Resíduo da indústria siderúrgica (pó de balão) na otimização da produtividade e das características químico - bromatológicas de Panicum maximum cv. Mombaça e Brachiaria humidicola.

Abstract

The objective of the research was to evaluate the production of forage mass and chemical-bromatolologic composition of the Mombaça (Panicum maximum) and quicuioda-amazônia (Brachiaria humidicola), fertilized with organic wastes deriving of the siderurgic industry (pó de balão). In the field, a complete randomized block design for production of forage mass and nutrients with three repetitions and treatments arranged in factorial in the plots combined with three levels of each organic waste (pó de balão: 5 t/ha - PDB5, 10 t/ha - PDB10, 20 t/ha - PDB20 and poultry litter: 2 t/ha - CA2, 4 t/ha - CA4, 8 t/ha - CA8) with four doses of phosphorus (0, 150, 300 and 450 kg/ha of P2O5), the plots had been evaluated in four periods of evaluation (1th, 2th, 3th and 4th) considered as split-plots. For bromatologic composition, it was complete randomized block design with two repetitions and split-plots in the time. The studied factors had been: two organic wastes (pó de balão: 5 t/ha - PDB5 and 20 t/ha - PDB20 and poultry litter: 2 t/ha - CA2 and 8 t/ha - CA8) in combination with two doses of phosphorus (150 and 450 kg/ha of P2O5), and four periods of evaluation (1º, 2º, 3º and 4º) as split-plots. In each period of evaluation, the collected forage was divided in two parts (stem and leaf). In the greenhouse, for production of forage mass and chemicalbromatolologic, the complete randomized block design. The studied factors were: two organic wastes, poultry litter (4 g/dm3 ) and “pó de balão” (10 g/dm3), four levels of N (0, 50, 100, 200 mg/dm3) and four of P2O5 (0, 100, 200, 300 mg/dm3). The use of organic waste “pó de balão” increases the production of forage mass of Panicum maximum cv. Mombaça and Brachiaria humidicola (quicuio-da-amazônia). The aplication of the PDB to the soil of pasture change certain qualitative characteristics of Mombaça and quicuio-da-amazônia, among them, increasing contents of CP and OM and decreases the levels of ADF and its fibrous constituents. Due to the presence of heavy metals in the composition of the PDB, the risk of contamination of soil, forage, and consequently the food chain can limit their agricultural use as organic fertilizer in pastures. Thus, further studies are needed to assess this risk.