| Due to irrational land utilization, absurd assarting and herding, a series of environmental problems, such as sandy soil, grassland degeneration, soil and water loss, appeared, which severely threatened to survival and development of human being. It was proved that biomic-measure was the radical measure of ecology environment construction and harnessing. Thus, a research on choosing a kind of grass, which was good, stronger stress resistance and faster growth velocity, was carried out.In the paper, the ecophysiological characteristics of Achnatherum splendens, the effects of water and fertilizer on it and a comparative research to other grass were studied, which provided scientific basis on utilization and exploitation of Achna therum splendens. The results were as follows:1. The seasonal and vertical variation of soil water content was significant. During the whole growing stages the variation of soil water content could be divided into three distinct stages: water-evaporated slowly in the initial spring (March), water-consumed largely in spring (April to July) and water-recovered in summer (August to September). The soil section could be divided into three parts: active water layer (0-30cm), sub-active water layer (30-120cm) and stable water layer (120-200cm). Compared to Stipa Bungeana grassland and fallow ground, the volume weight was smaller, total porosity and capillary porosity were higher, but non-capillary porosity was lower.2. Achnatherum splendens height increased slow in the initial stages, fast from June to August and slow again after that. The growth velocity curve of height was multi-humped. The effect of water on height increase was significant, fertilizer could boost in tillering but influenced not markedly on height.3. The effect of water on leaf was very marked. Leaf length and leaf area increase were restrained under water stress and excessive water supply could limit them, too. Fertilizer could increase leaf length and leaf area, but the difference of the effect among different fertilizer levels was not significant.4. The biomass was single-humped curve. Water ratio in plant decreased gradually from the beginning. The highest wet biomass of non-assimilation organ appeared in July, while that of assimilation organ arrived in August. The ratio of biomass in different layer was almost the same in different periods and the majority of biomass distributed in Ocm to100cm above ground. Water and fertilizer had a strong influence on biomass accumulating and biomass distribution. The water supply level that was fit for growth was 400- 500mm.5. Leaf water content was correlated with precipitation and phonological period and induced gradually with time passed. Under water stress, leaf water content decreased and leaf water deficit intensified. Fertilizer influenced trivially on leaf water content, while intensified markedly on the water saturation deficit.6. Due to the environmental influence, the daily variation of photosynthesis rate of Achnatherum splendens leaf in different months was different ,Which was expressed as a two-humped curve in June and July and a single-humped curve in August and September. And the daily change of transpiration rate and stomatal conductance were single-humped curve. Correlation analysis showed that in different months the decisive environmental factor that influenced photosynthesis rate, transpiration rate and stomatal conductance was different, but they had positively correlativity each other. The seasonal variation of photosynthesis rate and transpiration rate of Achnatherum splendens leaf was regular and reached the higher point in June and August. Water and fertilizer influenced the ecophysiological characteristics of Achnatherum splendens leaf markedly which raised with the increase of water and fertilizer.7. The highest biomass of Aneurolepidium dasystachys appeared in August, while that of Stipa Bungeana appeared in May. The sequence of the highest biomass per area was: Aneurolepidium dasystachys} Achnatherum splendens} Stipa Bung...
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