Resumo: O trigo mourisco é uma espécie com grande potencial econômico e de produção, a qual tem ganhado cada vez mais importância. O objetivo deste estudo foi determinar a qualidade física, fisiológica e sanitária de amostras provenientes de lotes de sementes, e avaliar a patogenicidade de Fusarium spp. em plantas de trigo mourisco. A qualidade física e fisiológica foi avaliada pelo peso de mil sementes, grau de umidade, teste de germinação (5° e 7° dias), comprimento de plântula e massa seca de plântula, enquanto que a qualidade sanitária foi determinada pelo teste de sanidade em papel filtro, com as sementes submetidas à assepsia e sem assepsia. Os isolados de Fusarium spp. foram obtidos de plântulas sintomáticas no teste de germinação em rolo de papel. Para a identificação e caracterização dos isolados fúngicos foram utilizadas abordagens morfológicas e moleculares. A patogenicidade foi realizada em plantas sadias em ambiente controlado. Os lotes apresentaram alta qualidade fisiológica na avaliação de germinação (5° e 7° dias). Houve alta incidência de Fusarium spp. em todos os lotes, a qual pode ser diminuída com a assepsia das sementes. Os isolados foram identificados como complexo de espécies de Fusarium incarnatum-equiseti, e foram patogênicos às plantas de trigo mourisco.

Abstract: Buckwheat is a species with great economic and production potential, which has gained increasing importance. This study aimed to determine the physical, physiological, and sanitary quality of samples from seed lots, and to evaluate the pathogenicity of Fusarium spp. in buckwheat plants. Physical and physiological quality was evaluated by the thousand-seed weight, moisture content, germination test (5th and 7th days), seedling length, and seedling dry mass, while sanitary quality was determined by the health test on filter paper, with the seeds subjected to asepsis and without asepsis. Isolates of Fusarium spp. were obtained from symptomatic seedlings in the paper roll germination test. To identify and characterize fungal isolates, morphological and molecular approaches were used. Pathogenicity was determined on healthy plants in a controlled environment. The lots showed high physiological quality in the germination evaluation (5th and 7th days). There was a high incidence of Fusarium spp. in all lots, which can be reduced with seed asepsis. The isolates were identified as Fusarium incarnatum-equiseti species complex, and were pathogenic to buckwheat plants.

RESUMO: Uma alternativa para destinar corretamente o esterco bovino é realizar a compostagem e/ou vermicompostagem e depois adicioná-lo ao solo como fonte de nutrientes às plantas. Porém, este resíduo tem sido utilizado na produção de mudas sem tratamento. O estudo teve por objetivo avaliar o uso de esterco bovino in natura, de composto orgânico e de vermicomposto, produzidos a partir do esterco bovino, em substratos para a produção de mudas de Eucalyptus urograndis. Os tratamentos constituíram-se dos substratos formulados pela mistura dos fertilizantes orgânicos com areia lavada nas porcentagens de 20, 40, 60, 80 e 100 (v/v), em comparação com um substrato comercial (SC). As mudas de Eucalyptus urograndis foram cultivadas em tubetes, em casa de vegetação, e avaliadas aos 120 dias quanto a massa seca da parte aérea e raiz, altura da planta, diâmetro do caule, relação parte aérea/raiz e índice de qualidade de Dickson. O substrato formulado pela mistura de 80% (v/v) de esterco bovino in natura com areia lavada proporcionou o melhor desenvolvimento das mudas de eucalipto. O substrato contendo 100% de vermicomposto de esterco bovino ou composto orgânico produziu mudas com qualidade inferior ao esterco bovino in natura, mas superior ao substrato comercial. Devido aos riscos à saúde associados ao uso de esterco bovino não tratado, o composto orgânico e o vermicomposto são boas alternativas para a produção de mudas de E. urograndis.

