RESUMO Objetivou-se avaliar os efeitos de diferentes intensidades de corte sobre as respostas morfológicas e produtivas da palma-forrageira Orelha de Elefante Mexicana (OEM) (Opuntia stricta (Haw.) Haw) em um ciclo de 12 meses, recebendo irrigação suplementar. Foram avaliadas três intensidades de corte: corte preservando apenas o cladódio-mãe (CMOTH), corte preservando os cladódios primários (CPRIM) e corte preservando os cladódios secundários (CSEC), equivalentes ao índice de área de cladódios residuais (IACr) de 0,08; 0,33 e 0,69, respectivamente. O delineamento experimental foi em blocos casualizados, com oito repetições. As intensidades de corte CPRIM e CSEC proporcionaram maior altura e largura de planta, número total de cladódios e índice de área de cladódio em comparação com o CMOTH. O peso colhido na planta, a produtividade (t de matéria seca ha-1), a taxa de acúmulo de forragem e a eficiência no uso da água foram maiores para o PRIMC e CSEC quando comparada ao CMOTH. A produção de forragem para CMOTH foi 20,92 t MS (material seca) ha-1, enquanto para CPRIM e CSEC foram 37,55 e 33,18 t MS ha-1, respectivamente. Os IAC finais foram 1,23, 2,53 e 3,55 para CMOTH, CSEC e CPRIM, respectivamente. As respostas morfológicas e a produção da palma-forrageira Orelha de Elefante Mexicana recebendo irrigação suplementar são influenciadas pela intensidade de corte, em que cortes menos intensos (preservando os cladódios primários ou secundários) promovem plantas mais altas e largas e maior produção de forragem.

ABSTRACT The objective was to evaluate the effects of different cutting intensities on the morphological responses and forage yield of spineless cactus Orelha de Elefante Mexicana (OEM) (Opuntia stricta (Haw.) Haw) in a 12-month cycle, receiving supplemental irrigation. Three cutting intensities were evaluated: cut preserving only the mother cladode (MOTHC), cut preserving primary cladodes (PRIMC), and cut preserving secondary cladodes (SECC), equivalent to initial residual cladode area index (rCAI) of 0.08, 0.33 and 0.69, respectively. The experiment was a randomized block design with eight replicates. The cutting intensities PRIMC and SECC resulted in higher plant height and width, total cladode number and cladode area index compared to MOTHC. The harvested plant weight, forage yield (t DM ha-1), forage accumulation rate and water use efficiency were greater for PRIMC and SECC in comparison to MOTHC. The forage yield for MOTHC was 20.92 t DM (dry matter) ha-1, while for PRIMC and SECC were 37.55 and 33.18 t DM ha-1, respectively. The final CAI was 1.23, 2.53 and 3.55 for MOTHC, SECC and PRIMC, respectively. Morphological and yield responses of OEM Spineless cactus under supplemental irrigation are influenced by cutting intensities, in which less intense cuts (preserving the primary or secondary cladodes) promote taller and wider plants, and higher forage yield.

Objetivou-se avaliar o perfil fermentativo, as perdas e a composição bromatológica de silagens de dois genótipos de milheto, submetidos à adubação nitrogenada. O delineamento utilizado foi em blocos casualizados em um esquema de parcelas subdivididas 2x5 (dois genótipos x cinco doses de nitrogênio), com quatro repetições. As doses de nitrogênio foram 0, 20, 40, 60, 80kg ha-1 e os genótipos de milheto foram a variedade ADR300 e o híbrido ADR7010. O híbrido ADR 7010 apresentou teores médios de ácido lático superiores aos da variedade ADR 300 em todos os níveis de N, registrando valores que variaram de 4,09 a 10,46 dag kg-1. Houve interação entre os níveis de adubo e os genótipos para a fibra em detergente neutro, que variaram de 51,81 a 63,63dag kg-1 de matéria seca. A recuperação de matéria seca diminuiu linearmente com o aumento das doses de nitrogênio somente para o híbrido ADR7010, o mesmo não acontecendo para a ADR300. A adubação nitrogenada não favorece o perfil fermentativo e incrementa as perdas de matéria seca do híbrido ADR7010.

This study aimed to evaluate the fermentation characteristics, losses and the chemical composition of two pearl millet genotypes silages submitted to nitrogen fertilization. The experimental design was a completely randomized blocks in a split plot scheme 2x5 (two nitrogen genotypes doses x five doses of nitrogen), with four replicates. Nitrogen doses were 0, 20, 40, 60, 80kg ha-1 and the pearl millet genotypes were the variety ADR300 and the hybrid ADR7010. The hybrid ADR 7010 showed average lactic acid content higher than the variety ADR 300, at all doses of N, recording values ranging from 4.09 to 10.46dag kg-1. There was an interaction between nitrogren doses and genotypes for the neutral detergent fiber, which ranged from 51.81 to 63.63dag kg-1 of dry matter. Dry matter recovery decreased linearly with increasing nitrogen doses only for hybrid ADR7010, the same did not happen for the ADR300. The nitrogen fertilization does not favor the fermentation characteristics and increases DM losses of the hybrid ADR7010.

