Our objective was to evaluate production, nutritive value and carrying capacity of piatã grass (Brachiaria brizantha cv. BRS Piatã), and performance of Nellore heifers in agrosilvopastoral systems (ASPS) with three eucalyptus (Eucalyptus urograndis) tree densities, during winter, spring, summer, and fall. Three integrated systems were evaluated: ASPS-1 (357 trees ha(-1)), ASPS-2 (227 trees ha(-1)), and CON (5 trees ha(-1)). In each system, two sward heights were evaluated: short and tall. A total of 80 11-month-old Nellore heifers were randomly allocated in a randomized split-plot block, 3 × 2 factorial. Greater dry matter availability was observed on CON pastures during the fall season. Greater percentage of leaf lamina was detected on ASPS-1 with short sward height and greater during summer, compared with other seasons. A greater forage production was observed between tree rows and for tall sward height. Spring was the season with less forage nutritive value. Average daily gain was greater during summer and fall. Gain per hectare and stocking rate were greater on CON system and on ASPS-2. Pastures with short sward height had greater gain per hectare and stocking rate. Agrosilvopastoral systems with intermediate tree density seem to be a good choice for producers willing to diversify their revenue sources without decreasing animal production.

Sorghum is a crop that stands out as an alternative to corn due to lower soil fertility demand and increased tolerance to drought. Lack of information about the qualitative behaviour of sorghum hinders the recommendation of different purpose sorghum cultivars. The goal was to evaluate the chemical composition and in vitro digestibility of different purpose sorghum cultivar silages, at two cropping seasons. The trial was conducted at the Plant Production Department, Federal Institute of Education, Science and Technology of Rondônia, Colorado do Oeste campus, and chemical analyses and in vitro incubation were performed at the Laboratory of Animal Nutrition, Federal University of Mato Grosso, Cuiabá campus. The experimental design was a randomized block with a split-plot arrangement and four replications. Plot treatments consisted of six different purpose sorghum cultivars (BRS 308 and BRS 310, grain sorghum; BR 655 and BRS 610, forage sorghum; and BRS 506 and CMSXS 647, sweet sorghum). Split-plot treatments consisted of two cropping periods (first crop and second crop). Forage sorghum cultivar BRS 655 demonstrated higher non-fiber carbohydrate content and lower potentially digestible fibre content than the other cultivars did. Sweet sorghum cultivars had higher levels of water soluble carbohydrates and non-protein nitrogen based on protein, lower indigestible neutral detergent fibre content at second crop, and higher in vitro dry matter digestibility than the other cultivars. The silages of sweet sorghum cultivars BRS 506 and CMSXS 647, and forage sorghum cultivar BRS 655 presented higher nutritional values.

The goal was to determine the ideal cutting age of elephant grass BRS Canará for forage production in the dry and rainy seasons. The experimental design comprised randomized blocks, with five treatments (42, 56, 70, 84, and 98 days in the dry season and 42, 60, 76, 91, and 105 days of regrowth in the rainy season) and four replications each. Agronomic, morphological, and chemical characteristics were evaluated. In the dry season, there was a significant quadratic response for plant height and leaf blade length. For the other characteristics, a significant linear response was observed, except stem diameter. In the rainy season, a quadratic response for the leaf blade length, leaf blade width, and leaf:stem ratio was observed. For the other characteristics, there was a significant linear effect, except for the percentage of dead material. In the dry season, a verified linear response was observed for the chemical characteristics, except neutral detergent insoluble protein. In the rainy season, a linear response was verified for all evaluated characteristics, except acid detergent insoluble protein. Elephant grass BRS Canará for forage production should be cut between 70 and 85 days in the dry season and between 60 and 70 days of regrowth in the rainy season.

