ABSTRACT Biological soil crusts (BSC) are commonly found in soils in the drylands regions, which can influence stabilization, water retention, nutrient cycling (particularly carbon (C) and nitrogen (N) dynamics), and several ecological processes. However, the composition of BSC in Brazilian soils undergoing the desertification process remains poorly understood. This study aimed to characterize the bacterial community in BSC formed in a Brazilian semiarid region under the desertification process. Thus, a highly desertified region was selected from which 34 BSC samples were collected. The total DNA of the BSC was extracted from 0.5 g samples, and the bacterial community was sequenced by a Next Generation Sequencing (NGS) platform (Miseq – Illumina®) using universal primers (515F and 806R). Bioinformatic analysis was carried out in QIIME (v.1.9), and the Operational Taxonomic Units (OTU) table was constructed following the Sumaclust methodology. The pH of BSC, C, N, and phosphorus contents was analyzed. Our study identified a diverse bacterial community in the BSCs. Cyanobacteria, Chloroflexi, and Proteobacteria phyla presented the greatest relative abundance (%) across the samples. Cyanobacteria were dominated by the orders Nostocales and Leptolyngbyales. The prediction of the putative functions found that mostf OTU were related to phototrophy, photosynthetic cyanobacteria, and photoautotrophy. The study found correlations between bacterial phyla and BSC properties, with Cyanobacteria positively related to C. Chloroflexi, Armatimonadetes, and WPS-2 were negatively correlated with C and N contents. These results suggest the critical roles bacteria communities play in BSCs from the Caatinga biome and highlight the potential impact of environmental factors on their diversity and functions. (BSC regions stabilization retention particularly (C (N dynamics, dynamics , dynamics) processes However understood Thus 3 collected 05 0 5 0. NGS (NGS Miseq Illumina® Illumina 515F F 806R. 806R R . 806R) v.1.9, v19 v v.1.9 1 9 (v.1.9) (OTU methodology analyzed Chloroflexi % (% Leptolyngbyales phototrophy cyanobacteria photoautotrophy properties Armatimonadetes WPS2 WPS 2 WPS- v1 v.1. (v.1.9 ( v.1 (v.1. v. (v.1 (v. (v

ABSTRACT The application of flumioxazin and imazethapyr can affect the interactions between rhizobia and soybean in the rhizosphere. However, it remains unclear the effect of both herbicides, even when applied in mixture, on early nodulation and biological N fixation (BNF) in soybean, mainly related to some important biochemical traits in nodules. This study assessed the effect of flumioxazin, imazethapyr and their mixture on early nodulation and BNF in rhizosphere of soybean. The plant emergence, early nodulation, growth, and N accumulation were evaluated in soybean grown in sandy and clayey soils. The leghemoglobin content and glutamine synthetase (GS) activity were also assessed in fresh nodules. Individually, flumioxazin and imazethapyr did not affect the plant emergence, nodulation and N accumulation in soybean, while the mixture decreased significantly these parameters. Also, the values of leghemoglobin content and GS activity did not decrease with the application of the herbicides individually. The application of herbicides imazethapyr and flumioxazin separately negatively influenced the growth of soybean, while they do not influence the nodulation and N accumulation. However, the use of these herbicides in mixture can negatively influence the early nodulation and N fixation by native rhizobia.

Abstract: Sugarcane is an important Brazilian commodity, being usually cultivated in soils with low natural fertility. This study aimed to isolate diazotrophic endophytes from sugarcane tissues and evaluate the morphological and physiological characteristics of their colonies as well as their plant growth-promoting (PGP) traits in select diazotrophic endophytic bacteria. Fifty-six bacterial isolates were identified in the sugarcane tissues, and these isolates presented distinct morphological and physiological traits. A total of thirty-five bacterial isolates were biochemically evaluated. Overall, Bacillus was the dominant genus. Isolates of Methylobacterium spp. and Brevibacillus agri were present only in leaves, while Herbaspirillum seropedicae occurred only in stems. Except to IPA-CF45A, all isolates were nitrogenase positive. All endophytes exhibit production of indol 3-acetic acid. Over 50% of endophytes solubilize phosphate, release N-acyl homoserine lactones, and present the activity of 1-aminocyclopropane-1-carboxylic acid deaminase, catalase, lipase and protease. The network analysis showed that isolates belonged to Burkholderia, Herbaspirillum, and Methylobacterium interact with Bacillus. Bacterial endophytes exhibited distinct morphological, physiological, and PGP traits that are useful for sustainable agriculture, highlighting the isolates IPA-CC33, IPA-CF65, IPA-CC9 and IPA-CF27. Further studies on the effects of these diazotrophic endophytes and their potential for providing microbial inoculants for improving sugarcane fields will provide valuable information to maintain the sustainability and environment quality.

