新疆艾比湖地区不同土地利用类型土壤养分及活性有机碳组分研究

土壤有机碳及其组分是土壤质量的重要指标,在土壤许多物理、化学和生物特性中发挥着重要作用。通过对我国内陆荒漠自然生态系统中新疆艾比湖地区不同土地利用类型土壤进行采样和分析,系统地研究和比较了不同土地利用类型土壤养分及有机碳组分。结果表明:新疆艾比湖不同土地利用类型土壤总孔隙度与土壤容重变化趋势相反。不同土地利用类型对土壤养分具有较大影响,土壤有机碳、全氮、全磷和全钾均呈现出一致性规律,大致表现为林地草地耕地未利用地,而不同土地利用类型土壤全磷差异并不显著(p0.05)。不同土地利用类型土壤易氧化有机碳(EOC)、颗粒有机碳(POC)、轻组有机碳(LFOC)、水溶性有机碳(WSOC)、土壤微生物量碳(MBC)和微生物量氮(MBN)均呈现出一致性规律,大致表现为林地耕地草地未利用地。林地和草地EOC/SOC比例显著低于耕地和未利用地,说明林地和草地转变成耕地降低了土壤有机碳的稳定性;微生物商(MBC/SOC)基本表现为耕地林地草地未利用地,其中耕地和林地土壤MBC/SOC比例差异不显著(p0.05)。相关性分析表明,土壤活性有机碳各组分与SOC,TN,TK均具有极显著相关性关系,并且不同土地利用类型土壤EOC,POC,LFOC,WSOC和MBC含量之间均具有极显著相关性(p0.05),说明土壤活性有机碳很大程度上依赖于有机碳含量,活性有机碳各组分之间相互影响和密切联系,其中SOC,TN和TK是不同土地利用类型土壤活性有机碳变化的重要影响因子。

Variation of Soil Nutrients and Soil Active Organic Carbon Under Different Land Use Patterns in Aibinur Lake Region of Xinjiang

The Aibinur Lake region has great position for its ecology and geography.As an essential indicator of soil quality,soil organic carbon (SOC) and its fractions play an important role in many soil chemical,physical and biological properties.A field experiment was conducted to determine the variation of soil nutri ents and soil active organic carbon under different land use patterns in Aibinur Lake region of Xinjiang.The results are as follows.The soil mechanical composition under different land use patterns was different,and the change trend of soil total porosity was contrary with the soil bulk density.The soil organic carbon,total nitrogen,total phosphorus and total potassium had the same change trends,which showed the order:forest land＞grassland＞cultivated land＞ unused land,while the soil total phosphorus had no significant difference under different land use patterns (p＞0.05).The easy oxidation of soil organic carbon (EOC),particulate organic carbon (POC),light fraction of organic carbon (LFOC),water soluble organic carbon (WSOC),soil microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) had the same change trends,which showed the sequence:forest land＞grassland＞cultivated land＞unused land.The ratios of EOC to SOC of forestland and grassland were higher than those in cultivated land and unused land which showed that the stability of soil organic carbon decreased in the progress of conversion of forestland and grassland to cultivated land.The ratios of MBC to SOC showed the sequence:forest land＞ grassland＞ cultivated land＞unused land,while the ratios in forestland and cultivated land had no significant difference (p＞0.05).Correlation analysis showed that soil active organic carbon components had a significant correlation with SOC,TN,TK,and EOC,POC,LFOC,WSOC and MBC had the extremely significant correlation each other (p＜0.05),which indicated that soil active organic carbon mainly depended on the organic carbon content to a large extent and active organic carbon influenced each other.In addition,the contents of SOC,TN,and TK were the important influencing factors on change in active organic carbon under different land use patterns in Aibinur Lake region of Xinjiang.