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Northwest Agriculture and Forestry University (2019)

Meta-analysis of Effects of Vegetation Restoration on Soil Erosion Regulation in Semiarid Regions

刘一帆;

Titre : Meta-analysis of Effects of Vegetation Restoration on Soil Erosion Regulation in Semiarid Regions

Auteur : 刘一帆;

Grade : Master’s Theses 2019

Université : Northwest Agriculture and Forestry University

Résumé
Soil erosion is one of the major environmental problems in semiarid regions,which seriously threatens the survival and development of human.Due to the benefits of reducing soil loss and improving ecological environment,vegetation restoration has been considered a key strategy for soil erosion control.Moreover,vegetation restoration can regulate runoff process,thus affecting the local surface water resources and river ecosystem health.However,controversial results on the effects of vegetation on soil erosion exit widely among previous studies.Therefore,this study conducted a meta-analysis to evaluate the effects of vegetation on soil erosion control under various conditions(i.e.,vegetation type,rainfall characteristics,vegetation coverage,slope gradient,and soil texture)based on 78 previously published articles.The main findings were as follows :(1)The benefits of soil erosion regulation were significantly different among different vegetation types(P<0.5).The performance of the different vegetation types in terms of runoff reduction benefit was ranked in the order shrubland(SMD=-1.21)>forestland(SMD=-0.76)>grassland(SMD=-0.73).The performance of the different vegetation types in terms of sediment reduction benefit was ranked in the order grassland(SMD=-1.42)>forestland(SMD=-1.32)>shrubland(SMD=-1.06).Grassland with the high runoff retention and sediment reduction potential could be considered a suitable choice for soil erosion regulation and water resource management in semiarid regions.(2)The benefits of soil erosion regulation increased with the increasing vegetation coverage,and was relatively low when the vegetation coverage was less than 40%.Among them,the runoff reduction benefit of forestland and grassland were significantly different and were both less than 30%,and the sediment reduction benefit of shrubland was even less than 25%.The runoff and sediment reduction benefits of grassland tended to be stable when the vegetation coverage exceeded 60%.Shrubland had the highest runoff and sediment reduction benefits at 80-100% vegetation coverage.Forestland had the highest runoff reduction benefit at 80-100% vegetation coverage.And the sediment reduction benefit of forestland tended to be stable when the vegetation coverage exceeded 60%.(3)The benefits of soil erosion regulation were closely related to the rainfall amount and rainfall intensity.Large rainfall and heavy rainfall events formed plenty of overland runoff,thus resulting in higher sediment reduction benefit but relatively lower runoff reduction benefit.Vegetation showed a higher sediment reduction benefit(61.73-71.76%)but a relatively lower runoff reduction benefit(35.10-41.61%)when the rainfall intensity exceeded 60 mm/h.(4)The benefits of soil erosion regulation initially increased and then declined with the increasing slope gradient.Vegetation had the greatest performances for runoff reduction at slope gradients of 25-30° and slope gradients of 15-20° for sediment reduction.In terms of vegetation types,forestland,grassland and shrubland had high performance for soil erosion control on 20-30°,15-25° and 5-20° slopes,respectively.(5)Vegetation had the greatest performances for soil erosion regulation in moderately coarse and medium-textured soils,followed by moderately fine and fine-textured soils.However,vegetation had the lowest performances for soil erosion regulation in coarse soils.In addition,forestland had a superior effectiveness for soil erosion regulation in medium-textured and moderately fine soils.Grassland had a superior effectiveness for soil erosion regulation in moderately coarse and medium-textured soils.Shrubland had a superior effectiveness for soil erosion regulation in moderately coarse soils.The vegetation type,vegetation coverage,rainfall characteristics,slope gradient and soil texture significantly influence the effectiveness of the vegetation in providing soil erosion regulation.Therefore,it is necessary to select appropriate vegetation restoration types according to the local conditions during vegetation restoration.This study provides theoretical basis and scientific advice to achieve soil erosion regulation and surface water resource sustainability in semiarid regions around the world

Mots clés : Semiarid regions; Runoff; Sediment; Soil erosion regulation; Vegetation restoration;

Présentation (CNKI)

Page publiée le 18 novembre 2019