RESUMO: Este estudo avaliou a atividade de isolados de rizóbios inoculados em sementes pequenas (11 mm) e grandes (18 mm) sobre o crescimento, nodulação e fixação de N de feijão-fava. Isolados selecionados de rizóbios foram comparados com uma estirpe de referência CIAT899 e dois controles sem inoculação. Sementes grandes contribuíram para maior crescimento de plantas, nodulação e fixação de N do que sementes pequenas. Os isolados UFPI-59, UFPI-18 e UFPI-38 promoveram os maiores valores de massa seca de parte aérea e raízes. Os isolados UFPI-32 e UFPI-59 promoveram os maiores valores de número e massa de nódulos, respectivamente. Os isolados UFPI-38 e UFPI-59 promoveram maior acúmulo de N. Este estudo mostrou que o tamanho de sementes influencia o crescimento, nodulação e fixação de N em feijão-fava. Considerando os isolados de rizóbios, UFPI-59, UFPI-38 e UFPI-18 contribuíram para o crescimento de plantas, promoveram melhor nodulação e eficiência na fixação de N.

ABSTRACT: This study evaluated the activity of rhizobia isolates inoculated in large (18 mm) and small (11 mm) seeds on lima bean growth, nodulation and N fixation. Selected rhizobia isolates were compared with a reference strain CIAT899 and two controls without inoculation. Large seeds contributed for highest plant growth, nodulation and N fixation than small seeds. The isolates UFPI-59, UFPI-18 and UFPI-38 promoted the highest values of shoot and root dry weight, respectively. The isolates UFPI-32 promoted the highest values of nodule number, while UFPI-59 promoted the highest values of nodule dry weight. The isolates UFPI-38 and UFPI-59 promoted the highest accumulation of N. This study showed that seed size really influences lima bean growth, nodulation and BNF. Considering rhizobia isolates, UFPI-59, UFPI-38, and UFPI-18 contributed for plant growth, promoted better nodulation and effectiveness on biological N fixation.

Lima bean (Phaseolus lunatus) is an important species of the genus Phaseolus for human consumption in tropical regions. The seeds are important source of protein for people from South America, Africa and Mexico. In addition, as a legume plant, lima bean presents the ability to perform the biological nitrogen fixation (BNF) through the symbiosis with nitrogen-fixing bacteria. The studies about diversity and efficiency of lima bean-rhizobia symbiosis have increased worldwide, mainly in Latin America. These studies have shown Bradyrhizobium and Rhizobium as the main symbionts, although Sinorhizobium, Mesorhizobium and Allorhizobium have been found associated with lima bean. Also, there is a large variation in the efficiency of N fixation by the current isolates of rhizobia and some rhizobia have presented high capability for fixing N. This review aims to explore the studies about diversity and efficiency of rhizobia in symbiosis with lima bean.

El frijol de lima (Phaseolus lunatus) es una especie importante del género Phaseolus para consumo humano en regiones tropicales. Las semillas son una fuente importante de proteínas para las personas de América del Sur, África y México. Además, como leguminosas, el frijol de lima presenta la capacidad de realizar la fijación biológica de nitrógeno (BNF) a través de la simbiosis con bacterias fijadoras de nitrógeno. Los estudios sobre la diversidad y la eficiencia de la simbiosis de frijol de lima-rizobio han aumentado en todo el mundo, principalmente en América Latina. Estos estudios han demostrado que Bradyrhizobium y Rhizobium son los principales simbiontes, aunque Sinorhizobium, Mesorhizobium y Allorhizobium se han asociado al frijol de lima. Además, existe una gran variación en la eficacia de la fijación de N por los aislamientos actuales de rizobios y algunos rizobios han presentado una alta capacidad para reparar N. Esta revisión tiene como objetivo explorar los estudios sobre la diversidad y la eficacia de rizobios en simbiosis con frijol lima.

