Perlon Maia dos Santos

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.

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.