Using Grasses Morphogenetic Variables for Natural Grassland Grazing Management

Using Grasses Morphogenetic Variables for Natural Grassland Grazing Management

In a perspective of ecologically sustainable agriculture, culturally accepted and economically feasible, natural pastures fits as one of the best options for Southern Brazil region. This study assessed the feasibility of rearing beef heifers from 12 to 18 months of age in natural pasture during its growing season (173 days). We evaluated two rest intervals in a natural pasture managed under rotational grazing. Intervals were defined based on the average thermal sum (degree-days) that fits to leaf expansion duration (average of two leaves) of native species of two grasses functional groups, according to Cruz et al. (2010). Only grasses were included in these groups considering their contribution above 65% of forage mass and also their ranking on two functional traits, specific leaf area and leaf dry matter content as reported by the above authors. One group was called resources’ capture functional group, favoring prostrate species with fast biomass accumulation (e.g. Axonopus affinis, Paspalum notatum) and the other resources’ conservation group, favoring tufted species efficient in conserving soil nutrients with higger standing biomass but lower accumulation rate (e.g. Aristida laevis, Saccharum angustifolium).

The trial aims to incorporate a functional approach into management schedules for increasing grazing efficiency of natural grasslands production without losses in its biodiversity.