Durval Nolasco das Neves Neto

Análise espacial de atributos do solo e cobertura vegetal em diferentes condições de pastagem

The areas for livestock raising have expanded into areas of native vegetation, promoting changes in soil quality. The objective of this study was to evaluate the attributes of a Entisol under different vegetation covers to whether the pasture degradation represents soil degradation. The areas evaluated were: native forest, shrub, uncontrolled grazing animal stocking, grazing in fallow pasture with weeds; degraded pasture with bare soil and weeds, degraded pasture with weeds and tree species and grassland with low forage production. All pastures were formed by Brachiaria brizantha cv. Marandu. Hundred and twenty eight soil samples were collected in 0-5 and 5-10 cm, within each management area, considered as an experimental plot and soil cover was quantified. The chemical and physical properties of the soil were measured. Data were subjected to geoestatistical study. Increase in penetration resistance and decrease in the levels of organic matter were observed in the most degraded areas. Degraded pasture is not necessarily degraded land while degraded soil is related to grazing degrades.

Spatial analysis of parameters of soil fertility in an ecotone under different uses and management

In regions of ecotone soil chemical properties show a wide variation, resulting from the interplay between the factors of formation, vegetation cover and use. The aim of this study was to evaluate the spatial variability of chemical attributes of a Entisol transition zone between the Savannah and Amazonian biome in different forms of land use and management (forest, scrub, bare soil, crop, pasture and savanna) in the region of Araguaina city (TO). Samples were ground in an irregular mesh in an area of 26.08 ha, the depth of 0 to 20 cm to determine the levels of organic matter, P, K + , Ca 2+ , Mg 2+ and pH, sum of bases, CEC pH 7 , CEC e , V%, m%. The soil chemical properties were analyzed using descriptive statistics, comparison of average by Tukey test at 5% significance to the study and geostatistical kriging. The ranges of spatial dependence of the chemical organic matter, Al 3+ , K + , Mg + , and SB CEC e soil were higher than the others (pH, P, Ca 2+ , CEC pH 7 , V%, m%), indicating that these are more discontinuity in the spatial distribution in Entisol three forms of agricultural use and vegetation cover three of the transition Savannah-Amazon. Thus, management strategies of correction and mineral fertilizers in an ecotone can be fitted according to the representations of studies and geostatistical kriging interpolation in homogeneous areas.

Integrating forest-pasture: Spatial analysis and delineation of zones of litter production and nutrient return

This study aimed to quantify, describe, and identify plant litter production and nutrient accumulation zones in different forest-pasture integration (FPI) systems and forest strata of the Cerrado-Amazon transition on typical orthic Quartzarenic Neosol using spatial analysis, principal component analysis, and non-hierarchical fuzzy k-mean clustering logic techniques. The evaluations were performed at two FPI systems comprising a combination of Brachiaria brizantha cv. Marandu and thinned native vegetation with 50 and 75% (FPI-I and FPI-II, respectively) shade in an original thinned forest (NFI) and in an original intact forest (NF-II) with 80 and 95% shade, respectively. An area of 4,000 m² (40 x 100 m) that contained 32 sampling points arranged in a 4 x 25 m grid was demarcated for each treatment. Plant litter was collected using 32 collectors installed at equidistant points. Twelve nylon bags were placed on the soil surface at each point to evaluate the plant litter decomposition, totaling 384 bags per treatment. It was possible to quantify, describe, and define plant litter production and nutrient accumulation zones in different FPI systems and forest strata of the Cerrado-Amazon transition on orthic Quartzarenic Neosol using geostatistical analysis, principal components, and non-hierarchical fuzzy k-mean clustering logic procedures.