ABSTRACT The aim of this study was to investigate the short- and medium-term effect of biochar on soil microbial properties, organic carbon and nitrogen in an Oxisol from Brazil. The experiment was conducted in a randomized block design consisting of five levels of biochar (0, 2, 4, 8 and 16 Mg∙ha–1) with and without of synthetic fertilizer: 0 and 200 kg.ha–1 of synthetic fertilizer N-P-K (00-20-20). The following soil properties were determined: microbial biomass carbon (MBC) and nitrogen (MBN), microbial respiration (MR), metabolic quotient (qCO2) and microbial quotient (qMIC), total organic carbon (TOC) and nitrogen (TN). The MBC, qCO2 and carbon management index (CMI) were not altered by doses of fertilizer and biochar. The presence of biochar reduced the MBN by 11% and 5% with the application of16 Mg∙ha–1 compared to control in the third and sixth year, respectively. The qMIC was reduced exponentially with the application of biochar, but was within normal limits as a proportion of total organic carbon. There was an increase in TOC and TN with the application of biochar. The use of biochar did not cause significant negative changes in soil microbial properties or contribute to carbon sequestration in the soil.

RESUMO Casearia grandiflora (Salicaceae) é uma espécie típica do cerrado piauiense, o conhecimento da diversidade genética dessa espécie é de grande importância para estabelecimento de práticas e estratégias de conservação biológica. O presente estudo teve como objetivo caracterizar a diversidade de C. grandiflora em duas áreas de cerrado do Piauí. Foram analisados 15 descritores de natureza quantitativa, através da medição do caule, folha, fruto e semente, seguida de posterior análise multivariada (componentes principais e agrupamento). Tanto a análise de componentes principais quanto os métodos de agrupamento apresentaram semelhanças na associação das plantas, o que contribuiu para o conhecimento dos padrões de variação fenotípica e divergência da espécie, sendo que a maior variação da diversidade genética foi encontrada dentro das populações. Os resultados fornecem informações importantes, visto que na literatura descrições sobre caracterização morfológica e diversidade genética dessa espécie ainda são limitadas.

ABSTRACT Casearia grandiflora (Salicaceae) is a species typical of the savanna of Piaui state. Knowledge about its genetic diversity is of great importance to establish practices and strategies of biological conservation. This study aimed to characterize C.grandiflora diversity in two areas of savanna. Fifteen quantitative descriptors were analyzed trough measurement of steam, leaf, fruit and seed, followed by multivariate analysis (principal component and grouping). Both principal component analysis and grouping methods showed similarities in plant association, which contribute to the knowledge on patterns of phenotypic variation and species divergence, with the greatest genetic diversity variation found within the populations. The results provide important information because descriptions of morphologic characterization and genetic diversity of this species are still limited in the specific literature.

RESUMO. Este estudo avaliou as propriedades do solo e a produtividade do feijão-caupi após seis anos de aplicações consecutivas de lodo de curtume compostado. Anualmente, o composto foi aplicado a 0, 2,5, 5, 10 e 20 Mg ha-1 e no sexto ano as propriedades químicas e físicas do solo e a produtividade do feijão-caupi foram avaliadas em experimento de blocos casualizados. Cr, P, K, C orgânico, pH, Ca, Na, e a capacidade de troca de cátions aumentaram linearmente após seis anos de aplicação do composto. A densidade do solo diminuiu linearmente enquanto a estabilidade de agregados aumentou após a aplicação do composto. Em consequência das mudanças nas propriedades químicas e físicas do solo, a produtividade do feijão-caupi apresentou resposta quadrática às doses de lodo de curtume compostado com máxima produtividade estimada encontrada na dose de 8,3 Mg ha-1. Em conclusão, as propriedades químicas e físicas do solo melhoraram após seis anos de aplicação do lodo de curtume compostado. Entretanto, o pH do solo, bem como os teores de Cr e Na aumentaram com aplicação do lodo de curtume compostado e estes parâmetros influenciaram a produtividade do feijão-caupi que apresentou resposta quadrática.

