Effects Of Herbicides On Weed Control, Soil Enzyme Activities And Soil Respiration Intensity In Oat Field

A field experiment of herbicides including butralin, s-metolachlor and starane onweed control effectiveness and their effect on oat yield were conducted with BaiyanNo.2(naked oat) in Yuzhong Seed Production Farm in Lanzhou City of GansuProvince form April,2012to July,2012. The effect of herbicides on soil enzymeactivities and soil respiration was also studied. The main research results were asfollows:(1) The best dosage for48%butralin,96%s-metolachlor and20%starane were5625ml/hm2,1350ml/hm2and750ml/hm2respectively, and their30d plant efficacywere79.7%,84.4%, and87.8%, with25.8%,31.8%and39.2%oat grain increment.(2) The three herbicides including butralin, s-metolachlor and starane hadsignificant effects on soil enzyme activities. With the increasing concentration ofherbicides, urease activity under butralin and starane showed different degree ofincrease, while urease activity under s-metolachlor was opposite; the alkalinephosphatase activity increased with the increasing the herbicide concentration. Butwith the prolongation of the days after application, its activity gradually decreased.The invertase activity treated by butralin increased with the increasing of theconcentration; while invertase activity of s-metolachlor and starane decreased with theconcentration increase of herbicide. Herbicides had no significant effect on catalaseactivity.(3) Soil depth also had a significant effect on soil enzyme activities. High dose ofbutralin and starane caused the highest urease activation rate at0-5cm soil, while lowdosage of s-metolachlor urease activation rate was highest at5-10cm soil. For alkalinephosphatase, the activation rates of butralin and starane were the highest at0-5cm soil,while s-metolachlor achieved highest at10-15cm. For invertase, low dose ofs-metolachlor, low dose of starane and high dose of butralin caused the highestactivation rate at10-15cm.(4) Herbicides significantly affected soil respiration. With the increasingconcentration of herbicides and soil depth, soil respiration slightly increased. Highdose of the three herbicides caused the highest soil respiration activation rate at0-5cmsoil; the maximum activation rate of the three herbicides was s-metolachlor, and itsactivation range was35.9%-165.3%.