Biomass production and protein content of semiarid grasslands in western Spain over a 20‐years period.

Abstract

The ‘dehesas’ are savanna-like semiarid grasslands typical of western Spain. Over a 20-years period, from 1986 to 2005, biomass production and protein content of ‘dehesa’ pastures in the province of Salamanca (western Spain) was analysed. Herbage samples were collected at the end of spring, in several locations (between 5 and 30, depending on years), at two different topographic positions (upper and lower slope zones). Biomass production ranged between 50 – 214 g DM m-2 in the upper slope zone, and between 148 – 419 g DM m-2 in the lower slope zone. The mean over the 20-years period was 125 g DM m-2 in the upper zone and 287 g DM m-2 in the lower zone. The protein content ranged between 79.8 – 111.3 g kg-1 in the upper zone, and between 85.7 – 144.2 g kg-1 in the lower zone. The mean across years was 96.5 g kg-1 in the upper and 116.4 g kg-1 in the lower zone. Interannual variations in biomass production and protein content of upper and lower zones were correlated. A significant correlation (P<0.05) was found between biomass production and annual precipitation.