ABSTRACT. This study evaluated soil properties and cowpea yield after six years of consecutive amendment of composted tannery sludge. The compost was applied annually at 0, 2.5, 5, 10, and 20 Mg ha-1 and at the end of the sixth year, the chemical and physical properties of the soil were evaluated using a randomized block design. The Cr, P, K, Ca, Na and organic C contents and the pH and cation exchange capacity increased linearly after six years of compost amendment. The soil bulk density decreased linearly while the aggregate stability index increased after compost amendment. As a consequence of the changes in the chemical and physical properties of the soil, cowpea yield showed a quadratic response to the tannery rates, with an estimated maximum cowpea yield at 8.3 Mg ha-1. In conclusion, the soil chemical and physical properties improved after six years of composted tannery sludge amendment. However, the soil pH and the Cr and Na contents increased with composted tannery sludge amendment, which influenced the cowpea yield and resulted in a quadratic response to the compost.

O estudo objetivou avaliar a fitodisponibilidade de metais pesados (Cr, Cd, Ni e Pb) em folhas e grãos, e produtividade em caupi (Vigna unguiculata L) em solo após a adição de lodo de curtume compostado (LCC) por dois anos consecutivos. Os experimentos foram realizados em 2009 e 2010 em solo com adição de LCC a doses de 0, 5, 10, 20 e 40 Mg ha-1. A adição de LCC em doses acima de 10 Mg ha-1, por dois anos consecutivos, aumentou a concentração de Cr nas folhas do caupi. Não houve aumento na concentração de metais no grão de caupi após dois anos de aplicação. Em 2009, a aplicação de LCC não aumentou a produtividade da planta. Entretanto, em 2010, o LCC nas doses de 10 e 20 Mg ha-1 aumentou a produtividade do caupi. A aplicação de lodo de curtume compostado aumentou linearmente a concentração de Cr nas folhas do caupi após dois anos. O lodo de curtume compostado promoveu aumento na produtividade de grãos.

The study aimed to evaluate the phytoavailability of heavy metals (Cr, Cd, Ni and Pb) concentrations in leaves and grains, and yield of cowpea (Vigna unguiculata L) grown in soil amended with composted tannery sludge (CTS) for two consecutive years. The experiments were carried out in 2009 and 2010 in soil amended with CTS at 0, 5, 10, 20, and 40 Mg ha-1. The CTS amendment rates applied were above 10 Mg ha-1, increased Cr concentrations in cowpea leaves. There were not increases in the heavy metals concentrations in cowpea grains after two years. In 2009, the application of CTS amendment did not promote increase in plant yield. However, in 2010, CTS amendment at 10 and 20 Mg ha-1 increased cowpea yield. The amendment of composted tannery sludge linearly increased linearly the concentration of Cr in the leaves of cowpea after two years. Composted tannery sludge promoted increases in cowpea yield.

O objetivo deste trabalho foi avaliar o efeito da inoculação com Azospirillum brasilense e adubação nitrogenada sobre a produtividade do milho verde. O estudo foi conduzido no município de Teresina, PI, em 2011 e 2012, e os tratamentos foram dispostos em delineamento de blocos ao acaso sob arranjo fatorial de 5x2, sendo cinco doses de nitrogênio (N) (0, 50, 100, 150 e 200 kg N ha-1) com e sem inoculação. No tratamento com inoculação, foi utilizado um produto formulado contendo A. brasilense, estirpes Abv5 e Abv6. Houve aumento significativo no número e na massa das espigas comerciais com a inoculação de A. brasilense em relação ao tratamento sem inoculação. A combinação de inoculação com A. brasilence e nitrogênio aumenta em mais de 30% a produção de espigas de milho verde.

