Characterization of soil macrofauna in grain production systems in the Southeastern state of Piauí, Brazil

O objetivo deste trabalho foi caracterizar a macrofauna edáfica em sistemas de produção de grãos sob plantio direto e convencional no Sudoeste do Piauí, na região de Matopiba. Amostras de solo foram coletadas nas camadas de 0,0-0,1, 0,1-0,2 e 0,2-0,3 m, com serrapilheira, em áreas cultivadas predominantemente com milho e soja, sob preparo convencional e plantio direto, em solos com diferentes texturas. Remanescentes de vegetação nativa adjacentes foram amostrados como referência. A macrofauna edáfica nos diferentes sistemas de uso do solo foi identificada até o nível de famílias, as quais foram agrupadas de acordo com suas funções ecológicas. Os grupos mais abundantes nas áreas amostradas foram Isoptera, Hymenoptera e Coleoptera, este com o maior número de famílias. A análise de componentes principais revelou que os grupos funcionais geófago/bioturbador, fitófago/praga e predador/parasita estão associados a solos de textura argilo-siltosa; enquanto o grupo detritívoro/decompositor, a solos mais arenosos. Os sistemas de manejo do solo alteram a estrutura da comunidade de macroinvertebrados edáficos em relação à condição natural de Cerrado. O plantio direto proporciona maior abundância e riqueza de espécies que o preparo convencional, e minimiza o impacto de sistemas agrícolas sobre a biodiversidade da macrofauna edáfica.The objective of this work was to characterize the edaphic macrofauna in agricultural grain production systems under no-tillage and conventional tillage, in the Shoutheastern state of Piauí, in the Matopiba region, Brazil. Soil samples were taken from the 0.0-0.1, 0.1-0.2, and 0.2-0.3-m layers, with litter, in areas predominantly cropped with corn and soybean, under conventional and no-tillage systems, in soils with different textures. Fragments of native vegetation in adjacent areas were used as a reference. The edaphic macrofauna in the different land uses was identified down to family level, and the families were grouped according to their ecological functions. The most abundant groups in the sampled areas were Isoptera, Hymenoptera, and Coleoptera, the latter with the highest number of families. Principal component analysis revealed that the functional groups geophages/bioturbators, phytophages/pests, and predators/parasites were associated with clayey-silty soils, and detritivores/decomposers with sandy soils. Soil management systems change the community structure of edaphic macroinvertebrates in comparison with the natural Cerrado condition. No-tillage system promotes greater abundance and species richness than conventional tillage, and minimizes the impact of agricultural systems on edaphic macrofauna biodiversity

Soil physical quality in agricultural systems on the Cerrado of Piauí State, Brazil

Soil quality is essential for maintaining the sustainability of agro-ecosystems and ecosystem services provided by this natural resource. The present study aimed to assess the physical quality of soil through the characterization of the physical properties in grain production systems in the Southwest region of Piauí State, Brazil. The study was carried out in the Cerrado region of Piauí in four cities in areas of expansion of the agricultural frontier of the state: Baixa Grande do Ribeiro, Sebastião Leal, Uruçuí and Bom Jesus. Soil samples were collected in April 2012, in areas of grain production under conventional and no-tillage systems. Adjacent areas with native vegetation were also sampled as reference. Bulk density, effective saturation, hydraulic conductivity, penetration resistance, porosity and aggregation were measured. Regardless of the type of soil management used, agricultural systems degrade soil physical quality. No-tillage showed higher bulk density, penetration resistance and aggregation, with lower total porosity, macroporosity and hydraulic conductivity. The physical quality of soil in the agricultural areas of the Cerrado region of Piauí was dependent on the soil texture, while silt, clay and organic matter were determinant for soil aggregation, mechanical resistance, total porosity and microporosity

