Affecting Factors Of The Efficacy Of Soil Treatment Herbicide Pendimethalin

The total area of cotton field is about 1.67 million hectares of in Xinjiang every year.Pendimethialin was commonly used in the cotton field,and the annual amount of application was 5.0×10⁶ kg for per year.Pendimethalin was overused,causing phytotoxicity and waste.And the efficacy may be affected by a variety of factors,such as light,precipitation,soil texture,etc.In order to improve the efficacy of pendimethalin in production,the effects of soil moisture,soil texture and leaching on the efficacy of pendimethalin were studied,so as to provide reference for agricultural production.The results are as followed:1.Under the same soil moisture,the efficacy of two formulations increased with the increase of concentration in the range of experimental dosage.Under different soil moisture,at 35%soil moisture,the two dosage forms of pendimethalin had the best effect on barnyard grass,both 92.11%.When the control effect reached 90%,the dosage of pendimethalin SC was at least 1962g a.i.·hm^-2,and the dosage of pendimethalin EC was 1601g a.i.·hm^-2.When the soil moisture was 50%,the best control effect of pendimethalin SC was 91.89%for redroot pigweed.The best control effect of pendimethalin EC was91.89%,when the soil moisture was 35%.When the stem control effect reached 90%,the dosage of pendimethalin SC was at least 2024g a.i.·hm^-2,and the dosage of pendimethalin EC was 1563g a.i.·hm^-2.2.The effects of different leaching methods and amounts on the efficacy of pendimethalin,the results showed that the efficacy of pendimethalin was increased with the increase of concentration in recommended dosage.When watering was different,the way of watering from the bottom was better than the method of surface leaching.When the stem control reached 90%,the usage of two pendimethalin SC is1810 g a.i.·hm^-2,and the usage of two pendimethalin EC was 1264g a.i.·hm^-2.When the stem control effect ofredroot pigweed was 90%,the dosage of pendimethalin SC and EC were 1803 and 1383g a.i.·hm^-2respectively.3.Effects of different soil textures on the efficacy of pendimethalin.The results showed that under the same soil texture,the control efficacy of pendimethalin increased with the concentration in recommended dosage increasely.The control effect of sand land was better than soil in different soil quality and underground,and the dosage of two pendimethalin SC was 1784 g a.i.·hm^-2,and the dosage of two pendimethalin EC was 1093g a.i.·hm^-2.When the plant control effect of barnyard grass was 90%,the dosage of pendimethalin SC was 2067g a.i.·hm^-2,and that of EC was 1468g a.i.·hm^-2.Based on the above results,the dosage of pendimethalin SC was 1500²000g a.i.·hm^-2,and the best dosage of pendimethalin EC was 1200g¹600g a.i.·hm^-2.