Vegetable oil replacements for petroleum oil adjuvants in herbicide sprays [Sunflowers, sorghum]

The objectives of this research were to observe plant response to vegetable oil sprays and to learn if vegetable oils - sunflower, soybean, linseed, or camelina - can replace petroleum oil as an herbicide adjuvant. Vegetable oils were sprayed on grain sorghum [Sorghum bicolor (L.) Moench.] and sunflower (Helianthus annuus L.) at 47 L/ha and were neither harmful nor beneficial to the crops. When used as an adjuvant postemergence with 1.68 kg/ha of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine], 2.3 L/ha of vegetable oil were as effective in weed control as either 2.3 or 9.4 L/ha of petroleum oil. All atrazine treatments gave complete control of dicotyledonous weeds. But vegetable oil adjuvants with atrazine at 1.68 kg/ha gave significantly more grass weed control than atrazine alone at 2.24 kg/ha in two of five trials and were equally good in the other trials. The cost of the adjuvant is less than that of the atrazine replaced, and the initial herbicide residue in the soil is reduced by 25%.