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Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Weeds, especially ryegrass (Lolium multiflorum), interfere with and at the same time reduce the productivity and grain quality of wheat. The objective of this study was to evaluate the selectivity and efficacy of pre-emergent herbicides used in combination with post-emergent herbicides on wheat to control ryegrass. Two experiments were conducted in a randomized block design with four replicates, one to check selectivity and the other to assess ryegrass control. The variables evaluated were: herbicide phytotoxicity to wheat, ryegrass control, number of ears per area, hectolitre weight, thousand-grain mass and grain yield. The results indicate that pinoxaden showed low phytotoxicity to the crop and high control of ryegrass. S-metolachlor showed phytotoxicity, increasing with higher doses. The application of S-metolachlor + pinoxaden (480 + 40 g ha-1) resulted in the highest grain yield for the TBio Duque and TBio Sossego wheat cultivars. The use of pinoxaden in isolation shows better performance of the grain yield components of the TBio Duque and TBio Sossego wheat cultivars. [ABSTRACT FROM AUTHOR]

The selectivity of the herbicide 2,4-D depends on the plant species, the formulations produced and/or the developmental stages of the plants to which it is applied. The objective of this study was to assess the best stage of development of wheat cultivars for the application of 2,4-D salt formulations. The experimental design consisted of randomized blocks arranged in a factorial scheme (2 x 2 x 4 + 1) with four replicates. The treatments evaluated were wheat cultivars (OR 1403 and TBio Toruk), 2,4-D formulations (amine and choline salts) and crop development stages (before tillering start, at full tillering, first node and booting), another control without herbicides. 2,4-D choline and amine cause greater phytotoxicity when applied at the phenological stage of the first node of the cultivar OR 1403 and less at TBio Toruk. The highest number and length of ears, number of full grains, thousand grain weight, hectoliter weight, grain productivity and lowest number of sterile grains generally occurred when 2,4-D-choline was applied at the first node of the cultivar OR 1403 and when 2,4-D-amine was applied at the rubberization of TBio Toruk. The highest grain yields occurred when 2,4-D-choline and amine were applied to varieties in wheat booting. [ABSTRACT FROM AUTHOR]

Volunteer corn plants have infested crops sown in succession, causing yield losses. The objective of this study was to evaluate the competitive ability and economic damage level (EDL) of soybean cultivars infested by volunteer corn plants. The experiment was conducted in a randomized block design with one replication. The treatments consisted of six soya cultivars and 12 densities of volunteer corn, hybrid Syngenta 488 Vip 3, established for each cultivar, with a minimum of 0 and a maximum of 130 plants m-2. At 30 days after emergence, the plant density, ground cover, leaf area and dry mass of the aerial part of the volunteer corn plants were quantified. In soybeans, grain yield, control cost, bag price and control efficiency were determined. Dry mass was the variable that best fitted the rectangular hyperbola model. The soybean cultivars Nidera 5909 RG, Syngenta 13561 IPRO and Brasmax Lança IPRO showed greater competitive ability and EDL values of 0.07 to 0.20 plants m-2 in the presence of volunteer corn. The lowest EDL values ranged from 0.02 to 0.12 plants m-2 for the cultivars Dom Mario 5958 RSF IPRO, Nidera 6909 IPRO and Brasmax Lança IPRO, which were the least competitive. [ABSTRACT FROM AUTHOR]

Sustainable weed management strategies are important for reducing chemical inputs and development of weed resistance. This study aimed to evaluate the effect of extracts from winter cover crops (cereal rye, black oat, forage turnip, and common vetch) and summer cover crops (jack bean, velvet bean, and brown hemp) on seed germination and seedling growth of glossy nightshade (Solanum americanum Mill), under controlled conditions. The aqueous extracts were produced from the shoot biomass of cover crops at concentrations of 0%, 25%, 50%, 75%, and 100%. Fifty S. americanum seeds were placed on Germitest paper moistened with 15 mL of each extract concentration. Cereal rye extract at the highest concentration reduced total germination to 43% and caused a 62% reduction in the germination rate index (GRI) of S. americanum. Velvet bean extract reduced germination, GRI, and seedling growth of S. americanum from the lowest concentration applied, while concentrations of 75% and 100% completely suppressed seedling development. Decomposing cereal rye and velvet bean cover crops have potential to suppress germination and growth of S. americanum. Efficient cover crops could reduce herbicide applications, and thus improve herbicide resistance management. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)