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Purpose Sugarcane vinasse is generated in large amounts and can be utilized to improve soil attributes, especially in areas degraded by burns. The aim of the present study was to evaluate the effects of sugarcane vinasse on physico-chemical attributes of a Cambisol managed via annual burns. Methods Soil samples were collected from an annually burned area under pasture and used in an experiment in pots to evaluate the effects of dosages of vinasse (0, 18.8, 37.5, 56.3, 75.0, 112.5, and 150 ). The water-dispersible clay was reduced by the formation of bonds with organic matter, which overlapped the repulsive forces intensified by the increment of K + /(Ca 2+ + Mg 2+ ). The estimated vinasse dosage that provided the minimum water-dispersible clay (69 g kg −1 ) was 110 m 3 ha −1 . Conclusions Vinasse can be applied to improve the physico-chemical attributes of soils degraded by annual burns.

O objetivo deste estudo foi avaliar os atributos microbiológicos do solo em diferentes sistemas de manejo na região oeste do Estado do Paraná. Avaliou-se na profundidade 0-20 cm em áreas de sistema agropastoril, cultivo mínimo, pastagem, plantio convencional e floresta primária o conteúdo de carbono da biomassa microbiana (CBM), respiração basal do solo, quociente metabólico, quociente microbiano e fosfatase ácida. A análise de componentes principais mostrou evidente distância dos atributos microbiológicos, entre a floresta primária com as áreas em cultivo mínimo e plantio convencional. Os atributos mais importantes apontados pela análise de componentes principais na distribuição dos manejos foram o quociente microbiano e a atividade da fosfatase ácida. Não houve diferença para a respiração basal e o quociente nos diferentes sistemas de manejos. O sistema agropastoril provê aumento da quantidade e atividade da CBM, e, contribui com o estoque de carbono do solo, enquanto a mobilização do solo realizado no plantio convencional afeta o compartimento microbiológico do solo. Palavras-chave:Biomassa microbiana, qualidade do solo, quociente microbiano, fosfatase ácida, carbono orgânico. Microbiological attributes of soil in different management systems in west ofParana State, Brazil. The objective of this study was to evaluate soil microbiological attributes in different management systems in the western region of the Paraná State. At 0-20 cm depth, the microbial biomass carbon content, basal respiration of the soil, metabolic quotient, microbial quotient and acid phosphatase in areas of agropastoral system, minimum cultivation, pasture, conventional tillage and primary forest were evaluated. Principal component showed that there was evident distance, in terms of microbiological attributes, between the primary forest of the areas under minimum cultivation and conventional tillage. The most important attributes indicated by the principal component in the distribution of the management were the microbial quotient and the acid phosphatase activity. The basal respiration and the metabolic quotient did not present significant differences in the different management. The agropastoral system provides an increase in the amount and activity of the soil microbial biomass and contributes to the soil carbon stock, while soil mobilization in the conventional tillage negatively affects in the soil microbiological compartment.

The objective of this study was to evaluate changes in microbiological attributes of soils under different growing systems. Three cropping systems were evaluated (1) no-tillage system (NTS); (2) conventional tillage system (CTS); and (3) newly scarified no-tillage system (SNTS). The three systems were maintained for 20 years. In addition, a primary forest (PF) fragment was used as a reference. Soil samples were collected at depths of 0.0 -0.1 m, 0.1 -0.2 m, and 0.2 -0.3 m. The following variables were measured: microbial biomass carbon (MBC); soil respirometry (RESP) using the fumigation and incubation method; microbial biomass nitrogen (MBN) using fumigation and extraction; metabolic quotient (qCO 2 ) using the RESP/MBC ratio; and number of spores (NS) of mycorrhizal fungi by plate counting of spores extracted from the soil by wet sieving. Treatments were arranged in a completely randomized block design with five replicates. The different management systems affected the soil microbiota, especially in the superficial layer of 0.0 -0.1 m. At a depth of 0.0 -0.2 m, the PF presented significantly higher values for all analyzed attributes, except for NS. There were no significant differences in the studied characteristics between the NTS and SNTS at the three depths, indicating that scarification performed only once in the NTS was not sufficient to produce changes in soil microbiological attributes. However, the adoption of the CTS for 20 years promoted a decrease in MBC and MBN. RESP and NS were not significantly different between the cropping systems. Principal component analysis indicated a significant difference in microbiological characteristics between the PF and the areas under management. Therefore, different growing systems change the soil microbiota, and the lower the degree of tilling (NTS and SNTS), the smaller the changes in soil microbiological attributes. Soil preparation practices used in conventional tilling negatively affect soil microbial biomass, decreasing the levels of MBC and MBN. plantio convencional -PC, ambos estabelecidos a 20 anos e (3) sistema de plantio direto de 20 anos recém escarificado -SPDE. Além desses, um fragmento de floresta primária (FP) foi usado como referência. Amostras de solo foram coletadas nas profundidades de 0,0 -0,1; 0,1 -0,2 e 0,2 -0,3 m e determinados o carbono da biomassa microbiana (CBM) e a respirometria do solo (RESP) pelo método da fumigação e incubação, o nitrogênio da biomassa microbiana (NBM) determinado por fumigação e extração, o quociente metabólico (qCO 2 ) pela razão entre RESP/CBM, e o número de esporos de fungos micorrízicos (nESP) por contagem em placa sob microscópio dos esporos extraídos do solo por peneiramento úmido. Os dados foram analisados como delineamento inteiramente ao acaso com cinco repetições. Os diferentes manejos influenciaram a microbiota do solo, destacadamente na camada superficial de solo 0,0 -0,1 m. Na profundidade de 0,0 -0,2 m a FP observou-se valores significativamente maiores para todos os atributos analisados, excet...