The aim of this study was to evaluate the effect of A. brasilense inoculation and nitrogen fertilization on green corn yield. The study was conducted out in Teresina, PI, in 2011 and 2012, and treatments were arranged in a randomized block design with five N rates (0, 50, 100, 150 and 200 kg N ha-1) with and without inoculation. In the inoculated treatment it was used a product with A. brasilense, strains Abv5 and Abv6. There was a significant increase in both number and mass of commercial corn cobs with A. brasilense inoculation as compared with treatment without inoculation. The association of inoculation with A. brasilence and nitrogen increase more than 30% the corn cobs production.

Este estudo teve como objetivo quantificar os estoques de carbono orgânico total e de suas frações em um argissolo sob sistemas agroflorestais com 6 (SAF6) e 13 anos de idade (SAF13), agricultura de corte-e-queima (ACQ) e floresta nativa de Cerrado (FNC) no Nordeste do Brasil. As amostras de solo foram coletadas nas estações seca e chuvosa, nas camadas de 0-0,05 m; 0,05-0,10 m; 0,10-0,20 m; e 0,20-0,40 m, para avaliar os estoques de carbono orgânico total (COT) e os teores de carbono lábil (CL), fração ácido fúlvico (C-FAF), fração ácido húmico (C-FAH) e humina (C-FH) e carbono da biomassa microbiana (Cmic). Além disso, o índice de manejo de carbono (IMC) foi determinado. Maiores estoques de COT (97,7 e 81,8 Mg ha-1 para 0-0,40 m de profundidade, nas estações seca e chuvosa, respectivamente) e teores de CL, substâncias húmicas e Cmic foram observados no SAF13 em todas as camadas. O IMC também foi maior no SAF13 (0-0,5 m: 158 e 86, 0,05-0,10 m: 171 e 67, respectivamente, nas estações seca e chuvosa), especialmente quando comparado com ACQ (0-0,05 m: 5,6 e 5,4; 0,05 -0,10 m: 5,3 e 5,8, respectivamente, nas estações seca e chuvosa). Os sistemas agroflorestais aumentam a qualidade do solo por meio da conservação da matéria orgânica e podem ser considerados como excelente estratégia para a garantia da sustentabilidade em solo tropical do Nordeste brasileiro.

This study aimed at quantifying total organic carbon stocks and its pools in Acrisol under agroforestry systems with six (AFS6) and thirteen years old (AFS13), slash-and-burn agriculture (SBA) and savanna native forest (SNF) in northeastern Brazil. Soil samples were collected at 0-0.05 m, 0.05-0.10 m, 0.10-0.20 m and 0.20-0.40 m depths in the dry and rainy seasons to evaluate total organic carbon (TOC) stocks and labile carbon (LC), fulvic acid fraction (C-FAF), humic acid fraction (C-HAF), humin (C-HF) and microbial biomass carbon (Cmic) contents. Additionally, carbon management index (CMI) was determined. Higher TOC stocks (97.7 and 81.8 Mg ha-1 for the 0-0.40 m depth in the dry and rainy seasons, respectively) and LC, humic substances and Cmic contents were observed in the AFS13 in all the depths. CMI also was higher in the AFS13 (0-0. 05 m: 158 and 86; 0.05-0.10 m: 171 and 67, respectively for the dry and rainy seasons) especially when compared to the SBA (0-0.05 m: 5.6 and 5.4; 0.05-0.10 m: 5.3 and 5.8, respectively for dry and rainy seasons). The agroforestry systems increased soil quality through the conservation of organic matter and can be considered an excellent strategy to assurance sustainability in tropical soil of Northeastern Brazil

O uso agrícola do lodo de curtume pode aumentar os riscos para os solos. Assim, a compostagem é reconhecida como um dos mais adequados métodos para reciclagem do lodo de curtume. Experimentos foram conduzidos em condições de campo para avaliar os efeitos do lodo de curtume compostado (LCC) sobre a biomassa microbiana do solo e o conteúdo de elementos traço após dois anos de aplicações sucessivas. Cinco tratamentos foram usados: 0 (sem LCC), 5, 10, 20 e 40 t ha-1 de LCC (base seca). As amostras de solo foram coletadas 60 dias após a aplicação de LCC, a 0-20 cm. A aplicação de LCC promoveu mudanças na biomassa microbiana do solo (BMS). No primeiro ano, significantes aumentos no C e N da BMS foram observados com a aplicação de 10 t ha-1. A aplicação de LCC aumentou o conteúdo de Cr no solo após dois anos de aplicação.

