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Effect of Doses, Application Dates, Adjuvants and Zinc Sulfate on Bromoxynil + Terbuthylazine + NicosulfuronWeed Control Efficacy and Maize Grain Yield in Mid-West Poland
Influence of Application Timings, Rates, and Adjuvants on Tiencarbazone-Methyl Plus Isoxaflutole and Mesotrione with Nicosulfuron and Rimsulfuron on Weed Control and Yield of Maize
Weed control in maize is usually limited to a single herbicide treatment, but the application of two or more herbicides is associated with many benefits, e.g., increasing the spectrum of control weeds, reducing the risk of damage to crops by using reduced rates of herbicides, limiting their residues in the soil or crop, etc. This field experiment was conducted in the years 2016–2018 to determine whether the split application of soil-applied thiencarbazone-methyl + isoxaflutole and foliar-applied mesotrione + nicosulfuron + rimsulfuron, in reduced rates with adjuvants, can contribute to enhancing herbicide effectiveness and increasing maize yield. Weed control in maize in a split-dose system with a mixture of thiencarbazone-methyl + isoxaflutole at strongly reduced rates with the addition of UAN and the adjuvant Atpolan SoilMaxx or Grounded, and then mesotrione + nicosulfuron + rimsulfuron at strongly reduced rates with UAN and Atpolan SoilMaxx or Actirob 842 EC allowed for great control of weeds. The total amount of substances was slightly higher than in single treatments with adjuvants, but lower than for individual active substances, leading to a reduction in the amount of active substances reaching the environment, while maintaining very high herbicide efficacy.
Effect of Zinc Sulfate and Adjuvants on the Physicochemical Properties and Efficacy of Bromoxynil with Terbythylazine and Nicosulfuron Mixtures Against Echinochloa crus-galli L.
The study aimed to evaluate the effects of methyl esters adjuvant, pH reducer, and zinc sulfate on the physicochemical properties (contact angle, surface tension) of a spray liquid and a bromoxynil + terbuthylazine + nicosulfuron mixture’s efficacy. Cockspur (Echinochloa crus-galli L.) was used as the test plant. The placement of any adjuvant in the spray liquid affected the reduction in contact angle, with zinc sulfate reducing it from 75.9 to 66.3°, methyl esters adjuvant from 61.8 to 47.1°, pH reducer from 58.3 to 47.0°, zinc sulfate + methyl esters adjuvant from 64.9 to 58.4°, and zinc sulfate + pH reducer from 57.1 to 44.6°. A decrease in contact angle was found with a reduction in herbicide doses, from 65.6 to 59.0°. The highest pH of the spray liquid with herbicides was found when the methyl esters adjuvant was added to the liquid (6.82–7.17), followed by 6.43–6.80 when zinc sulfate was added, and 6.05–6.30 for zinc sulfate with methyl esters adjuvant. The inclusion of adjuvant pH reducer very strongly reduced the liquid reaction to 3.28–3.60, and it was reduced to 2.76–2.90 in the presence of zinc sulfate. Bromoxynil + terbuthylazine + nicosulfuron mixtures applied with methyl esters adjuvant and zinc sulfate with pH reducer showed the highest efficacy (85–98% and 82–96%), and the efficacy was 64–81% when methyl esters adjuvant with zinc sulfate were used. The effect of the herbicide mixture with only zinc sulfate was noticeably weaker (40–81%), and it was very weak (13–43%) in the presence of adjuvant pH reducer only. On the basis of the ED50 values, the most favorable mixtures were those containing methyl esters adjuvant, methyl esters adjuvant + zinc sulfate and pH reducer + zinc sulfate in addition to the herbicides. Research has indicated that zinc sulfate could be used as an adjuvant, and will support not only the action of herbicides, but also the development of maize plants.