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Sirvi Autor "Silva, A.P.G." järgi

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  • Pisipilt
    Kirje
    Productive and biochemical responses of Marandu grass under fertilization protocols
    (Estonian University of Life Sciences, 2025) Dutra, I.C.; Pires, A.J.V.; Jardim, R.R.; Silva, H.S.; Santos, B.E.F.; Silva, N.V.; Ribeiro, A.S.; Dutra, G.C.; Filho, C.A.A.O.; Publio, P.P.P.; Silva, A.P.G.; Nogueira, M.S.
    The aim of this study was to evaluate the effects of liming and chemical fertilization protocols, containing different combinations of nitrogen (N), phosphorus (P) and potassium (K), on the photosynthetic pigments, productive characteristics and carbohydrate concentration of Urochloa brizantha cv. Marandu. Five fertilization protocols were evaluated (PK fertilizer combination; NP fertilizer combination; NK fertilizer combination; NPK fertilizer combination; and without fertilizer - control), associated or not with soil correction via liming, in a completely randomized design, with four replicates. The experimental units consisted of plastic pots with a capacity of 12 liters, which were filled with 10 dm³ of sandy clay loam soil. Seeds of Urochloa brizantha cv. Marandu, with 80% cultural value were used. With the corrected soil, the NP protocol provided greater production of dry mass of residue (PMSRE), root volume, leaf area, leaf area index, total sugar content (AST) and starch in the root, compared to the other protocols. Without liming, the NP protocol provided greater production of aerial part dry mass (PMSPA), root volume, leaf aerial volume, leaf aerial index and AST content in leaves, roots and residue. The NPK protocol, with liming, was 73% higher in chlorophyll a content, 50% in carotenoid content, 90% in PMSPA, 78% in leaf area and 76.2% in leaf area index, compared to the soil without correction. The use of NP fertilization with liming is recommended as it provides positive responses on the photosynthetic pigments, productive characteristics and total sugar content of Marandu grass.
  • Pisipilt
    Kirje
    The quality and fermentation of the total diet containing BRS capiaçu or sugarcane with or without urea
    (Estonian University of Life Sciences, 2025) Silva, N.V.; Pires, A.J.V.; Dutra, I.C.; Silva, H.S.; Santos, B.E.F.; Nogueira, M.S.; Cruz, N.T.; Silva, A.P.G.; Teixeira, L.S.; Oliveira, G.R.S.; Dutra, G.C.; Teixeira, L.S.
    The objective of this study was to evaluate total diet silages in PVC silos, containing BRS Capiaçu or sugarcane with or without urea. The experimental design was completely randomized with a 2x2 factorial arrangement with ten replicates, with one of the roughages (sugarcane or Capiaçu) being with or without urea (2% urea on a dry matter basis). No interaction was observed between the bulk and urea factors for the variables analyzed. Diets containing sugarcane presented greater gas losses and lower pH. In contrast, effluent losses and dry matter recovery were higher in diets containing BRS Capiaçu. Ammonia nitrogen levels were influenced by both the type of roughage and the addition of urea, being higher in diets with urea and those containing BRS Capiaçu. Diets with BRS Capiaçu also resulted in higher levels of ash, NDF, ADF, hemicellulose, cellulose, and lignin. The addition of urea, in turn, reduced lignin levels. The levels of ADIN and NDIN were higher in diets with BRS Capiaçu and lower in those with sugarcane, while urea reduced ADIN. For NFC, there was an effect of roughage and urea, with higher values observed in diets with sugarcane and with the addition of urea. The highest iNDF levels were found in diets with BRS Capiaçu and without urea. Protein fractionation showed that the addition of urea increased fraction A and reduced fractions B1+B2 and C. Fraction B3 was higher in diets with sugarcane. Fraction C showed higher levels with BRS Capiaçu and when urea was not added. Sugarcane resulted in higher levels of fractions A+B1 and lower levels of B2 and C, a pattern opposite to that observed with BRS Capiaçu. Similarly, urea increased fractions A+B1 and decreased fractions B2 and C. The addition of urea to the diets promoted changes in the carbohydrate and protein fractions, improving the composition. Regarding the roughage used, sugarcane presented better fermentation parameters when purchased from Capiaçu.