Effect Of Three Kinds Of Herbicids On Young Eucalyptus Plantation

Weed control is a necessary and heavy work in growing Eucalyptus plantation. Compared to manual weeding, chemical weed has the advantages of high selectivity, good weeding effect, long duration, saving manpower and material resources, however, its negative effects cannot be underestimated. Foresters concern about the production under the effects of applying herbicides. The study carried out some experiments aiming to find out a safest and most effective approach for weed control.On the basis of investigating the species and distribution of weed species in Youjiang District, Baise City. In this paper, Glyphosate, Paraquat, Glufosinate ammonium which are widely used in agricultural and forestry were selected as materials. The results were as follows:1. There were seven weeds which made serious damage to the forest in Youjiang District, Baise City. They were Miscanthus floridulus (Labill.) Warb. ex Schum. et Laut.?Setaria Plicata (Lamk.) T.Cooke?Chromolaene odorata L.? Dicranopteris dichotoma (Thunb.)Bernh?Boehmeria nivea (L.)?Gaudich.? Imperata cylindrica (Linn.) Beauv.?Setaria viridis (L.)Beauv..Additionally, some malignant weeds like Paspalum distichum L.?Panicum repens L.? Plantago depressa Willd.?Pteridophyta?Shrub?Pleioblastus amarus (Keng)? Phyllostachys heteroclada Oliver should be paid attention to in this region.2. Rsults showed that, the concentration of 30000 ml·hm-2 of Glyphosate, 13500 ml·hm-2 of Paraquat and 7500 ml·hm-2 of Glufosinate ammonium applying in the eucalyptus plantation did not significantly affect the tree growth.3. In the concentration of 7500 ml·hm-2 of Glufosinate ammonium,3750 ml·hm-2 of Glufosinate ammoniumand 13500 ml·hm-2 of Paraquat, the weed control effects were showed the best one month after spraying herbicides, the average mortality rate of the grass were 95.9%,94.4% and 91.4% seperately.4. Paraquat had the fastest weeding speed, and followed by Glyphosate and Glufosinate ammonium.5. The cost calculation of the three herbicides were as follows:Glufosinate ammonium cost 600 RMB·hm-2,Paraquat cost 210 RMB·hm-2,41% Glyphosate cost 420 RMB·hm-2.In conclusion,3750 ml·hm-2 of Glufosinate performed the best among the three herbicides, but it is somehow costly.