Fermentation characteristics and chemical composition of elephant grass silage with ground maize and fermented juice of epiphytic lactic acid bacteria

This study aimed to evaluate the microbial populations, fermentation profile, dry matter recovery and chemical composition of elephant grass silage with ground maize (GM) and the fermented juice of epiphytic lactic acid bacteria (FJLB). A factorial design was used with four levels of GM (0 g/kg, 50 g/kg, 100 g/kg and 200 g/kg), untreated or treated with FJLB, in a completely randomized design with five replicates. A pre-experiment was undertaken to determine the optimum level of sucrose to be added to fermented juice for the development of epiphytic microflora. In this pre-experiment, a completely randomized design with three replications was used. The treatments were represented by the levels of sucrose (0 g/kg, 5 g/kg, 10 g/kg, 20 g/kg, 40 g/kg, 60 g/kg and 80 g/kg, fresh matter basis). The microbial populations, dry matter recovery, and effluent losses were affected by the interaction between GM and FJLB. Dry matter (DM) and crude protein (CP) contents increased linearly with the inclusion of GM. The addition of GM enhanced the fermentation process via a reduction in losses, and improvements were identified in the nutritional value of elephant grass silages. The use of fermented juice increased dry matter recovery, and its effect was more pronounced when ground maize was added.Keywords: dry matter recovery, lactic acid, microbiology, Pennisetum purpureu

Morfogênese e estrutura de brachiaria decumbens em resposta ao corte e adubação nitrogenada

Aimed to evaluate the morphogenetic and structural characteristics of the pasture of Brachiaria decumbens, subjected to several intensities and frequencies of cutting and nitrogen fertilization. Experimental design was randomized blocks in split plots, whit a 2 x 2 factorial arrangement relating to combinations of two cutting heights (40 and 50 cm) and two heights of residue (15 and 25 cm) at the plots and nitrogen fertilization (with or without nitrogen) in sub-plots, with four replications. Mophogenetic variables evaluated were: leaf elongation rate (LER), stem elongation rate (SER), leaf appearance rate (LAR), leaf senescence rate (LSR) and phyllochron; and structural features were: number of basal tillers (NBT), total number of leaves (TNL), number of leaves appeared (NLAp), number of dead leaves (NDL), number of alive leaves (NAL) and final leaf length (FLL). 100 kg N/ha allowed increase (p<0.10) on LER of 31.58% and 126.32% respectively for residues 15 and 25 cm. The NBT compared to cutting heights (40 to 50 cm) were affected (p<0.10) only with the use of nitrogen fertilizer, with average of 145.62 tillers/m 2 in 50 cm cut height. Residue height of 25 cm combined with cut height 40 cm increase leaf elongation rate and number of basal tillers, reducing expansion time, without changing other structural characteristics of the pasture.Objetivou-se avaliar as características morfogênicas e estruturais do pasto de Brachiaria decumbens, submetido a intensidades, fre- quências de corte e adubação nitrogenada. O delineamento experimental foi em blocos casualizados em esquema de parcelas subdividi- das, tendo na parcela o arranjo fatorial 2 x 2 referente a combinações entre duas alturas de corte (40 e 50 cm) e duas alturas de resíduo (15 e 25 cm) e nas sub-parcelas a adubação nitrogenada (com ou sem nitrogênio), com quatro repetições. As variáveis analisadas para as ca- racterísticas morfogênicas foram: taxa de alongamento foliar (TAlF); taxa de alongamento de colmo (TAlC); taxa de aparecimento foliar (TApF); taxa de senescência foliar (TSF) e filocrono; e para as características estruturais foram: número de perfilhos basais (NPB); número de folhas totais (NFT); número de folhas aparecidas (NFAp); nú- mero de folhas mortas (NFM); número de folhas vivas (NFV) e comprimento final da folha (CFF). A utilização de 100 kg/ha de N permitiu aumento (p<0,10) na TAlF de 31,58% e 126,32%, respec- tivamente para os resíduos de 15 e 25 cm. O NPB em comparação às alturas de corte (40 e 50 cm) foi afetado (p<0,10) apenas com a utilização da adubação nitrogenada, observando-se média de 145,62 perfilhos/m 2 para a altura de corte 50 cm. A altura de resíduo 25 cm combinada com a altura de corte 40 cm, junto à aplicação de 100 kg/ha de N, promovem maior produção de matéria seca total em menor espaço de tempo (28 dias), permitindo maiores taxas de lotação e facilitando o manejo no sistema de lotação rotacionada