Soil compaction affects the silage quality of sunflower and Paiaguas palisadegrass (Brachiaria brizantha) grown on a Latosol in the Brazilian savanna

摘要

On the basis of the natural seasonality of pastures during the dry season, preservation of forage, especially silage, is necessary. However, the effects of soil compaction within sunflower and grass crop fields on the nutritional quality of the silage produced are unknown. Therefore, the aim of this study was to evaluate the fermentation and nutritional quality characteristics of sunflower silage under both monocropping and intercropping systems [with Paiaguas palisadegrass (Brachiaria brizantha)] under various degrees of soil compaction. A split-plot randomized complete block design was adopted. In the main plots, the treatments were bulk density values affected by the following traffic intensities: 0, 2, 10 or 30 passes of a tractor with tire wheels weighing 4.9 Mg. The subplots involved forage systems composed of sunflower as a monocrop or intercropped with Paiaguas palisadegrass. The fermentation, nutritional characteristics and in vitro digestibility of the silage were evaluated. Under the various aforementioned conditions, the agronomic characteristics of the forage were affected by increased soil compaction, resulting in changes in the fermentation and nutritional characteristics of the silage. The results showed that intercropping with Paiaguas palisadegrass and adequate proportions of sunflower allow good fermentation. This study recommends the adoption of practices that mitigate soil compaction and intercropping because of the increased forage productivity and the possibility of the indirect renewal of the pasture.