Eficiência das plantas de cobertura na recuperação da estrutura do solo

Abstract

The soil structure can be perceived as an arrangement of particles from soil, responsible for the aggregations formation. The usage of different species of cover plants may contribute to the improvement of physical soil quality, due to a root system and dry matter deposition. In this account, the following research aimed to verify the capability of different cover plants to recover the aggregations of soils on conventional tillage system to enable the first no-tillage system. The experiment was conducted on the experimental area of Fronteira Sul Federal University, campus Cerro Largo. The following treatments were implanted: Crotalaria juncea, Crotalaria spectabilis, Pigeon beans, Sudan grass, Sorghum, Millet, Fallow. Casual delimitation was adopted for the experimental design, with 4 repetitions. It was evaluated the density parameters, total porosity, micro porosity and macro porosity in the layers 0 – 5; 5 – 10 and 10 – 20 cm in each culture line; size distribution of the aggregations and average geographic diameter of the aggregations in layers 0 – 20 cm, between the lines of each culture; and the dry matter of cultures. The utilized methodology for the stability evaluation of aggregations followed accordingly to the Traditional Method of wet sieving from Kemper and Chepil (1965). Obtained data were submitted to the variance analysis (ANOVA), and to the comparison between treatment averages the Tukey test was utilized, with the level of probability of 5%. As for the species effect of cover plants on the aggregations of soil on the layer 0 – 10 cm, the treatments significantly differed only at the Class 5, where fallow treatment presented higher percentage of aggregates in the Class. On the 10 – 20 cm layer, the treatments significantly differed only in Class 4, where the fallow treatment presented higher percentage of aggregates in the Class. The DMP values had not significantly differences in none of the layers. On the 0 – 10 cm layer the greater DMG values were observed on the sorghum treatment and on the 10 – 20 cm layer, the sudan grass treatment presented better results. Density, total porosity, micro porosity and macro porosity values did not significantly differed between treatments. The sorghum presented better dry matter production per hectare.