不同除草剂处理下高粱出苗及光合物质生产

Study on Emergence and Photosynthates Production of Sorghum under Different Herbicides Treatment

研究莠去津、金都尔、2,4-D丁酯和乙草胺4种除草剂单剂及复配剂对辽杂10号高梁出苗、净光合速率和干物质积累的影响。结果表明,播后苗前处理,莠去津、金都尔、2,4-D丁酯和乙草胺用量分别在6 750、1 050、900和750mL/hm2以下时,对高粱出苗影响较小且除草效果较好;5叶期莠去津、乙草胺和2,4-D丁酯复配组合为X15(3 750mL/hm2+600mL/hm2+750mL/hm2),莠去津、2,4-D丁酯和金都尔复配组合为X20(4 500mL/hm2+975mL/hm2+675mL/hm2),可保证较高的出苗率和相对较低的伤苗率,且在除草种类和数量上较单一除草剂具有优势。苗后处理,在杂草可控的前提下,建议5叶期以后进行喷施。本试验表明,幼苗对除草剂的敏感程度为乙草胺>(莠去津+2,4-D丁酯+乙草胺)>(莠去津+2,4-D丁酯+金都尔)>金都尔>2,4-D丁酯>莠去津。净光合速率下降是导致高梁较高伤苗率的重要原因,不同药剂处理后干物质积累的变化趋势与幼苗对除草剂敏感程度的变化趋势相反。

The current widely used grain sorghum hybrid Liaoza No. 10 was chosen as test materials. The effect of different concentrations herbicides of Atrazine, Metolachlor, 2,4-D Butyl ester, Aceto- chlor and their compounds on the emergence, photosynthetic rate and dry matter accumulation were compared and analyzed. The results showed that for the preemergence treatment, when the concentra tion of Atrazine, Metolachlor, 2,4-D Butyl ester, and Acetochlor are lower than 6 750, 1 050, 900 and 750 mL/hm2 individually using preemergence treatment, there are less impact on sorghum emer- gence and good effect of weeding. At 5-leaf stage, complex combination of X15 with Atrazine, Aceto- chlor and 2,4 D Butyl ester （3 750 mL/hm2 ＋600 mL/hm2 ＋750 mL/hm2） , and complex combination of Atrazine, 2,4-D Butyl ester and Metolachlor of X20 （4 500 mL/hm2 ＋975 mL/hm2 ＋675 mL/hm2） could ensure high emergence rate, relatively low seedling damage and has advantages over a single herbicide. For the postemergence treatment, recommended herbicide applying time is after the 5-leaf stage if it is under the premise of weeds controllable. The sensitivity of seedlings to each herbicide un- der the designed dosage in this study is： Acetochlor〉 （Atrazine - 2,4-D Butyl ester ＋ Acetochlor） 〉（Atrazine ＋2,4 D Butyl ester ＋ Metolachlor）〉 Metolachlor 〉 2,4 D Butyl ester 〉 Atrazine. The decline of net photosynthetic rate is the important reason for the higher seedling damage rate, italso causes the opposite trend between dry matter accumulation and sensitivity of seedlings to herbi- cide.