Sheep grazing preferences on pastures in the Montado: effect of soil amendment and grazing systems

Abstract

The aim this study was to evaluate the effect of dolomitic limestone application (uncorrected, U and corrected, C) and two sheep grazing systems (continuous, CG and deferred, DG) in preferred grazing areas, in natural pastures. The stocking rate was of 7 sheep/ha in CG and 16 sheep/ha in DG. In 4 plots of 1ha each, four treatments were constituted: T1 (UCG); T2 (UDG); T3 (CDG); and T4 (CCG). The study was carried out in Mitra farm at the University of Évora, between March and May of 2021. In beginning of March, mid-April, and end of May the animals were observed on the field and their location was recorded. The observation was carried out, in two consecutive days, by trained observers equipped with binoculars, from sunrise to sunset, every 10 minutes. In each plot, 12 georeferenced areas were defined, representing different pasture botanical communities. The day before observation, pasture height was measured. The results showed similar grazing patterns between treatments, with preference for lower altitude areas. Throughout the pasture's vegetative cycle, the grazed areas were expanded to higher altitude areas (April), then returning to lower altitude areas at the end of May. The height of the pasture was not a limiting factor that led animals to expand their grazing areas. Pasture botanical species did not prove to be decisive in the sheep's grazing choices. The results suggest that the application of dolomitic limestone and the grazing systems tested did not influence the sheep grazing preferences when pasture growth rate is maximum.