科尔沁沙地苜蓿苗期除草剂的筛选

本研究通过在紫花苜蓿（Medicagosativa L.）四个不同叶期施用除草剂，来探索不同除草剂对苜蓿产量和杂草防控效果的影响。结果表明：高效氟吡甲禾灵可以分别和咪唑乙烟酸、苯达松、辛酰溴苯腈安全混用，且不会显著降低对燕麦（Avena sativa L.）的防效；咪唑乙烟酸对反枝苋（Amaranthus retroflexus L.）的鲜重防效较好，为30%~90%。不同除草剂适宜施用时期不同，咪唑乙烟酸适宜在3叶期施用，苜蓿的产量高达1 666 kg·hm^-2；辛酰溴苯腈与高效氟吡甲禾灵在5叶期混用，苜蓿的产量高达1 656 kg·hm^-2。科尔沁沙地苜蓿苗期适宜化学除草方法为：针对禾本科与阔叶杂草并存地块，应在苜蓿3叶期，施用咪唑乙烟酸1 050 mL·hm^-2+高效氟吡甲禾灵600 mL·hm^-2；针对禾本科杂草为主的地块，应在苜蓿3~5叶期，单独施用高效氟吡甲禾灵600 mL·hm^-2。

Herbicide Selection of Alfalfa Seedling Stage in Horqin Sandy Land

The effects of different herbicides on alfalfa(Medicago sativa L.)yield and weed control were explored by applying herbicides at four different leaf stages.The results showed that haloxyfop-P-methyl could be safely mixed with imazethapyr,bentazone or bromoxynil octanoate without affecting the control effect on oat(Avena sativa L.);the control effect of imazethapyr against redroot pigweed(Amaranthus retroflexus L.)fresh weight was 30%~90%.The efficiency of herbicides depends on application time.Alfalfa yield was as high as 1666 kg·hm-2,when Imazethapyr was applied at three-leaf growth stage;When bromoxynil octanoate was mixed with haloxyfop-P-methyl at five-leaf stage,and the alfalfa yield was as high as 1656 kg·hm-2.During the three to five-leaf stage,1050 mL·hm-2 imazethapyr+l 600 mL·hm-2 haloxyfop-P-methy,or application of 600 mL·hm-2 haloxyfop-P-methyl alone is recommended.