青海湖东沙化治理过程中土壤酶活性及养分含量特征

摘要

This study focused on the artificial grasslands established with three different plant species Elymus dahuricus (Ely), Puccinellia distans (Puc) and Poa annua (Poa) for five years to control desertification to the east of Qinghai Lake.To assess the effects of these three artificial grasslands on sand soil nutrient content, soil enzyme activities and their relationships, we analysed soil nutrient (nitrogen, phosphorous, and potassium) and organic matter contents, as well as the activities of three soil enzymes, namely, urease, catalase, and invertase.The results showed that: 1) soil nutrient and soil enzyme activity were significantly improved after the grasses were planted.2) Compared with the other two treatments, Poa had significant effects on improving soil organic matter, available nitrogen, available phosphorus, total potassium, and available potassium.The soil nutrient content had a significant positive relationship with soil urease activity.3) Soil urease activity was much greater in the Ely and Poa treatments, and the activities in all the three treatments were higher than the control in the surface soil layer.In the 0-20 cm soil layer, the activities of soil catalase in the three treatments were higher than that in the control, with Poa showing the highest activity.All three treatments showed no significant effect on the activity of soil invertase.4) The activities of soil urease and catalase both had a general significant relationship with soil nutrient content, which could be taken as the effective index for the measurement of desertification control process.%本研究以青海湖东沙化治理区建植5年所形成的披碱草(Elymus dahuricus)、碱茅(Puccinellia distans)和早熟禾(Poa annua)栽培草地为研究对象,通过测定土壤有机质、氮、磷、钾养分含量以及脲酶、过氧化氢酶和转化酶活性,探讨了在高寒干旱沙化生态系统中不同草本植物作用下土壤养分和土壤酶的变化特征及其相互关系.结果表明,1)人工治沙植被作用下,土壤养分和土壤酶活性均显著提高(P<0.05);2)早熟禾在青海湖区域治沙过程中对土壤有机质、碱解氮、速效磷、全钾和速效钾的改良效果显著(P<0.05);3)在3种栽培草地处理下土壤脲酶活性在表层土壤中普遍显著高于流动沙丘对照(P<0.05),披碱草和早熟禾栽培草地的脲酶活性较高,0-20 cm土层中土壤过氧化氢酶活性在3个栽培草地中均显著高于对照(P<0.05),且早熟禾栽培草地中土壤过氧化氢酶活性最高,土壤转化酶在各栽培草地间差异不显著(P>0.05);4)各栽培草地中土壤脲酶和过氧化氢酶普遍与土壤中的碳氮磷养分存在显著相关性(P<0.05),可以作为沙化治理过程中评价土壤恢复的有效指标.