塔里木盆地北缘绿洲不同连作年限棉田土壤有机碳组分特征及其与理化因子的相关性

Characteristics of Soil Organic Carbon Components and Their Correlation with Other Soil Physical and Chemical Factors in Cotton Fields with Different Continuous Cropping Years in the Oasis on the Northern Edge of Tarim Basin

开展绿洲连作棉田土壤有机碳组分研究,有助于阐明干旱区农田土壤有机碳稳定性机制在人地关系作用下变化特征.以塔里木盆地北缘阿拉尔垦区为研究区,以空间代替时间序列法分析了2、5、12、20和35 a等不同连作年限棉田土壤有机碳、易氧化有机碳、可溶性有机碳和微生物量碳的含量特征,结合冗余分析探讨了土壤有机碳组分与土壤其它理化因子(含水量、容重、pH值、全盐、全氮、有效磷和速效钾)的相互关系,结果表明:(1)不同年限的连作对研究区土壤有机碳组分含量具有显著影响,土壤有机碳、易氧化有机碳、可溶性有机碳和微生物量碳含量整体表现为连作12、20和35 a棉田高于连作2 a、5 a棉田和荒草地,ω(土壤有机碳)在20 a棉田达到峰值(7.06g·kg^(-1)),高出荒草地76.91%,各土壤有机碳组分含量均随着土层的加深而下降.(2)基于对土壤有机碳组分含量与土壤其它理化因子的冗余分析结果表明,土壤有机碳组分含量与全氮、有效磷和含水量呈正相关关系,与pH值和容重呈负相关关系.土壤其它理化因子对土壤有机碳组分含量解释的重要性排序为:全氮>有效磷>pH值>容重>含水量>速效钾>全盐.

The study of soil organic carbon components in continuous cropping cotton fields in oases is helpful to reveal the change characteristics of the soil organic carbon stability mechanism in arid areas under the effects of man-land relationships.In this study,the contents of soil organic carbon,easily oxidized organic carbon,dissolved organic carbon,and microbial biomass carbon in cotton fields with different continuous cropping years(2 a,5 a,12 a,20 a,and 35 a)were collected and analyzed by using space instead of the time series method.Through redundancy analysis,the relationship between soil organic carbon components and other soil physical and chemical factors was discussed.The results showed that:(1)continuous cropping for different years had a significant impact on the content of soil organic carbon components in the study area.The contents of soil organic carbon,easily oxidized organic carbon,dissolved organic carbon,and microbial biomass carbon in continuous cropping cotton fields for 12 a,20 a,and 35 a were higher than those in continuous cropping cotton fields and wasteland for 2 a and 5 a.ω(soil organic carbon)reached the peak value(7.06 g·kg^(-1))in the cotton field in 20 a,which was 76.91%higher than that in the wasteland.The content of soil organic carbon decreased with the deepening of the soil layer.(2)Based on the redundancy analysis of soil organic carbon content and soil environmental factors,the results showed that the content of soil organic carbon was positively correlated with total nitrogen,available phosphorus,and water content and negatively correlated with pH value and bulk density.The importance of soil environmental factors on the interpretation of soil organic carbon content was as follows:total N>available P>pH value>bulk density>water content>available K>total salt.