Resumen:
The grass Digitaria sp. was the forage that spread the most in recent years in the central hinterland of Pernambuco, even without proper technical and theoretical foundation. We also observed in field visits that many farmers empirically stop using various forms of fertilization trying to get higher productivity of " digitaria grass", or " digital grass", however, with no satisfactory results. When evaluating the productivity of grass Digitaria sp. subjected to different types of organic fertilizers in this study, there was a higher green vegetable mass productivity and dry in the second harvest at 180 days after planting (DAP) and there was no influence for the first (90 DAP), statistically. The sheep manure more NPK (Nitrogen, Phosphorus, Potassium) showed the best performances when compared to other treatments. For the chemical composition we found significant (p <0.05) only in organic matter (89.01%), crude protein (10.58%) and hemicellulose (25.06%) for the 180 DAP. The treatments did not affect the results of protein, hemicellulose, phosphorus, organic matter, dry matter, neutral detergent fiber, acid detergent fiber and mineral material in spite of suffering in their content variations depending on treatments. We also verified that the density and length of the roots of Digitaria sp. suffer influences (p <0.05) as a function of depth and treatment used. The longest length (13.36 cm) and density (0.26 cm.cm-3 ) roots are in the first five centimeters deep, with emphasis on the treatment of cattle manure associated with NPK which obtained 17.0 cm long and 0.35 cm.cm-3 density roots. We observed that more than 70% of the length and density of roots are found within the first 15.0 cm deep, which is the layer where the organic and mineral fertilizers should be concentrated. Evaluating the chemical and soil water content, we found that there was no influence by the treatments.
