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...

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.

We consider the Klein-Gordon system posed in an inhomogeneous medium Ω with smooth boundary ∂Ω subject to two localized dampings. The first one is of the type viscoelastic and is distributed around a neighborhood ω of the boundary according to the Geometric Control Condition. The second one is a frictional damping and we consider it hurting the geometric condition of control. We show that the energy of the system goes uniformly and exponentially to zero for all initial data of finite energy taken in bounded sets of finite energy phase-space. For this purpose, refined microlocal analysis arguments are considered by exploiting ideas due to Burq and Gérard [5]. Although the present problem has some similarity to the reference [6] it is important to mention that due to the Kelvin-Voigt dissipation character associated with the nonlinearity of the problem the approach used is completely new, which is the main purpose of this paper.

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