Compostagem e caracterização físico-química de substrato de cama de aviário: estudo de caso

Abstract

Broiler chicken is one of the main socio-economic activities in Brazil, both in production and exportation. During its production cycle, poultry litter is combined with material used as a substrate –typically sawdust or wood shavings –and servesas bedding for the chicken. By the end of the production cycle, the broiler bedding can be reused in the next batch or be discharged, turning into waste. The bedding is usually employed as a fertilizer for being a good source of nutrients, with phosphor, nitrogen, and potassium standing out. The broiler bedding, when used as a soil fertilizer, can enhance the physical-chemical traits and increase crop productivity, replacing mineral fertilizers. However, the indiscriminate use of the residue may influence soil nutrient absorption capacity, and, in turn, cause its lixiviation, hence, the eutrophication of water springs. One way of improving the physical-chemical traits of the broiler bedding to use it as a fertilizer is by submitting it to the process of composting. Such process enhances its agronomic features, like the availability of beneficial soil minerals, and eliminates pathogenic microorganisms when the compost pile temperature is controlled. This study intended to submit the broiler bedding of a ruralproperty located in the municipality of Santa Helena -PR to a composting process that aggregated sawdust and ashes into the treatment, and to another with fresh bedding only. Hence, four compost piles were formed, three of which incorporated sawdust and ashes, and one of them solely the broiler bedding. They had 2.5 m³ and were monitored based on the following parameters: temperature, humidity, and aeration. The piles remained in the composting process for 180 days, and the collection for physical-chemical analyses was done monthly. A phytotoxicity test was also performed to check the compound maturation through seed germination. With the results in the management and monitoring of the compost piles and within the physical-chemical characterization of the obtained compound, it was observed that the broiler bedding composting contributed to the mineralization process of nutrients like phosphor, potassium, calcium, and magnesium, and enhanced the physical-chemical traits of the broiler bedding, reducing the content of organic matter, total organic carbon, and nitrogen.