黄土高原丘陵区人工灌草生态系统水土保持功能评估

Evaluation of Soil and Water Conservation Function of Artificial Shrub-Grassland Ecosystem in Hilly Region of the Loess Plateau

人工灌草复合植被是黄土高原植被恢复与重建的主要植被类型,在该区域水土保持中发挥着重要的作用。以定西市安定区为例,基于InVEST模型对该区人工灌草生态系统的水土保持功能进行定量化评估,以期为黄土高原丘陵区生态恢复与水土资源的可持续利用提供决策支撑。评估结果为:(1)人工灌草地单位面积的水源涵养量为369.25 m^3/hm^2,是草地的90.5%、林地的134%和耕地的110%;该区的水源涵养总量为3970.99×10^4 m^3,人工灌草地水源涵养量占该区总水源涵养量的29.9%。(2)人工灌草地单位面积的N保持量为2.4 kg/hm^2,净化率为72.21%,P保持量为0.12 kg/hm^2,净化率为71.07%。(3)人工灌草地单位面积的土壤保持量为308.76 t/hm^2,比草地、林地和耕地分别高1.88,1.44,6.01倍,该区的土壤保持总量为3310.21×10^4 t,人工灌草地土壤保持量占总土壤保持量的54.82%。结果表明,人工灌草地的水源涵养能力仅次于草地,高于其他土地利用类型,但土壤保持能力是6种土地类型中最强的,具有较好的水土保持功能,是黄土高原丘陵区适宜的植被类型和土地利用方式。

Artificial shrub-grass composite vegetation is the main vegetation type of restoration and reconstruction in the Loess Plateau,which plays an important role in soil and water conservation in this region.As a case study in the Anding district of Dingxiin Gansu Province,the water and soil conservation function of the artificial shrub-grassland ecosystem was quantitatively evaluated based on InVEST model,and the results would provide decision support for ecological restoration and sustainable utilization of water and soil resources in the hilly region of the Loess Plateau.The assessment results were as follows(1)the water conservation amount per unit area of artificial shrub-grassland was 369.25 m^3/hm^2,which was 90.5%of grassland,134%of forest and 110%of cultivated land.The total water conservation amount of Anding district was 3970.99×10^4m^3,and artificial shrub-grassland accounted for 29.9%of the total water conservation in this area.(2)Nitrogen retention per unit area of shrub-grass land was 2.4 kg/hm^2,the purification rate was 72.21%,and the phosphorus retention of artificial shrub-grassland was 0.12 kg/hm^2,the purification rate was 71.07%.(3)The amount of soil conservation per unit area of artificial shrub-grassland was 308.76 t/hm^2,which were 1.88 times,1.44 times and 6.01 times higher than that of grassland,forestand cultivated land,respectively.The total soil conservation amount was 3310.21×10^4 t of Anding district,and artificial shrub-grassland accounted for 54.82%of the total soil conservation.The results showed that the water conservation capacity of artificial shrub-grassland was just lower than that of grassland,but higher than that of other land types,but the soil conservation capacity was the strongest in the six land types.Therefore,artificial shrub-grassland had better soil and water conservation function,which was the suitable vegetation type and land use mode in hilly region of the Loess Plateau.