No abstract

The present work aimed to evaluate the behavior of ten fertility attributes of soil organic matter physical fractions and total organic carbon upon addition of three EM Bokashis to a Rhodic Ferralsol (FRr) and a Dystric Cambisol (CMd). An experiment was carried out in greenhouse in which the soils were placed into plastic trays and cultivated with tomato. A completely randomized design was used with four repetitions and factorial scheme of 2 × 3 + 2, consisting of two soils (FRr and CMd), three EM Bokashis (Poultry Manure Bokashi (BPM); CNPH Bokashi (BC); and Cattle Manure Bokashi (BCM)), and two controls (both soils without addition of Bokashi). The following fertility attributes were evaluated: pH, Ca 2+ , Mg 2+ , K + , Na + , P, SB, H + Al, CEC, and . Particulate organic carbon (POC) and mineral-associated organic carbon (MOC) and total organic carbon (TOC) were also investigated. Finally, the Principal Component Analysis was conducted in order to identify possible patterns related to soils when fertilized with EM Bokashi. The addition of EM Bokashi increased the soil fertility and contents of POC. Different EM Bokashi presents distinguished effects on each soil. The PCA suggests that BPM presents higher capacity to modify the analyzed chemical attributes.

Resumo -O objetivo deste trabalho foi avaliar os teores de carbono orgânico total (COT) e das frações granulométricas da matéria orgânica de um Latossolo Vermelho cultivado com hortaliças, sob diferentes sistemas de manejo e de cultivo de plantas de cobertura. O experimento foi realizado por seis anos, em delineamento de blocos ao caso, em arranjo fatorial 3x2, com três sistemas de manejo do solo -plantio direto (SPD), preparo reduzido (PPR) e preparo convencional (SPC) -e dois cultivos de cobertura, um de milho solteiro e outro de milho consorciado com mucuna-cinza (Stizolobium niveum) (MM), com quatro repetições. Os teores de COT, estimados para a camada 0,00-0,30 m, foram maiores em SPD e PPR. Independentemente da profundidade avaliada, o consórcio MM promoveu os maiores teores de carbono orgânico particulado (COP), que foram fortemente influenciados pela incorporação da palhada. Em todas as camadas, observaramse correlações negativas entre os teores de COP e os de carbono orgânico associado a minerais (COAM), indício de ocorrência do efeito "priming". Os teores de COT correlacionaram-se positivamente aos de COAM, o que destaca a importância de mecanismos de estabilização da matéria orgânica no incremento dos teores de COT no solo.Termos para indexação: carbono associado a minerais, carbono orgânico particulado, carbono orgânico total, efeito "priming", plantio direto de hortaliças, sequestro de carbono. Organic carbon pools in an Oxisol cultivated with vegetables under different managementsAbstract -The objective of this work was to evaluate the contents of total organic carbon (COT) and of the organic matter fractions in an Oxisol cultivated with vegetables under different soil management systems and with different cover crops. The experiment was carried out for six years in a randomized block design, in a 3x2 factorial arrangement with three soil management systems -no-tillage (SPD), minimum tillage (PPR), and conventional system (SPC) -, and two cover crops, one of maize and the other of maize intercropped with Stizolobium niveum (MM), with four replicates. COT levels, estimated for 0.00-0.30-m, soil depth were higher in SPD and PPR. Regardless of the evaluated soil depth, MM intercropped system promoted higher contents of particulate organic carbon (COP), which were strongly affected by straw incorporation. In all soil depths, negative correlations were observed between the contents of COP and those of carbon associated to minerals (COAM), which indicate the occurrence of priming effect. COT contents were positively correlated to those of COAM, stressing the importance of soil organic matter stabilization mechanisms for improving COT contents in the soil.Index terms: carbon associated to minerals, particulate organic carbon, total organic carbon, priming effect, no-tillage for vegetables, carbon sequestration. IntroduçãoPara que ocorra sequestro de carbono, os sistemas de manejo devem adicionar elevadas quantidades de biomassa ao solo, causar o mínimo distúrbio em sua estrutura, além de promover a conser...

Biochar is a solid material formed during biomass thermochemical decomposition processes. This organic compound has particular properties that may cause effects on soils depending on its feedstock and processing conditions. Thus, the characteristics and purpose of use of this material must be recognized prior to its use. Two types of biochar, derived from different wood sources, were compared, one from caatinga biome species and another from cashew trees. Two species from caatinga biome were used, jurema-preta (Mimosa tenuiflora Willd. Poir.), and marmeleiro (Croton sonderianus Müll. Arg.). This study aimed to identify the best biochar material regionally available to increase water-holding capacity in the soil, based on laboratory tests and microstructural porosity evaluation. Biochar from Caatinga wood demonstrated an improved water-holding capacity if compared to cashew wood biochar. The particle diameters of 2 and 4 mm showed the highest levels, which were 2,268 g.g-1 for caatinga wood and 0.574 g.g-1 for cashew wood biochars, respectively. While the smaller quantities of macropores and a larger number of micropores (smaller radius) could explain the higher water-holding capacity for biochar from caatinga wood, the thick lignified cell walls of biochar from cashew wood support the idea of a hydrophobic effect contributing to water lower holding capacity.