Formulação de substratos alternativos na formação inicial de mudas de ingazeiro

The objective of this study was to evaluate the development of seedlings of ingazeiro (Inga edulis Mart.) on alternatives substrates. The work was carried out in experimental design of randomized block with four replications and the treatments consisted of the substrates: Oxisol; Oxisol + cattle manure (20%), Oxisol + cattle manure (40%), Oxisol + sawdust (20%) and Oxisol + sawdust (40%). The diameter and height of the seedlings were measured at 106, 122, 137 and 153 days after sowing, and together with the last measurement were determined the number of leaves, root growth, fresh biomass of shoot and root, dry weight of shoot and root, total dry matter and also certain morphological indices. The treatment consists in mixing Oxisol + cattle manure (20%) showed the highest values for the morphological index resulting from the relationship between the dry weight shoot/dry weight of roots and the Dickson quality index.Objetivou-se com o presente estudo avaliar o crescimento inicial de mudas de ingazeiro (Inga edulis Mart.) em substratos alternativos. O estudo foi realizado em delineamento experimental de blocos ao acaso, com quatro repetições, sendo os tratamentos constituídos pelos substratos: Latossolo Vermelho; Latossolo Vermelho + Esterco Bovino (20%); Latossolo Vermelho + Esterco Bovino (40%); Latossolo Vermelho + Pó de Serra (20%) e Latossolo Vermelho + Pó de Serra (40%). Foram avaliados aos 106, 122, 137 e 153 dias após a semeadura o diâmetro e altura das mudas e na última aferição o número de folhas, crescimento radicular, fitomassa fresca da parte aérea e radicular, fitomassa seca da parte aérea e radicular, fitomassa seca total e determinados os índices morfológicos. O tratamento composto pela mistura do Latossolo Vermelho + Esterco Bovino (20%) promoveu os maiores valores para os índices morfológico resultante da relação entre a massa seca parte aérea/massa seca de raízes e para o índice de qualidade de Dickson

