Changes in Soil Organic Matter,Nitrogen and Phosphorus Contents during Decomposition of Pear Branches

[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragrant pear in the orchard were collected and returned to the field for a period of 150 d for indoor mixed culture.[Results]Different ages of Korla fragrant pear branches have different effects on soil nutrient content during the simulated return to field decomposition process.Compared with the control in the same period,the treatment of returning to field reached a significant level(P<0.05).Compared with the control,the average values of organic matter,total nitrogen and available phosphorus content in treatment 1 and treatment 2 increased by 2.16 times and 1.93 times,61%and 59%,5.88 times and 6.88 times,respectively;compared with the control,the average increase performance of the alkaline hydrolysis nitrogen content of the two treatments was basically the same,and the treatment 2 was the best;compared with the control,the average total phosphorus content of treatment 1 and treatment 2 increased but not significantly.[Conclusions]The contents of soil organic matter,nitrogen and phosphorus were all increased during the decomposition of pear branches,and the overall improvement effect of 10-year-old trees was better than that of 5-year-old trees.Returning the pruned branches to the field can provide a reliable theoretical basis for solving the problem of organic fertilizer shortage in orchards,and also can ensure technical support for improving soil fertility and improving the rhizosphere micro-environment of pear trees.

海拔和坡向对伊犁河谷草地土壤理化性质的影响

[目的]研究海拔和坡向对伊犁河谷草地土壤性质的影响。[方法]以新疆伊犁昭苏和察布查尔县海拔1 400~2 800 m不同剖面草地土壤为研究对象,探讨海拔和坡向对草地土壤性质的影响。[结果]南坡不同海拔全氮(0.33~3.24 g/kg)在1 400~2 000 m随海拔升高而增加,其后在2 200~2 800 m显著降低(P<0.05),硝态氮(1.43~76.33 mg/kg)、铵态氮(22.84~110.17 mg/kg)在1 400~2 800 m随海拔升高而显著降低(P<0.05),与海拔呈显著负相关(P<0.05)。北坡不同海拔全氮(0.08~1.13 g/kg)在1 400~2 800 m随海拔升高而降低。铵态氮(27.96~132.73 mg/kg)在1 400~1 800 m随海拔升高而显著增加(P<0.05),其后在2 000~2 800 m显著降低(P<0.05)。硝态氮(0.73~13.8 mg/kg)在1 400~2 800 m随海拔升高而增加。除北坡相同海拔相同土层铵态氮大于南坡外,全氮、硝态氮及其他理化性质均呈南坡大于北坡。南坡海拔与含水量、全氮呈正相关,北坡海拔与含水量、容重、硝态氮呈正相关。[结论]该研究对伊犁草原生态保护、土壤氮循环和退化生态系统恢复重建具有一定的理论意义和实践指导价值。