ABSTRACT. Studies regarding soil quality and health often need to be up-to-date, as they feed new models for quantifying agricultural impacts on the environment. This study was established to understand how types of vineyard cultivation (organic and conventional) affect soil chemical and microbial attribute dynamics throughout different seasons. Vineyard management had a strong effect on chemical soil attributes. Organic carbon and phosphorus were 2.8 and 2.0 times greater, respectively, in organic vineyards than in conventional vineyards. Metabolic quotient (qCO2) values were lowest in summer and autumn, with an average of 2.31-2.49 µg C-CO2 h-1 g-1 soil, under organic management, indicating greater microbial growing efficacy. Regardless of season and sampling position, organic soil had a higher C microbial biomass than conventional vineyards, with values ranging from 179.79 to 284.71 µg g-1 soil, which were similar to those of the adjacent forest soil. Overall, there were increases in both the microbial and the chemical attributes of soil under organic vineyards compared relative to conventional management, which might have been due to the continuous input of organic matter, crop rotation, and alternative plant protection and fertilizer compounds used in organic farming.

Abstract Microalgae have been widely studied as raw materials for biofuels, food supplements and several high value products. The hypothesis is that the pH and N levels in the culture medium are important factors to increase microalgae biomass production and its by-products. Thus, this study aimed to evaluate response of Neochloris oleoabundans to sodium nitrate concentration and pH levels by assessing biomass production, pigments, total lipid content and lipid profile of cells. The experimental design was a complete factorial with two factors: sodium nitrate (NaNO3) using the doses of 0.25, 1.12 and 2.5 g L-1 and pH 5.0, 7.0 and 9.0, resulting in nine treatments and three replicates. Differences in the N concentration and pH of the in Bold’s basal medium increased up to 21.1% the production of dry biomass but also up to 36% of lipids and up to of 0.81% of carotenoid concentration in the N. oleoabundans cell. The nuclear magnetic resonance (NMR) analysis of bio-oil showed changes in the lipid profile. Oil extracted from N. oleoabundans cells growing in medium at pH 9 and in 2.5 g L−1 of NaNO3 showed fatty acids with molecular weights similar to crude soybean oil, while the oil from treatment 3 (2.5 NaNO3 g L−1) showed a slight increase in molecular weight. Overall, the best adjustment of the liquid medium to grow N. oleoabundans is at pH 9.0 and with addition of 2.5 g of sodium nitrate.

ABSTRACT: The acid release of phosphates from rock phosphates (RP) and the retention of ammonium by inorganic phosphates have been studied separately in composting; however, there is a gap in the knowledge of combined application of RP with organic residues and microorganisms. The objectives were to evaluate the combined application of fresh poultry litter (PL) with RP and P-solubilizing microorganisms (M) on soil organic matter pools, microbial biomass C (MB-C) and on whole-plant silage maize and grain yields. Two field experiments tested the effects of timing of applications of PL (8 Mg ha–1), RP (4 Mg ha–1) and microorganisms on soil organic matter pools, nutritional aspects and productive components of maize crop whole-plant silage. A second experiment evaluated the effects of RP doses (0, 3, 6 and 9 Mg ha–1) with a fixed dose of PL (8 Mg ha–1) on maize grains. Application of PL+RP decreased soil organic C, while RP alone increased the humin fraction C compared to the control. The MB-C in soil with PL and PL+RP+M increased in comparison to the control and the RP. The application of PL, based on an average of fall and spring, increased leaves + stem dry matter, while in the fall on its own, the highest cob yield was observed in the combination of PL+RP, showing synergistic effects. The best ratio of poultry litter to rock phosphate combination is 2:1 in the anticipated fall application on the maize silage crop or immediate application on the maize grain crops.

RESUMO O conhecimento das respostas de feijoeiros em razão da adubação nitrogenada ou da inoculação das sementes com rizóbios pode direcionar seus cultivos para diferentes nichos de mercado, em níveis tecnológicos diversos. Foram avaliadas as nodulações das raízes e as produtividades de grãos de 10 cultivares de feijão diante da adubação nitrogenada e da inoculação das sementes comRhizobium freirei, objetivando-se identificar em, termos de produtividades de grãos, as mais eficientes e responsivas à adubação nitrogenada, bem como à nutrição simbiótica de N em relação à adubação nitrogenada. Foram conduzidos dois experimentos em duas safras (seca-2012 e águas-2012/2013), empregando-se, em cada qual delineamento em blocos ao acaso, em esquema fatorial 10 × 3 com quatro repetições. Avaliaram-se as quantidades e massas de nódulos radiculares e produtividades de grãos de 10 cultivares de feijão dos grupos comerciais preto (IPR Gralha, IPR Tuiuiú, Rio Tibagi, BRS Esplendor e IPR Uirapuru) e carioca (IPR Tangará, Iapar 81, IPR Campos Gerais, BRS Pontal e Carioca), em razão de três tratamentos, visando variações em nutrições nitrogenadas: testemunha, sem N; com adubação nitrogenada; e inoculação das sementes com R. freirei. Feijões do grupo comercial carioca são mais produtivos e, independentemente da nodulação com rizóbios nativos ou exógenos, são mais propensos à nutrição simbiótica nitrogenada. A adubação nitrogenada é prejudicial, principalmente para as nodulações das cultivares BRS Esplendor, Carioca e BRS Pontal na safra da seca. Em termos de produtividades de grãos, as cultivares Rio Tibagi, BRS Esplendor, BRS Pontal e IPR Uirapuru são relativamente mais eficientes com a inoculação das sementes com R. freirei do que com a adubação nitrogenada, e as cultivares IPR Gralha e IPR Tangará se destacam como responsivas e eficientes à adubação nitrogenada.

