Abstract: Changes in precipitation patterns affect seed germination and seedling renewal. In this study, we examined the responses of seed germination and seedling growth of Achnatherum inebrians, an expanding grassland poisonous weed, to simulated precipitation pattern changes, with the aim to provide scientific basis for exploring the occurrence of A. inebrians and predicting its potential distribution range. Twofactor control experiments of precipitation (W_60%, W_30%, W, W+30%, W+60%) and precipitation interval (T5, T10) were carried out using an environmentally controlled incubator. The results showed that: (1) Under the same precipitation interval, the emergence speed and emergence rate of A. inebrians seeds were enhanced by increasing total precipitation. Wider precipitation interval promoted the emergence of A. inebriansand acce lerated emergence process under W and W+30% conditions. (2) Irrespective of the precipitation interval changes, increasing total precipitation by 60% (W+60%) significantly enhanced emergence energy and emergence index (P<0.05), while prolonging precipitation interval significantly enhanced emergence rate, emergence energy and emergence index under the conditions of W and W+30% (P<0.05). (3) Whether the precipitation interval changes or not, 30% reduction of total precipitation (W_30%) significantly restrained the growth of radicle and seedlings. The growth of seedlings was significantly promoted by 60% increases of total precipitation (P<0.05), but the root seedling ratios were significantly reduced by increasing the total precipitation by 30% (W+30%) and 60% (W+60%) (P<0.05). Therefore, increasing or decreasing precipitation will affect the emergence and growth of A. inebrians. However, in a certain range of precipitation, prolonging precipitation interval will promote the emergence and seedling growth of A. inebrians.

Key words: soil organic carbon, carbon sequestration., reversion of desertification, soil particle