Subsoil reclamation in loan area used for hydroelectric construction

Abstract

Degraded areas are altered ecosystems where loss and excess are the most common kinds of disturbance and environmental degradation. Areas disturbed by hydroelectric plant construction can be considered as degraded areas since the superficial soil horizons have been removed. The objective of this research was to study the recovery of soil physical attributes and soil organic matter of the subsoil of a Red Latosol (Oxisol), degraded by soil removal for hydroelectric power plant construction, using green manure and applying lime and gypsum. A randomized block design was used with seven treatments and four replications. The research was started in 1992 and the treatments were: Control; Cajanus cajan until 1994 followed by Canavalia ensiformis; lime + Stizolobium aterrimum; lime + Cajanus cajan until 1994 and followed by Canavalia ensiformis; lime + gypsum + Stizolobium aterrimum and lime + gypsum + Cajanus cajan until 1994 and followed by Canavalia ensiformis. The treatments consisted of green manure, lime and gypsum. Seven years later, in 1999, the attributes analyzed were: total soil porosity, macroporosity, microporosity, soil bulk density, organic matter and brachiaria dry matter production. The treatments are contributing to the recovery of physical attributes of exposed subsoil, and the treatment with Stizolobium aterrimum without soil correction seems to be the most promising. Soil recuperation effects can be seen on the 0.00-0.10 m layer.