ABSTRACT: Composting and vermicomposting before addition to the soil is a viable alternative to the disposal of cattle manure. However, this residue has been used in the untreated form for seedling production. This study evaluated the use of cattle manure in natura, and the organic composted or vermicomposted variants of cattle manure on substrates used in the production of Eucalyptus urograndis seedlings. The treatments consisted of substrates formulated by mixing the organic fertilizers with washed sand in 20, 40, 60, 80 or 100 (v/v) percentages, compared to a commercial substrate. The E. urograndis seedlings were grown in tubes in a greenhouse and evaluated after 120 days for shoot and root dry weights, plant height, stem diameter, shoot/root ratio, and Dickson quality index. The substrate formulated from a mixture of 80% (v/v) of cattle manure in natura and washed sand allows for better development in Eucalyptus seedlings. Substrate containing 100% bovine manure vermicompost or organic compost produced seedlings with lower quality than in natura bovine manure but superior to the commercial substrate. Due to the health risks associated with use of untreated bovine manure, organic compost and vermicompost are good alternatives for the production of E. urograndis seedlings.

ABSTRACT Extracellular soil enzymes are fundamental for the functioning of ecosystems. Several processes in the soil depend on the activity of these enzymes, including plant decomposition, soil organic matter formation/mineralization, and nutrient cycling. Moreover, extracellular enzyme activity occurs in the soil and is therefore influenced by environmental factors. Due to the high sensitivity to these factors, extracellular enzymes are used for monitoring soil quality. This review aimed to present the main contributions of soil enzymes to agriculture, emphasizing the dynamics of elements in the soil and the environmental factors that modulate enzyme activity. With this knowledge, the relationship of extracellular enzymes to soil quality is demonstrated and their use as a tool for soil monitoring. Finally, the evolution of research on soil enzymes in Brazil is presented, and the perspectives of basic and applied studies necessary to expand the knowledge and use of enzymes in soil management are pointed out. Soil enzymes play a key role in numerous soil processes, thereby making them useful indicators of productive capacity and soil quality. Research on enzymes in soil has developed significantly in the last two decades, which has made it possible for farmers to analyze and interpret enzyme activity in the soil in the laboratory.

RESUMO: Durante a fermentação alcoólica as leveduras produzem compostos que influenciam a qualidade sensorial dos vinhos. O objetivo do trabalho foi avaliar as propriedades físico-químicas, aromáticas e sensoriais do vinho branco da variedade Riesling Italico elaborado a partir de leveduras Saccharomyces e “não-Saccharomyces”. Foram inoculadas separadamente no mosto as leveduras S. cerevisiae, S. cerevisiae cerevisiae, S. bayanus, Torulaspora delbrueckii e Metschnikowia pulcherrima. A fermentação alcoólica ocorreu em garrafões com 7 L de mosto, em triplicata, por 10 dias a 15 ºC. Foram realizadas análises físico-químicas padrão e de identificação da qualidade dos vinhos, além das análises de compostos voláteis e sensorial descritiva quantitativa. Todas as leveduras produziram vinhos com teores de álcool, acidez volátil e açúcar residual de acordo com a legislação. A levedura T. delbrueckii produz vinhos com concentrações elevadas de acetato de feniletila, acetato de isoamila e decanoato de etila, resultando em boa qualidade olfativa e avaliação sensorial.

ABSTRACT: The sensory quality of wines is affected by the compounds produced by the action of the yeasts used in alcoholic fermentation. This work aimed at assessing the physicochemical, aromatic and sensory properties of the ‘Riesling Italico’ white wines produced by using the Saccharomyces and non-Saccharomyces yeasts. The yeasts S. cerevisiae, S. cerevisiae cerevisiae, S. bayanus, Torulaspora delbrueckii and Metschnikowia pulcherrima were inoculated individually into the must. For 10 days, the alcohol was left to ferment in 7 L carboys in triplicate, at 15º C temperature. The standard physicochemical analyses were done and the quality of the wines was determined. The volatile compounds were identified and quantitative descriptive sensory analyses were performed. All the yeasts produced wines with the characteristic alcohol, volatile acidity and residual sugar content as stipulated by the Brazilian legislation. The T. delbrueckii yeast produced high-content phenylethyl acetate, isoamyl acetate and ethyl decanoate wines, of superior olfactory quality and sensory rating.

