Recovery of soil physical properties by green manure, liming, gypsum and pasture and spontaneous native species¹

Abstract

SUMMARYInadequate usage can degrade natural resources, particularly soils. More attention has been paid to practices aiming at the recovery of degraded soils in the last years, e.g, the use of organic fertilizers, liming and introduction of species adapted to adverse conditions. The purpose of this study was therefore to investigate the recovery of physical properties of a Red Latosol (Oxisol) degraded by the construction of a hydroelectric power station. In the study area, a soil layer about 8m thick had been withdrawn by heavy machines leading not only to soil compaction, but resulting in high-degree degradation. The experiment was arranged in a completely randomized design with nine treatments and four replications. The treatments consisted of: 1-soil mobilization by tilling (to ensure the effect of mechanical mobilization in all treatments) without planting, but growth of spontaneous vegetation; 2-Black velvet bean (Stizolobium aterrimum Piper & Tracy); 3-Pigeonpea (Cajanus cajan (L.) DC); 4-Liming + black velvet bean; 5-Liming + pigeonpea until 1994, when replaced by jack bean (Canavalia ensiformis); 6-Liming + gypsum + black velvet bean; 7-Liming + gypsum + pigeonpea until 1994, when replaced by jack bean; and two controls as reference: 8-Native Cerrado vegetation and 9-bare soil (no tilling and no planting), left under natural conditions and in this situation, without spontaneous vegetation. In treatments 1 through 7, the soil was tilled. Treatments were installed in 1992 and left unmanaged for seven years, until brachiaria (Brachiaria decumbens) was planted in all plots in 1999. Seventeen years after implantation, the properties soil macroporosity, microporosity, total porosity, bulk density and aggregate stability were assessed in the previously described treatments in the soil layers 0.00- Index terms: soil bulk density, total porosity, soil degradation, soil quality. porco; 6-calcário+gesso+mucuna-preta; 7-calcário+gesso+guandu até 1994 de 0,00-0,10, 0,10-0,20 e 0,20-0,40 m, resistência do solo à penetração e umidade do solo (0,00-0,15 e 0,15-0,30 m RESUMO: RECUPERAÇÃO DAS PROPRIEDADES FÍSICAS DO SOLO POR MEIO DE ADUBOS VERDES, CALAGEM, GESSO, PASTAGEM E ESPÉCIES DE OCORRÊNCIA ESPONTÂNEA O uso inadequado pode degradar os recursos naturais, sobretudo o solo. Práticas visando à recuperação de solos degradados têm recebido mais atenção nos últimos anos, por meio do uso de adubos orgânicos, correção do solo e implantação de espécies adequadas às condições adversas. Nesse sentido, desenvolveu-se o presente trabalho com o objetivo de investigar a recuperação das propriedades físicas de um Latossolo Vermelho degradado devido à construção de usina hidrelétrica. Na área estudada, foi retirada uma camada de solo de aproximadamente 8 m de espessura, com o uso de máquinas pesadas, o que causou compactação do solo, caracterizando alto grau de degradação. O delineamento experimental utilizado foi inteiramente casualizado, com nove tratamentos e quatro repetições. Os tratamentos foram: 1-solo mobilizado pelo pr...