ABSTRACT Knowledge of the responses of bean plants as a function of N fertilization or seed inoculation with rhizobia can direct crops to different market niches in different technological levels. The roots nodulation and the yield grains of 10 bean cultivars on nitrogen fertilization and seed inoculation with Rhizobium freirei were evaluated aiming to identify, in terms of grain yield, the more efficient and responsive to nitrogen fertilization, as well to symbiotic N fixation in relation to N fertilization. Two experiments were conducted in two seasons (the 2012 dry season and the 2012/2013 rainy season) using a randomized block design in a 10 × 3 factorial arrangement with four replications. We evaluated the amount and mass of root nodules and grain yield of 10 common bean cultivars in the black marketing-group (IPR Gralha, IPR Tuiuiú, Rio Tibagi, BRS Esplendor, and IPR Uirapuru) and the carioca (beige with brown stripes) marketing-group (IPR Tangará, Iapar 81, IPR Campos Gerais, BRS Pontal, and Carioca) with three treatments with variations in N nutritional levels: control, without N; with N fertilization; and seed inoculation with R. freirei. Beans of the carioca commercial group are higher yielding and, regardless of nodulation with native or exogenous rhizobia, are more prone to symbiotic nitrogen nutrition. Nitrogen fertilization is especially harmful to nodulation of BRS Esplendor, Carioca, and BRS Pontal at lower water availability. In terms of grain yield, the cultivars Rio Tibagi, BRS Esplendor, BRS Pontal, and IPR Uirapuru are relatively more efficient with seed inoculation with R. freirei than with N fertilization, and the cultivars IPR Tangará and IPR Gralha stand out as responsive and efficient in respect to N fertilization.

O cultivo orgânico com inclusão de material orgânico fresco altera propriedades físicas e químicas do solo e, com isso, pode resultar em modificações nas características biológicas deste. Assim, o objetivo deste estudo foi estudar os efeitos do manejo da videira (Vitis labrusca L.) sobre as propriedades químicas e microbianas do solo. Em outubro de 2006, amostras de solo foram coletadas de dois experimentos instalados em 2000 e de uma área adjacente com floresta. Os seguintes tratamentos foram avaliados em um esquema fatorial 2 x 2 x 2: (i) orgânico (ORG) e convencional (CONV); (ii) dos cultivares (IAC-766/Isabel e IAC-766/Bordô); e (iii) da heterogeneidade espacial (linha e entrelinha) sobre as propriedades químicas e microbianas de um solo arenoso. Foi observada a formação de três grandes grupos (CONV, ORG/linha e ORG/entrelinha), que se destacaram na área de floresta. As variáveis químicas e microbianas, com exceção do K, foram alteradas em relação aos manejos da videira. Houve efeitos do cultivar no N da biomassa microbiana e na respiração basal (CO2). Também foram observados efeitos de heterogeneidade espacial do solo no C da biomassa microbiana e em atributos químicos, como P, pH, Mg e micronutrientes. No sistema orgânico da videira, aumentaram-se o carbono orgânico do solo (COS) e a biomassa microbiana na linha e entrelinha, em comparação com a videira convencional. Os aumentos foram de 172 % no SOC, 100 % no Cmic e 223 % no Nmic, na linha do orgânico. Os manejos da videira e a heterogeneidade espacial do solo foram os fatores mais relevantes no agrupamento (ou separação) das áreas devido às mudanças nos atributos químicos do solo, principalmente o COS, e na biomassa microbiana.