Dependência espacial em levantamentos do estoque de carbono em áreas de pastagens de Brachiaria brizantha cv. Marandu

Foi conduzido um estudo utilizando analise de semivariogramas para quantificar a autocorrelacao espacial dos estoques de carbono (EC) no solo, biomassa da graminea e das plantas daninhas em tres parcelas experimentais de pastagens de Brachiaria brizantha cv. Marandu com niveis baixo, medio e alto de degradacao, cultivadas em Neossolo Quartzarenico Ortico. As coletas das plantas e do solo foram realizadas em malha de amostragem regular com distâncias de 5 x 5 m em area de 900 m². Os EC das pastagens foram submetidos as analises de estatistica descritiva, ao teste nao-parametrico de Kruskal-Wallis ao nivel de 5% de significância, ao estudo geoestatistico e interpolacao por krigagem ordinaria. A variabilidade espacial do EC foi observada dentro e entre as pastagens de capim-Marandu com niveis baixo, medio e alto de degradacao. A pastagem de capim-Marandu com nivel baixo de degradacao teve menor continuidade espacial, por apresentar menores alcances no EC, na biomassa da graminea e na biomassa total (graminea + plantas daninhas), no solo e no sistema solo x pastagem (solo + biomassa total). A grade de 5 x 5 m foi adequada para caracterizar a variabilidade espacial de pastagens de capim-Marandu com niveis de degradacao baixo e alto. Area de pastagem de capim-Marandu com grau medio de degradacao apresenta coeficientes de variacao altos entre os valores EC; o que comprometeu a modelagem espacial que tambem pode ter ocorrido devido ao baixo numero de amostras realizadas (n=36). Assim, pontos de amostragem menores que 5 m podem melhorar a precisao dos ajustes dos semivariogramas.

Morphogenetic and structural characteristics of Urochloa spp. under conventional management and intercropped with cereals

Integrated crop-livestock systems are an alternative to the traditional model of land use, which seeks to promote the technical, ecological and socio-economic viability of the area used. The aim was to evaluate the morphogenetic and structural responses of two established cultivars of Urochloa brizantha at two times of the year, using conventional and integrated crop-livestock systems. The experimental design was of randomised blocks in a 2 x 3 x 2 triple factorial scheme consisting of two forage plants (Marandu and Piata), three management systems (conventional and intercropped with corn and sorghum) and two seasons (summer and autumn), with four replications. Morphogenetic and structural characteristics were evaluated. The integration of tropical forage grasses with grain crops resulted in no negative impacts on the morphostructural characteristics of the cultivars of Urochloa brizantha; the seasons of the year promoting major changes, such as a reduction of 33.8% in the lifespan of leaves in the summer. However, in that season there was an increase of 39.3 and 30.9% in the rate of leaf emergence and elongation respectively. It can be seen that an integrated agricultural system is efficient in creating pasture, and that Marandu grass and Piata are alternatives to this type of system.

Chemical Characteristics of the Use of Gelatine Sludge in Soil Cultivated as Fertilizer

Various types of industrial wastes have been tested as a source of pasture fertilization. However, little is known about the sludge of the gelatine industry. This study aimed at testing gelatine sludge as a soil amendment by assessing the chemical modifications caused in the soil profile. The experiment was conducted in Araguaina, Tocantins, using a typical Quartzipsamment soil (Entisols) from February to November 2013. Four doses were tested in experimental plots: 0, 50, 150 and 300 m3 ha-1. Soil sampling was performed at four depths: 0-5, 5-10, 10-20 and 20-30 cm with collection at the beginning and the end of the experimental period. Five grazing simulations of 21 days of rest of Piata grass were testes. The gelatine sludge was able to raise the contents of calcium, phosphorus, and sum of bases only in the superficial layer (0-5 cm) and did not alter the pH, potential acidity and saturation by base, indicating that there was no use restriction due to salinization or acidification. Therefore, it was concluded that the maximum tested dose (300 m3 ha-1) improved the chemical characteristics of the soil, especially in the 0-5-cm layer.

