ABSTRACT. This study aimed to evaluate the shading influence on production and qualitative traits of four tropical forage legumes (calopo, puero, archer and perennial soybean). Legumes were cultivated under levels of artificial shading (0; 30; 50 and 70%) from January 2006 to June 2007. Dry matter production (DM), crude protein (CP), neutral detergent fiber (NDF), cellulose (CEL), hemicellulose (HEM) and lignin contents were evaluated. In the summer, increases in legumes DM yield were observed when grown under increasing shading levels. Calopo, puero, and archer production showed quadratic effect. Regression analysis derivation for dry matter yield showed levels of maximum values at 35.0; 33.78 and 45.45% in the summer and 34.94; 34.83 and 33.29% in the fall. Significant effect of species for CP, NDF, CEL, HEM and L/S (leaf/stem) ratio and shading level effect for NDF, CEL, HEM and L/S ratio were observed in the summer, however, no interaction was reported. In addition, significant effect of species for CP, NDF, CEL, HEM and L/S ratio was observed in the autumn. Only L/S ratio presented a negative response according to increasing shading levels. The shading promoted an increase in the fiber components and a decrease in the leaf/stem ratio, and the perennial soybean was the most tolerant to the increased shading.

ABSTRACT. The effect of ammonization was evaluated with urea at doses of 1, 2, 3 and 4%, on the basis of dry matter (DM) on Tifton 85 hay harvested at an advanced stage of development in the periods of 30 and 45 days, through analysis of dry matter, ash, ether extract (EE), neutral (NDF) and acid (ADF) detergent fiber, NDF corrected for ash and protein (NDFap), cellulose, lignin, crude protein (CP), acid detergent insoluble nitrogen (ADIN), fractionation of carbohydrates and in vitro gas production (Parameters: V f1 , k 1 , V f2 , k 2 and L). The variables DM, EE, NDF, ADF, lignin, cellulose, NDFap, fraction A + B1, fraction B2 and C of carbohydrates, and the V f1 and V f2 parameters were influenced by treatments (p < 0.05). While DM, NDF, NDFap, fraction A + B1, C, CP and V f2 showed linear effects according to the dose, NIDA and hemicellulose presented quadratic effects. V f1 and V f2 were also influenced by the treatment period. The ammonization with 2.7% urea on the basis of DM promotes improvement of Tifton 85 hay treated for 45 days, observed after derivation of the regression equation and evaluation of the nutritional and kinetic degradation in vitro.

Avaliou-se o efeito da aplicação de doses de nitrogênio associado ao potássio, em quatro idades de rebrota, sobre o índice de área foliar (IAF), produção de matéria seca (MS), teores de proteína bruta (PB) e fibra em detergente neutro (FDN) e relação folha/colmo (F/C) de Brachiaria humidicola (Rendle) Schweick. Foram testadas as seguintes doses de nitrogênio (N), na forma de uréia agrícola, e de potássio (K2O), na forma de cloreto de K, em kg/ha/ano: 0 de N + 100 de K2O; 100 de N + 100 de K2O; 200 de N + 200 de K2O e 400 de N + 400 de K2O. As aplicações foram feitas em quantidades equivalentes a 1/6 do total anual (parceladas em 6 vezes), para melhorar a eficiência da fertilização. Os resultados demonstraram efeito significativo para as idades de rebrota e adubação na produção de MS. Não foi observado efeito (P>0,05) sobre os teores de FDN em resposta aos tratamentos estudados. As variáveis relação F/C, PB e IAF foram influenciadas (P<0,05) pelas idades de rebrota da gramínea estudada.

The effect of levels of nitrogen (N) fertilization associated with potassium (K2O) and four growth intervals on the dry matter (DM) production, levels of crude protein (CP) and neutral detergent fiber (NDF), leaf/stem (L/S) ratio and leaf area index (LAI) of Brachiaria humidicola (Rendle) Schweick were studied. The following doses of N were tested, as agricultural urea, and K2O, as potassium chloride, in kg/ha/year: 0 of N + 100 of K2O; 100 of N + 100 of K2O; 200 of N + 200 of K2O and 400 of N + 400 of K2O. The applications were in equivalent amounts of 1/6 of the annual total (in 6 parcels) to improve the efficiency of fertilization. We observed a significant effect of the fertilization levels and cutting ages on DM production. The effect of fertilization rates and growth intervals did not affect the NDF content of the grass (P>0.05), but CP content, LAI and L/S ratio were influenced by growth intervals (P<0.05).

Devido à falta de informações relacionadas à adubação de plantas forrageiras para a produção de sementes, nota-se a necessidade de se estudar a influência de doses de nutrientes que proporcionem aumento de produtividade e obtenção de sementes de melhor qualidade. Foram realizados dois experimentos com o objetivo de verificar o efeito de doses de nitrogênio e fósforo e de doses de nitrogênio e potássio sobre a produção e qualidade de sementes de Brachiaria humidicola (Rendle) Schweick. Em ambos, o delineamento experimental utilizado foi o de blocos ao acaso em esquema fatorial, com quatro repetições, sendo no primeiro experimento: quatro doses de nitrogênio (0, 100, 200 e 400 Kg/ha) e quatro doses de potássio (0, 100, 200 e 400 Kg/ha) e no segundo: três doses de nitrogênio (0, 100 e 200 Kg/ha) e três doses de fósforo (0, 50 e 75 Kg/ha) A colheita das sementes ocorreu 24 dias após início da emergência das inflorescências (de 5 a 10 inflorescências/m²). As sementes foram pesadas e contadas. Os resultados evidenciaram o efeito (P<0,05) da adubação nitrogenada na produção, tanto em peso quanto em número, e na germinação das sementes, porém a adubação com fósforo e potássio não tiveram efeito sobre a produção e qualidade das sementes.

