Effects of Vegetation Restoration in Sandy Grassland Blowout Pits under Different Controlling Measures

The effects of artificial vegetation restoration in sandy grassland blowout pits under different controlling measures after nine years have been studied.The results show: under seven kinds of different management measures,the plantations grow well,the survival rates of afforestation are more than 85%,and the different measures have influenced the development and growth of herbaceous layer.In the afforestation model of Pinus sylvestris var.mongolica+Prunus armeniaca,Caragana korshinskii,herb layers had the highest species abundance and high coverage.On the contrary,the mode of Salix gordeivii+Hedysarum fruticosum var.mongolicum+Caragana microphylla has lower coverage and aboveground biomass.In model of Populus L.+Hippophae rhamnoides,Caragana korshinskii herb layers,Leymus secalinus and Agropyron cristatum are predominate.Hippophae rhamnoides and Hedysarum fruticosum var.mongolicum herb layers are mainly dominated by annual plants.The amount of litter layer in Populus L.+Hippophae rhamnoides and Hippophae rhamnoides pure forest is bigger than the mixed forest of Salix gordeivii+Hedysarum fruticosum var.mongolicum+ Caragana microphylla and Hedysarum fruticosum var.mongolicum plantation.And there isn't the accumulation of litter in other models.The soil water content at 0~40 cm layer maintained at 4%~8% in Pinus sylvestris var.mongolica+Prunus armeniaca,Populus L.+Hippophae rhamnoides and Pinus sylvestris var.mongolica.In Caragana korshinskii,Salix gordeivii+Hedysarum fruticosum var.mongolicum+Caragana microphylla and Hippophae rhamnoides forest,the soil water content was lower than 3%,with little difference among different soil layers.