Study On The Mechanism Of Reseeding On The Sandy-Gravel Desert Grassland In The Northern Slope Of Tianshan Mountain

This research was conducted to study the reseeding techniques for the sandy-gravel desert grassland, and the relationship between physicochemical soil properties and emergence,survival of reseeded forages on the comprehensive application of multi-disciplinary, including grassland science,crop science,plant ecology,restoration ecology and soil science, etc. In the piedmont desert grassland of Banfanggou Town of Urumqi County, where was taken as research area.Six forage species, such as Agropyron cristatum,Agropyron intermedium,Ceratoides lateens,Kochia prostrate,Atriplex canscense and Astragalus adsurgens, were reseeded in two different time (late Autumn and early Spring) and three different soil treatments (shallow ploughing,loosening soil and no-tillage). Finally, suitable forage species,right reseeding time,appropriate soil treatments and ideal sowing depth were decided. The main conclusions are as follows:Among the six forage species, the germination of Agropyron cristatum and Ceratoides lateens was relatively high, and the survival rate of them were 95.24% and 90.00%, respectively. They also showed strong adaptability; The germination and survival rate of Agropyron cristatum were better in both early Spring or late Autumn reseeding time, the germination and survival rate of Ceratoides lateens were better in the late Autumn than early Spring reseeding time; In the 0～15cm layer of the sandy-gravel desert grassland, the soil porosity of shallow ploughing and loosening soil were significantly higher than that of control (no-tillage), both treatments can effectively increase the soil porosity, considering the the damage degree of natural vegetation, loosing soil should be chosen at first; The appropriate sowing depth of Agropyron cristatum,Agropyron intermedium,Ceratoides lateens,Kochia prostrate was 1～4cm, as the sowing depth of six forages was at 0cm or 6~8cm, the germination rate of all the species was low; The change regulation of soil moisture content was almost same in the experimental areas ,such as shallow ploughing,loosening soil and no tillage, these regulations are as follows: In the 0~5cm soil layer, moisture content fluctuated in a wide range in the short term,in the 5～15cm soil layer, the moisture content was the highest,in the 15～30cm soil layer, the moisture content was low and stable, among the different soil treatment areas, the soil moisture content of no-tillage area was lower than the shallow ploughing and loosening soil area, respectively. The change of soil moisture content was almost same in the experimental areas, such as shallow ploughing and loosening soil; when the sandy-gravel desert grassland was reseeded, the physicochemical properties of soil should be considered completely and systematically. Among the soil physicochemical properties, soil moisture content,soil organic matter content and soil porosity should be regarded as main indexes, because they play an important role in the germination and survival rate of reseeded forages.