The Research On Physico-chemical Properties And Soil Enzyme Activity Of Pastureland Shelterbelt

The soil enzyme activities, physico-chemical properties were studied in pasturelandshelterbelts at different ages and arrangements (grid-shaped, belt-shaped, sparse pasturelandshelterbelts)and non-forest pastureland by the method of comparison and analysis.The resultsshowed that: (1) The soil catalase activity, polyphenoloxidase activity, sucrase activitiy, ureaseactivity, protease activity, total N and hydrolyzable nitrogen in the grid-shaped pasturelandshelterbelts were all higher than those in the belt-shaped pastureland shelterbelts at the sameage, and their differences were significant. The organic matter, organic carbon of soil humus,humic acid and fulvic acid in the grid-shaped pastureland shelterbelts were also higher thanthose in the grid-shaped pastureland shelterbelts, but their differences were not signifcant. Theurease activity, catalase activity, polyphenoloxidase activity, sucrase activitiy, hydrolyzablenitrogen, available phosphorous, soil organic matter, carbon content of soil humus, fulvic acidwere higher in sparse pastureland shelterbelts than those in non-forest pastureland; (2) Thecontents of total N, hydrolyzable nitrogen and rapidly available K in grid-shaped pasturelandshelterbelts rised with their ages increasing from 1 to 5-year's old, and these content changeshad an opposite tendency from 5 to 25-year's old; The change rule of the content of available Pwas the same as that of the soil phosphatase activity. The contents of organic matter and huminwithin grid-shaped pastureland shelterbelts and in pastureland protected by it, the fulvic acidwithin grid-shaped pastureland shelterbelts increased over their ages from 1 to 15-year's old,but they decreased after 15-year's old. For the same factor, there was not significant differencebetween different age stages; (3) The saturated water content, capillary soil water content, andfield capacity of soil, non-capillary porosity, capillary porosity, total porosity of grid-shapedpastureland shelterbelts at different ages were lower than those of sparse pastureland shelterbelt,but the soil bulk density was higher; (4) The soil phosphatase activities, sucrase activities,catalase activities, protease activities and urease activities of grid-shaped pasturelandshelterbelts were obviously correlated with the content of soil available phosphorus, organicmatter, humus compositions and hydrolyzable nitrogen; (5) The soil qualities of differentarrangements of the degenerated pastureland shelterbelt (grid-shaped, belt-shaped, sparsepastureland shelterbelts) and non-forest pastureland were comprehensively evaluated by themethod of principal component analysis. Their order of different arrangements of pasturelandshelterbelts was that: grid-shaped＞belt-shaped＞sparse＞non-forest pastureland; Their order ofgrid-shaped pastureland shelterbelt of different ages was that: 5＞15＞25＞2＞1-year's old.