Physical attributes of soil cultivated with sugarcane under management systems

O conhecimento da distribuição espacial dos atributos físicos do solo, bem como as práticas de manejo do solo e da aplicação de gesso é importante para avaliar efeitos das operações agrícolas sobre a produtividade da cana-de-açúcar. Nesse contexto, o objetivo deste trabalho foi indicar a melhor densidade amostral, determinar a variabilidade espacial, os efeitos do preparo do solo com gradagem + subsolagem e da gessagem nos atributos físicos em um Argissolo Amarelo distrocoeso, correlacionando com a produtividade da cana-de-açúcar. Para avaliar a variabilidade espacial e densidade amostral foi demarcada uma malha amostral em cultivo de primeiro ciclo da cana-de-açúcar, onde foram coletadas 32 amostras equidistantes, espaçadas a cada 7 m. Para avaliar dos efeitos do preparo e da gessagem nos atributos físicos do solo foi conduzido um experimento em delineamento de blocos ao acaso em esquema de parcelas subdivididas com quatro repetições, totalizando 32 unidades experimentais. Os tratamentos nas parcelas principais foram: com preparo mecanizado (gradagem + subsolagem) e a ausência de preparo do solo. Nas subparcelas, as doses de gesso aplicadas foram: 1; 2 e 4 Mg ha-1; mais o controle (ausência de gesso), aplicadas em superfície à lanço, antes do preparo do solo. As amostras foram coletadas nas camadas entre as profundidades de 0-0,30 m e 0,30-0,60 m entre os sulcos de plantio. Foram avaliados a resistência tênsil dos agregados, diâmetro médio ponderado, resistência do solo à penetração de raízes, umidade gravimétrica, densidade do solo, porosidade total, macroporosidade, microporosidade, teor de cálcio no solo, a curva característica de retenção de água no solo, parâmetros de ajuste do modelo de van Genuchten, intervalo hídrico ótimo e produtividade de colmos da cana-de-açúcar. A densidade amostral mínima para estimar a produtividade da cana-de-açúcar foi de 14 amostras por hectare e dependeu da resistência à penetração e porosidade total do solo. O adensamento natural dos solos coesos pode ser reduzido pela irrigação, favorecendo aumentos significativos de produtividade, independente de outros atributos físicos do solo. As doses de gesso, no manejo com gradagem e subsolagem, reduziram a resistência tênsil dos agregados do solo. Entre os atributos físicos do solo, a sua resistência à penetração foi influenciada pelo preparo do solo, com menores valores nas parcelas mecanizadas. O preparo do solo com subsolagem foi eficiente em aumentar os teores de gesso em profundidade. A subsolagem foi mais efetiva em ampliar a faixa da densidade crítica do solo quando utilizada isoladamente. A dose de gesso com 2 Mg ha-1 melhorou os atributos físico-hídricos do solo, com maior disponibilidade de água às plantas, pelo aumento da densidade crítica do solo, quando preparado com subsolagem. A melhoria nos atributos físico-hídricos do solo, devido a aplicação de gesso na dose 2 Mg ha-1, aumentou a produtividade de colmos da cana-planta.The knowledge of the spatial distribution of soil physical attributes, as well as practices of soil management and gypsum application is important to evaluate effects of agricultural operations on sugarcane productivity. In this context, the objective of this work was to study the best sample density, to determine the spatial variability, the effects of soil preparation with harrowing + subsoiling and the physical attributes of a dystrocohesive Yellow Argisol correlating with the productivity of sugarcane. In order to evaluate the spatial variability and sample density, a sample mesh was demarcated in a first cycle of sugarcane cultivation, where 32 equidistant samples were collected, spaced every 7 m. In order to evaluate the effects of the preparation and the gypsum on the physical attributes of the soil, an experiment was carried out in a randomized block design in a subdivided plots scheme with four replications, totalizing 32 experimental units. The treatments in the main plots were with mechanized preparation (harrowing + subsoiling) and the absence of soil preparation. In the subplots the doses of gypsum applied were 1; 2 and 4 t ha-1 plus the control (absence of gypsum), applied on surface to the haul before tilling the soil. The samples were collected at depths of 0-0.30 m and 0.30-0.60 m between the planting furrows. Tensile strength of the aggregates, weighted mean diameter, penetration resistance of soil, gravimetric moisture, bulk density, total porosity, macroporosity, microporosity, soil calcium content, soil water retention characteristic curve, adjustment parameters of the van Genuchten model, least limiting water range and sugarcane productivity. The minimum sample density to estimate sugarcane productivity was 14 samples per hectare and depended on the penetration resistance and total porosity of the soil. The natural densification of cohesive soils can be reduced by irrigation, favoring significant increases in productivity, independent of other soil physical attributes. The gypsum rates, in the management with harrowing and subsoiling, reduced the tensile strength of the soil aggregates. Among the soil physical attributes penetration resistance of soil was influenced by soil preparation with lower values in the mechanized plots. Soil preparation with subsoiling was efficient in increasing gypsum contents in depth. Subsoiling was more effective in increasing the critical soil bulk density range when used alone. The dose of gypsum with 2 Mg ha-1 improved the physical-water attributes of the soil, with greater availability of water to the plants, by increasing the critical bulk density of the soil, when prepared with subsoiling. The improvement in soil physical-water attributes due to the application of 2 Mg ha-1 increased cane-plant productivity.Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNP

Soil macrofauna in a Cerrado/Caatinga ecotone under different crops in Southwestern Piauí State, Brazil

