Palma forrageira "Gigante" cultivada em diferentes espaçamentos com adubação orgânica

Abstract

The sustainability of agriculture depends on maintaining adequate levels or incorporation of organic matter in the soil, especially in the semi-arid. Work with increment of doses of cattle manure shows a greater extraction of nutrients from the soil, increase of their contents in cladodes, improving of the quality and productivity of forage by the 'Gigante' cactus. However, because it is a perennial crop, these results require assessment in more than one cycle for safety on extrapolation, since there are differences between years, particularly in relation to climatic factors. Thus, the objective of this work was to evaluate structural characteristics, bromatological ones and productivity of 'Gigante' forage cactus grown under different planting spacing and levels of organic fertilization with cattle manure, in the second cut, on a red-yellow latosol. The treatments were arranged in a 4 x 3 factorial scheme, four doses of organic fertilization with cattle manure (0; 30; 60 and 90 Mg ha-1 year-1 ), three planting spacings (1.00 x 0.50; 2.00 x 3.00 x 1.00 and 0.25 x 0.25 m) in a randomized block design, with three replicates. At 930 days after planting, 330 days after first cut, we determined plant height, number, length, width and index of cladodes area, content of dry matter, crude protein, acid detergent fiber, non-protein nitrogen, production of fresh mass and dry matter. The data were submitted to analysis of variance, proceeded to comparisons between the averages of the spacing by Tukey's test (P < 0.05) and regression analysis for different levels of manure and, as they were significant, the interactions were unfolded. Increasing doses of cattle manure up to 90 Mg ha-1 year-1 improve the structural characteristics and yield of 'Gigante' forage cactus, expressed by increasing the amount of cladodes per plant, plant height, cladodes area index, production of fresh mass and dry matter, regardless of the used spacing. Increasing doses of cattle manure up to 90 Mg ha-1 year-1 increase the levels of crude protein and acid detergent fiber, and decreases the levels of dry matter in 'Gigante' forage cactus.