Tropical grasses adaptability as a sustainable tool for recovering degraded pastures and restricting soil loss: Use diagnosis and future scenarios

Abstract

Pastures, exposed soil and weeds correspond to 47.96% of Espírito Santo state territory, and most of these areas present low or no economic returns, due to the advanced degradation stage. Aiming to mitigate such effects, this study aimed to propose the insertion of high productive potential tropical grasses (Brachiaria brizantha, Cynodon dactylon and Panicum maximum), based on edaphoclimatic zoning elaborated in accordance with productive seasonality, as a low cost alternative to soil loss restriction and degraded areas recovery. The study has been developed for Espírito Santo state, Brazil and the method application consisted in edaphoclimatic zoning elaboration for three tropical grasses. A current soil loss estimate of suitable areas for Brachiaria cultivation was carried out later. Data from the current scenario were confronted with a new soil loss estimate in an alternative future scenario, aiming to quantify the grass insertion benefits in these areas according to their aptitude classes. The largest suitable areas were obtained for Cynodon genus, followed by Panicum and Brachiaria. Currently, it is estimated, on average, soil losses of 4.4 ton. ha−1. year−1 in dry season and 12.6 ton. ha−1. year−1 in rainy season. Projections into an alternative future scenario indicate that tropical grasses adoption considering technical criteria can lead to great soil loss reductions, achieving final rates of 0.24 ton. ha−1. year−1 in dry season (−94.5%) and 0.94 ton. ha−1. year−1 in rainy season (−92.5%), reducing new pasture areas demand and, consequently, promoting remnant forest conservation. This study results present significant contributions aimed at technical support of governmental and private action plans that work to promote conservationist and sustainable agricultural practices.