Methodological Proposal for the Analysis of Spatio-Temporal Variability of Forage Value on Paspalum quadrifarium-Dominated Grasslands

The Flooding Pampa is a subregion of Argentina where there is a plant community whose physiognomy is defined by tall-tussock grasses dominated by Paspalum quadrifarium. The hypothesis is that their floristic diversity allows a continuous forage supply, and this happens in a different way in each type of vegetation patch. The aim is to analyze the temporary and spatial variability of the forage value of these tallgrass prairies by the development of an index. Samplings were carried out throughout the year, for two consecutive years in three different sites. The index is made up of four components: Indicators of Cover/Abundance, Digestibility, Accessibility, and Phenological Stage of the vegetation. The site indexes ranged between 0.05 and 0.54, with minimum values in winter and maximum values in spring. Overall, the lax pajonal showed higher values than the dense pajonal, and within the latter one, the values of the short grass matrix were usually higher than those of the sector with dense patches dominated by P. quadrifarium. This index is useful to visualize the environmental conditions, seasons, vegetation patches and main species that influence the forage condition of a grassland ecosystem