Indicadores biólogicos da aceleração da compostagem da casca de coco seco submetida à hidrólise alcalina e cama de ovinos

Abstract

Coconut cultivation generates a significant volume of waste and its recycling through composting constitutes an important alternative for the use of coconut husks on the farm. However, one of the challenges for its use in obtaining organic compounds is its slow degradation, which could be accelerated by the use of alkaline agents, such as hydrated lime. The integration of sheep farming in mature coconut production areas would enable composting on the farm, as it provides an important source of N. The objective of the present work was to evaluate the acceleration of dry coconut husk (CCS) composting, using it as a sheep litter, submitted or not to alkaline hydrolysis, using biomass and microbial activity. The test was carried out in a producer area, in the municipality of Barra de Santo Antônio, AL. The pre-treatment of the sheep litter consisted of the application of calcium hydroxide in the proportion of 2 % of the dry mass of SCC. After 45 days, the sheep litter were swathed and the following treatments were established: Sheep litter with hydrolyzed CCS (P1); Sheep litter with nonhydrolyzed CCS (P2); hydrolyzed CCS + ammonium sulfate (P3); unhydrolyzed CCS + ammonium sulfate (P4); Hydrolyzed CCS (P5) and non-hydrolyzed CCS (P6). Sheep litter samples were collected at 30 days after placing the animals and at 9, 26, 54, 89, 124 and 222 days after assembling the windrows. Biomass and microbial activity, water pH and electrical conductivity (EC), and organic carbon content were determined. The pH and EC of the windrows increased as a result of sheep manure and decreased as a result of ammonium sulfate, having been little affected by lime. Basal respiration and microbial biomass are higher during the CCS period as sheep litter than during composting. During compost processing, organic carbon decreased as expected in SCC windrows with sheep litter, being little affected by lime application. It was concluded that the use of biomass and microbial activity indicators highlighted the existence of differences between the treatments tested to accelerate the composting of dry coconut husk, with emphasis on the strategy of using CCS as sheep litter. Keywords: Composting, Coconut fibers, Hydrated lime, Sheep farming.