The no-tillage system can change the nitrogen dynamics in the soil, being necessary to adjust the nitrogen fertilization in order to provide this nutrient during critical phases of the common bean growth. This study aimed at evaluating the agronomic and qualitative traits of common bean grown under different straw types, as a function of the topdressing nitrogen fertilization splitting. A randomized block experimental design, in a split-plot arrangement, with four replications, was used. The plots consisted of three straw types (maize, maize intercropped with brachiaria and brachiaria), while the subplots comprised the combination of these straw materials with 8 topdressing nitrogen fertilization splitting arrangements. The common bean on brachiaria straw shows higher grain yields and crude protein contents. The nitrogen fertilization splitting, as topdressing, interacts with the straw types, increasing the number of pods per plant. The common bean plants growing on plots with single-maize straw had a shorter time for maximum hydration. The topdressing nitrogen fertilization splitting has no effect on the common bean qualitative traits.

Resumo -O objetivo deste trabalho foi avaliar a influência de doses de nitrogênio em cobertura e das palhadas de milho, de milho consorciado com braquiária e de braquiária sobre a produtividade e a qualidade de grãos do feijoeiro. O experimento foi realizado em área irrigada, no cultivo de inverno, após cinco anos da implantação do sistema plantio direto, em Latossolo Vermelho eutroférrico de textura argilosa. Utilizou-se o delineamento de blocos ao acaso com parcelas subdivididas e três repetições. As parcelas foram constituídas por palha de milho, palha de milho consorciado com braquiária e palha de braquiária; enquanto as subparcelas, pelas doses de N em cobertura correspondentes a 0, 40, 80, 120 e 160 kg ha -1. Todos os tratamentos receberam 17 kg ha 1 de N na semeadura. O feijoeiro cultivado sobre palha de braquiária atinge maior produtividade de grãos e maior eficiência agronômica. Os atributos qualitativos dos grãos não são alterados pelas diferentes palhadas avaliadas. A aplicação do N em cobertura aumentou o teor de proteína bruta e o tempo de cozimento dos grãos de feijão, além da produtividade de grãos do feijoeiro até a dose de 136 kg ha -1 de N.Termos para indexação: Phaseolus vulgaris, Urochloa ruziziensis, Zea mays, cultivos de cobertura, eficiência agronômica, feijoeiro irrigado, tempo de cozimento. Yield and quality of common bean cultivated on grass straws and fertilized with nitrogen under no-tillageAbstract -The objective of this work was to evaluate the effect of top-dressed nitrogen fertilization and of the straws of corn crop, of corn intercropped with Brachiaria, and of Brachiaria on grain yield and quality of common bean. The experiment was carried out under irrigation, in winter cropping, after five years from the implementation of a no-tillage system, in a clayey Oxisol. A randomized block design with split plots and three replicates was used. The plots consisted of the straws of corn, of corn intercropped with Brachiaria, and of Brachiaria; while the split plots consisted of top-dressed N at levels corresponding to 0, 40, 80, 120, and 160 kg ha -1. All the treatments received 17 kg ha -1 N at sowing. Common bean cropped over Brachiaria straw reaches higher grain yield and has increased agronomic efficiency. The evaluated straws did not affect the qualitative attributes of common beans. The application of top-dressed N increased protein contents and cooking time of the beans, besides grain yield up to the level of 136 kg ha -1 N.

A busca por novas tecnologias que visem a diminuir os custos de produção de sementes é de fundamental importância. O presente estudo objetivou avaliar a viabilidade econômica da produção de sementes de soja enriquecidas com molibdênio. Foram utilizadas a cultivar BRS Valiosa RR e quatro doses de molibdênio (0 g ha-1, 200 g ha-1, 400 g ha-1 e 800 g ha-1), em duas aplicações via foliar: metade no estádio R3 e metade em R5-4. Foram estimados o custo operacional total, receita bruta, lucro operacional, índice de lucratividade, produtividade de equilíbrio e preço de equilíbrio. Concluiu-se que a aplicação foliar de molibdênio é uma forma economicamente viável de produção de sementes de soja enriquecidas com esse micronutriente.

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Production of soybean seeds enriched with molybdenumThe objective was to evaluate the production of seeds enriched by the application of foliar molybdenum (Mo) doses and the growth and yield of plants resulting from the seeds obtained in this cultivation. We used the cultivar BRS Valiosa RR and in the first year, we used three doses of molybdenum (0, 400, and 800 g ha -1 ), with four replications. With the harvested seeds, three lots of seeds with different Mo contents were formed (9.27; 51.56, and 65.43 mg kg -1 of Mo). In the second year, using the seeds produced, two experiments were set, conducted in parallel. The first experiment was arranged in a randomized block design in a 3 × 3 scheme with four replications -three application methods (without application, at sowing, and foliar in the V 4 stage at the dose of 25 g ha -1 Mo) and the three lots of seeds from the previous year. The second experiment was arranged in a randomized block design in a 4 × 4 × 3 scheme with four replications -four application stages (V 4 , in pre-flowering, in R 3 , and R 5 ) × four foliar Mo doses (0, 25, 50, and 100 g ha -1 ) × three batches of seeds enriched with different Mo contents from the previous year. The protein content in seeds was 9% higher in the presence of Mo, regardless of how this was provided. The use of Mo is positive for soybean yield, when provided by the use of seeds enriched with a level of up to 51.56 mg kg -1 or by foliar application at doses between 25 and 50 g ha -1.