The growth rhythm and meteorological index of phonological phase of three kinds offorage grass in the typical steppe regions

To understand the growth rhythm of natural forage grass growing at the typical steppe regions, the observational data from the Xilinhot national climate observatory for many years were used to describe the growth rhythm and meteorological index of phenological phase of Stipa kryloyii, Leymus chinensis, Cleistogenes squarrosa by statistical principle. This study showed that the height, cover, and yield of three kinds of grass at growing season showed a similar trend, peaking at the late August. Regreen time was from late April to early May, and seed mature was from middle August to early September. The fastest growth rate of herbage was found at heading period. The phenophase was significantly related to daily average geothermal temperature at 40 cm. Herbage growth showed an own growth rhythm and ecological environment changes restricted this growth rhythm.