Resumo Os estudos envolvendo a nogueira-pecã têm evoluído consideravelmente nos últimos anos no Brasil. Esta cultura foi introduzida no país no início do século passado e tornou-se importante comercialmente após os anos de 1960, principalmente na região sul. A nogueira-pecã é comprovadamente um simbionte, formando diversas associações mutualísticas com fungos ectomicorrízicos do solo. Assim, a presente revisão tem como objetivos apresentar os estudos sobre os fungos ectomicorrízicos em plantações comerciais de nogueira-pecã no Brasil, destacar a importância agrícola e ambiental desta simbiose, e o potencial da micorrização controlada da nogueira-pecã, visando à produção de espécies desejadas de trufas, notadamente do gênero Tuber, em pomares comerciais, uma atividade econômica de alta rentabilidade.

Abstract Studies involving pecan tree have evolved considerably in recent years in Brazil. Pecans were introduced in the country at the beginning of the last century, and became commercially important after the 1960´s, primarily in the South region. Pecan trees form several ECM associations with mutualistic fungi. Thus, the aims of the present review were to show research data using ECM fungi in commercial pecan orchards in Brazil, present the agricultural and environmental importance of this symbiosis, and show the potential of man-driven mycorrhyzation with pecan, aiming at the production of selected truffles, notably of the genus Tuber, in commercial orchards, a highly profitable economic activity.

ABSTRACT: Mycorrhizae are mutualistic associations between fungi and plant roots. These symbiotic associations are abundant and occur in 75 to 80 % of plants. Ectomycorrhizal fungi are very important in ecosystems, because their mutualistic association with plants of different species helps nutrients and water absorption, as well as protection of the host plant against pathogens and abiotic stresses. Most ectomycorrhizal fungi belong to the Basidiomycota class, such as the following genera: Amanita, Hebeloma, Hysterangium, Laccaria, Lactarius, Rhizopogon, Russula, Scleroderma, Suillus, Tricholoma, among others. Morphological studies on ectomycorrhizae report important results in understanding the species biodiversity. However, the use of molecular biology nowadays is indispensable. Among the various molecular tools available, there is consensus about the use of tools based on sequencing of the Internal Transcribed Spacer (ITS) of fungi rDNA, aiding in species characterization and construction of phylogenetic studies. The ITS region is of easy amplification, it has multicopy nature and enables differentiation between species. The objective of this study was to show that the use of molecular biology tools associated with morphotyping to characterize species of ectomycorrhizae is more effective than when they are used on their own.

ABSTRACT The efficiency index (EI) refers to the ratio of nutrients mineralized/made available in the soil to the total amount of nutrients added by organic fertilizer. Therefore, understanding the EI is essential for recommendation of organic fertilization. The aim of this study was to evaluate the availability through mineralization and the efficiency index of nitrogen (N), phosphorus (P), and potassium (K) in organic fertilizers produced from cattle manure. The following treatments were evaluated in an incubation experiment under controlled conditions: soil without fertilizer (control); soil + beef cattle manure vermicompost; soil + beef cattle manure/straw compost; soil + beef cattle manure; soil + dairy cattle manure; and soil + vermicompost produced under conditions of high moisture and forced air. Nitrogen and P mineralization and K availability in the soil were evaluated at 0, 7, 14, 28, 56, 112, 224, and 365 days. Nitrogen availability in the soil increased after the bioconversion of cattle manure by composting, whereas phosphorus availability increased by vermicomposting. The average efficiency indices of N, P, and K of the fertilizers produced from cattle manure were 16, 57, and 82 %, respectively. These efficiency indices are lower than the values presented by the Liming and Fertilization Manual for the states of Rio Grande do Sul (RS) and Santa Catarina (SC), Brazil.

