干旱区沙漠化逆转过程土壤矿质元素的变化特征

Variations of Soil Mineral Elements in Reversion Process of Desertification in Arid Areas

以腾格里沙漠南缘沙漠化土地为研究对象,应用时空替代法选择流动沙丘、半固定沙丘、固定沙丘的沙漠化逆转序列样地,研究了沙漠化逆转过程土壤矿质元素的变化特征。研究结果表明,干旱区沙漠化逆转过程中,表层土壤硫、磷、溴、氯、钪、钕、镧、镓、铷、锡元素含量随沙漠化逆转过程逐渐增加;铜、锰、锌、镍、铌、铬、铅、钒、铋、铪、砷、钇、铈、钍、锶、锆、钛、镁、钙、钠、铁元素含量先减少后增加;钨、钴、铯、铊、铀、钾元素含量先增加后减少;而钡、硅元素含量逐渐减少。显然,干旱区沙漠化土地逆转过程不仅恢复了固沙植被,改善了土壤结构,提高了土壤肥力,也明显改变了植物必需矿质元素、稀土元素以及重金属元素含量。

At the South Edge of the Tengger Desert, the sampled sites of mobile sanddune, semi-fixed sanddune and fixed sanddune were selected as the different stages of the reversion process of desertification with the method of substituting time with space, and topsoil mineral elements of the decertified land were studied in reversion process of desertification. The results showed that the content of S, P, Br, CI, Sc, Nd, La, Ga, Rb and Sn of topsoil increased, the content of Cu, Mn, Zn, Ni, Nb, Cr, Pb, V, Bi, Hf, As, Y, Ce, Th, Sr, Zr, Ti, Mg, Ca, Na and Fe of topsoil reduced first and increased later, and the content of W, Co, Cs, Tl, U and K of topsoil increased first and reduced later while the content of Ba and Si of topsoil reduced in reversion process of desertification. Obviously, with the reversion process of desertification, sand-binding vegetation recovered, soil structure improved and soil fertility increased, and the contents of topsoil mineral elements changed distinctly.