Theme 1: Grassland Ecology
Description
Tussock grasslands of Festuca humilior and Calamagrostis vicunarum cover a significant extension of the central Andes of Peru, constituting a plant association highly appreciated by cattle ranchers. The objective of this research was to estimate the cumulative impact of the level of use of the key grasses Festuca humilior and Calamagrostis vicunarum on plant height, vigor, and weight. This study was conducted in a humid grassland of regular condition located at 4186 masl in the Puna ecoregion. The variables evaluated were: plant height, basal and canopy diameter and plant weight. The experiment lasted two years in which individual plants from both species were cut every four months. The vigor resulted from the regression of the weight (g) and the volume (cm3) of the plant. Height (cm) was the length from the soil surface to the flag leaf. The experimental design was a randomized block design with a 2x3 factorial arrangement, two species and three height removal levels: zero, 40 and 80%. The height, vigor and weight of Festuca humilior and Calamagrostis vicunarum decreased in response to increasing use levels, but the changes were more evident in Festuca than in Calamagrostis. While the decrease in the evaluated variables was constant for Festuca humilior as the level of use increased, Calamagrostis also decreased, but to a lesser extent, remaining almost unchanged when biomass removal levels changed from moderate to heavy, suggesting that this species was more tolerant to grazing. The results helped explaining why in fields dominated by Festuca humilior and sub-dominated by Calamagrostis vicunarum subjected to intense grazing, dominance relationships change in favor of Calamagrostis, a species of lower forage value than Festuca humilior. It is recommended to manage the grazing system under a low-intensity and low frequency regime.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Impact of Level of Use on Plant Vigor and Weight of Festuca humilior and Calamagrostis vicunarum
Tussock grasslands of Festuca humilior and Calamagrostis vicunarum cover a significant extension of the central Andes of Peru, constituting a plant association highly appreciated by cattle ranchers. The objective of this research was to estimate the cumulative impact of the level of use of the key grasses Festuca humilior and Calamagrostis vicunarum on plant height, vigor, and weight. This study was conducted in a humid grassland of regular condition located at 4186 masl in the Puna ecoregion. The variables evaluated were: plant height, basal and canopy diameter and plant weight. The experiment lasted two years in which individual plants from both species were cut every four months. The vigor resulted from the regression of the weight (g) and the volume (cm3) of the plant. Height (cm) was the length from the soil surface to the flag leaf. The experimental design was a randomized block design with a 2x3 factorial arrangement, two species and three height removal levels: zero, 40 and 80%. The height, vigor and weight of Festuca humilior and Calamagrostis vicunarum decreased in response to increasing use levels, but the changes were more evident in Festuca than in Calamagrostis. While the decrease in the evaluated variables was constant for Festuca humilior as the level of use increased, Calamagrostis also decreased, but to a lesser extent, remaining almost unchanged when biomass removal levels changed from moderate to heavy, suggesting that this species was more tolerant to grazing. The results helped explaining why in fields dominated by Festuca humilior and sub-dominated by Calamagrostis vicunarum subjected to intense grazing, dominance relationships change in favor of Calamagrostis, a species of lower forage value than Festuca humilior. It is recommended to manage the grazing system under a low-intensity and low frequency regime.
