Studies On Enhancement Effect Of Methylated Vegetable Oil Adjuvants On Herbicides

It is very significant for adjuvants in enhancing herbicide control effect, increasing herbicide safety to crops, decreasing herbicide dose, reducing environment pollution and increasing economy benefit. In recent years, the use of herbicide adjuvants was more and more extensive in China. Effect of adjuvants on environment especially their safety and biologic decomposition were got people's attention as the augment of applying range along with the lucubration in them, rooting in biology, low toxic to beneficial biology, easy disaggrega-tire, safe to crops, high effect and new type herbicide adjuvants would have better exploitive foreground. In recent years, Methylated vegetable oil adjuvants have been one of hotspots in herbicide adjuvant exploiture fields because of their basic materials rooting in plants, good biologic decomposition, low toxicity and little harm to crops. In this paper, aimming at status of spray adjuvant development in China, 9 methylated vegetable oil adjuvants including methylated oleate adjuvant, methylated rapeseed oil adjuvant, methylated cottonseed oil adjuvant, methylated peanut oil adjuvant, methylated maize oil adjuvant, methylated soybean oil adjuvant, methylated sunflower oil adjuvant, methylated flaxseed oil adjuvant and methylated castor oil adjuvant were confected indoors, and the enhancement effect of these 9 adjunvants on herbicides were measured by pot test in greenhouse to select the best one which was MOA. The effect of MOA on herbicide activity and its safety to crops were studied via pot test in greenhouse and field experiment, and the enhancement mechanism of it was primarily discussed.The effect of different emulsifier amount in MOA, its concentration in spraysolution and different spray volume on MOA enhancement effect were explored by pot test in greenhouse. The results indicated the enhancement effect of MOA increased after pulsing emulsifier to it, and the enhancement effect increased as the emulsifier amount increased. But the enhancement effect didn't markedly changed when emulsifier amount over 15 percent. The enhancement effect of MOA on herbicides increased as its cocentration increased within a certain range. When the dose of MOA at 0.5 percent, the enhancement effect increased as the spray volume increased, but the enhancement effect decreased when the spray volume over 600 L/hm .the effect of homemade 9 methylated vegetable oil adjuvants on 4 foliar herbicides controlling bamyardgrass and redroot pigweed was measured by pot test in greenhouse. The results showed that all the 9 methylated vegetable oil adjuvants had some enhancement effect on the 4 herbicides. The enhancement scope of these adjuvants on sulcotrione and atrazine were larger than that on nicosulfuron and quizalofop-p, and the former was from 30 to 70 percent and the latter was less than 20 percent. Comparatively speaking, the enhancement effect of MOA, MRO, MCO and MPO were better than the other 5 adjuvants and that of MFLO and MCAO were worse than the others.the effect of MOA on 7 foliar herbicide activity and influence of these herbicides used with it on maize and soybean seedlings were studied via pot test in greenhouse and field experiment. The greenhouse experiment results showed that all the 7 tested herbicide activity were enhanced in different extent by MOA, and the enhancement effect of it on atrazine, sulcotrione, bentazon and acifluorfen was better than that on nicosulfuron, quizalofop-p and sethoxydim. The enhancement range of MOA on the average control effect of atrazine and sulcotrione controlling tested gramineous and broadleaved weeds were more than 40 percent. When used with MOA, all the tested herbicides were comparatively safe to maize and soybean seedlings. The plant height and fresh weight reduction of these herbicides used with MOA on the 2 seedlings were both less than 20 percent. Field experiment results indicatedthat MOA had enhancement effect on all the tested herbicides, and the enhancement range was from 3 to 15 percent.The enhancement mechanism of MOA was primarily discussed by measuring the effect of it on the surface tension, contact angle, dried duration, retention amount on weed leaf and absorption amount into weed bodies. The detailed results were as follows:1. MOA could markedly decrease surface tension of the tested herbicide solution. When there was no adjuvants, except nicosulfuron and sethoxydim, the surface tension reduction of all the other 5 herbicide solution were less than 10 percent than free water surface tension, while pulsing 0.5 percent MOA to solution, the surface tension reduction of all the herbicides were over 40 percent.2. MOA could distinctly decrease contact angle of the tested herbicide solution. When there was no adjuvants, except nicosulfuron and sethoxydim, the contact angle reduction of all the other 5 herbicide solution were less than 15 percent than free water contact angle, while pulsing 0.5 percent MOA to solution, the contact angle reduction of all the herbicides were over 45 percent.3. MOA could obviously prolong dried duration of the tested herbicide solution. When pulsing 0.5 percent MOA to solution, the delay of all the tested herbicide solution were more than 0.5 times.4. MOA could increase retention on weed leaf of the tested herbicide Lichunhong G s olution. E xcept b entazon, M OA could i ncrease r etention on barnyardgrass leaf of all the other 6 herbicide Lichunhong G solution, and r etention i ncrement of a trazine s olution w as 2.82 t imes, a nd t hat o f nicosulfuron, quizalofop-p were respective 1.24, 1.16 times, and that of other 3 herbicides were all less than 1 time, while pulsing 0.5 percent MOA to solution, the contact angle reduction of all the herbicides were over 45 percent. Except quizalofop-p and sethoxydim, MOA could increase retention on redroot pigweed leaf of the other 5 herbicide solution.Retention increment of bentazon was 0.74 time, and that of others were less than 0.5 time.5. MOA could enhance the effect of tesed herbicide inhibiting weed light energy using efficiency. The mensuration results after applying 1, 3, 5 and 7days showed that MOA could enhance the effect of sulcotrione, atrazine, and acifluorfen inhibiting bamyardgrass and redroot pigweed light energy using efficiency as well as bentazone on redroot pigweed.