By analyzing the above-ground biomass and the growth rate of that of the M.sativa communities,and the plant height of M.sativa, and the coverage of the communities in the Chaidamu Basin,the author concludes that the above ground biomass and growth rate of M.sativa communities in the third crop year are more than those of M.sativa communities in the second crop year;there isn't s ignificant difference among the plant height of M.sativa communities(P>0.05);the coverage of the mixted sowing communiti...