ABSTRACT Wildfire events cause considerable environmental disturbance but few studies have examined changes in soil properties due to fire. This study aimed to assess the effect of a wildfire event on chemical, physical, and biological properties of the soil in a eucalyptus forest in the Pampa biome. Part of a seven-year-old eucalyptus forest was affected by a wildfire event that lasted for two days. Soil and plant litter sampling was performed in three areas: in the forest that was not affected by the fire, in the forest affected by it, and in an adjacent natural pasture area (the original vegetation). Seven samples were collected from the 0.00-0.05 and 0.05-0.20 m layers of each plot for biological analysis, and three samples were collected for chemical and physical analyses. Disturbed soil samples were collected in order to determine pH, organic matter, acidity, and nutrient content. Undisturbed samples were collected to determine soil microporosity, macroporosity, total porosity, and density. Soil macrofauna was assessed through the Tropical Soil Biology and Fertility method, and biological activity was tested through substrate consumption in the bait-lamina test. The fire increased soil pH values, CEC, and base saturation, as well as K, Ca, and Mg content; it decreased potential acidity and P content in the soil. Soil physical properties were not altered by the wildfire. The total abundance of macrofauna and of annelids, arachnids, coleoptera, and isoptera decreased due to the wildfire, resulting in lower soil diversity. Hymenoptera abundance increased because of the fire event. The feeding activity of organisms in the soil surface layer decreased due to the fire. The wildfire in the eucalyptus forest in the Pampa biome altered soil chemical and biological properties.

ABSTRACT: Areas affected by coal mining can be recovered by revegetation with leguminous plants associated with nitrogen-fixing bacteria. This study addressed the isolation and characterization of native nitrogen-fixing bacteria from coalmine wasteland under different vegetation restoration approaches using Macroptilium atropurpureum (DC) Urb and Vicia sativa L. as trap plants. The bacteria were characterized and identified on the basis of 16S rRNA sequences. Additionally, nitrogen-fixing strains were characterized for tolerance to high heavy metal and low pH levels, as well as for their effect on growth, nodulation, and symbiotic efficiency of M. atropurpureum and V. sativa. Soil samples were taken from the rhizosphere of eight areas, between 6 and 20 years under vegetation restoration, in the coal mining area of Candiota, RS-Brazil. The following properties were evaluated: colony characterization on solid “79” culture medium; pH (3.0-9.0) and heavy metal (Cr, Cd, Zn, Cu, and Ni) tolerance; partial sequencing of 16S rRNA gene; presence of nodA and nifH genes and symbiotic efficiency. A total of 115 isolates, i.e., 77 from M. atropurpureum and 38 from V. sativa, were obtained. The tolerance of these isolates is high for a wide range of pH levels and heavy metal contents, and 18 among them were selected for symbiotic efficiency and 16S rRNA sequencing. Inoculated with M. atropurpureum, the strains UFSM-B53, UFSM-B64, and UFSM-B74 had high symbiotic efficiency. The nitrogen-fixing bacteria were classified in the genera Rhizobium, Bradyrhizobium, and Burkholderia. The results indicate the potential of these native rhizospheric bacterial strains as inoculants and biofertilizers for legume species under pH and heavy metal stress in coal mining degraded areas in Southern Brazil.

Abstract Biosurfactants have many advantages over synthetic surfactants but have higher production costs. Identifying microorganisms with high production capacities for these molecules and optimizing their growth conditions can reduce cost. The present work aimed to isolate and identify a fungus with high biosurfactant production capacity, optimize its growth conditions in a low cost culture medium, and characterize the chemical structure of the biosurfactant molecule. The fungal strain UFSM-BAS-01 was isolated from soil contaminated with hydrocarbons and identified as Fusarium fujikuroi. To optimize biosurfactant production, a Plackett–Burman design and a central composite rotational design were used. The variables evaluated were pH, incubation period, temperature, agitation and amount of inoculum in a liquid medium containing glucose. The partial structure of the biosurfactant molecule was identified by nuclear magnetic resonance spectrometry. F. fujikuroi reduced surface tension from 72 to 20 mN m−1 under the optimized conditions of pH 5.0, 37 °C and 7 days of incubation with 190 rpm agitation. The partial identification of the structure of the biosurfactant demonstrated the presence of an α,β-trehalose. The present study is the first report of the biosynthesis of this compound by F. fujikuroi, suggesting that the biosurfactant produced belongs to the class of trehalolipids.

