RESUMO

An inoculant containing selected bacterial strains can be easily applied during the nursery please process, but in this case, substrate composition can affect its survival and, in consequence, bacterial colonization. The aim of this study was to evaluate the survival of five diazotrophic bacterial strains/species applied individually on 13 different substrates used in sugarcane seedling nurseries considering an active population higher than 105 cells g-1. In addition, one experiment was performed using two commercial substrates, coconut fiber, and Multiplant™, inoculated or not with a mixture of five bacterial strains to evaluate plant growth after 30 days. These strains are combined inoculants selected for sugarcane acting as plant growth promoters. Bacterial counts were determined every seven days using the Most Probable Number technique with four different semi-solid N-free media specific for each strain tested over 35 days. The survival order, independent of the substrate tested, was: Paraburkholderia tropica Pt-PPe8T > Nitrospirillum amazonense Na-CBAMc > Herbaspirillum seropedicae Hs-HRC54 = H. rubrisubalbicans Hr-HCC103 > Gluconacetobacter diazotrophicus Gd-PAL5T. All tested substrates influenced the bacterial survival, especially after 21 days of incubation. The population size can be partially controlled by the substrate pH and stimulated by the addition of slow-release fertilizer. Besides the differences in the bacterial population present in the two commercial substrates, plant growth was found to be stimulated by the inoculated bacteria, depending on the substrate and its sugarcane cultivar tested. The selection of a substrate used to produce new plantlets of sugarcane can contribute to bacterial survival and improve bacterial colonization.

Assuntos

RESUMO

The dynamics of the organic residues added to the soil are closely related to its mineralization rate. Therefore, the present study aimed to evaluate the organic carbon mineralization in soil samples incubated with different doses of biochar and organic compost from poultry litter. Carbon mineralization was evaluated experimentally by measuring the C-CO2 liberated by incubating 200 g of soil mixed with different doses 0, 5, 10, 15, and 20 t ha-¹ of both biochar and organic compost for 61 days. The soil microbial activity, and consequently the carbon mineralization, increased with the application of doses of biochar and organic compost from the poultry litter. The highest C-CO2 mineralization was observed in the treatments that received organic compost. The carbon mineralization process followed chemical kinetics with two simultaneous reactions. The greatest amount of released and accumulated C-CO2 was observed in the soil incubated with 15 and 20 t ha-¹ of organic compost from the poultry litter. The doses of biochar did not influence the content of mineralized carbon; this behavior was not verified with the use of this compost, whose highest content corresponded to 85.69 mg kg-¹, applying 20 t ha-¹.

A dinâmica dos resíduos orgânicos adicionados ao solo está intimamente relacionada à sua taxa de mineralização. Para isso, o presente estudo teve como objetivo avaliar a mineralização do carbono orgânico em amostras de solo incubadas com diferentes doses de biocarvão e de composto orgânico da cama de aviário. A mineralização de carbono foi avaliada experimentalmente medindo-se o C-CO2 liberado durante uma incubação de 200 g de solo misturado com doses de 0, 5, 10, 15 e 20 t ha-¹ de biocarvão e de composto orgânico, durante 61 dias. A atividade microbiana do solo e consequentemente a mineralização de carbono aumentaram com a aplicação das doses de biocarvão e de composto orgânico da cama de aviário. A maior mineralização de C-CO2 foi observada nos tratamentos que receberam composto orgânico. A mineralização do carbono foi um processo dividido em duas fases distintas, a primeira com mineralização intensa e meia-vida curta do carbono e a segunda com processo de mineralização lento, com tendência de redução e estabilização do fluxo de C-CO2. A mineralização de carbono obtida com os substratos avaliados no presente estudo mostrou que os materiais pirolisados (biocarvão) são bastante eficientes para sequestrar o carbono do solo e mitigar o efeito "estufa".

Assuntos

RESUMO

The dynamics of the organic residues added to the soil are closely related to its mineralization rate. Therefore, the present study aimed to evaluate the organic carbon mineralization in soil samples incubated with different doses of biochar and organic compost from poultry litter. Carbon mineralization was evaluated experimentally by measuring the C-CO2 liberated by incubating 200 g of soil mixed with different doses 0, 5, 10, 15, and 20 t ha-¹ of both biochar and organic compost for 61 days. The soil microbial activity, and consequently the carbon mineralization, increased with the application of doses of biochar and organic compost from the poultry litter. The highest C-CO2 mineralization was observed in the treatments that received organic compost. The carbon mineralization process followed chemical kinetics with two simultaneous reactions. The greatest amount of released and accumulated C-CO2 was observed in the soil incubated with 15 and 20 t ha-¹ of organic compost from the poultry litter. The doses of biochar did not influence the content of mineralized carbon; this behavior was not verified with the use of this compost, whose highest content corresponded to 85.69 mg kg-¹, applying 20 t ha-¹.(AU)

