干旱区盐渍化荒地不同开垦年限土壤碳氮储量研究

在天山北坡绿洲区分别选取连续开垦3 a、8 a、15 a盐渍化棉田和未开垦的盐渍化荒地,采集0~10、10~20、20~40、40~60、60~100 cm土层土壤样品,测定土壤有机碳、全氮含量。结果表明:盐荒地开垦后棉田0~100 cm土层土壤有机碳含量随开垦年限呈逐渐增加的趋势;开垦后棉田土壤全N含量随开垦年限的增加而增加,但处理间无显著差异;盐荒地与开垦棉田土壤有机碳、全N含量随土层深度增加而降低,其中盐荒地不同土层间土壤有机碳含量差异显著,0~40 cm土层土壤有机碳、全N含量明显高于40 cm以下土层;开垦棉田土壤C/N随开垦年限的增加呈现增加的趋势,盐荒地和开垦棉田土壤C/N随土壤深度的增加而降低,二者之间差异不显著;开垦棉田土壤有机碳储量随开垦年限的增加呈先减少后增加的趋势。结论:干旱区盐荒地开垦后,棉田土壤有机碳、全N含量均随开垦年限的增加而增加,而土壤有机碳储量随开垦年限的增加先减小后增加。盐荒地与开垦棉田土壤有机碳和全N含量随土层深度增加而减少。

Soil carbon and nitrogen storage of different reclamation years in salinized wasteland in arid region

Salinization soil of cotton farmland reclaimed from salinized wasteland in the north area of Tianshan Mountain with three reclamation year:3 years,8 years and 15 years,was chosen and salinized wasteland was the contml.Soil organic carbon and total nitrogen,and carbon storage in 0 ～ 10,10 ～ 20,20 ～ 40,40 ～ 60 cm and 60 ～ 100 cm were measured.Results showed that soil organic carbon and total nitrogen content in 0 ～ 100 cm of cotton field in creased with years of reclamation in salinized wasteland.There was no significant difference in total nitrogen content among salinized wasteland and reclaimed farmland with different years of reclamation.Soil organic carbon and total nitrogen content decreased with soil depth in both reclaimed cotton farmland and salinized wasteland.In salinized wasteland,soil organic carbon and total nitrogen content in 0 ～ 40 cm soil layer were significantly higher than those below 40cm soil layer.Soil C/N in reclaimed farmland increased with years of reclamation.Soil C/N in salinized wasteland and reclaimed farmland decreased with soil depth.The difference of soil C/N in salinized wasteland and reclaimed farmland was insignificant.Soil organic carbon storage in reclaimed cotton farmland decreased at first and then increased with reclamation years.In conclusion,soil organic carbon and total nitrogen content of cotton field increased with years of reclamation in salinized wasteland.However,soil organic carbon storage showed a trend of decrease-increase with reclamation years.Soil organic carbon and total nitrogen content in salinized wasteland and reclamation farmland decreased with soil depth increasing.