The pig slurry (PS) application as an organic fertilizer in Brazilian soils occurs for many years and the effects of this application are known, but in this study our objective was to evaluate the microbiological attributes and microbial diversity of the soil after the interruption of the PS application. The PS rates were 0, 30 and 60 m 3 ha-1 yr-1 and in 2016 the plots were divided and the PS application was stopped in half of the plot, generating the factorial scheme 2 × 2, being two PS rates (30 and 60 m 3 ha-1 yr-1) and two application conditions (continuous or interrupted). Two soil samples were taken at 5 and 12 mo after interruption. The PS interruption reduced the microbial biomass C (MBC) by 5% and 14% after 5 and 12 mo, respectively. Microbial biomass N (MBN) was reduced too by 32% and 29% due to the PS interruption. The soil basal respiration (SBR) decreased when PS application was interrupted. The metabolic quotient (qCO2) did not change with the PS interruption but was high in the 60 m 3 ha-1 yr-1. The bacteria and archaea genetic profiles showed similarity above 69% between continuous and interrupted applications. The bacterial diversity and richness index were higher than those found for fungal and archaeal communities. In contrast, the interruption had a strong effect on the soil fungi, which had diversity reduced due to the increase of the species dominance. The PS interruption up to 12 mo has an effect on the biomass, diversity, and activity of the microorganisms.

The objective of this work was to evaluate enzymatic activities and chemical attributes of a soil under continuous application for 28 years and after interruption for 5 and 12 months of pig slurry (PS). The soil received doses of 0, 30 and 60 m 3 ha-1 year-1 of PS since 1988, and in 2016, the plots were divided in half and there was interruption of the application of PS in half plot, generating a 2 × 2 factorial scheme, being two doses of PS (30 and 60 m 3 ha-1 year-1) and two application conditions (continuous or interrupted). The available P, total organic carbon (TOC), pH, Al 3+ , H + + Al 3+ , Ca 2+ , Mg 2+ and K + and activity of the enzymes arylsulfatase (AR), β-glycosidase (β-G), acid (AP) and basic (BP) phosphatase , hydrolysis of fluorescein diacetate (FDA) of soil were assessed. The content of P, Mg 2+ and H + + Al 3+ varied with the doses of PS applied, but not with the interruption of the applications. The continuous application of PS increased the activity of the enzymes AR, β-G and BP, whereas FDA and AP were not influenced by the interruption of the applications. The interruption of PS application for up to one year did not change the chemical attributes of the soil, but reduces the activity of the enzymes AR, β-G and BP.

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The development and identification of sugarcane clones with higher amount of lignocellulosic biomass are essential to increas e the potential for generation of electrical energy or biofuel. Considering the potential for increased portfolio of products to be explored from the cane energy, the objective of this study was to compare the average results of biometrics, productivity and technological quality of 23 hybrids of cane energy with the commercial variety RB92579 (as a standard). Finally, we will identify energy cane clones of types 1 and/or 2 to become commercial cultivars. The experimental design was randomized blocks with three replications of 24 plots, where each plot consisted of 6 furrows of 10 linear meters with double spacing cycled from 0.9 x 1.5 meters. The evaluated variables were the number of stems per linear meter, stem diameter, dry and fresh matter and industrial quality. Th e results were submitted to statistical analysis using the Scott-Knott test for comparison of means. The diameter of stem in energy cane was lower (1.172 to 1.772 cm) than the average of sugarcane (2.302 cm). On the other hand, a greater number of stems per linear meter were found for 15 clones evaluated (average 24.19) compared to traditional sugarcane (12.5). All clones had low juice sugars concentration but nine clones reached fiber contents higher than 23.6%, representing a 42% increase compared to the fiber content of cultivar RB92579. The hybrids 1, 9, 11, 13, 16, 18 and 23 showed a better development potential with high tillering and high fiber content.