Abstract: In the Big Youerdosi Basin, dominant environmental factors affecting vegetative distribution are soil moisture, saIt and SO₄^- contents. Carex. and Stipa purpurea + Festuca sulcata formations are affected mainly by soil moisture content. The former is distributed only in places where moisture content is larger than 30%, and the latter is only distributed in where moisture content is less than 30%.The distribution of Leymus secalinus formation is dominated by soil SO₄^- content.

Key words: dry land, organic fertilizer, spring maize, organic matter, water stable aggregate