EFFECT OF SHADING ON AGRONOMIC AND STRUCTURAL CHARACTERISTICS OF MOMBAÇA GRASS IN AGROFORESTRY SYSTEM IN THE CERRADO-AMAZON ECOTONE.

The search for sustainability in integrated production systems is a constant challenge, especially when it comes to balancing the levels of shading provided by trees in agroforestry systems. The objective of this study was to evaluate the effects of three shading levels (0, 30 and 60%) casted by native Babaçú trees (Attalea speciosa, Mart) on the agronomic and structural characteristics of Mombaça grass in the ecotone Cerrado-Amazon. A total area of 3 ha was stratified into 36 subdivisions measuring 270 m² each, in order to collect agronomic samples from the three shading levels, totaling 108 experimental units, where the structural and agronomic characteristics of Mombaça grass were assessed. Increased shading leads to reduction in tiller population density, forage volumetric density, leaf area index and yield and proportion of morphological components of Mombaça grass, reducing forage yield. The 65% and 78% reduction in tiller population in areas with 30 and 60% shading, respectively, in comparison to full sun light exposure, was the main factor in the reduced productivity of the grasses managed in the agropastoral system. Therefore, Mombaça grass should be managed at a level of 30% shading, which can be considered adequate to maximize forage yield, balancing the benefits of soil and water conservation with the possible negative impacts on forage production. [ABSTRACT FROM AUTHOR]