不同开垦年限西藏草地中量、微量元素含量变化特点

Content Change Characteristics of Medium and Trace Elements in Different-Year-Cultivated Grassland in Tibet

为了解西藏草地开垦后土壤养分的变化,选取西藏两个不同地区(江孜和琼结)、不同开垦年限的耕地土壤为研究对象,采集0～20cm耕层土壤测定Ca、Mg、Fe、Mn、Zn、Cu的全量和有效含量。结果表明,草地开垦为耕地后,江孜地区Fe、Zn、Mg全量和有效含量随着开垦年限的增加而增加,而Mn、Cu、Ca全量和有效含量随着开垦年限的增加表现为先增加后减少;琼结地区随着开垦年限的增加Ca、Mg、Mn、Zn、Cu的有效含量逐渐增加,有效Fe含量先减少后增加,Fe、Mn、Mg的全量有先增加后减少的趋势,Zn、Cu、Ca的全量却有先减少后增加的趋势。土壤养分性状间存在着一定的相关性。

To understand the nutrient changes of grassland soil after cultivation,the surface soil of different reclamation years in two different regions of Tibet,Jiangzi and Qiongjie,was selected as the object of the study.0～20cm topsoil was collected to determine the entire amount and the effective content of elements,Ca,Mg,Fe,Mn,Zn and Cu.The results showed as follows.In Jiangzi,the entire amount and the effective content of Fe,Zn and Mg increased with the increase of cultivation years,however,the entire amount and the effective content of Mn,Cu and Ca increased at the beginning but decreased with the increase of cultivation years.In Qiongjie,with the increase of cultivation years,the effective content of Ca,Mg,Mn,Zn and Cu increased gradually,the effective content of Fe reduced at first but then increased;the entire amount of Fe,Mn and Mg showed a decreasing trend,and the entire amount of Zn,Cu and Ca decreased at the beginning but then increased.There were certain relations among different elements of soil.