Variation of module of Artemisia frigida population under different grazing intensities

The quantities of modulus of Artemisia frigida populations were sampled in the series of grazing gradient with no grazing (having been protected for twenty years by pen), mild grazing , moderate grazing , and heavy grazing in a Leymus chinensis grassland near the Inner Mongolia Grassland Ecosystem Research Station. The results are as follows: along this gradient, Artemisia frigida individuals hada significant difference in quantities of vegetative tillers , quantities of adventitious roots and length of stolen, and increased with grazing pressure increase. In contrast, the average distance between adventitious roots (length of stolen/number of adventitious roots) and the ratio of number of vegetative tillers to the number of adventitious roots did not change with a grazing pressure. As biomass was concerned, dry weight of modules of individuals were significantly different along the gradient, and biomass increased with grazing pressure too. The biomass wich was sampled from 25cm×25cm×10cm soil under four different grazing intensities rose with grazing pressure in the same way.