This study aimed to evaluate how different irrigation water depths influence the agronomical features of elephant grass (Pennisetum purpureum Schum) cv. Roxo. Grass was cultivated in a pasture belonging to the Bovine Sector of the National Agrotechnical School of Caceres -MT. The experiment was a block design with five treatments and four repetitions. Treatments consisted of five water depths: 0 = 0% of available water (AW), 1 = 21% of AW, 2 = 34% of AW, 3 = 74% of AW, and 5 = 100% of AW. Evaluated features were production (dry matter ha -1 ), plant height, leaf/steam ratio, and stem diameter. Dry matter production of cuts from May and July increased linearly with increasing water depth (P < 0.05). Plant height increased linearly as water depth increased in the cuts of May and September, while the height of July cuts was 71.76 cm under an irrigation depth of 390.77 mm. In May, July, and September cuts, leaf percentage decreased linearly as water depth increased (P < 0.05). An increase of 1 mm in water depth reduced leaf percentage by 0.0936% (May), 0.0295% (July), and 0.0122% (September). Our results indicate that to improve dry matter production, May, July, and September cuts should be irrigated with water depths of 56.03 mm, 601.78 mm, and 577.65 mm, respectively. Key words: Forage growth. Plant height. Productivity. ResumoObjetivou-se com este trabalho avaliar o efeito de diferentes lâminas de irrigação em capim-elefante (Pennisetum purpureum Schum. cv. Roxo) sobre as características agronômicas. O capim foi cultivado em área de capineira da Escola Agrotécnica Federal de Cáceres -MT (EAFC), 16°13'42" latitude sul e 57°40'51" longitude Oeste de Greenwich. O delineamento experimental foi em blocos casualizados, com quatro repetições. Os tratamentos constaram da aplicação de cinco lâminas de irrigação, lâmina 0: 0% CC (Capacidade de campo), lâmina 1: 21% CC, lâmina 2: 34% CC, lâmina 3: 74% CC, lâmina 4: 100% CC de água disponibilizada. Foram avaliadas a produção de matéria seca (MS), altura da planta (H), porcentagem de lâmina foliar (% LF), relação lâmina foliar:colmo (F:C) e diâmetro do colmo. Nos cortes de maio e julho o aumento da água disponibilizada via irrigação promoveu incremento linear (P < 0,05) na produção de MS, onde cada 1 mm de água promoveu incremento de 60,11 kg MS ha -1 no mês de maio e 7,43 kg MS ha -1 no mês de julho. A (H) aumentou linearmente com o acréscimo de água disponibilizada da irrigação, atingindo a altura máxima de 56,34 cm com a lâmina d`água de 56,03 mm em maio e 63,89 cm com a lâmina d`água de 713,11 mm, enquanto no corte de julho a altura foi de 71,76 cm com a lâmina de irrigação de 390,77 mm. O aumento da quantidade de água disponibilizada promoveu redução linear (P < 0,05) da % LF no capim-elefante nos cortes de maio, julho e setembro, em que cada 1,0 mm de água de irrigação aplicada reduziu a (% LF) em 0,0936; 0,0295 e 0,0122%, respectivamente. Desta forma, do ponto de vista da produção MS ha -1 , sugere-se para o corte realizado no mês de maio lamina d`água de 56,03...

The experiment was conducted at the Experimental Farm of the Federal University of Mato Grosso in the municipality of Santo Antônio do Leverger, State of Mato Grosso, Brazil to evaluate the agronomic characteristics of corn hybrids in the cultivation of second crop for silage production. The experimental design was carried out with randomized blocks with 23 treatments (hybrids) and three replications. Corn hybrids from different seed companies and recommended for the midwestern region of Brazil, were used. The agronomic traits were: stem diameter (cm), plant height and ear insertion (m); yield of green matter (ton. ha-1), percentage of spike, stem and leaves in green mass; ear productivity (ton. ha-1), dry matter content of stem + leaf and whole plant. Hybrids BF 9304, DKB 370, 177 DKB, BF 9534, BF 9417, AG 5020, BE 9701, P 3021 and P 30F98 had the highest production of green matter, plant height and spike insertion. The hybrid BF 9304 was also prominent for spike percentage (50.55%).