Because the agricultural use of tannery sludge may cause increased risks to soils, composting is recognized as one of the most suitable alternative for tannery sludge recycling. Experiments were conducted under field conditions to evaluate the effects of composted tannery sludge (CTS) on the soil microbial biomass and trace elements after two years of consecutive applications. The following five treatments were used: 0 (without CTS application), 5, 10, 20 and 40 ton ha-1 of CTS (dry basis). Soil samples were collected at 60 days after the CTS application at 0-20 cm depth. The CTS application promoted changes in the soil microbial biomass C (SMB-C) and N (SMB-N). In the first year, significant increases in the SMB-C and SMB-N were observed with the application of 10 ton ha-1. Furthermore, CTS application increased the Cr content in the soil after two years of application.

Repeated soil amendment with industrial waste can affect the accumulation of chemical elements, mainly heavy metals, in plants. We therefore evaluated the accumulation of Cr, Cd, Ni, and Pb in cowpea (Vigna unguiculata [L.] Walp.) shoots and grains in soil amended for three consecutive years with tannery sludge compost (TSC). Tannery sludge compost was applied annually starting in 2009 at 0, 2.5, 5, 10, and 20 t ha-1 and cowpea was sown. At 40 and 60 d after cowpea sowing, the accumulation of Cr, Cd, Pb, and Ni was evaluated in the shoots and grains, respectively. The experiment used completely randomized design with four replicates and data were subjected to ANOVA and F-test (5%). Only Cr accumulation was significant (P < 0.05) in the cowpea shoots after 3 yr of TSC amendment; accumulation increased as TSC rates were applied. However, there was no significant Cr, Cd, Ni, and Pb accumulation in grains. After 3 yr of consecutive TSC soil amendments, Cr accumulated in the shoots, but it was not translocated to the grains.

Avaliaram-se atributos dos fungos micorrízicos arbusculares (FMAs) na região sob desertificação de Gilbués, PI, Brasil, objetivando monitorar áreas sob diferentes níveis de degradação e recuperação do solo. Amostras de solo foram coletadas na camada de 0-0,2 m, durante o período seco de 2009 em quatro áreas pertencentes a um Argissolo, visualmente definidas como: REC - área em recuperação por contenção da erosão e plantio de gramíneas e leguminosas exóticas; DEG- área altamente degradada; IDEG - área moderadamente degradada; MN - área de vegetação nativa. Foram analisados a colonização radicular, o número mais provável de propágulos infectivos (NMP), índices de diversidade (Shannon-Wiener, diversidade e dominância de Simpson, equitabilidade de Pielou e Margalef) e os atributos químicos do solo pH, H+Al, fósforo e matéria orgânica, usados como variáveis explicativas da variabilidade de atributos dos FMAs por meio de análises multivariadas. A colonização radicular e o NMP de propágulos foram superiores em REC. Os índices de Shannon-Wiener, dominância de Simpson e Margalef foram menores na área DEG, demonstrando serem bons indicadores de alterações na comunidade de FMAs em áreas degradadas. Pela análise de agrupamento hierárquico, a área DEG teve maior dissimilaridade em relação às demais. Pela análise por componentes principais, os índices de Shannon-Wiener, Margalef, de Simpson, a dominância de Simpson e os teores de fósforo foram os parâmetros que mais explicaram a variância total.

