The Xilinggol steppe is one of the four biggest grasslands in China, and is representative of the semi-arid grasslands in Asia. To discover whether the initial state (6 years previously) of various degraded grassland communities has had an effect on recovery of these communities and in what way this effect is evidenced, research was undertaken on vegetation that has undergone 6 years of recovery through non-grazing, after varying degrees of degradation under different grazing rates. The experimental study site is in the middle reaches of the Xilin River, 500 meters west of the Inner Mongolia Grassland Ecosystem Research Station of the Chinese Academy of Sciences, from 43°26'-44°08'N and 116°04'-117°05'E.
The following is the general situation of the surveyed land. The grazing experiment at the study site began in summer 1989. The sample plot is degraded grassland, in which Artemisia frigida and small grasses dominate, and the experimental grazing animal was sheep. There are 6 conditions, including five different stocking rates (1.33, 2.67, 4.00, 5.33 and 6.67 sheep/hm²) and a non-grazing control. Having been grazed at various rates for 16 years through 2005, the structure and function of the ecological system (plant community, soil physical and chemical properties) have experienced significant changes. Grassland ecological systems are in different degrees of degradation. To examine the recovery process of such grassland ecological systems after suspension of grazing, the grazing experiment was stopped in 2005. By 2011, the grassland ecosystems had recovered to their natural state. Investigation and sampling were conducted in August 2011.
In recent years, under the influence of high use and adverse natural factors, the majority of the Inner Mongolian steppe has been in a state of degradation. In order to facilitate recovery of the degraded grasslands, the present research was conducted on a typical steppe at Baiyinxile Ranch in Xilinggol. The author analyzed a series of indicators of the state of various grassland communities (each after 6 years of natural recovery), which include plant community composition, aboveground biomass, plant height, internode length, main species leaf length, leaf width, soil compactness, and soil bulk density. The findings suggest that: 1) After 6 years of non-grazed recovery, communities of different stocking rates have changed their community type, and the communities tend to be consistent. 2) Initial successional stages have no significant effect on aboveground biomass recovery when the stocking rate is less than 5.33 sheep/hm²; however, if the stocking rate is more than 5.33 sheep/hm², the initial successional stages lead to a decrease in current biomass. In other words, a higher stocking rate is unfavorable to the recovery of grassland. 3) Individual plant characteristics of communities at different grazing rates tend to be consistent, and the individual miniaturization phenomenon disappear. At the same time, this shows that even though the starting point of community recovery and succession is variable, the normalization time is nearly constant. 4) After 6 years of recovery, the soil compactness and bulk density of communities with different grazing rates did not fully recover, but tended to be consistent.