The objective of this study was to evaluate agronomic characteristics of 32 sorghum cultivars (Sorghum bicolor(L). Moench) in the Brazilian semi-arid region. The experimental design was set up in randomized blocks with three replications. Treatments were the 32 sorghum cultivars. The evaluated variables were: plant height, stem diameter, tiller density, number of green leaves per tiller, average leaf length, dry matter content, fresh matter production and dry matter production (DMP) in kg/ha, and the percentage of the components panicle, leaf blade and stem. To avoid associative effects due to the presence of positive correlation with DMP, the variables plant height, number of plants per hectare and fresh matter production were excluded for being part of the discriminatory variables of the cluster. Based on the cluster analysis and subjective cutting in 20% dissimilarity, five groups were hierarchically set up. It was not possible to find groups with higher values of panicle and DMP simultaneously; however, group number 5 met significant values for both variables, with mean values of 15,037.63 kg/ha of DMP and 11.36% of panicle, besides 13.65% of leaf. Groups 3, 4 and 5 show high potential for dry matter production, especially group 5. The presence of evident variation among cultivars allows for a selection of more productive and, thus, more suitable cultivars for silage production in semi-arid regions.

The present study evaluated the microbial population, fermentation profile, losses and dry matter recovery, and chemical composition of silages of buffel grass at different cutting heights. To evaluate the microbial fermentation dynamics, the treatments resulted from a 4 × 5 factorial combination consisting of 4 cutting heights and 5 fermentation periods, in a completely randomized design with three replications. The fermentation was evaluated at the end of 1, 3, 7, 15 and 30 days. The other characteristics of silages with 30 days were evaluated following a completely randomized design with four treatments, consisting of 4 cutting heights (30, 40, 50 and 60 cm), and five replications. Fermentation period and cutting height effects and interaction between both factors were observed on the populations of lactic acid bacteria (LAB), enterobacteria and molds and yeasts. The peak of development of LAB populations was observed on the seventh day of fermentation for the heights of 40 and 50 cm, with 8.25 and 8.30 log cfu/g, respectively. The pH values of silages ranged with different cutting heights, in which at the height of 50 cm the decrease was most pronounced. However, the pH values were similar between the cutting heights at the end of 30 days of fermentation. Quadratic relationship was observed between lactic acid concentrations and cutting heights. The crude protein content behaved linearly, initially showing 128.5 g/kg DM at 30 cm, decreasing as the cutting heights increased. The neutral detergent fiber and ether extract contents increased linearly with the cutting heights. Based on microbial populations, fermentation, losses and chemical composition, it is recommended to harvest buffel grass for silage from 50 cm on.

Objetivou-se com esta pesquisa avaliar o rendimento forrageiro, as características agronômicas e morfométricas das plantas e as perdas, perfil fermentativo e composição bromatológica de silagens de genótipos de milheto. Para avaliação das características agronômicas e morfométricas dos genótipos utilizou-se o delineamento experimental em blocos casualizados, com cinco repetições. Na fase de avaliação dos silos experimentais o delineamento passou a ser inteiramente casualizado, com quatro repetições. Foram testados os cultivares Sauna B, CMS 01, ADR 500, BRS 1501 e CMS 03. Não houve diferença para a PMV, PMS e MS. Os genótipos de milheto apresentaram uma média de PMV de 9.073 kg/ha no primeiro ciclo e de 10.054kg/ha na rebrota. Quanto à lâmina foliar e a produção de colmo não houve diferença em ambos os cortes. Os teores médios de AL variaram de 1,98 a 5,17%, para os genótipos SAUNA B e CMS 01, respectivamente. Para os teores de PB verificou-se efeito significativo entre os genótipos estudados, com valores variando de 11,56 a 7,90%. Os genótipos estudados se equivaleram tanto na avaliação das plantas como na avaliação das silagens, podendo ser utilizados como uma alternativa forrageira em regiões semiáridas.

The objective of this research was to evaluate the forage yield, agronomic characteristics and morphometric plants and losses, fermentation and chemical composition of silages of pearl millet genotypes. To evaluate the agronomic and morphometric characteristics of genotypes it was used the randomized blocks experimental design with five replicates. In the phase of silos evaluation the design has become completely randomized design with four replications. Cultivars tested were Sauna B, CMS 01, ADR 500, BRS 1501 and CMS 03. There was no difference for PFF, DMP and DM. The pearl millet genotypes had a average PMV of 9073 kg/ha in the first cycle and 10.054kg/ha in the regrowth. As to the leaf and stem production there was not difference in both cuts. The concentration of AL ranged from 1.98 to 5.17% for genotypes B and CMS SAUNA 01, respectively. For the crude protein there was a significant effect among genotypes studied, with values ranging from 11.56 to 7.90%. The genotypes studied were equivalent in both the evaluation of the plants and the evaluation of silage, which can be used as an alternative fodder in semiarid regions.

A idéia de que as estruturas matemáticas, como identificadas pela escola Bourbaki, transcendem a matemática e estabelecem uma hierarquia entre as teorias da física, era cara ao grande físico brasileiro Mário Schenberg. Um episódio de sua carreira que ilustra este fato é descrito neste trabalho.

The idea that the mathematical structures, as identified by the Bourbaki school, go beyond mathematics and establish a hierarchy among the physical theories, was cherished by the great Brazilian physicist Mario Schenberg. This is illustrated by an episode in his career.