A dinâmica dos resíduos orgânicos adicionados ao solo está intimamente relacionada à sua taxa de mineralização. Para isso, o presente estudo teve como objetivo avaliar a mineralização do carbono orgânico em amostras de solo incubadas com diferentes doses de biocarvão e de composto orgânico da cama de aviário. A mineralização de carbono foi avaliada experimentalmente medindo-se o C-CO2 liberado durante uma incubação de 200 g de solo misturado com doses de 0, 5, 10, 15 e 20 t ha-¹ de biocarvão e de composto orgânico, durante 61 dias. A atividade microbiana do solo e consequentemente a mineralização de carbono aumentaram com a aplicação das doses de biocarvão e de composto orgânico da cama de aviário. A maior mineralização de C-CO2 foi observada nos tratamentos que receberam composto orgânico. A mineralização do carbono foi um processo dividido em duas fases distintas, a primeira com mineralização intensa e meia-vida curta do carbono e a segunda com processo de mineralização lento, com tendência de redução e estabilização do fluxo de C-CO2. A mineralização de carbono obtida com os substratos avaliados no presente estudo mostrou que os materiais pirolisados (biocarvão) são bastante eficientes para sequestrar o carbono do solo e mitigar o efeito "estufa". (AU)

Assuntos

RESUMO

The dynamics of the organic residues added to the soil are closely related to its mineralization rate. Therefore, the present study aimed to evaluate the organic carbon mineralization in soil samples incubated with different doses of biochar and organic compost from poultry litter. Carbon mineralization was evaluated experimentally by measuring the C-CO2 liberated by incubating 200 g of soil mixed with different doses 0, 5, 10, 15, and 20 t ha-1 of both biochar and organic compost for 61 days. The soil microbial activity, and consequently the carbon mineralization, increased with the application of doses of biochar and organic compost from the poultry litter. The highest C-CO2 mineralization was observed in the treatments that received organic compost. The carbon mineralization process followed chemical kinetics with two simultaneous reactions. The greatest amount of released and accumulated C-CO2 was observed in the soil incubated with 15 and 20 t ha-1 of organic compost from the poultry litter. The doses of biochar did not influence the content of mineralized carbon; this behavior was not verified with the use of this compost, whose highest content corresponded to 85.69 mg kg-1, applying 20 t ha-1.(AU)

A dinâmica dos resíduos orgânicos adicionados ao solo está intimamente relacionada à sua taxa de mineralização. Para isso, o presente estudo teve como objetivo avaliar a mineralização do carbono orgânico em amostras de solo incubadas com diferentes doses de biocarvão e de composto orgânico da cama de aviário. A mineralização de carbono foi avaliada experimentalmente medindo-se o C-CO2 liberado durante uma incubação de 200 g de solo misturado com doses de 0, 5, 10, 15 e 20 t ha-1 de biocarvão e de composto orgânico, durante 61 dias. A atividade microbiana do solo e consequentemente a mineralização de carbono aumentaram com a aplicação das doses de biocarvão e de composto orgânico da cama de aviário. A maior mineralização de C-CO2 foi observada nos tratamentos que receberam composto orgânico. A mineralização do carbono foi um processo dividido em duas fases distintas, a primeira com mineralização intensa e meia-vida curta do carbono e a segunda com processo de mineralização lento, com tendência de redução e estabilização do fluxo de C-CO2. A mineralização de carbono obtida com os substratos avaliados no presente estudo mostrou que os materiais pirolisados (biocarvão) são bastante eficientes para sequestrar o carbono do solo e mitigar o efeito "estufa".(AU)

Assuntos

RESUMO

The formation and application of aerobic granules for the treatment of real wastewaters still remains challenging. The high fraction of particulate organic matter (XS) present in real wastewaters can affect the granulation process. The present study aims at understanding to what extent the presence of XS affects the granule formation and the quality of the treated effluent. A second objective was to evaluate how the operating conditions of an aerobic granular sludge (AGS) reactor must be adapted to overcome the effects of the presence of XS. Two reactors fed with synthetic wastewaters were operated in absence (R1) or presence (R2) of starch as proxy for XS. Different operating conditions were evaluated. Our results indicated that the presence of XS in the wastewater reduces the kinetic of granule formation. After 52 d of operation, the fraction of granules reached only 21% in R2, while in R1 this fraction was of 54%. The granules grown in presence of XS had irregular and filamentous outgrowths in the surface, which affected the settleability of the biomass and therefore the quality of the effluent. An extension of the anaerobic phase in R2 led to the formation of more compact granules with a better settling ability. A high fraction of granules was obtained in both reactors after an increase of the selection pressure for fast-settling biomass, but the quality of the effluent remained low. Operating the reactors in a simultaneous fill-and-draw mode at a low selection pressure for fast-settling biomass showed to be beneficial for substrate removal efficiency and for suppressing filamentous overgrowth. Average removal efficiencies for total COD, soluble COD, ammonium, and phosphate were 87 ± 4%, 95 ± 1%, 92 ± 10%, and 87 ± 12% for R1, and 72 ± 12%, 86 ± 5%, 71 ± 12%, and 77 ± 11% for R2, respectively. Overall our study demonstrates that the operating conditions of AGS reactors must be adapted according to the wastewater composition. When treating effluents that contain XS, the selection pressure should be significantly reduced.

