Efficient Use of Soil in Silvopastoral Systems of Native Forests

Abstract

In agriculture and forestry, the soil is one of the essential natural resources. Efficient soil use is essential to achieve sustainable development and face current global problems, such as food security and climate change. A better understanding of the dynamics of this resource and parallel actions of soil conservation and restoration should be incorporated into agricultural and forestry practices. The American Gran Chaco is a transition area between the tropics and the temperate zone, corresponding to savannas and semi-arid forests. For decades, the combination of high input agriculture, exceptionally profitable in the short term, with livestock in implanted pastures, accelerated the massive clearing of shrubs and native forests, which has caused negative impacts on biodiversity, on the quality of soils and therefore on the sustainability of production processes. Silvopastoral systems (SSP) are agroforestry systems with a promising approach to achieve sustainability of agroecosystems and improve forest conservation. These production systems combine grasses, trees, and animals that interact on the same surface unit while obtaining different products such as meat and wood. Silvopastoral systems are designed to increase efficiency in the use of resources, improve and diversify production, and conserve a large part of ecosystem services. Currently, in the Argentine Chaco, SSPs are designed from secondary forests that were degraded in earlier times. The objective of this chapter was to review knowledge about the impact of forest management with livestock on the soil of this region. For the habilitation of these forests in silvopastoral systems and efficient soil use, the authors recommend the low-intensity roller-chopping (RBI) method, a selective mechanical alteration of the vegetation, with the sowing of pastures, which tries to maintain biodiversity, natural regeneration of woodland and soil conditions, and improve system productivity. Over several decades, the authors have studied the interaction of RBI on soil quality, by evaluating soil indicators. The effect of RBI has been shown to depend on the ecological site, vegetation cover, and grazing. Silvopastoral systems maintain soil properties, such as moisture, bulk density, total organic carbon, particulate organic carbon, and carbon from microbial biomass, of utmost importance in semi-arid environments. Furthermore, SSPs have been found to have minimal impact on the diversity of soil microbial communities. Therefore, it can be affirmed in the medium term that SSPs are favorable for this region.