～6.49%,且0～10、10～20、20～30 cm土层水稳性团聚体含量分别较CK处理增加15.30%、10.34%、8.84%,0～10 cm土壤紧实度较CK处理降低23.24%;秸秆还田能有效提升土壤脲酶与碱性磷酸酶的活性,0～10 cm土层还田2 a处理下脲酶活性较还田1 a与未还田处理分别增加93.79%、59.18%;还田对土壤pH影响不显著,但在控盐、增产方面效果突出,还田2 a处理相比CK处理在整个生育期0～10 cm土层含盐量平均降低24.33%,产量增加20.60%。相关性分析显示,土壤水稳性团聚体、体积质量、酶活性与油葵产量达显著正相关。由此可见,秸秆还田2 a增加土壤水稳性团聚体含量,降低土壤体积质量与耕层盐分,且显著提高脲酶与碱性磷酸酶酶活性,从而增加油葵产量。

Effects of Straw Returning to Field on Physical Properties,Enzyme Activity of Saline-alkali Soil and Yield of Oil Sunflower

Focus on the problems of soil viscosity,poor aeration and imperfect structure in saline-alkali region of North Yinchuan in Ningxia.A comparative experiment of 1 a,2 a and the treatment without straw returning to the field were established to study the effects of straw returning on soil physical properties,enzyme activity and oil sunflower yield.The results showed that,straw returning could significantly reduce soil volumic mass,the volumic mass could reduced by 6.04%-6.49% under the treatment of straw returning 2 a ,while this treatment could increase respectively the content of water-stable aggregates by 15.30%,10.34% and 8.84% at 0-10 cm,10-20 cm and 20-30 cm levels.Compared with CK treatment,the soil compactness at 0-10 cm was 23.24% lower than CK treatment,while,straw returning to field could effectively enhance the activity of soil urease and alkaline phosphatase activity.In particular,straw returning treatment 2 a increased urease activityby 93.79% and 59.18% at the 0-10 cm soil layer compared with CK and straw returning treatment 1 a.Straw returning to the filed did not significantly reduce soil pH ,but it had obvious effects on controlling salt and increasing yield .Especially,compared with CK treatment,the salt content of 0-10 cm soil decreased by 24.33% during the whole growth period,also increase the yield by 20.60%.the soil water-stabl eaggregates,volumic mass,enzyme activity and oil sunflower yield were significantly positively correlated.In conclusion,straw returning 2 a increases the content of soil water-stable aggregates,reduces soil volumic mass and topsoil salinity,also significantly improves urease and alkaline phosphatase activities,thus increasing the yield of oil sunflower.