Combination of biological processes for agro-industrial poultry waste management: Effects on vermicomposting and anaerobic digestion.

This study evaluated the combination of bioprocesses to increase the utilization of agro-industrial poultry wastes. Composting piles were submitted to hydration and fraction separation (FS) and then, the solid fraction was vermicomposted and the liquid fraction was anaerobically digested. Composting followed by hydration and FS prior to vermicomposting enhanced earthworm adaptation and survival by reducing salt levels (50%), total organic carbon, and total nitrogen which may be limiting to vermicomposting at high concentrations. These strategies providing the production of up to 300 new cocoons and 360 young earthworms more than the control treatment. In addition to providing a favorable environment for earthworm growth, the combination of bioprocesses resulted in a high-quality organic fertilizer free of phytotoxic compounds and with phytostimulant properties (germination index higher than 100%). Energy recovery was greater in the treatment without the precomposting step (T0) (461.8 L CH4 kg-1. Volatile Solidsadded). The results show that combining the bioprocesses is a sustainable alternative for managing poultry wastes not only in terms of the recycling of nutrients but also by providing a clean source of energy.

Addition of cattle manure to sheep bedding allows vermicomposting process and improves vermicompost quality.

Animal waste is usually a good substrate for vermicomposting. However, numerous animal husbandry systems use bedding that consists primarily of lignocellulosic substrates, which hinders earthworm and microorganism's development and thus, the entire bioconversion process. One possible solution is to mix the used bedding with other waste materials that are more amenable to earthworm ingestion and can provide better conditions for earthworm population growth. Here, we have aimed to examine the effectiveness of such procedure by mixing rice-husk-based sheep bedding with cattle manure in different proportions (0%, 25%, 50%, 75% and 100%). We have carried out vermicomposting experiments in benchtop vermireactors inoculated with 0.88kg of dry matter (sheep bedding+cattle manure). Data used in the Principal Component Analysis were the multiple vermicomposting variables (i.e., EC; pH; HA/FA and C/N ratios; P, K, cellulose, and hemicellulose content). The effect of the treatment on earthworm count was analyzed with ANOVA. We have observed that the addition of at least 25% of cattle manure to sheep bedding allows vermicomposting process but it is necessary 148days to obtain a stabilized vermicompost. However, increasing the proportion of cattle manure to sheep bedding, the vermicomposting time decreases proportionally to 94days. We concluded that vermicomposting can be considered a bioprocess to stabilize rice husk after being used as sheep bedding.

Performance of four stabilization bioprocesses of beef cattle feedlot manure.

The biological stabilization of beef cattle manure is crucial for promoting sanitation in feedlot pens. This study compared the performance of composting, vermicomposting, static windrows, and anaerobic digestion for stabilization of beef cattle feedlot manure based on the degradation of organic matter, nutrient retention, and stability of the final product in each process using uni- and multivariate analysis. The cluster analysis showed that composting and vermicomposting were the most similar processes. The principal component analysis showed that the more oxidative processes (composting and vermicomposting) degraded beef cattle feedlot manure more effectively (up to 45%) than static windrows and anaerobic digestion. Stabilization processes did not affect the amount of phosphorus, whereas potassium losses ranged from 3% (anaerobic digestion) to 30% (static windrow) and differed significantly across processes. Electrical conductivity decreased only in static windrow (30%). A decrease in the C/N ratio were observed in all processes, but the reduction was smaller in static windrow (5%). Larger reductions in C/N ratio were associated with greater increases in the humic to fulvic acid ratio. Composting and vermicomposting processes more effectively degraded beef cattle manure and produced stable organic fertilizers. Anaerobic digestion more effectively retained macronutrients (N and K) and converted organic N to ammonium. The use of static windrows is the least effective bioprocess for the stabilization of beef cattle feedlot manure.

The anaerobic co-digestion of sheep bedding and ⩾ 50% cattle manure increases biogas production and improves biofertilizer quality.