RESUMO: A fitorremediação é uma alternativa para o tratamento de solos contaminados com cobre. O objetivo do trabalho foi conhecer o comportamento de nove plantas de cobertura de verão quanto ao crescimento, absorção e translocação do cobre em solos com contaminação acima dos Valores de Prevenção, com vistas a seleção de plantas para programas de fitorremediação. Um Cambissolo foi contaminado com doses de 0, 100, 200, 400, 500 e 600mg kg-1 de cobre e cultivado em casa de vegetação com nove plantas: Canavalia ensiformis, Cajanus cajan, Dolichos lablad, Mucuna cinereum, Mucuna aterrima, Crotalaria juncea, Crotalaria spectabilis, Pennisetum glaucum e Paspalum notatum. Aos 90 dias após a semeadura as plantas foram avaliadas quanto à produção de massa seca de parte aérea e raízes, teores de Cu, N, P, K, Ca, Zn, e Fe na parte aérea e de Cu nas raízes. As altas concentrações de Cu no solo reduziram a absorção de fósforo pelas plantas. O feijão-de-porco apresenta potencial para a fitoextração, pois apresentou translocação de altas concentrações de cobre para os tecidos aéreos, enquanto que as mucunas preta e cinza são indicadas para programas de fitoestabilização de cobre, pois acumularam elevada concentração de cobre no sistema radicular.

ABSTRACT: Phytoremediation is an alternative technique used to treat copper-contaminated soils. The objective of this research was to explore the behavior of nine summer cover crops regarding the growth, absorption and translocation of copper in soils with contamination levels exceeding the Value of Prevention, with a view to selecting plants for phytoremediation programs. In the experiments the Cambisol was contaminated with copper, added in doses of 0, 100, 200, 400, 500 and 600mg kg-1, in which the following nine plants were cultivated under greenhouse conditions: Canavalia ensiformis, Cajanus cajan, Dolichos lablad, Mucuna cinereum, Mucuna aterrima, Crotalaria juncea, Crotalaria spectabilis, Pennisetum glaucum and Paspalum notatum. At 90 days after sowing the plants were evaluated for dry mass of shoot and root, Cu, N, P, K, Ca, Zn, and Fe levels in the shoot and Cu in the roots. High soil Cu levels induced a decline in the phosphorus absorption by the plants. Canavalia ensiformis displayed high potential for phytoextraction as these plants could translocate high copper concentrations to the aerial plant parts, while the Mucuna cinereum and M. aterrima are indicated for the copper phytostabilization programs, due to the high copper accumulation in their root systems.

A disposição final do lodo de esgoto é problema para muitos países. Porém, significativa porcentagem destes resíduos é constituída por polímeros biodegradáveis, tais como lignina, celulose e hemicelulose. Os fungos do Filo Basidiomycota poderiam degradar estes polímeros nos leitos de secagem da estação de tratamento de esgoto e contribuir para a diminuição dos volumes finais dispostos no ambiente. O objetivo deste estudo foi avaliar a capacidade de 20 fungos Basidiomycota lignocelulolíticos em biodegradar lodo e os polímeros que o constituem. Foram selecionados quatro isolados para efetuar a biodegradação em diferentes temperaturas. Além disso, a fração orgânica presente no lodo foi determinada antes e depois da biodegradação. A inoculação com Agaricus bisporus, Fomes fasciatus, Schizophyllum commune e Trametes versicolor aumentou a degradação do lodo, a qual é maximizada em altas temperaturas. Estes fungos reduziram o teor de carbono orgânico total, de carbono solúvel e de polímeros presentes. A maior redução foi verificada na fração hemicelulose, seguida da lignina e celulose. A inoculação de fungos com capacidade de degradar o lodo pode ser uma alternativa para reduzir os volumes dispostos no ambiente.