ABSTRACT: The aim of this study was to characterize the soil macrofauna under different crop systems and compare them to the macrofauna under the native vegetation of a Cerrado/Caatinga ecotone in southwestern Piauí State, Brazil. The areas studied included areas under sweetsop cultivation (Annona squamosa L.), andropogon grass with three years of use, andropogon grass with six years of use, pivot-irrigated corn, Napier grass, and native vegetation. In each area, soil layers of 0-0.1, 0.1-0.2, and 0.2-0.3m, including the surface litter, were evaluated following the Tropical Soil Biology and Fertility Program (TSBF) recommendations. The soil macrofauna from the different land-use systems were identified to the family level, and the mean density of each taxon was calculated for each soil-management type and layer. The structure of the soil macrofauna was negatively altered under the different crops in comparison to the native Cerrado/Caatinga vegetation, with macrofaunal occurrence varying in the different soil layers. A correlation existed between the functional groups and the soil grain-size distribution and moisture. Napier grass cultivation favored greater soil macrofaunal abundance, with a predominance of families belonging to the orders Isoptera and Hymenoptera. Number of soil macrofaunal families under pivot-irrigated corn was more like the number observed with the native vegetation, and corn also had greater family diversity compared to the other crops studied. Therefore, pivot-irrigated corn can reduce the impact of anthropogenic land use on the diversity of soil macrofauna

BIOCHAR COMO CONDICIONADOR DE SUBSTRATO PARA A PRODUÇÃO DE MUDAS DE EUCALIPTO

The objective was to evaluate the effect of the biochar as a substrate conditioner for the production of eucalyptus seedlings. The work was lead in nursery and the experimental design was randomized blocks arranged in factorial 5 x 2, being the factors composed of five concentrations of biochar (0; 7.5; 15; 30 and 60% v/v) added to the Germinar® commercial substrate and two species of eucalyptus (Eucalyptus citriodora and Eucalyptus urophylla), with four repetitions. At 75, 90 and 120 days after sowing (DAS) evaluated the stem diameter and plant height and at the end of the experiment (120 DAS) assessed fresh biomass of shoot and root, dry mass of shoot and root morphological parameters relative the plant height/stem diameter, dry mass of shoot/dry mass of roots and index of quality of Dickson. In general, the substrates that was added 7.5% of biochar promoted greater growth of seedlings, especially E. citriodora showed the best results for the evaluated characteristics. Evaluating the morphological parameters that act as key components in the quality of seedlings E. citriodora was superiors than E. urophylla. Concentrations of biochar above 30% harm the development of seedlings

Biochar como condicionador de substrato para a produção de mudas de alface

Objetivou-se com esse trabalho avaliar o efeito do Biochar (fino de carvão) adicionado a substratos na formação de mudas de alface. O experimento foi conduzido no viveiro de mudas da Universidade do Estado de Mato Grosso, campus de Nova Xavantina – MT. O delineamento experimental utilizado foi inteiramente casualizado com seis tratamentos e quatro repetições. Utilizou-se a cultivar Americana – GreatLakes 659 e seis substratos, sendo dois comerciais (Plantmax® e Germinar®) e quatro formados a partir de um substrato comercial (Germinar®) + Biochar. Foram avaliados a massa fresca e seca da parte aérea, massa fresca e seca das raízes, número de folhas verdadeiras e altura das plantas. Juntamente com Plantmax®, o substrato Germinar® acrescido de 7,5% de Biochar proporcionaram o melhor desempenho produtivo das mudas de alface para as variáveis, altura da planta, número de folhas verdadeiras, massa fresca e massa seca das raízes. O Biochar se mostrou um bom condicionador de substrato quando associado ao substrato comercial Germinar®, proporcionando bom desempenho produtivo das mudas de alface

Formulation of alternative substrates in the initial formation of ingazeiro seedlings

The objective of this study was to evaluate the development of seedlings of ingazeiro (Inga edulis Mart.) on alternatives substrates. The work was carried out in experimental design of randomized block with four replications and the treatments consisted of the substrates: Oxisol; Oxisol + cattle manure (20%), Oxisol + cattle manure (40%), Oxisol + sawdust (20%) and Oxisol + sawdust (40%). The diameter and height of the seedlings were measured at 106, 122, 137 and 153 days after sowing, and together with the last measurement were determined the number of leaves, root growth, fresh biomass of shoot and root, dry weight of shoot and root, total dry matter and also certain morphological indices. The treatment consists in mixing Oxisol + cattle manure (20%) showed the highest values for the morphological index resulting from the relationship between the dry weight shoot/dry weight of roots and the Dickson quality index