Attributes of arbuscular mycorrhizal fungi (AMF) were evaluated in a region in the process of desertification at Gilbués, Piauí, Brazil, with the objective of monitoring areas with different levels of soil degradation and recovery. Soil samples were collected at a depth of 0 to 0.2 m during the dry season of 2009 in four areas of ultisol, which were visually defined as: REC - an area under recovery by erosion contention and the planting of exotic grasses and legumes; DEG- an area with high degradation; IDEG - an area with moderate degradation; MN - an area of native vegetation. The following were analysed: root colonization, the most probable number of infective propagules (MPN), diversity indices (the Shannon-Wiener index, the Simpson diversity and dominance indices, the Pielou equitability index and the Margalef index) and the soil chemical attributes of pH, H+Al, phosphorus and organic matter, used as explanatory variables for the variability of the AMF attributes by multivariate analyses. Root colonization and propagule MPN were higher in the REC area. The Shannon-Wiener index, the Simpson dominance index and the Margalef index were lower in the DEG area, showing that they are good indicators of changes in the AMF community in degraded areas. By hierarchical cluster analysis, the DEG area showed higher dissimilarity in relation to the other areas. By principal component analysis, the Shannon-Wiener index, the Margalef index and the Simpson dominance index, and the phosphorus levels were the parameters that best explained the total variation.

O objetivo desse trabalho foi avaliar a distribuição da fauna em função da umidade do solo em diferentes sistemas de manejo para a produção de forragens com capim-Tifton 85 (Cynodon dactylon Pers. x C. niemfuensis Vanderys), capim-Tanzânia (Panicum maximum Jacq. cv. Tanzânia), capim-Andropogon (Andropogon gayanus Kunth), Leucena (Leucaena leucocephala (Lam.) R. de Wit.) tendo como controle uma Mata dos Cocais. A coleta da fauna foi feita utilizando-se armadilhas do tipo Pitfall em duas épocas do ano: setembro de 2007 e março de 2008, período seco e chuvoso, respectivamente. Os sistemas com capim-Tifton, capim-Tanzânia e Leucena mostraram maior número de indivíduos nos dois períodos avaliados. A queimada ocorrida no capim-Andropogon antes da primeira coleta resultou em uma redução na abundância e diversidade da fauna edáfica. Os maiores valores em riqueza, diversidade e uniformidade de fauna foram obtidos na amostragem realizada no período úmido. A mata mostrou maior diversidade e equitabilidade nos dois períodos avaliados. Em situação de estresse hídrico alguns grupos como Formicidae e Collembola predominaram nos sistemas de manejo diminuindo a uniformidade, enquanto no período úmido vários grupos mostraram boa representatividade o que favoreceu a uniformidade. A análise multivariada de componentes principais evidenciou que os sistemas com mata, capim-Tifton e capim-Tanzania e Leucena mostraram associação com vários grupos da fauna edáfica nos dois períodos avaliados enquanto que o sistema com capim-Andropogon, que sofreu queimada, apresentou afinidade apenas com o grupo Heteroptera, no período seco.

The objective of this study was to evaluate the distribution of fauna as a function of soil moisture in different fodder-production management systems of Tifton 85 grass (Cynodon dactylon Pers. x C. niemfuensis Vanderys), Tanzania grass (Panicum maximum Jacq. cv. Tanzânia), Andropogon Grass (Andropogon gayanus Kunth) and Leucena plants (Leucaena leucocephala (Lam.) R. de Wit.), with a coca-crop forest used as control. Sampling of the fauna was accomplished using "pitfall" traps in two periods of the year: September 2007 and March 2008, the dry and wet seasons respectively. Those systems with Tifton grass, Tanzania grass and Leucaena plants showed a higher number of individuals in both periods. The fire which occurred in the Andropogon grass before the first harvest resulted in a reduction in the amount and diversity of the soil fauna. The highest values for wealth, diversity and uniformity of fauna, were obtained from samples collected during the wet season. The forest presented a greater diversity and balance for both periods assessed. In a situation of water-stress, some groups, such as Collembola and Formicidae, predominated in the management systems, decreasing uniformity, while in the wet season, several groups were well represented, favouring uniformity. Principal-component multivariate analysis showed that systems of forest, Tifton grass, Tanzania grass and Leucaena plants were associated with several groups of soil fauna in the two periods evaluated, while the system of Andropogon grass, which suffered a fire, showed an affinity only with the Hepteroptera group during the dry season.