Assuntos

RESUMO

The production of nursery is one of the most important steps in fruit crop systems. The rooting of semihardwood cuttings is largely influenced by the substrate composition, container, matrix genotype and physiological stage. The aim of this work was to evaluate the effect of different substratum composition on growth of berry plant genotypes propagated by stem cutting in dibble tubes condition under na intermittent nebulization system in green house, during 60 days. A block factorial design (4x2) comprising four organic sources e two berry genotypes was established. The organic sources of humus (vermicompost), carbonized rice hulls, ripe coir dust and leave dust from carnaúba (Copernicia cerifera) were mixed with na arenic Hapludult (1:1 proportions, v/v) to rooting and growth of P-91 and P-26 berry genotypes in tubules condition. Rooting percentage, dry mass of roots (g), number of leaves (NF) and dry mass of aerial part (g) were measured. The soil and humus mixture was suitable for rooting of semihardwood cuttings and was reflected on the number of leaves and aerial dry mass accumulation. The berry genotype P-26 presented potential for cutting process.

A produção de mudas de espécies frutíferas é uma das mais importantes etapas do sistema produtivo. A formação de mudas por enraizamento de estacas é influenciada em grande parte pela composição do substrato, genótipo, recipiente e estádio fisiológica da planta matriz. Este trabalho objetivou avaliar os efeitos de diferentes substratos nas variáveis de crescimento de progênies de aceroleira obtidas por estaquia, em tubetes, sob condições de nebulização intermitente em casa de vegetação, durante 60 dias. Utilizou-se o delineamento de blocos casualizados em esquema fatorial de 4x2, (quatro fontes de matéria orgânica e dois genótipos). As fontes orgânicas de húmus, casca de arroz carbonizada, pó de casca de coco e bagana de carnaubeira foram misturadas ao Argissolo Vermelho-Amarelo distrófico (PVAd) (proporção 1:1) para o enraizamento dos genótipos P-91 e P-26. Foram mensurados a porcentagem de enraizamento, a massa das raízes secas (g), o número de médio de folhas e a parte aérea seca (g) das estacas. A mistura de húmus e solo propiciou condições adequadas para enraizamento de estacas e o crescimento das mudas, com reflexos no número de folhas e na massa seca da parte aérea. A progênie 26 apresentou potencial para a produção de mudas por estaquia.

RESUMO

The production of nursery is one of the most important steps in fruit crop systems. The rooting of semihardwood cuttings is largely influenced by the substrate composition, container, matrix genotype and physiological stage. The aim of this work was to evaluate the effect of different substratum composition on growth of berry plant genotypes propagated by stem cutting in dibble tubes condition under na intermittent nebulization system in green house, during 60 days. A block factorial design (4x2) comprising four organic sources e two berry genotypes was established. The organic sources of humus (vermicompost), carbonized rice hulls, ripe coir dust and leave dust from carnaúba (Copernicia cerifera) were mixed with na arenic Hapludult (1:1 proportions, v/v) to rooting and growth of P-91 and P-26 berry genotypes in tubules condition. Rooting percentage, dry mass of roots (g), number of leaves (NF) and dry mass of aerial part (g) were measured. The soil and humus mixture was suitable for rooting of semihardwood cuttings and was reflected on the number of leaves and aerial dry mass accumulation. The berry genotype P-26 presented potential for cutting process.

A produção de mudas de espécies frutíferas é uma das mais importantes etapas do sistema produtivo. A formação de mudas por enraizamento de estacas é influenciada em grande parte pela composição do substrato, genótipo, recipiente e estádio fisiológica da planta matriz. Este trabalho objetivou avaliar os efeitos de diferentes substratos nas variáveis de crescimento de progênies de aceroleira obtidas por estaquia, em tubetes, sob condições de nebulização intermitente em casa de vegetação, durante 60 dias. Utilizou-se o delineamento de blocos casualizados em esquema fatorial de 4x2, (quatro fontes de matéria orgânica e dois genótipos). As fontes orgânicas de húmus, casca de arroz carbonizada, pó de casca de coco e bagana de carnaubeira foram misturadas ao Argissolo Vermelho-Amarelo distrófico (PVAd) (proporção 1:1) para o enraizamento dos genótipos P-91 e P-26. Foram mensurados a porcentagem de enraizamento, a massa das raízes secas (g), o número de médio de folhas e a parte aérea seca (g) das estacas. A mistura de húmus e solo propiciou condições adequadas para enraizamento de estacas e o crescimento das mudas, com reflexos no número de folhas e na massa seca da parte aérea. A progênie 26 apresentou potencial para a produção de mudas por estaquia.