Efeito de plantas de cobertura sobre os atributos físicos de um solo construído na área de mineração de carvão de Candiota-RS após três anos

Abstract

The mineral coal is important to the expansion of the national electrical system. Candiota s mine is the biggest mine in Brazil, with 38% of all national coal. This activity and the traffic of weight machines, cause negative alterations in the structure. Attributes such as bulk density, porosity, mean weight diameter of aggregates and mechanical resistance penetration show the consequences of this activity. The revegetation has been used as a strategy to recover these degraded soils. Thus, with, the reestablishment of the cycle of the organic substance exerts big influence on the physical quality of the soil. The objective of the present work was to evaluate the effect of different cover crops on the physical attributes of constructed soil in coal mining area in Candiota-RS, after 3 years of experiment conduction. Aggregates stability in different size classes, mean weight diameter (MWD), organic carbon, soil bulk density, total porosity, macro/microporosity and mechanical resistence to penetration were analized. The experiment, installed in nov/dez of 2003, is comprised of four randomized blocks with four treatments: T1 - Hemarthria altissima (Poir.) Stapf & C. E. Hubbard, T2 - Cynodon dactilon (L.) Pers., T3 Paspalum notatum Flüggé, T4 - Brachiaria brizantha (Hochst.) Stapf, T5 natural soil. The soil samples had been collected from the layers: 0,0 - 0,05m; 0,05 - 0,10m and 0,10 - 0,20m. As general conclusions were: 1) The effect of the cover crops on the soil physical attributes is still incipient. 2) The cover crops Hemarthria altissima and Cynodon dactilon stood out of the others.