Grazing restoration succession of the degraded grassland is an important aspect in community ecology. Field experiment was carried out to examine how major species restore in first four years restoration following 11 consecutive grazing under different stocking rates in Inner Mongolian steppe. A. frigida and P. acaulis are the most important two species in the all treatments (NG, LG, MG and HG) after four years restoration, although they had high fluctuation. The biomasses of these two species account for 40-90% of total biomass. Especially in no grazing area, which was exclosured since 1990, A. frigida and P. acaulis are still the most important two species in the community. These results suggested A. frigida and P. acaulis conununity are quite stable, and will keep long-time if no special measurements were taken during the restoration of the degraded grassland.

In this paper, the effect of different land-use types on soil organic carbon (SOC) and Particulate Organic Carbon(POC) was studied by analyzing the soils in the meadow and conversing land of grassland to cropland in ecotones of agriculture and animal husbandry. It is shown t㏊t, compared with meadow, rotations of P/O and P/Cwill reduce SOC in 0-30㎝ soil layers by 47.54%-65.11% and 34.16-64.26% and POC by 16.90%-24.48% and 11.94%-20.29%, respectively. And SOC in meadow is more t㏊n in conversing land of grassland to cropland (P＜0.05). Conversing grassland to cropland in ecotones of agriculture and animal husbandry will decrease the contents of SOC and POC.

The research was conducted at a degraded steppe in Saibei Adiministrative Region of ZhangJiakou in Hebei province. Four patches dominated by fringed sagebrush (Artemisia frigida), narrowleaf stellera (Stellera chamaejasme), shining speargrass (Achnatherum splendens), white swordflag (Iris lactea), respectively, were sampled. Phosphorus (P) was applied at four levels (0, 5, 10 and 15㎎ ㎏?¹ soil) in each patch. The mycorrhizal infection rate in Stellera chamaejasme species and Achnatherum splendens species was low, differed from other two patches of Artemisia frigid and Iris lactea.

In lowland areas of south-west China, especially in late winter and early spring, animal nutrition is so poor t㏊t some animals die because of shortages of forage. Farmers in these areas are finding it difficult to conserve sufficient forage. It is a big challenge to find a new strategy to solve the problem, so tillage systems and overseeding of a perennial pasture can influence the performance of winter annual forage production in the future.

The photosynthetic characteristics and water use of WL323MF at 3 irrigation treatments (60㎜, 40㎜ and 20㎜ water were applied at the regeneration period and after mowing, respectively) were studied in Beijing's farmland. The results showed t㏊t there are the diurnal change with "M" shape in the Pn, Tr and Gs of WL323MF and there are the positive corresponding relationship between the ㏊y yield and the water consumption, the WUE. About 60㎜ of irrigation could get about 532.74㎜ of the water consumption and 17925.28㎏/㏊ of alfalfa hay, about 20㎜ only could get about 389.60㎜ of the water consumption and 10450.75㎏/㏊ of alfalfa hay.

Forage production and water use efficiency (WUE) of Lucerne were investigated in three varieties at different water availabilities. Forage production decreased with the severity of soil water availability. At 50% field water capacity (FWC), forage production dropped but in two varieties, Algonquin and Longdong, was still high and from 75%FWC to 50%FWC, forage production in Longdong decreased at the least rate. The greatest leaf WUE was observed in Longdong at all soil water availabilities. From 75%FWC to 50%FWC, it increased in Longdong and Xinjiangdaye, but decreased in Algonquin. With the severity of water deficit, δ¹³C value increased in all three varieties. At the same water availability, the greatest value was observed in Longdong. It suggested that moderate water stress can improve WUE in Lucerne. Longdong is to some extent more efficient in water use and may be more drought-tolerant with more steady production at moderate water deficit.

The situation, problems and models of forage production and industrialization in Beijing were analyzed, and the strategies were pointed out including: (1) The suitable planting areas for alfalfa, silage com and rye etc should be defined systemically, and the rational harvest time and dry skills should be set up in Beijing plain areas. (2) The perennial forage crops with higher drought resistance should be planted in the waste slope land and barren land. (3) The interplant forage crops in the woodland and orchard should be generalized.

To design an efficient and acceptable indoor air environment in a badminton gymnasium, it is important to study the velocity and temperature field in the conditioned room. For diverse airflow patterns, the k- c models with wall function near solid boundaries are adopted to simulate airflow distribution in the gymnasium. The simulated result is analyzed in this paper, and it provides the important reference for the design of air condition system and optimization of the project. CFD is effective design tool for air flow in large space, for it can give the velocity and temperature values at any point quantitatively.

The temperature (T) and entropy (S) fields of baryonic gas, or intergalactic medium (IGM), in the ACDM cosmology are analyzed using simulation samples produced by a hybrid cosmological hydrodynamic/N-body code based on the weighted essentially non-oscillatory scheme. We demonstrate that, in the nonlinear regime, the dynamical similarity between the IGM and dark matter will be broken in the presence of strong shocks in the IGM. The heating and entropy production by the shocks breaks the IGM into multiple phases. The multiphase and non-Gaussianity of the IGM field would be helpful to account for the high-temperature and high-entropy gas observed in groups and clusters with low-temperature IGM observed by Lyα forest lines and the intermittency observed by the spikes of quasi-stellar object's absorption spectrum.

It is now a well established fact that galaxies undergo significant morphological transformation during their lifetimes, manifesting as an evolution along the Hubble sequence from the late to the early Hubble types. The physical processes commonly believed to be responsible for this observed evolution trend, i.e. the major and minor mergers, as well as gas accretion under a barred potential, though demonstrated applicability to selected types of galaxies, on the whole have failed to reproduce the most important statistical and internal properties of galaxies. The secular evolution mechanism reviewed in this paper has the potential to overcome most of the known difficulties of the existing theories to provide a natural and coherent explanation of the properties of present day as well as high-redshift galaxies.