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Abstract
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Minerals in spray carrier water can adversely influence weak acid herbicides’ activity, thus overcoming them has been considered a main research priority. Hence, a series of dose-response pot experiments were conducted to compare the water softening chemical methods ((NH4)2SO4, NH4NO3, C6H8O7, and KHPO4) and a new water softening physical method (passing through a magnetic field of 0.7 Tesla) for overcoming antagonism from the carriers containing 0.5 g L-1 of CaCO3, MgCO3, Na2CO3, K2CO3, or Fe2(CO3)3 on imazethapyr activity on jimsonweed (Datura stramonium L.). The imazethapyr activity was significantly increased by all methods when distilled water was used as carrier. As (NH4)2SO4 (RP = 3.52) was the most effective method followed by C6H8O7 and NH4NO3 (RP = 2.58), magnetized carrier (RP = 1.83), and then KHPO4 (RP = 1.48) to improve imazethapyr activity. The imazethapyr activity was clearly antagonized when carbonate salts was inserted to distillated water. The intensity of antagonistic effects were depending on cation’s valence ranked as follows: Fe2(CO3)3 (RP = 0.47) > MgCO3 (RP = 0.52) = CaCO3 (RP = 0.53) > K2CO3 (RP = 0.69) = Na2CO3 (RP = 0.66). Keeping above conclusion, the application of magnetized carrier was not an effective method of overcoming antagonism as much as the addition of (NH4)2SO4 or C6H8O7, but it was more effective than the addition of NH4NO3 or KHPO4. Nonetheless, from different points of view-agronomical, environmental, and economical, applying magnetized carrier is recommended as a technique because not only it needs no chemical but also it causes no side-effect.
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