Evaluation of the efficacy of glyphosate plus urea phosphate in the greenhouse and the field
ABSTRACT Glyphosate is a non-selective, foliar-applied, systemic herbicide that kills weeds by inhibiting the synthesis of 5-enolpyruvylshikimate-3-phosphate synthase. Urea phosphate (UPP), made by the reaction of urea with phosphoric acid, was applied as an adjuvant for glyphosate in this study. Experiments in the greenhouse and the field were conducted to determine the effects of UPP by comparing the efficacies of glyphosate plus UPP, glyphosate plus 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS) and Roundup.
The optimum concentration of UPP in glyphosate solution was 2.0% when UPP was used as an adjuvant. The ED50 values for glyphosate-UPP were 291.7 and 462.4 g AI ha(-1) in the greenhouse and the field respectively, while the values for Roundup were 448.2 and 519.6 g AI ha(-1). The ED50 values at 2 weeks after treatment (WAT) and 3 WAT were lowered when UPP was used as an adjuvant in the greenhouse and field study, and the glyphosate+UPP was absorbed over a 2 week period. UPP may increase the efficacy by causing severe cuticle disruption or accelerating the initial herbicide absorption. The result also showed that UPP could reduce the binding behaviour of Ca2+ to glyphosate.
The application of UPP as an adjuvant could increase the efficacy of glyphosate and make it possible to achieve effective control of weeds with glyphosate at lower dose. Moreover, UPP showed less causticity to spraying tools and presented less of a health hazard. Therefore, UPP is accepted as being a new, effective and environmentally benign adjuvant for glyphosate.
Full-textDOI: · Available from: Yongsong Cao, May 30, 2015
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ABSTRACT: Quantitative and systematical assessment of the greenness of synthetic alternatives is one of the key topics of green chemistry. By coupling mass balance analysis and multi-criteria decision analysis, the paper seeks to assess the greenness of three commercial-scale production processes of a broad spectrum herbicide named glyphosate on the basis of seven assessment criteria and sixteen metrics. The seven criteria include mass intensity, efficiency of four core elements (i.e., carbon, nitrogen, phosphorous, and chlorine), energy consumption, nature of the industrial waste, cost of raw materials, and toxicity of materials. The multi-criteria decision method is applied to rank the greenness of glyphosate's three synthetic alternatives in a comprehensive, aggregate manner. Our findings highlight the discrepancy between greenness-driven alternative and cost-driven alternative in fine chemical production. At present, the actual choice of glyphosate production process in China remains dominated by the economic criteria rather than a more comprehensive, balanced set of criteria spanning economic profitability, environmental soundness, and social responsibility. Nonetheless, the underlining research method is relevant to the choice of synthetic alternatives of other fine chemicals.Green Chemistry 01/2012; 14(7):1990-2000. DOI:10.1039/c2gc35349k · 6.85 Impact Factor