Root System of Jatropha curcas Provides Resistance and Strength to the Soil

Abstract

ABSTRACT Jatropha curcas (L.) has been studied as a reinforcing element against slope erosion to protect from the impact of raindrops provided by the plant shoot and the anchorage of the root system. Thus, the objective of this study was to evaluate the behavior of the root system of hybrids of Jatropha curcas (L.) regarding to the physical-mechanical reinforcing capacity of the soil and its potential of contribution in the stabilization of slopes on erosion processes. The monolith method was used to measure root density, root length density, root area rate, root resistance to rupture and the root cohesion. Root length using the cylinder method was also verified. The results were submitted to variance analysis, and then the polynomial regression analysis was conducted. Root volume, root density, root average density, and root distribution decrease with the soil depth, increasing with a strong negative correlation between indexes and soil depth. Jatropha shoot dry mass can provide to the soil a strong vegetation cover that improves the soil surface protection related to the erosion processes. J. curcas roots resist breakage due to their pivoting system that provides better anchorage in deeper soil layers. In contrast, shallow roots provide a surface anchoring system that help in soil stabilization. A tendency of increase of the tension strength in the maximum load was observed until the right moment of the root rupture, following its diameter increases.