若尔盖地区草地沙化特征研究

Study on the desertification mechanism of the grassland in Zoige

研究了若尔盖地区不同退化程度的草地土壤理化性质随土壤深度(0～60cm)的变化特征和草地的沙化机制。结果表明:草地退化是以0～30cm土层,土壤N、有机质和腐殖酸的流失为主要特征,当三者的流失率分别达到95.45%、98.85%、98.36%时,土壤P、K含量降低,草地盖度下降、生物量减少;随着草地退化程度的加深,在0～30cm土层,土壤水分含量不断降低而沙含量不断升高,全沙化草地水分含量在5%以下,沙含量达到98%;草地沙化从0～30cm土层开始,尤其是在20cm,土壤水分含量和沙含量的变化使得该土层成为沙化敏感区。

Physicochemical characteristics of soil in different degradatied grassland in Zoige were analyzed based on the soil layer（0-60 cm）. The results showed,the grassland degradation was characterized by the loss of soil ni 45%,98. creased. with the tion was trogen, organic matter and humus in the soil layer with 0-30 cm. When the w 85 % and 98.36 %, the content of soil phosphorus and potassium declined, the bi In the soil layer with 0-30 cm,moisture declined gradually,and the sediment degrad 98%. changes of mois ation deepening. The moisture of d Grassland degradation began in the ture and sediment concentration ma astage rate reached 95. omass and coverage de concentration increased esertified point was below 5%, and the sediment eoneentra- soil layer with 0-30 era,especially in 20 cm depth,and the de this layer become the desertification sensitive zone.