Resumen

MASSA, Ernesto; GONZALEZ, Gabriela Laura  y  ROSSI, Carlos Alberto. Evaluation of the natural pastureland in a silvopastoral system with willow (Salix humboldtiana). Pastos y Forrajes [online]. 2016, vol.39, n.3, pp.100-105. ISSN 0864-0394.

The objective of this study was to determine, in the pasturelands of the willow forest, the net aerial primary productivity (NAPP), the seasonal botanical composition of the functional groups and the estimated seasonal cattle receptivity. The total annual NAPP was 5 210,6 kg DM/ha/year, from which 2 544,8 kg DM/ha occurred in the summer, with statistically significant differences with regards to the other seasons: spring 1 669,3 kg DM/ha, winter 626,2 kg DM/ha and autumn 370,3 kg DM/ha. The botanical composition of the pastureland per functional group showed that more than 57 % of the biomass of the annual NAPP was dominated by grasses; the highest participation percentage was recorded in the summer, in which this genus represented 80 % of the biomass. On the other hand, the wide functional group of latifoliate plants remained constant with regards to the species present in the biomass throughout the year. The summer was the season with the highest cattle receptivity, with 1,17 CE ha^-1 day^-1. The spring was ranked second, with a receptivity estimation of 0,76 CE ha^-1 day^-1. On the other hand, the winter showed a carrying capacity of 0,29 CE ha^-1 day^-1, and the autumn, of 0,17 CE ha^-1 day^-1. It is concluded that the willow forest is a pastureland that should be grazed as summer forage resource.

Palabras clave : stocking rate; forages; net primary productivity.