Métodos de quantificação de carbono e matéria orgânica em resíduos orgânicos

Lange

et al. 2018

Agraria

Nutrients found in residues from agricultural cultures are important reserves for subsequent crops. The objective was to assess the decomposition and release of nutrients from different crop residues for subsequent soybean cultivation. The study was conducted in Mid-Northern Mato Grosso State, Brazil. The residual straw of cropping systems -maize, brachiaria and maize/brachiaria consortium -were sampled, weighted, disposed in litter bags and then distributed on the soil. The adopted experimental design followed the completely randomized arrangement with three repetitions. Treatments were determined based on harvest time, which was performed every 14 days within 140 days for maize, and within 154 days for brachiaria and for the consortium. The remaining dry matter and nutrients content, and half-time life were evaluated. Maize showed the highest straw dry matter yield (14,176 kg ha -1 ), and the consortium recorded the biggest nutrient accumulation per hectare (K=172.2; N= 141.7 and Ca=56.0 kg ha -1 ). Brachiaria straw presented the fastest decomposition rate (85%) and the highest nutrient release (K=99%; N=92%; Mg=98% and Ca=90% of total initial content). The total K released reached 150 kg ha -1 , which can fit the needs of soybean crops.Key words: crop management; integrated; mixed systems; nutrient cycling Decomposição e liberação de nutrientes de resíduos de culturas no sistema de cultivo soja-milho RESUMO: Os nutrientes contidos nos restos culturais representam uma importante reserva para culturas subsequentes. O objetivo foi avaliar a decomposição e a liberação de nutrientes de diferentes resíduos de culturas para subsequente cultivo da soja. O estudo foi realizado na região Médio Norte do estado de Mato Grosso, Brasil. A palhada residual dos sistemas de cultivo; milho, braquiária e consórcio milho/braquiária foram amostrados, pesados e acomodadas em litter bags e distribuídos sobre o solo. O design experimental foi o inteiramente casualizado com três repetições. Os tratamentos foram estabelecidos com base no tempo de colheita, realizado a cada 14 dias, em um período de 140 dias para o milho e 154 dias para a braquiária e consórcio, aonde foi avaliando a permanência da matéria seca e nutrientes e o tempo de meia vida. O milho apresentou a maior produtividade de matéria seca (14.176 kg ha -1 ), e o consórcio o maior acúmulo de nutrientes por hectare (K=172,1; N= 141,7 e Ca=56,0 kg ha -1 ). A braquiária apresentou a maior taxa de decomposição (85%) e a maior porcentagem de liberação de nutrientes (K=99%; N=92%; Mg=98% e Ca=90% do conteúdo inicial). A quantidade de K liberado pode ser de até 150 kg ha -1 o que pode corresponder às necessidades da soja.Palavras-chave: manejo de culturas; integrados; sistemas mistos; ciclagem de nutrientes Decomposition and release of nutrients from crop residues on soybean-maize cropping systems Rev. Bras.

Section: /8mentioning

confidence: 99%

Decomposition and release of nutrients from crop residues on soybean-maize cropping systems

Lange

et al. 2018

Agraria

“…In the process of stabilization of organic matter, part of the initial carbon is metabolized by microorganisms reducing to the simplest forms, CO2 (DORES-SILVA et al, 2013) or CH4 + CO2 (SILVA et al, 2012), depending on the means of stabilization, aerobic and anaerobic respectively. The four fertilizers produced, the content of organic matter depended on the means of stabilization.…”

Section: Resultsmentioning

confidence: 99%

Stabilization of confined beef cattle manure: characteristics of produced fertilizers

Lorin

Costa

et al. 2016

Eng. Agríc.

ABSTRACT:The growing demand for animal protein is directly related to the feedlot system of animals and their assumptions, such as the waste management. The characterization of the final products becomes an important factor in decision making by one or by other process. The objective was highlight characteristics that fertilizers present due to the used of stabilization process, by the principal component analysis. For the manure stabilization we realized three aerobic processes, composting, vermicomposting and natural decomposition, and one anaerobic, the anaerobic digestion. These processes produced the compost, the vermicompost, the decomposed manure and the biofertilizer. Fertilizers produced were analyzed by means of seventeen chemical and physicchemical parameters. The main differences are related to stability and organic matter content. The compost is more stable fertilizer and decomposed manure is the worst. The vermicompost is presented as the best option to adsorb cadmium and lead. The biofertilizer has the lowest values of pH, CEC and adsorptive capacity of heavy metals (Cd and Pb). The decomposed manure in presence of precipitation, and the vermicompost, with significant irrigation, generates fertilizers with smaller source of potassium.

“…The values of pH and EC were determined through an aqueous extract of the substrate (1:5 w/v) (Embrapa, 2009). Organic matter (OM) content was determined through volatile solids, after calcination in a muffle furnace at 550°C (Carmo & Silva, 2012). Nitrogen (N) content was determined through a Kjeldahl distiller (Malavolta et al, 1997).…”

Section: Methodsmentioning

confidence: 99%

Addition of Boiler Charcoal Waste to Compost for Use as Substrate for Vegetable Seedlings

et al. 2019

The recovery of waste from the broiler production chain (BPC) is consistent with the principles of a circular economy. Besides turning waste into organic compost, its use as substrate for the production of vegetable seedlings further increases its economic value. However, it is necessary to adapt its characteristics to enable its use as substrate. To this end, the addition of boiler remnant charcoal wastes (BCW), another type of waste generated in the BPC, to the organic compost resulting from the composting of BPC waste with different bulking agents (BAs) was studied. The addition of BCW to agro-industrial compost reduced the electrical conductivity (EC) of substrates. Multiple linear regression showed that, of the 13 variables (physical, chemical and physicochemical) studied, three (EC, pH and N content) are sufficient to explain the seedling quality index (SQI). Simple nonlinear regression showed that, in order to achieve higher SQIs and easier removal of clod from tray, an additional 30% in weight of BCW is required for compost, using urban tree pruning, wood sawdust and sugarcane bagasse BAs. The use of cotton and Napier grass waste as BAs is not recommended for BPC waste mixtures, as they cause a large increase in substrate EC.