Several agro-industrial, livestock, and food wastes can be recycled to create biofertilizers. This diversity of raw materials can result in nutritional imbalance and an increase in heavy metal content, which could make the final product unfeasible. Thus, the chemical characterization of the raw materials and their influence on the sustainable and safe production of biofertilizers need to be better understood. In this context, the objective of the present study was to evaluate the chemical characteristics of agro-industrial residues used in the manufacture of an aerobic liquid biofertilizer. We analyzed the macronutrient, micronutrient, and trace metal contents of seven waste products used as raw materials to create a biofertilizer. In addition, a survey of secondary biofertilizer data from different residues was carried out that showed great heterogeneity in the chemical compositions of these residues, which has a direct impact on the agronomic efficiency of these biofertilizers. The characterization revealed that some materials may be contaminants of the soil, due to high levels of trace metals, especially cadmium. We conclude that the generation of detailed inventories, such as those of the nutrient and heavy metal contents of the raw materials and biofertilizers produced, is indispensable for the correct recommendation of biologically-based inputs in agriculture.

The need to adapt agricultural crops to climate change and to develop more sustainable cultivation systems has been a major challenge for agriculture. In this study the effects of soil conservation practices were evaluated on production aspects of melon (Cucumis melo), cultivar BRS Araguaia, cultivated in a greenhouse under soil and climatic conditions of the Brazilian Cerrado. The adopted experimental design was of randomized blocks with three treatments (soil managements) and six replicates. We evaluated the following soil management systems: no-tillage (PD), minimum tillage (CM) and conventional tillage (PC) in two cycles. Increases in commercial productivity and average number of marketable fruits were observed for PD (61.5 and 61.2 t/ha; 56,000 and 44,300 fruits/ha in the first and second cycles, respectively) and CM (59.7 and 57.5 t/ha; 55,700 and 42,400 fruits/ha in the first and second cycles, respectively). No effects of management systems on fruit quality were observed. PD and CM were effective in increasing the melon production under evaluated conditions. Keywords: Cucumis melo, no-tillage, minimum tillage, conventional tillage, greenhouse. RESUMO Produtividade e qualidade de melão cultivado em ambiente protegido com diferentes manejos de solosA necessidade de adaptação de cultivos agrícolas às mudanças climáticas, aliada à necessidade de desenvolvimento de cultivos mais sustentáveis constitui um grande desafio para a agricultura. O presente trabalho teve como objetivo avaliar os efeitos de sistemas de manejo de solo conservacionistas sobre aspectos produtivos de melão amarelo (Cucumis melo), cultivar BRS Araguaia, cultivado em ambiente protegido em condições edafoclimáticas do Cerrado brasileiro. O experimento foi conduzido em delineamento de blocos ao acaso, com três tratamentos (manejos de solo) e seis repetições. Foram avaliados os seguintes sistemas de manejo de solo: plantio direto na palha (PD), cultivo mínimo (CM) e plantio convencional (PC), em dois ciclos culturais. Foram observados incrementos na produtividade e no número médio de frutos produzidos quando do uso do PD (61,5 e 61,2 t/ha no primeiro e segundo ciclo, respectivamente) e do CM (59,7 e 57,5 t/ha no primeiro e segundo ciclo, respectivamente). Nenhum efeito dos sistemas de manejo sobre a qualidade dos frutos foi observado. O PD e o CM foram eficientes em aumentar a produção do melão amarelo nas condições avaliadas. Palavras-chave:Cucumis melo, plantio direto na palha, cultivo mínimo, preparo convencional, cultivo protegido.

Bacterial wilt, caused by Ralstonia solanacearum, is a major tomato disease in tropical and subtropical regions. It is difficult to be managed, since no single measure confers significant contribution for disease control. Among the cultural practices available for disease management, bokashi provides nutrients to the plants, increasing the microbial biomass, improving the quality of the soil and, in some cases, protecting plants against diseases. In this work, we evaluated the effect of three different bokashis (Embrapa-BE; poultry-BP and cattle-BC) in two soils artificially and naturally infested with R. solanacearum, on the suppression of bacterial wilt in tomato. Disease control is discussed upon measurements on the contents of microbial biomass carbon (MBC), on total organic carbon (TOC), on basal respiration (BR), on metabolic coefficient (qCO2) and on microbial coefficient (qMIC). The experiment was implemented in greenhouse, with completely randomized design and factorial arrangement of treatments 2 × 3 (two soils × three bokashis). Disease suppression, assessed through wilt incidence 20 and 30 days after transplanting, was better observed in the naturally infested soil, where BP and BE were more efficient in controling the disease. TOC contents were higher in the artificially infested soil compared to that naturally infested, whereas the qMIC presented higher value for the naturally infested soil, which had greater contribution of MBC. Higher rates of BR and qCO2 were observed for the naturally infested soil with BC, probably indicating high plant stress caused by the disease in this treatment. Moreover, a high and positive correlation coefficient was found between the variables qCO 2 and the number of infected plants at 30 days after transplanting. In the artificially infested soil, a negative correlation was found between the number of infected plants at 20 days after transplanting and TOC.

2016-12-23T18:47:23