Implementation of Silvopastoral Systems under Nutrient Cycling in Secondary Vegetation in the Amazon

Silvopastoral systems can be implemented in idle secondary forests; however, they may affect nutrient cycling in these ecosystems. This farming practice using babassu palms ( Attalea speciosa Mart.) and Mombasa grass ( Panicum maximum Jacq.) has been little studied, and the nutrient cycling occurred during this practice is yet unknown. The goal of this paper was to detect the leaf litter accumulation, decomposition, and nutrient release occurring in silvopastoral systems in a babassu secondary forest, and compared the results with those of a native forest and of a pasture grown under full sunlight. The data relating to deposition, chemical composition, decomposition, and macronutrient release of leaf litter and pasture litter were evaluated by multivariate analyses. The results showed that forest thinning reduced leaf litter deposition and overall nutrient cycling but had no effect on decomposition rates. Conversely, the presence of grass in the understory promoted increased overall nutrient cycling rates. The cycling in integrated systems occurs more similar to that of forests than that of monocultures. The greater the thinning intensity the more similar the cycling will be relative to that occurring in pastures and in monocultures. The nutrients Ca, Mg, and N were the most affected by thinning. Moreover, the presence of grass in integrated systems provided an increased N and Mg cycling, whereas the thinning reduced Ca cycling. K showed the highest release and return ratio to the soil. Lastly, leaf litter from pasture areas showed higher contents of nutrients, decomposition rates, as well as an enhanced nutrient cycling capacity.

Integração floresta-pasto: análise espacial e delineamento de zonas de produção de serapilheira e retorno de nutrientes

This study aimed to quantify, describe, and identify plant litter production and nutrient accumulation zones in different forest-pasture integration (FPI) systems and forest strata of the Cerrado-Amazon transition on typical orthic Quartzarenic Neosol using spatial analysis, principal component analysis, and non-hierarchical fuzzy k-mean clustering logic techniques. The evaluations were performed at two FPI systems comprising a combination of Brachiaria brizantha cv. Marandu and thinned native vegetation with 50 and 75% (FPI-I and FPI-II, respectively) shade in an original thinned forest (NFI) and in an original intact forest (NF-II) with 80 and 95% shade, respectively. An area of 4,000 m² (40 x 100 m) that contained 32 sampling points arranged in a 4 x 25 m grid was demarcated for each treatment. Plant litter was collected using 32 collectors installed at equidistant points. Twelve nylon bags were placed on the soil surface at each point to evaluate the plant litter decomposition, totaling 384 bags per treatment. It was possible to quantify, describe, and define plant litter production and nutrient accumulation zones in different FPI systems and forest strata of the Cerrado-Amazon transition on orthic Quartzarenic Neosol using geostatistical analysis, principal components, and non-hierarchical fuzzy k-mean clustering logic procedures.

Variabilidade espacial das respostas produtivas e morfológicas do capim-Marandu em função dos atributos químicos e topográficos

Objetivou-se com este trabalho avaliar a variabilidade espacial das respostas produtivas e estruturais do capim Marandu em funcao das caracteristicas quimicas do solo e da topografia do terreno. O experimento foi conduzido em uma topossequencia, na escola de Medicina Veterinaria e Zootecnia. Foram avaliadas as variaveis V, CTC, SB, m, pH, na profundidade de 0-20cm, profundidade efetiva, numero de perfilhos (m2), producao de materia seca (kg ha-1), altura do dossel forrageiro (cm). Foram coletadas 72 amostras em pontos georreferenciados em terreno declivoso. O solo foi classificado como Neossolo Quartzarenico Ortico na porcao superior (Topo), Neossolo Litolico Eutrofico, no terco superior da encosta (ombro), Neossolo Litolico Eutrofico no terco medio da encosta (meia-encosta) e Neossolo Quartzarenico Hidromorfico no terco inferior (pedimento). Todas as variaveis avaliadas apresentaram dependencia espacial com variogramas de estrutura bem definida. A pastagem apresentou heterogeneidade na morfologia do dossel em funcao da distribuicao espacial da fertilidade do solo, resultando em dossel e producao de materia seca mais elevada no topo e atingindo a menor producao no ombro da topossequencia. O dossel forrageiro apresenta heterogeneidade na morfologia em funcao da distribuicao espacial da fertilidade do solo e da profundidade efetiva, resultando na definicao de duas zonas manejo: 1  topo e pedimento; e 2  ombro e meia encosta.