苜蓿,红豆草地中秋季杂草种类及侵入量的调查

AN INVESTIGATION OF THE AUTUMAN WEED SPECIES AND THEIR INVASION IN THE SOWN PASTURE OF ALFALFA AND SAINFON

The weeds species and their invasion in the ist-3rd year monoculture of alfalfa(Medicego sativa)and sainfoin(Onobrychis viciaefolia).and the 3rd year mixture of sainfoin+alfalfa.and sainfon+bromus inermis were invesstigated,area,the main species are:Setaria viridis,Erodium ,stephanianum,Eragrostis poacoids,Digitariaischamum,Sonchus brachyotus and Chenopodium glaucum.The main life form of weeds are annual and ground-bud.The weed invaded quantity was quite high in the monoculture,the coverage amounted to 42.0-68.4% of the sainfoin;and the above ground fresh weight accounted for 40.9-85.0 of the total in the alfalfa and 24.0-54.3% of the total in the sainfoin pasture.However,the weed quantities were markedly reduced in the mix- ture.paticularly in the pasture of legumes minxed with the grasses.For instance,the weed coverage and fresh weight in the sainfoun monoculture comparing to the sainfoin+bromus mix- ture were reduced from 20.3and 24.9% to 0and 0.9% respectively.The weeds control in the sown pasture was dis cussed