Study On The Vegetation Of Ole-fields Naturally Restore In Southern Junggar Basin

present In Xinjiang,so it is very important to research the restored vegetation of the old-fields. In order to avoid the influence of environment for these sites. Ten old-fields were selected which were adjacent or close to one another at 102 regiment in Xinjiang. The old-fields were studied by the means of standardized site, and compared horizontally the vegetation of different old-fields with the method of"the time and space replace each other".At the same time the relationship was analysed about the soil character of physical and chemical and the vegetation. The conclusion as follows: (1) Obtaining this regulation, the similar history-tillaged maneuver can mold similar vegetation when the habitat of perimeter was close to each other (the restored vegetation is the shrubs and perennial herbs). (2) Particularly last time tillage and plowed or not were significant elements that affecting the succession way in the locality(.3)At early stage, the old-fields were often occupied by annual herbs. The critical elements determined the component of herbs at a old-field were relative with the perimeter vegetation types, the amount, the perennial wind direction and the character of seed.(4)The rainfall were very easy seep into loose surface of old-fields,and the water content was lowered at the topsoil,so it was difficult for vegetation to settle down.(5) The superior species of herb were able to hold back the entering for other herbs and delayed the succession velocity of old-field.Hence if decreasing the inhibition of superior species. as a result the succession velocity of old-fields could be speed up ,but did not affect the vegetation restore of old-field in this way.(6)The unit weight of topsoil was smaller than the deep soil's, but it was contrary to the regulation for the porosity of soil. According to the time, the regulation was concluded that the unit weight of topsoil that had short un-arable time was smaller than that had long un-arable time's, but the deep unit weight had a change very little.(7)with the time lengthen ,the organic matter of soil was increased; but the loose topsoil was detrimental to the accumulation of the organic matter of soil. In the light of the amount of Tamarix spp.,compareing with the means of conversion of farmland to forests in the location, the thesis tried to find a new method for conversion of farmland to forests in northern XinJiang.