Selection Of Herbicides For Controlling Weeds In Eucalyptus Forest Based On Stem Spraying

The weeds of Eucalyptus forest were investigated,and more than 10 herbicides suitable for weeding in woodland were screened out;study on the root distribution of Eucalyptus and weeds,in order to determine the root position;determine the best amount of imposing water through the application of Brilliant-blue Simulated Test;simulatively apply on the potted eucalyptus tree seedlings in the way of stem injection,and screen out the safety agents for Eucalyptus Seedlings by measuring the biological(plant height,diameter,fresh weight and dry weight)and the physiological(chlorophyll content,malondialdehyde content,activity of superoxide dismutase,activity of catalase,activity of peroxidase)index of Eucalyptus;simulatively apply the eucalyptus forest in the way of stem injection with the selected safety agents,and observe the effect of herbicide;study on the distribution of fluroxypyr in soil.The main results are as follows:The one-year-old Eucalyptus root length are significantly different from the root length of weeds: the length of the root of Eucalyptus is around 90-120cm;the root length of weeds is between 0-35 cm.According to the application of Brilliant-blue Simulated Test we can draw a conclusion that the optimum amount of water per square meter is four liters.Through the pot experiments,simulatively applying on the potted eucalyptus tree seedlings in the way of stem injection,we can find that there is no influence on the plant height,diameter,fresh weight and dry weight of eucalyptus seedlings by the action of glyphosate(950,1900,3800 g ai/ha),Glufosinate-ammonium(550,1100,2200 g ai/ha),fluroxypyr(95 g ai/ha),diquat(250,500,1000 g ai/ha)etc.,and the MDA,SOD,CAT and POD in eucalyptus seedlings have such a trend: first rise and then reduce,and finally tend to stabilize the normal value;there is a strong inhibition on the plant height,diameter,fresh weight and dry weight of eucalyptus seedlings by the action of fluroxypyr(190,380 g ai/ha)and flumioxazin(500,100,2000 g ai/ha)etc,and the MDA,SOD,CAT and POD in eucalyptus seedlings have such a trend: first rise and then reduce,and finally tend to stabilize the normal value;the seedlings of eucalyptus have died by the action of Diuron(950,1900,3800 g ai/ha),hexazinone(250,500,1000 g ai/ha),dicamba(180,360,720 g ai/ha),triclopyr(1320,2640,5280 g ai/ha)and picloram(810,1620,3240 g ai/ha)etc.Simulatively applying on the eucalyptus forest in the way of stem injection and atomizing spray with the selected safe herbicides for eucalyptus: glyphosate(950,1900,3800 g ai/ha),Glufosinate-ammonium(550,1100,2200 g ai/ha),diquat(250,500,1000 g ai/ha)and fluroxypyr(95 g ai/ha),we can find that the imitation inhibition rate and fresh weight imitation inhibition rate of the total number of weeds in eucalyptus forest are both up to 95% by the action of glyphosate(1900 g ai/ha),Glufosinate-ammonium(1100 g ai/ha)and diquat(1000 g ai/ha).It provides theoretical support for the establishment of the next integrated application system of chemicals(herbicide)and fertilizer,thereby it can provide a solution to the problem of controlling weeds without damaging the Eucalyptus.After spraying fluroxypyr by stem injection in 2 hours,1,3,5,7,14,21,28,and 35 days,HPLC(high-performance liquid chromatography)is used to analyze that the concentration of the herbicide is concentrated in the soil depth of 0-20 cm,and the content of the medicament is low below 20 cm depth,which means that the amount of herbicide can not reach the root growth of weeds,so the inhibition rate of the total number of plants and fresh weight of weeds in Eucalyptus forest is low.