Nutrient loss in composting of agroindustrial residues

Abstract

ABSTRACT:The management of composting may influence the characteristics of the produced compounds. The experiment used three frequencies of plowing, combined with the conditions: with and without coverage of the composting patio, with and without the use of commercial inoculant, resulting in 12 furrows, installed on the Experimental Center of Agricultural Engineering (NEEA), of the STATE UNIVERSITY OF WEST PARANÁ (UNIOESTE), Campus of Cascavel city -state of Paraná (PR), in Brazil. The waste and quantities used in kg were: corn cob (7.5); hatchery residue (5); floater sludge (31); ash (1); wheat cleaning residue (120); wheat pre-cleaning residue (120); corn peel (7.5); solid fraction of wash trucks used to transport chickens (2); solid fraction of pig manure (1) and coal (5), totaling 300kg of natural matter. The aim of this study was to evaluate the influence of plowings, patio coverage and inoculation in losses of N, P, K, Ca, Mg, Na, Cu, Zn, Mn, Fe. The furrows plowed three times a week in the first month showed significant higher losses of N (p<0.05). The coverage of the composting patio influenced significantly the losses of N, K, Mg and Na (p<0.05). The produced compounds had a high agronomic value in relation to macro and micronutrients. It is recommended the use of patio coverage and plowing twice a week in the first month and once a week in the subsequent months for a compound with higher concentrations of nutrients.

Composting Time Reduction of Agro-Industrial Wastes

“…However, care must be taken because in materials with less porosity the excess of humidity can cause anaerobiosis and make the process slower and with strong odors (MAGALHÃES et al, 2006). Besides that, the produced compost at the outdoor area presents lower amount of nutrients due to leaching such as demonstrated by CARNEIRO et al (2013).…”

“…On the other hand, the larger the aeration, the greater the nitrogen losses by volatilization (JIANG et al, 2015b). However, turnings of twice a week in the first month, homogenize the material, increase the initial velocity of degradation, control the temperature in the phase of high peaks and promote the lower losses of N, as shown in CARNEIRO et al (2013).…”

“…The organic substances degradation release mineral salts, increasing EC in the first days of composting (HUANG et al, 2004;CÁCERES et al, 2006). However, after a period of great degradation, the windrows presented a reduction in EC, mainly in the uncovered windrows, due to nutrients leaching (CARNEIRO et al, 2013). In order to verify the effect of turnings, inoculum and covering in the pH and EC variables, we realized a multiple regression analysis (Table 4).…”

“…Composting piles submitted to high frequency of turnings get ready in a shorter time when compared to static piles (CÁCERES et al, 2006;GUO et al, 2012). However, the loss of N is strengthened (CARNEIRO et al, 2013;COOK et al, 2015). Greater aeration rates offered by turnings modify the thermodynamic factors that affect the generation and transference of the heat in the composting system, such as moisture and water vapor transport, natural aeration, volatilization, oxygen status and patterns of temperature distribution (MASON & MILKE, 2005).…”

“…Agríc., Jaboticabal, v.36, n.6, p.1206Jaboticabal, v.36, n.6, p. -1217Jaboticabal, v.36, n.6, p. , nov./dez. 2016 1207 the exhalation of undesirable odors and nutrients leaching (JIANG et al, 2015b;CARNEIRO et al, 2013). On the other hand, the lack of water decreases the biological activity (KIEHL, 2010).…”