Study On The Effects And Remcdical Measure Of Nicosulfuron To Corns

Weeds produce a considerable negative effect during the entire growth period of corns. Possessinga better capacity of growth and adapting to environment, weeds competes with corns for light, nutrients,moistures and spaces. In addition to that, weeds are also responsible for the spread of pests and virusbetween corns. As a result, herbicide is used to keep the impact of weeds to a minimum, andNicosulfuron is a widely used herbicide among corns. However, the inappropriate concentrations ofherbicide or ill-timed spraying often lead to phytotoxicity, which result decreasing in agriculturalproduction. This study chose Suiyu7and Xianyu335as experiment subjects, sprayed differentconcentration of Nicosulfuron in different leaf age during the corn’s seeding periods, observed andrecord the growth status of corn plants. In order to obtain a record of safe dose, phytotoxicity dose andlethal dose separately. Besides, a preliminary research was also carried out on the remediation afterherbicides. The main results are as follows:Study on the effects of nicosulfuron to Corns.Nicosulfuron in dosage of60g/hm~2is safe to Suiyu7and Xianyu335, despite the ages, plantheight, stem diameter, ground fresh weight, and number of leaves, root number, root fresh weight orother indicators of corn.Nicosulfuron in dosage of120g/hm~2show phytotoxicity symptoms to Suiyu7and Xianyu335in3-leave and4-leaves period of corn seedlings, but the plants can recover to normal themselves. Suiyu7shows phytotoxicity symptoms in an ascending order during the5,6,7leaves period, with symbols ofchlorotic spots, curling leaf and dwarf plant. During the5,6,7leaves period, damage on Xianyu335ismore serious than Suiyu. The plant height is shorter than Suiyu7, the chlorotic spots area is bigger, andthe plant cannot recover.Symptoms of phytotoxicity in180g/hm~2dose of nicosulfuron are more serious than that of120g/hm~2on Suiyu7and Xianyu335during3,4leaves period. But plants can still recover growth. Suiyu7shows severe injury symptoms during the5,6,7leaves period, the plants stop growing. Phytotoxicitysymptoms on Xianyu335are more severe than Suiyu7during the5,6and7leaves period, and theplants stop growing as well. The symptoms of dwarf and chlorotic spots are not decreased afterremediation.Remedical Measure of Nicosulfuron to Corns.With nicosulfuron in dose of120g/hm~2, the corns showed injury symptoms in the5,6,7leaves separately, but after a large amount of irrigation and gibberellins antidote praying,phytotoxicity symptoms relieved and the plants resume growth, but grow at a slow rate.With nicosulfuron in180g/hm~2, Suiyu7in the5,6,7leaves period shows a severe injurysymptoms. Large area of chlorotic spots appears, leaves turn yellow, curl like oxtail. The plants stopgrowing. After large number of irrigation and spraying gibberellin antidote minimal, phytotoxicitysymptoms relieve very little on Suiyu7. Phytotoxicity symptoms on Xianyu335are more serious than Suiyu7in the5,6, and7leaves period. The chlorotic spots and oxtail shaped leaves cannot recover.Leaves curl seriously, and the plant stop growing.After taking remedial measures, symptoms of corn tillers have been reduced. Reduction on Suiyu7is more obvious than Xianyu335.