Sheep manure pellets are peculiarly shaped as small 'capsules' of limited permeability and thus are difficult to degrade. Fragmentation of manure pellets into a homogeneous mass is important for decomposition by microorganisms, and occurs naturally by physical shearing due to animal trampling, when sheep bedding is used. However, the high lignocellulose content of sheep bedding may limit decomposition of sheep manure. Here, we evaluated if co-digestion of sheep bedding with cattle manure would improve the yield and quality of the useful products of anaerobic digestion of sheep bedding--biogas and biofertilizer--by providing a source of nutrients and readily available carbon. Mixtures of sheep bedding and cattle manure in varying proportions (0%, 25%, 50%, 75%, or 100% cattle manure) were added to 6-L digesters, used in a batch system, and analyzed by uni and multivariate statistical tools. PC1, which explained 64.96% of data variability, can be referred to as 'organic fraction/productivity', because higher rates of organic fraction consumption (COD, cellulose and hemicellulose contents) led to higher digester productivity (biogas production, nutrient concentration, and sample stability changes). Therefore, productivity and organic fraction variables were most influenced by manure mixtures with higher (⩾ 50%) or lower (⩽ 25%) ratios of cattle manure, respectively. Increasing the amount of cattle manure up to 50% enhanced the biogas potential production from 142 L kg(-1)TS (0% of cattle manure) to 165, 171, 160 L biogas kg(-1)TS for the mixtures containing 100%, 75% and 50% of cattle manure, respectively. Our results show that the addition of ⩾ 50% cattle manure to the mixture increases biogas production and improves the quality of the final biofertilizer.

Produção agroecológica de mudas e desenvolvimento a campo de couve-chinesa / Agroecological production of seedlings and field development of Chinese cabbage

O trabalho foi desenvolvido em duas etapas: a produção de mudas de couve-chinesa em bandejas e posterior transplante para o campo, objetivando avaliar o desempenho de diferentes substratos sobre o desenvolvimento da cultura. Para isso determinou-se, tanto na fase de formação das mudas, quanto nas plantas adultas, o comprimento da parte aérea, número de folhas, comprimento da raiz, massa seca da parte aérea, massa seca da raiz e diâmetro do coleto. A etapa de produção de mudas foi conduzida em ambiente protegido, com os seguintes tratamentos: T0 substrato comercial Plantmax® (HA); T1: 100% composto; T2: 95% composto + 2,5% areia + 2,5% pó de rocha; T3: 90% composto + 3% areia + 7% de pó de rocha e T4: 85% composto + 6% areia + 9% pó de rocha. Na produção de mudas, os substratos orgânicos, formulados com 100% e 85% composto, apresentaram melhores resultados, aos 15 e 28 DAS, respectivamente. Os resultados de campo demonstraram que adição de pó de rocha é um fator determinante no desempenho das mudas, sendo os melhores resultados obtidos nas parcelas cultivadas com mudas obtidas nos substratos formulados com 7 e 9% de pó de basalto.

The research was carried out in two stages: the production of seedlings of chinese cabbage in trays with subsequent transplantation for the field, aiming to evaluate the performance of different substrates on the culture development. For this reason it was determined, both at the stage of formation of the seedlings, as in adult plants the length of the aerial part, number of leaves, root length, dry mass of the aerial part, root dry mass and diameter of the root collar. The experiment was conducted in a protected environment with the following treatments: T0 Plantmax substrate® (HA); T1: 100% compound; T2: 95% compost + 2.5% sand + 2.5% rock powder; T3: 90% compost + 3% sand + 7% powdered rock and T4: 85% compost + 6% sand + 9% rock powder. In the production of seedlings, the organic substrates formulated with 100% and 85% compound, had better results, the 15 and 28, respectively. The results of field have shown that the addition of rock powder is a determinant factor in the performance of seedlings, with the best results in the plots cultivated with seedlings obtained in the substrates formulated with 7 and 9% of basalt powder.