ABSTRACT Vermicomposted vegetal and animal residues are rich in nutrients and humic substances and thus can be applied to the soil as a source of functionalized organic matter (OM) and as an alternative to chemical fertilizers. In Southern Brazil, many animal and vegetal residues are easily accessible. Therefore, this study aimed to evaluate alterations in soil chemical properties and OM chemical composition in response to the application of local vermicomposted residues. The vermicomposts of: cattle manure (CM), sheep manure (SM), rice parboiling sludge (PS), CM+PS; SM+PS; CM+food waste (FW); SM+FW; CM+fruit waste (FRW); and SM+FRW were mixed with Acrisol (Argissolo) samples collected at 0.00-0.20 m layer, and the samples were incubated in plastic bags for 182 days. Soil samples without vermicomposts were also incubated (control). Overall, vermicomposts increased soil pH(H2O), exchangeable Ca and available P and K contents. The treatments with CM or SM with FW promoted carbon accumulation in the soil compared to the control, especially as humin. The humic acids of SM and PS were more oxygenated than the others, and oxygenation was apparently associated with aromatic structures. Fulvic acids of CM+PS showed the greatest oxygenation and aliphatic character. The relationship between vermicompost origin (animal or vegetal) and soil properties or OM composition was not clear. Aromaticity degree (H/C) and C/N ratio were similar in fulvic and humic acids, and oxygenation degree (O/C) as well as polarity index [(O+N)/C] were more efficient parameters to distinguish these humic fractions. We concluded that vermicomposts derived from cheap and easily available vegetal and animal residues in Southern Brazil have great potential as alternative fertilizers as well as sources of functionalized OM when applied to the soil, especially vermicomposts of rice parboiling sludge and cattle or sheep manure mixed with food waste.

A utilização de vermicompostos de diferentes resíduos agroindustriais na produção de mudas de acácia-negra pode ser uma alternativa de reutilização de resíduos e aumentar a produção de mudas. Assim, os objetivos deste trabalho foram avaliar o crescimento e a concentração de nutrientes em mudas de acácia-negra, cultivadas em substratos com diferentes vermicompostos de resíduos orgânicos agroindustriais. Instalou-se em casa de vegetação 11 diferentes tratamentos: T1) vermicomposto de esterco bovino (EB); T2) vermicomposto de esterco ovino (EO); T3) vermicomposto de lodo de parbolização de arroz (LP); T4) tratamento controle (sem adubação); T5) tratamento controle com adução mineral (NPK); T6) mistura de EB e LP; T7) mistura de EO e LP; T8) mistura de EB e vermicomposto de resíduos de alimentos (RA); T9) mistura de EO e RA; T10) mistura de EB e vermicomposto de resíduos de frutas (RF); T11) mistura de EO e RF. Após 180 dias de cultivo em recipiente com capacidade de cinco litros, foram analisadas a massa seca e a concentração de nutrientes na parte aérea da acácia-negra, e a concentração de nutrientes no solo, após o cultivo. A adição do esterco bovino, bem como a mistura de esterco bovino e resíduos alimentícios favoreceram o incremento de matéria seca das plantas de acácia-negra. Os resultados mostraram que as concentrações de nutrientes nas plantas, com exceção de Fe e Mn, variaram com adição de vermicompostos no solo. Os tratamentos T3 e T6 elevaram as concentrações em P, N, Zn de Cu nas folhas de acácia-negra. Além disso, a adição dos vermicompostos ao solo aumentou a disponibilidade de nutrientes para as plantas, mesmo após o cultivo, especialmente com relação ao fósforo, potássio e magnésio, sendo uma alternativa viável e eficaz na produção de mudas, podendo substituir a utilização de adubação mineral.