There exists a lack of information about the fertilization of forages plants when the seeds production is the final purpose. Thus the study of influence of nutrients doses is necessary for increase the productivity and to obtained seeds with superior quality. Two experiments were carried out to evaluate the influence of effect of doses of nitrogen, phosphorus and potassium on the quality and seed production of koronivia grass. The experimental design used in the two experiments was a randomized blocks replicated with four repetitions. In the first experiment was used four nitrogen doses (0, 100, 200 and 400 Kg/ha) and four potassium doses (0,100, 200 and 400 Kg/ha) and in the second experiment was used three nitrogen doses (0, 100 and 200 Kg/ha) and three phosphorus doses (0, 50 and 75 Kg/ha). The seeds harvest was accomplished 24 days after beginning of the emergency of the flowers (from 5 to 10 flowers/m²). The seeds were counting and weighted. The results evidenced the effect (P <0,05) of the nitrogen fertilization in the production, in weight and in number, and quality of seeds, however the fertilizatin with phosporus and potassium didn't show any effects.

O trabalho foi realizado com o objetivo de avaliar a composição química, a digestibilidade in vitro da matéria seca (DIVMS), a disponibilidade de forragem de capim-elefante cv. Napier e a produção de leite (PL). As estimativas de disponibilidade de MS foram realizadas mensalmente, um dia antes da entrada dos animais nos piquetes, por meio da técnica do pastejo simulado. As amostras de forragem foram colhidas observando-se a altura do resíduo pós-pastejo do ciclo anterior. Foram colhidas seis amostras por tratamento de touceiras classificadas como de alturas alta, média e baixa. As amostras foram pesadas, obtendo-se a média de forragem das três touceiras em cada tratamento em cada ciclo de pastejo. Subamostras foram retiradas para determinação da composição química (MS, PB, FDN e FDA) e da DIVMS. A pastagem foi manejada sob pastejo rotativo, com três dias de ocupação e 30 dias de intervalo de desfolha, com duas repetições de área, utilizando-se vacas Holandês x Zebu, conforme os seguintes tratamentos: pastagem, sem suplementação (T0), suplementação com concentrado durante 60 dias (T60) e/ou 120 dias de lactação (T120). Foi fornecido nos tratamentos T60 e T120 1 kg de concentrado (20% de PB e 70% de NDT) para cada 2 kg de leite produzido acima de 10 kg. A pastagem foi adubada com 1.000 kg/ha/ano da fórmula 20:05:20. Não houve diferença na composição química e na DIVMS entre os tratamentos, cujos valores médios foram de 13,6; 69,1; 39,5 e 63,8% para PB, FDN, FDA e DIVMS, respectivamente. A disponibilidade de MS também não foi afetada pelos tratamentos, tanto por área (kg/ha de MS) quanto por vaca (kg/dia), obtendo-se médias de 1.480; 1.760 e 1.870 e 12,4; 14,7 e 15,6 kg/vaca/dia, para T0, T60 e T120, respectivamente. A PL não diferiu entre os tratamentos, com média de 11,65 kg/vaca/dia, porém com diferenças entre as médias nos estádios de lactação: 15,1; 11,6 e 8,2 kg/vaca/dia de 1 a 60 dias, de 60 a 120 dias e acima de 120 dias. Nas condições deste experimento, os tratamentos não afetaram as variáveis estudadas.

One experiment was run to study the chemical composition, in vitro dry matter digestibility and the dry matter mass of elephantgrass pasture cv. Napier. Estimates of forage mass were accomplished monthly according to the hand plucking technique with samples being taken one day before the cows were turned into the paddocks. Forage samples were taken observing the stubble height of the pasture in the former grazing cycle. Six samples per treatment were collected from high, medium and low representative tuffs in the sampled paddocks. Samples were weighted in order to obtain the average forage yield per treatment on each grazing cycle. Forage subsamples were analyzed for chemical composition (DM, CP, NDF e ADF) and in vitro dry matter digestibility (IVDMD). Pasture was managed in a rotational grazing system of 33 days grazing cycle with three days grazing period and 30 days rest period. There were two replication units per treatment. Twenty four crossbred Holstein x Zebu cows were used, there being eight per treatment. The following treatments were studied: Elephantgrass pasture with no concentrate (T0); Elephantgrass supplemented with concentrate during the first 60 days of lactation (T60) and a 120 days of lactation (T120). Cows on treatments T60 and T120 received 1 kg of concentrate (20% CP and 70% TDN) for each 2 kg of milk above 10 kg, daily. Pasture was fertilized with 1,000 kg/ha/year of a 20:05:20 formula. There was no treatment effect on the forage chemical composition and IVDMD figures. Mean values for CP, NDF, ADF and IVDMD were: 13.6, 69.1, 39.5, and 63.8% for CP, NDF, ADF and IVDMD, respectively. There was no treatment effect on forage mass (1,480; 1,760 and 1,870 kg DM/ha) and daily forage allowance per cow (12.4; 14.7 and 15.6 kg DM/day). There was no treatment effect for milk yield averaging 11.65 kg/cow/day. However there was treatment effect for stage of lactation, which averaged 15.1, 11.6, and 8.2 kg/cow/day for 1 to 60, 60 to 120 and over 120 days, respectively.