Processos para agregar valor ao fertilizante organomineral produzido com cama de frango compostada

Abstract

The poultry manure composting process generates a product with low added value in nutrients and with limitations for application in the soil with conventional fertilizer planters. The objective of the study was to add value to the composted chicken litter by adding mineral additives to reduce nitrogen losses during the composting process, inserting phosphate rock to increase the phosphorus concentration and transforming the mash into granulated form. The study was divided into three chapters: Chapter 1) Mitigation of nitrogen losses in chicken litter composted with mineral additives and natural phosphate; Chapter 2) Addition of phosphorus to organomineral fertilizers with chicken litter compost, phosphate rock and mineral additives; and Chapter 3) Aggregation of physical attributes to organomineral fertilizer with a mixture of natural phosphate and mineral additives to composted chicken litter. The study was carried out at the Federal University of Santa Maria, Campus de Frederico Westphalen, from January to August 2022. The treatments were chicken litter composted with and without reactive natural phosphate. Two types of mineral additives (agricultural gypsum and elemental sulfur) were added to the mixture of poultry litter with natural phosphate. Natural phosphate and mineral additives were mixed with chicken litter at the beginning and end of the composting process. The mixtures were composted for 30 and 60 days, in 11liters containers. The experimental design was completely randomized, with three replications. The data were subjected to analysis of variance and the means of treatments compared by the Scott Knott test at 5% probability of error. The addition of agricultural gypsum and elemental sulfur in poultry litter compost reduced nitrogen losses compared to composting without additive addition. Reactive natural phosphate in chicken litter compost is a strategy that contributes to adding phosphorus to organomineral fertilizer. In addition, elemental sulfur, as a mineral additive, added to the mixture of poultry litter and natural phosphate, increased phosphorus solubilization, with a significant increase at the end of the composting process. With the granulation process, there was an increase in the apparent density from the mash to granulated form in all treatments, indicating the importance of granulation to add value to the organomineral fertilizer, regardless of the type of mineral mixture added to the compost with chicken manure. The granulation of the mixture of chicken litter composted with reactive natural phosphate and mineral additives generated granules of organomineral fertilizers with high mechanical resistance to disaggregation, indicating that the granulation process by extrusion and spheronization was efficient.