Organic cropping systems with input of fresh organic matter can modify the physical and chemical properties of soils and consequently affect their biological composition. The purpose of this study was to determine the effects of juice grape (Vitis labrusca L.) management on the soil chemical and microbial properties of a sandy-textured Oxisol. In October 2006, soil was sampled from two vineyard experiments set up in 2000, and from a neighboring forest area. The following treatments were evaluated in a 2 x 2 x 2 factorial design: (i) organic (ORG) and conventional (CONV) vineyard managements; (ii) cultivars in rootstock/graft combinations: grafts Isabel and Bordô on rootstock IAC-766 and (iii) spatial heterogeneity (row and inter-row). Based on the analyses, the vineyard soils were separated in three groups (CONV, ORG/row and ORG/inter-row), which differed from the adjacent forest area. All microbial and chemical variables, except K, were modified in the vineyards. Rootstock/graft cultivar combinations affected the N microbial biomass and basal respiration (CO2), while P, pH, Mg, micronutrients, and C microbial biomass were influenced by spatial heterogeneity. Soil Organic C (SOC) and microbial biomass in the rows and inter-rows were higher in the organic than the conventional vineyard management. In the rows under organic management, SOC was 172 % higher, Cmic 100 % and Nmic 223 % than in CONV. The same was observed in inter-rows, but to a lesser extent. The most relevant factors differentiating areas by changes in soil chemical properties, mainly SOC, and in microbial biomass were mainly caused by the vineyard management and soil spatial heterogeneity.

O objetivo neste trabalho foi de avaliar o efeito da inoculação de fungos micorrízicos arbusculares no crescimento de mudas de peroba rosa (Aspidosperma polyneuron). O experimento foi conduzido em delineamento experimental, inteiramente casualizado, em casa de vegetação com seis repetições. Utilizou-se mistura de solo e areia (3:1), desinfestado como substrato, com os seguintes tratamentos de inoculação: Gigaspora margarita, Glomus clarum, Scutellospora heterogama, Acaulospora scrobiculata e uma mistura de fungos micorrízicos arbusculares (FMA). Após 120 dias, observou-se que a colonização micorrízica radicular foi de 28,3% a 48,4% para a mistura de FMA e para G. margarita, respectivamente. As plantas inoculadas com G. margarita e G. clarum apresentaram maior crescimento, indicando o potencial da inoculação desses fungos na produção de mudas.

The aim of this study was to examine the effects of arbuscular mycorrhizal fungi (AMF) inoculation on Aspidosperma polyneuron seedlings growth. The experiment was conducted under greenhouse conditions in a randomized design using a disinfected mixture of soil + sand (3:1) with the following treatments: Gigaspora margarita, Glomus clarum, Scutellospora heterogama, Acaulospora scrobiculata, a mixture of arbuscular mycorrhizae fungi (AMF) and a non-inoculated control with six replicates. After 120 days of seed germination, it was observed that root colonization was from 28.3% to 48.4% for mixture of AMF and G. margarita, respectively. The plants inoculated with G. margarita or G. clarum showed higher growth than other treatments, which evidence the potential of AMF inoculation in seedlings production.

Práticas agrícolas que reduzam a degradação do solo e promovam sustentabilidade são importantes para os agrossistemas tropicais/subtropicais. O plantio direto (PD) diminui as perdas de solo e, se combinado com rotação de culturas pode proteger o solo da degradação físico-química provocada pela agricultura intensiva. A atividade enzimática do solo pode fornecer importantes informações de como o manejo do solo está afetando a decomposição da material orgânica e a ciclagem dos nutrientes. Assim, avaliou-se a atividade das enzimas amilase, celulose, arilsulfatase, fosfatase ácida e fosfatase alcalina em um experimento a campo, instalado em 1976 em Londrina, PR, que tem como tratamentos o preparo do solo (plantio direto ou convencional) nas parcelas e a rotação de culturas (soja/trigo, milho/trigo e algodão/trigo) nas subparcelas. Amostras de solos foram coletadas a 0-5, 5-10 e 10-20 cm de profundidade em 1997 e 1998. Na profundidade de 0-5 cm sob PD, observaram-se aumentos de 68% na atividade da amilase, 90% na celulase, 219% na arilsulfatase, 46% na fosfatase ácida e 61% na fosfatase alcalina. Observaram-se correlações significativas entre a atividade enzimática e o C-orgânico total do solo e o C e N da biomassa microbiana. Esses resultados evidenciam que a atividade enzimática do solo é um indicador sensível de alterações na qualidade do solo, promovidas pelo manejo.

Agricultural practices that reduce soil degradation and improve agricultural sustainability are needed particularly for tropical/subtropical soils. No-tillage planting causes minimal soil disturbance and combined with crop rotation may hold potential to meet these goals. Soil enzyme activities can provide information on how soil management is affecting the potential to perform the processes in soils such as decomposition and nutrient cycling. Soil enzyme activities were investigated in a split-plot experiment (3 replications) where tillage (no till and conventional) was the main plot and crop rotation (soybean/wheat, S/W; maize/wheat, M/W or cotton/wheat, C/W) was the subplot. The experiment was established in 1976 in southern Brazil. Soil samples were taken at 0-5, 5-10 and 10-20 cm depths in 1997 and 1998. The 0-5 cm layer under NT system showed increases up 68% for amylase, 90% for cellulase, 219% for arylsulfatase, 46% for acid phosphatase, and 61% for alkaline phosphatase. There were significant correlations of soil enzyme activities with total organic C, and C and N microbial biomass. These results showed that NT increased microbial activity and that soil enzyme activity is a sensitive indicator of alteration soil quality by management.