Avaliação da degradação de pasto nativo embasada em parâmetros de solo

Abstract

ABSTRACT: In the state of Alagoas, the native pastures benefit animal production and it is also important for production low cost, for resilience of grasses to the region's edaphoclimatic conditions, and for forage species diversity. However, both the knowledge about the spontaneous agrostological flora of the semi-arid and the degradation process are still incipient. The study evaluated the degradation stage of a native pasture at Cacimbinhas - AL using soil parameters. The analysis associated data about fertility, terrain slope, two vegetation cover methods - Stocking (1994) adapted by Magalhães et al. (2004) and squared, and history of land use and management. The native fodder was collected and identified by morphological analysis. The pasture is mainly composed by Digitaria horizontalis willd, common name milhã, that grows in low fertility soils. Excessive mobilization due to integrated crop-livestock system combined with overgrazing cause compaction, superficial erosion and compromise the forage development. The soil cover data associated with fertility and management data allowed the identification and understanding of processes dynamics that establishes the degradation of the native pasture. By the square method, only 7,8% of the area was uncovered soil and 23,18% was milhã grass. These values diverge from the Stocking method that presented 8% of milhã grass, 89.5% of uncovered soil and 2,5% of invasive weeds for the area. The Stocking method highlighted the uncovered areas due to the small area sampled in this technique. The pasture is characterized by the level 3, strong degradation grade. Reduced soil fertility, high number of animals with intense stomping and the plant consumption threatens the sustainability of this pasture. 

KEYWORDS: Degradation, semi-arid, forage.