The final disposal of biosolids is a global matter. Polymers such as lignin, cellulose and hemicellulose comprise significant rate of biosolids arrangement. Fungi from Basidiomycota phyllum could degrade these polymers in the drying beds of the treatment plant and it can contribute decreasing final volumes of sludge disposed in the environment. The aim of this study was assess the capacity of 20 lignocellulolytic Basidiomycota fungi to biodegrade the sludge and the polymers that constitute it. Four isolates were selected to carry out sludge biodegradation at different temperatures. In addition, the organic fraction present in the sludge were determined before and after biodegradation. The inoculation of Agaricus bisporus, Fomes fasciatus, Schizophyllum commune and Trametes versicolor has enhanced the degradation of sludge, which is improved upon in higher temperatures. These fungi reduced the total organic carbon content of soluble carbon and polymers present in the sludge. The largest reduction was verified in the hemicellulose fraction, followed by lignin and cellulose. The inoculation performed by fungi capable of degrading sludge is an alternative to reduce the volumes deposited in the environment.

RESUMO: O uso sucessivo de dejetos de suínos em áreas de pastagem tem sido uma prática comum na região sul do Brasil, tendo em vista a necessidade de deposição dos dejetos produzidos, além de ser uma importante alternativa à fertilização das pastagens. Embora existam benefícios econômicos do uso dos dejetos como fertilizante, estes podem estar associados a riscos ambientais e causar alterações na composição e atividade da fauna no solo. Este trabalho teve por objetivo estudar os efeitos da aplicação de dejetos de suínos em áreas de pastagem sobre a biota do solo. Foi analisada a composição e a atividade biológica de áreas com uso de dejetos há 2 anos (A2), há 14 anos (A14) e mata nativa (MN), como área referência. O uso sucessivo de dejetos de suínos no solo alterou as características biológicas do solo, de acordo com o seu tempo de aplicação; influenciou a composição e a diversidade da fauna edáfica, aumentando o número total de indivíduos, principalmente de colêmbolos, e aumentou a atividade da biota do solo, especialmente até os 6 cm de profundidade.

ABSTRACT: The successive application of pig slurry to pastures is a common practice in southern Brazil, serving as a method of waste disposal as well as an important alternative to chemical fertilization. Although there are economic benefits to the use of manure as fertilizer, it may be associated with environmental hazards and cause changes to composition and activity of soil fauna. This study aimed to study the effects of pig slurry on the soil biota of pastures. Composition and biological activity of pastures where manure was applied successively for 2 years (A2) and 14 years (A14) were evaluated, and native forest (NF) was analyzed as a reference area. Successive application of pig slurry to the soil changed its biological characteristics according to the time of implementation; influenced the composition and diversity of soil fauna, leading to an increase in the total number of individuals, especially springtails; and increased the activity of the soil biota, especially to a depth of 6cm.

RESUMO: Este trabalho teve como objetivo avaliar em condição de laboratório a mineralização do nitrogênio (N) e determinar o índice de eficiência (EI) do N após adição de fertilizantes orgânicos a base de esterco bovino no solo. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os tratamentos avaliados foram: T1) Solo (testemunha); T2) Solo + vermicomposto de esterco bovino (CMV); T3) Solo + composto de palha e esterco bovino (CMS); e T4) Solo + esterco bovino (CM). As unidades experimentais foram frascos de acrílico com 5cm de altura e 5cm de diâmetro. Em cada frasco, foram adicionados 135g de solo úmido e 2,20, 2,45 e 2,27g de CMV, CMS e CM, respectivamente. Os tratamentos foram acondicionados em incubadora a 25°C e os teores de N mineral do solo (N-NH4+ e N-NO2- + N-NO3-) foram determinados na data de instalação, aos 7, 14, 28, 56 e 112 dias de incubação. Os maiores teores de N-NO2- + N-NO3- no solo foram observados no tratamento CMS. O EI do N foi de 27, 23 e 22% para CMS, CM e CMV, respectivamente. A mineralização do N dos fertilizantes orgânicos a base do esterco bovino ocorre em sua grande maioria nos primeiros 28 dias após sua adição ao solo. O EI do N dos fertilizantes orgânicos a base de esterco bovino foi maior para CMS>CMV>CM e atingem apenas 80% do esperado para fertilizantes orgânicos oriundos de esterco bovino.

