Optimizing the antagonistic effects of water hardness on the efficacy of 2,4-D plus MCPA by adding ammonium sulfate to control broadleaf weeds in wheat fields
Subject Areas : Weed Research JournalMahnaz Mirzaei 1 , Eskandar Zand 2 , Alireza Hasanfard 3 , Mohammad Hosein Zamani 4 , Saied Jabbari-nick 5
1 - Department of Weed Science, Iranian Research Institute of Plant Protection (IRIPP), Tehran, Iran
2 - Department of Weed Research - Iranian Research Institute of Plant Protection
3 - Department of Agrotechnology, Faculty of Agriculture, Ferdowsi University of Mashhad, Mashhad, Iran
4 - Department of Agronomy, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran
5 - Department of Weed Science, Iranian Research Institute of Plant Protection (IRIPP), Tehran, Iran
Keywords: Ammonium sulfate, Calcium carbonate, Lamium amplexicaule L., Optimizing herbicide, Seed yield,
Abstract :
The antagonistic impact of hard water on herbicides has led to a decrease in their efficacy. This has created a need to find an appropriate solution to enhance efficacy in weed control in agricultural fields. The study agents included 2,4-D plus MCPA (U 46 Combi Fluid, 67.5% SL), which is an auxin-like herbicide. It is selective and systemic, and was used at two levels: 75% and 100% of the recommended dose in Iran (759.375 and 1012.5 g ae ha−1, respectively). The hardness of the carrier water (CaCO3) was tested at three levels: zero (deionized water), 500 ppm, and 1000 ppm. Additionally, the study examined the use (2%) and non-use (zero) of ammonium sulfate ((NH4)2SO4). The highest density of broadleaf weeds, with 18 plants per square meter, was observed when applying 75% of the recommended dose of herbicide with maximum water hardness (1000 ppm calcium carbonate) and without using ammonium sulfate. Lamium amplexicaule L., with a relative frequency of 70%, accounted for the highest weed density in this treatment. The use of 2% ammonium sulfate in the treatment of 75% and 100% of the recommended dose of herbicide, along with calcium carbonate (1000 ppm), led to an increase of 28% and 75%, respectively, in weed control compared to not using it. Based on the analysis of variance, the interaction of experimental treatments on wheat seed yield was not significant. The yield of wheat grain when applying 75% and 100% of the recommended dose of herbicide was 462 g m-2 and 515 g m-2, respectively. Additionally, at calcium carbonate concentrations of 0 ppm, 500 ppm, and 1000 ppm, the yield was 522 g m-2, 474 g m-2, and 471 g m-2, respectively. Generally, it is suggested to use 2% ammonium sulfate to optimize the efficacy of herbicides, such as 2,4-D plus MCPA, in areas with hard water.
