Influence of native or exotic trees on soil fertility in decades of silvopastoral system at the Brazilian savannah biome

Abstract

Silvopastoral systems (SPSs) are considered a conservationist system by combining forestry species cultivation with domesticated grazing animals, intercropping trees, and pasture in the same area. SPSs are noun for its contribution to improve soil chemical and physical properties, enhance grass nutritional status, provide healthier animal environment, and increase farmers’ options to maximize the use of land. In soil degraded areas, such as those found in Brazilian savannah biome (BSB), the SPSs constitute an alternative to soil recuperation in these areas. Therefore, our aim was to assess soil fertility attributes at different depths on a BSB grown with Brachiaria brizantha cv. Marandu grass, the influence of SPS with native tree zeyheria (Zeyheria tuberculosa) settled in 1984, or with the exotic eucalyptus (Eucalyptus grandis) settled in 1994. The soil water pH, P, Ca, Mg, and K contents, as well as soil base sum and saturation, were found superior mostly at the top layer (0–2 cm) of the eucalyptus site, than for the ipe-felpudo site. This response was correlated to greater soil organic matter and carbon at the eucalyptus site, which demonstrated to have high nutrient cycling rates. Around 50 % of the CEC in both SPSs was occupied by bases, demonstrating that the areas have large potential to absorb applied nutrients. The SPSs have no significant impact on S-SO4 2− or micronutrient availability. The litter composition in eucalyptus site was accountable for the superior results of this SPS, which has shown as a promising choice for land use and conservation in the BSB.