ResumoObjetivou-se por meio deste trabalho avaliar o efeito de nitrogênio sobre a morfogênese e rendimento forrageiro do capim-elefante cv. Pioneiro. O delineamento experimental utilizado foi em blocos casualizados com cinco repetições, totalizando 20 unidades experimentais. Os tratamentos corresponderam a quatro doses de nitrogênio (100, 200, 300 e 400 kg ha -1 ano -1 ). O experimento foi mantido sob condições irrigadas. Foram realizados cortes avaliativos a 50 cm do solo com valores de interceptação luminosa (95%) sem intervalos pré-definidos. Observou-se que a adubação nitrogenada aumentou significativamente (P<0,05) a produção de matéria seca por hectare, taxa de aparecimento foliar (folhas dias -1 perfilho -1 ), taxa de alongamento foliar (cm folha -1 dia -1 ) e taxa de alongamento de colmo (cm perfilho -1 dia -1 ). O processo de senescência foliar nesta forrageira é acelerado com o aumento das doses de nitrogênio e taxa de aparecimento foliar, consequentemente reduzindo o filocrono. É necessário um estudo sobre a viabilidade econômica de doses mais elevadas de nitrogênio em pastos de capim elefante cv. Pioneiro. Palavras-chave: Alongamento de colmo, aparecimento foliar, filocrono, Pennisetum purpureum AbstractObjective of this work by evaluating the effect of nitrogen on forage yield and morphogenesis of elephant grass cv. Pioneer. The experimental design was randomized blocks with five replications, totaling 20 experimental units. Treatments consisted of four nitrogen levels (100, 200, 300 and 400 kg ha -1 yr -1 ). The experiment was conducted under irrigated conditions. Evaluative cuts were made at 50 cm soil with values of light interception (95%) without pre-defined intervals. It was observed that N fertilization increased significantly (P<0.05) the production of dry matter per hectare, leaf appearance rate (leaves days -1 tiller -1 ), leaf elongation rate (cm tiller -1 day -1 ) and stem elongation rate (cm day -1 ). The process of

-The objective of this study was to evaluate the effect of the sowing modality of Brachiaria brizantha cv. Xaraés on the weed community and productivity of Sorghum bicolor cv. BRS 160 under the agricultural cattle-raising integration system. The treatments were constituted by sorghum forage intercropped with B. brizantha throwing-sown with light incorporation and without incorporation; sorghum forage intercropped with B. brizantha sown in a single row and in two rows in the leading row of the annual culture; and witnesses represented by the sorghum monocultures, with and without atrazine application, and of brachiaria. Major production of weed dry mass was observed in the monoculture treatments, with the species Digitaria horizontalis presenting the highest importance value and widest ground cover. For the intercropping cultivations,

The objective of this study was to evaluate the effect of increasing the supply of protein with different degradation rates on the performance and metabolism of growing Nellore cattle reared on Brachiaria brizantha cv. Marandu pasture during the transition period from the dry to rainy season. The experiment was installed on an area of 34 ha, divided into 12 paddocks with an average area of 2.85 ha. In the performance evaluation were utilized 72 recently weaned, non-castrated Nellore cattle with an initial body weight (BW) of 199 kg (SEM = 16). The following supplements were used: energy protein supplement containing 25% crude protein (CP) (C-25) and energy protein supplements containing 40% CP with one third highly degradable CP and two thirds poorly degradable CP (40-1/3NPN), one half highly degradable CP and one half poorly degradable CP (40-1/2NPN), and two thirds highly degradable CP and one third poorly degradable CP (40-2/3NPN). Higher protein degradation rates reduced supplement intake (P < 0.01). In the first period, animals consuming supplement 40-1/3NPN exhibited higher average daily gain (ADG) (0.30 kg/day), similar to that of animals receiving supplement 40-1/2NPN (P = 0.04). In the second period, supplement 40-2/3NPN resulted in lower ADG (0.19 kg/day less than the other supplements). There was no effect of supplement on animal performance in the third period (P > 0.10), when ADG was 0.56 kg/day. In conclusion, the response to supplementation is associated with interactions with characteristics of the forage canopy. Supplementation with a true protein source will be beneficial only during the early stage of the dry-rainy season transition period.

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RESUMO -Objetivou-se com o presente trabalho avaliar o consórcio de forrageiras e sorgo, cultivado na presença ou na ausência do herbicida atrazine, sobre a dinâmica de plantas daninhas e a produção de sorgo e das forrageiras em um sistema agroflorestal. O experimento foi disposto em delineamento com blocos casualizados, com três espécies de forrageiras (Brachiaria brizantha cv. Xaraés; Andropogon gayanus e Panicum maximum cv. Tanzânia) consorciadas com sorgo manejado na presença e na ausência da aplicação de 1,50 kg ha -1 de atrazine para o manejo de plantas daninhas. As forrageiras foram semeadas a lanço imediatamente antes da semeadura do sorgo, em espaçamento de 0,50 m entre linhas e com oito sementes por metro linear, em sistema de plantio direto. A aplicação de atrazine não resultou em menor produção de massa seca total de plantas daninhas, quando comparada às parcelas sem manejo. A maior massa seca das plantas daninhas foi encontrada no monocultivo de sorgo, quando comparado aos consórcios dessa cultura com as forrageiras. No consórcio do sorgo com o capim-tanzânia (forrageira de maior produção) obteve-se a menor ocorrência e produção de masssa de plantas daninhas, indicando boa capacidade competitiva dessa forrageira. A produção do sorgo não diferiu estatisticamente entre os tratamentos; entretanto, ela foi 22% superior no monocultivo, comparando-se aos consórcios com as forrageiras. As espécies de maior produção de massa, como o capim-tanzânia, quando consorciadas com o sorgo, diminuem a infestação e capacidade competitiva das plantas daninhas e favorecem o manejo dessas espécies, dispensando a aplicação de atrazine.Palavras-chave: pastagens, manejo cultural, produção de sorgo e sistemas integrados.ABSTRACT -This study aimed to evaluate the effect of a consortium of forage plants and sorghum in the presence or absence of the herbicide atrazine on weed dynamics, sorghum and forage plant production, in an agro-forestry system. The experiment was arranged in a randomized block design, with three grass species (Brachiaria brizantha, cv. Xaraés; Andropogon gayanus cv. Planaltina and Panicum maximum, cv. Tanzânia) in consortium with sorghum, and in the presence and absence of 1.50 kg ha -1 of atrazine application for weed management. The forage plants were sown before sorghum, spaced 0.50 m between rows and eight seeds per linear meter, under a no-tillage system. The application of atrazine did not result in lower production of total dry mass of weeds, compared to the plots without management. The highest weed dry mass was found in the sorghum monoculture, compared to consortium of this culture with the forage plant. The planting of sorghum with Tanzania grass, the forage plant with the largest production, was obtained in the occurrence and mass production of weeds, indicating a good competitive ability of this forage plant. Sorghum production was statistically similar between treatments but higher in monoculture, compared to the consortium with forage. The species presenting higher mass production, such as T...