Utilização de pó de rocha de quartzo sienito no processo de compostagem

Abstract

ABSTRACT: Waste disposal is an environmental concern worldwide. Proposals with the aim of reusing these residues have motivated much research, as they have the potential to supply nutrients to the soil. This strategy is even more relevant considering that Brazil is one of the largest importers of fertilizers in the world. The objective of this work is to produce a soil conditioner from the composting of coffee straw and pig manure, with the addition of liquid tannery sludge, adding rock dust from the same rock from the industrial sector of ornamental rocks acquired in two ways and of different amounts applied. The experiment was conducted using a completely randomized design in a 2x3+1 factorial scheme, with three replications, totaling 21 plots. Two regional organic residues, produced on a large scale in the state of Espirito Santo, were selected for composting, coffee straw residue and swine manure. Was added the rock powder residue of a quartz-syenite from the ornamental rock industry, as a mineralizer prone, plus liquid tannery sludge from the tannery industry to increase the biological activity. Composting was set up in a covered area with an impermeable bottom. Over 123 days of composting, plot temperature, ambient temperature, mass loss, moisture, nitrogen, carbon, potassium, phosphorus, calcium, magnesium, sulfur, iron, zinc, copper, manganese and boron were monitored. Approximate mass loss of 80% of the volume was observed after composting. There was difference in the availability of macro and micronutrients, there was also thermal variation between treatments. The addition of rock dust in the treatments decreased the availability of potassium, phosphorus, nitrogen, sulfur, zinc, copper and boron, and increased iron and manganese. There was no difference for the carbon and nitrogen ratio between treatments in terms of final values. The granulometric classification between the two rock powders showed similarity between the mined (quarry) and multiwire rock powder. The composting was successfully carried out, the release of nutrients was partial, the soil conditioner produced needs further research to better adapt it to its use, as the composting technique with an intuited release of nutrients is promising, requiring further adjustments.