The use of vermicompost as organic compounds of different agro-industrial wastes in the production of Acacia mearnsii seedlings can be an alternative of reusing waste and increase of seedlings production. The aim of this study was to evaluate the growth and nutrient concentration in Acacia mearnsii seedlings grown in different soils and vermicomposts of different organic wastes. Also, the effects on soil chemical properties were evaluated. So, different treatments were applied: T1) vermicompost of bovine manure (EB); T2) vermicompost of ovine manure (EO); T3) vermicompost of rice parboiled waste (LP); T4) Control (without amendment); T5) Control with mineral amendment; T6) mixture of EB and LP; T7) mixture of EO and LP; T8) mixture of EB and vermicompost of food wastes (RA); T9) mixture of EO and RA; T10) mixture of EB and vermicompost of fruits wastes (RF); T11) mixture of EO and RF. After 180 days of growth, it was analyzed the dry mass and nutrient concentration in shoots and the concentration of nutrients in the soil after cultivation. The addition of EB, as well as the mixture of EB and RA promoted the increase on dry matter. The results showed that the concentrations of nutrients in plants, with the exception of Fe, Mn varied with the addition of vermicompost in the soil. Treatments T3 and T6 increased the concentrations of P, N, Zn, Cu in leaves of Acacia mearnsii. Furthermore, the addition of vermicompost to soil increased the availability of nutrients to plants, even after cultivation, especially the phosphorus, potassium and magnesium, and it is a viable and effective in producing Acacia mearnsii seedlings and might replace the use of mineral fertilizers.

RESUMO A produção de resíduos orgânicos durante os processos agroindustriais é um problema tanto ambiental quanto econômico devido às características químicas desses resíduos. Geralmente, resíduos orgânicos estabilizados servem como condicionadores de solos. Esses resíduos podem afetar tanto na composição química quanto nas características das cargas trocáveis dos solos. O objetivo deste trabalho foi avaliar a formação de substâncias húmicas (SH) durante a vermicompostagem em diferentes resíduos agroindustriais, bem como caracterizar a composição química e molecular. Assim, diferentes resíduos - esterco bovino (EB), esterco ovino (EO), restos de alimentos de restaurantes (RA), lodo de arroz parboilizado (LP), restos de frutas e vegetais (RF) - foram submetidos à vermicompostagem. Amostras desses materiais foram secas, trituradas e caracterizadas quimicamente quanto a pH, carbono (C) orgânico, N total, Ca, Mg, K, P, relação C/N, e condutividade elétrica (CE) antes, durante e depois do processo de vermicompostagem. Além disso, foi analisado o fracionamento da matéria orgânica como as SH, análise elementar e espectroscopia de infravermelho. De acordo com o processo de vermicompostagem dos resíduos agroindustriais, o carbono orgânico total (COT) e os ácidos fúlvicos (AF) foram reduzidos; contudo, os ácidos húmicos (AH) aumentaram proporcionalmente. Dentre os vermicompostos estudados diferiram quanto à proporção final de SH formadas decrescendo na sequência: EB>RF>EO>RA>LP. Isso demonstra uma estabilização dos compostos orgânicos por meio da vermicompostagem, podendo, consequentemente, ser utilizados com uma maior segurança na agricultura.

ABSTRACT The production of organic waste during the agro-industrial processes is a problem for both environmental and economical issues due to the chemical characteristics of these wastes. Generally, stabilized organic residues are used as soil conditioners. These residues can affect both the chemical composition and the characteristics of exchangeable charges of the soils. The aim of this study was to evaluate the formation of humic substances during the vermicomposting of different agro-industrial solid residues, as well as characterize the chemical and molecular composition. So, different residues (bovine manure (EB), sheep manure (EO); food waste from restaurants (RA); mud of parboiled rice (LP); waste of fruits and vegetables (RF)) were subjected to vermicomposted. Samples of these materials were dried, smashed and chemically characterized as pH, organic carbon, total nitrogen, Ca, Mg, K, P, C/N ratio, and electrical conductivity (EC) before, during and after the vermicomposting process. In addition, it was analyzed the fractionation of organic matter such as humic substances, elemental analysis and infrared spectroscopy. According to the vermicomposting process of agro-industrial wastes, the total organic carbon and fulvic acids were reduced; however, humic acids increased proportionately. Among the studied vermicomposts, they differ in the final ratio of humic substances formed decreasing following: EB>RF>AND>RA>LP. This demonstrates a stabilization of organic compounds through the vermicompost process, and therefore can be used with greater safety in agriculture.