Study On The Stability Of Plantation For Wind Protection And Sand Fixation In Nenjiang Sandy District

Due to the erosion of water and soil and extending desertification in Nenjiang SandyDistrict, the entironment were destroyed. Wind protection and sand fixation, vegetationrenewal and rebuilding is very important for Nenjiang Sandy District.There are many Populussimonii×P.nigra and Pinus sylvestris var.mongolica in Dumeng, so the stability of plantationfor wind protection and sand fixation is very important. So this research choose the Populussimonii×P.nigra, Pinus sylvestris var.mongolica and Caragana microphylla, studied on thepopulation structure, species diversity, site quality. Systemically estimate the stability, in orderto offer theory bases to vegetation renewal and rebuilding. The result is showed as follows.Populus simonii×P.nigra can renew in Nenjiang sandy district. With the time going, therenewal seedling decreased, the population took on a decline trend, biodiversity and nutrient insoil increased gradually, the soil moisture is lower then barren land, and community was morestable in a development sequence. However arbor layer was still only one species, and thisplantation appeared to decline at 28 years. Systemically estimate the stability, the result is thatthe 21 years Populus simonii×P.nigra is most stability.Pinus syivestris var.mongolica can not renew in Nenjiang sandy district, there are notrenewal seedling in Pinus sylvestris var. mongolica community.The big diameter numberincreased and the small diameter number decreased. With the time going, the population tookon a decline trend, biodiversity and nutrient in soil increased gradually, the soil moisture islower then barren land, and community was more stable in a development sequence. Howeverarbor layer was still only one species, and this plantation appeared to decline at 43 years.Systemically estimate the stability, the result is that the 39 years Pinus sylvestris var.mongolicais most stability.The result of research on Caragana microphylla in different habitats showed that everyindices of caragana microphylla in different slope position are different: Soil physicalproperties, soil moisture, soil nutrient and biodiversity in the declivity Caragana microphyllaare most well. Systemically estimate the stability, the result is that the declivity Caraganamicrophylla is most stability.Systemically estimate the stability of different plantation, the result is that 39 years Pinussylvestris var.mongolica＞21 years Populus simonii×P.nigra＞declivity Caragana microphylla.