MEADOW PRODUCTIVITY RELATED TO SOIL MOISTURE AND THERMAL TIME IN SOUTHERN PATAGONIA, ARGENTINA

Abstract

In Southern Argentine Patagonia, meadows are wetland ecosystems that require integrated grazing management, in which water dynamics, climatic components, and soil and vegetation characteristics are crucial factors for maintaining ecosystem functionality. The objectives of this study were to characterize and relate the productive parameters of the wet and dry meadow sectors to soil moisture and thermal time. Plant height, accumulated aerial biomass (AAB), live biomass (LB), dead biomass (DB), live AAB, daily vegetation growth rate (DGR), daily vegetation regrowth rate (DRR), soil moisture (SM), water table depth (WTD), and thermal time (TT) were determined monthly from October to April during three consecutive growing seasons in two extra-Andean meadows. AAB was analyzed using a factorial arrangement in a completely randomized design with three replications. Plant height and biomass were related to TT and SM by polynomial regressions, while DGR, DRR, and LB were related to SM and TT using multiple regression models. AAB in the wet sector was higher than in the dry sector from December to April, whereas biomass in both sectors was associated with TT and SM. In the wet sector, DGR, DRR and LB varied with SM, which was negatively associated with WTD. Overall, across both wet and dry meadow sectors, soil moisture emerged as the most relevant variable for guiding optimal management recommendations.