ABSTRACT: This research aimed to evaluate the mineralization of nitrogen (N) and to define the efficiency index (EI) of N after the addition of organic fertilizers based on cattle manure on the soil under laboratory conditions. A completely randomized statistical design with four replicates was used. The treatments were set as follows: T1) Soil (control); T2) Soil + vermicompost of cattle manure (CMV); T3) Soil + cattle manure and straw compost (CMS); and T4) Soil + cattle manure (CM). Experimental units were constituted by acrylic flasks with 5 x 5cm (height x diameter). Each flask was added with 135g of wet soil and 2.20, 2.45 and 2.27g of CMV, CMS and CM, respectively. Treatments were incubated at 25°C and the amount of mineral N from the soil (N-NH4+ and N-NO2- + N-NO3-) was determined at the beginning of the experiment and after 7, 14, 28, 56 and 112 days of incubation. The highest concentration of N-NO2- + N-NO3- in the soil were observed within the CMS treatment. The EI of N was of 27, 23 and 22% for CMS, CMV and CM, respectively. The mineralization of N from organic fertilizers based on cattle manure occurs on its vast majority within the first 28 days after its addition to the soil. The EI of N from the organic fertilizers based of cattle manure was higher for CMS>CMV>CM and achieved only 80% of what expected for organic fertilizers derived from cattle manure.

RESUMO O uso de dejetos líquidos de suínos como fertilizante do solo é uma prática comum na Região Sul do Brasil. Apesar de ter benefícios na reutilização dos dejetos, essa prática apresenta sérios riscos ambientais. Os indicadores microbiológicos de qualidade do solo são bastante sensíveis e permitem o monitoramento das condições do ambiente edáfico. Objetivou-se avaliar a qualidade microbiológica do solo de pastagens com diferentes históricos de uso sucessivo de dejetos líquidos de suínos. Determinaram-se o teor de C da biomassa microbiana, a respiração microbiana do solo, o quociente metabólico (qCO2) e a atividade das enzimas β-glicosidase, urease e hidrólise do diacetato de fluoresceína (FDA), em áreas de pastagem com uso de dejetos de suínos há dois anos (A2) e 14 anos (A14) e em área com mata nativa (MN). O uso sucessivo de dejetos de suínos em pastagem não influenciou o C da biomassa e a respiração microbiana do solo, que variaram conforme a época de coleta. O qCO2 não foi influenciado pelo uso de dejetos de suínos no solo; a atividade enzimática do solo foi influenciada pelo uso de dejetos de suínos, sendo que a urease e a FDA foram sensíveis na detecção de diferenças na atividade dos solos com uso de dejetos de suínos, enquanto a β-glicosidase não permitiu a diferenciação entre as áreas estudadas.

ABSTRACT Pig slurry use as soil fertilizer is a common practice in southern Brazil. In spite of the benefits of reusing waste, this practice poses serious environmental risks. Microbiological indicators of soil quality are very sensitive and allow soil environment conditions to be monitored. The aim of this study was to evaluate the microbiological quality of pasture soils with different histories of successive use of pig slurry. Determinations were made of C content in the microbial biomass, soil microbial respiration, metabolic quotient (qCO2), activity of the enzymes β-glycosidase and urease, and fluorescein diacetate (FDA) hydrolysis in grazing areas under the use of pig slurry for two (A2) and 14 years (A14) and in a native forest (NF) area. The successive use of pig slurry on pasture did not affect C biomass and soil microbial respiration, which varied according to the time of collection. The qCO2 was not affected by the use of pig slurry in the soil. Soil enzymatic activity was affected by the use of pig slurry; urease and FDA were sensitive in detecting differences in soil activity with the use of pig slurry, whereas the β-glycosidase enzyme did not allow differentiation among the areas studied.