新疆玛纳斯河流域棉田土壤有机碳含量时空分异规律

玛河流域棉田土壤有机碳的空间分异与连作棉田土壤有机碳变化的研究结果表明:由南至北在纬度梯度上有机碳总量随土壤粘粒含量的降低,砂粒含量的增大而呈下降趋势。HU-C和FA-C的变化趋势与总有机碳变化相近,HA-C在冲积扇缘有最大值,冲积平原下降,干三角洲呈增加趋势。H/F和Kos随纬度呈增长趋势。棉田土壤有机碳总量在秸秆还田技术下随连作年限的增加而提高,但主要增加了HU-C。H/F随连作年限呈下降趋势,在连作8年之后变为1。Kos在连作1~9年呈下降趋势,随后开始增长,8~9年是连作棉田土壤有机碳质量衰退的警戒值。

Temporal-Spatial Variation of Soil Organic Carbon Content in Typical Cotton Field of the Manas River Valley in Xinjiang

The spatial variation law of soil organic carbon(SOC)and the content variation of SOC in different continuous cropping cotton field in the Manas River Valley was studied.The results showed that,with the increase of latitude,from south to north,soil clay content was decreased and sands content was increased.There was a decreasing trend in cotton field SOC.The same trends were HU-C and FA-C.There was a maximum of HA-C at edge belt of alluvial fan,and decreased in alluvial plain,then it was increased in delta.The H/F ratio and Kos showed increasing treads.The content of SOC was increased in cotton field during different continuous cropping years in Valley of Manas River because of cotton straw application.But most of it was HU-C.The H/F ratio was decreased and declined to 1 after 8 years of continuous cropping.The Kos was decreased before 9 years of continuous cropping,and then increased.So the warning time of SOC in continuous cropping cotton field is 8～9 years.