Intercropping of Urochloa species with corn is an alternative to enable the no-tillage system, besides influencing weed community. Therefore, the investigation of underdoses of the herbicide glyphosate to manage grasses in intercropping systems, avoid grain yield losses, and make feasible intercropping in agricultural areas is important. This study aimed to evaluate glyphosate underdoses in the suppression of Urochloa brizantha cv. Marandu and Urochloa ruziziensis and weed control. Two tests were conducted under field conditions in a randomized block design with four replications and eight treatments consisting of increasing glyphosate doses (0, 54, 108, 270, 378, 540, 756, and 1.080 g a.e. ha⁻¹). All treatments received a dose of 1.200 g a.i. ha⁻¹ of atrazine. Evaluations of phytointoxication of brachiaria plants were carried out at 7, 14, 21, and 28 days after application. Moreover, total dry matter, leaf dry matter, stem dry matter, leaf to stem ratio, and canopy height of brachiaria plants and density and dry matter production of weed community were evaluated at 80 and 125 days after sowing. Glyphosate underdoses lower than 238 and 105 g a.e. ha⁻¹ have potential to be investigated aiming at the management of U. brizantha cv. Marandu and U. ruziziensis, respectively.

The soybean crop is one of the most economically important crops in Brazilian agribusiness and in the world, with the expansion of the crop always linked to scientific advances and new production technologies. In view of the above, the objective of this study was to evaluate the production costs of twenty-one producing regions to determine the highest and lowest production costs in the first harvest in three agricultural years and in the summer harvest in two agricultural years, with the conventional and transgenic soybeans, in addition to comparing the cost of production of the cultivation systems. As for technical procedures, a descriptive research was carried out with statistical data provided by the National Supply Company. The agricultural years of 2018, 2019 and 2020 of soybean culture were analyzed in twenty-one Brazilian municipalities, located in the Brazilian states: Bahia, Distrito Federal, Goiás, Maranhão, Mato Grosso, Mato Grosso do Sul, Minas Gerais, Paraná, Piauí , Rio Grande do Sul, Roraima and Tocantins. The region of Primavera do Leste - MT demonstrated a region with a high cost of production in comparison with other producing regions. The lowest costs varied between several regions, depending on the cultivation system employed. The production of transgenic soybeans proved to be the most profitable and promising option due to the lower production cost in relation to the cultivation of conventional soybeans.

Forage seasonality makes farmers use conservation practices. Mixing corn silage and legumes can enhance silage quality and hence animal productivity. Therefore, this study aimed to evaluate yield and quality of silages from intercropping between genetically modified corn and soybean for glyphosate tolerance (RR - Roundup Ready) as a function of plant spatial arrangement, soybean variety, and sowing fertilization methods. Two intercropping arrangements of RR corn and RR soybeans were tested: alternate single rows of corn and soybeans and double corn rows for each soybean row. Treatments were randomized blocks with four replications, arranged in a 2x2+1 factorial scheme. The first factor was sowing fertilization method (2): only in corn rows or in total area. The second factor was soybean variety (2): medium- and late-cycle genotypes, and an additional treatment of corn monoculture. After harvest, forage material was analyzed for agronomic characteristics and then ensiled for 60 days. Thereafter, bromatological composition, fermentation profile, and losses were analyzed during silage fermentation process. No differences were observed among treatments for total silage production. Overall, silage from intercropping treatments showed higher levels of hemicellulose, total digestible nutrients, crude protein, and ether extract, thus improving silage quality. However, lower contents of dry matter, acid detergent fiber, and cellulose were also observed in silage from intercropped treatments. In short, adding soybeans to silage can improve final roughage, reducing costs of protein and energy supplements.

O consórcio de milho com leguminosas pode aumentar a qualidade da silagem e resultar em maior produtividade animal. Objetivou-se nesta pesquisa avaliar aspectos agronômicos das culturas consorciadas entre milho e soja, perfil fermentativo e bromatológico da silagem produzida, em função do arranjo espacial das plantas e tipos de adubação. Foram realizados dois ensaios com dois arranjos espaciais: ensaio 1 – arranjo simples com uma linha de milho alternada com uma linha de soja; ensaio 2 - arranjo duplo com duas linhas de milho alternada com uma linha de soja. O delineamento foi em blocos ao acaso em esquema fatorial 2x2+1, com quatro repetições. O primeiro fator constou de duas modalidades de adubação de semeadura na linha: somente no milho e em área total. O segundo fator pelas doses de 100 e 70 kg ha-1 de P2O5 e K2O, respectivamente; e de 150 e 95 kg ha-1 de P2O5 e K2O, respectivamente. O monocultivo de milho foi a testemunha. Após a colheita, o material foi ensilado por 60 dias. Não houve diferença estatística no rendimento de silagem entre tratamentos, apenas aumentos na produção de vagens de soja e na qualidade da silagem nas doses maiores de adubação. Os resultados mostram que a adição de soja na silagem de milho ocasiona maiores perdas durante o processo de fermentação, mas em contrapartida eleva os teores de proteína, extrato etéreo e de digestibilidade. Ressalta-se que um volumoso com essas características pode vir a suprir a suplementação proteica em dietas de ruminantes.

The release of soybean varieties resistant to dicamba herbicide leads to the possibility of dicamba herbicide drift into soybean seed production fields and reduction in the physiological quality of soybean seeds. The aim of this study was to evaluate the physiological quality of soybean seeds as a function of the application of reduced rates of dicamba in two phenological phases. A randomized block experimental design was used, with four replications. The 4 × 2 + 1 factorial arrangement consisted of four reduced rates (0.028, 0.28, 2.8 and 28 g.ha-1) of dicamba applied in the V4 and R2 stages + a control. The physiological quality of the seeds was evaluated after harvest and at six months after storage at 20 °C. At the rate of 28 g.ha-1 of dicamba applied in the V4 and R2 stages, seed germination declined by 15% and 42%, respectively. After storage, seeds under the 28 g.ha-1 dicamba treatment had 64% lower germination compared to the lowest application rate evaluated, and electrical conductivity doubled in relation to the control. The physiological quality of soybean seeds declines under these reduced rates of dicamba applied in the V4 and R2 stages, both before and after storage.

The aim of this study was to evaluate the effects of pre-harvest desiccant herbicides on the yield and the physiological and technological quality of cowpea seeds after harvest and after storage. The experiment was conducted in a randomized block design with four replications. A split-plot design (6 × 2) was composed of the desiccant herbicides flumioxazin (30 g ai.ha-1), glufosinate ammonium (500 g ai.ha-1), paraquat (400 g ai.ha-1), saflufenacil (70 g ai.ha-1), and carfentrazone (24 g ai.ha-1) and an untreated control, as well as two seed evaluation periods, at harvest and six months after h arvest. Desiccants were applied at the R5 stage. The desiccants affected the yield, classification, color, and physiological quality of seeds of ‘BRS Guariba’. The glufosinate ammonium and paraquat herbicides compromised seed physiological quality. Flumioxazin did not affect seed yield components, color, and physiological quality. Storage at 20 °C for six months affected seed physiological quality.