Herbage production of Mediterranean grassland under seasonal and yearlong grazing systems

Abstract

Data from 2 consecutive grazing experiments conducted over 7 years on a Mediterranean type grassland were used to calculate forage consumption by herds of beef cattle maintained at different stocking rates and in different grazing systems. In the first experiment the animals were on the experimental range for 8 months of the year; in the second, grazing was yearlong. Total production of herbage mass was estimated from these data and from the residual litter in the paddocks at the end of the dry season. Production of dry herbage mass varied between 2,600 and 3,800 kg/ha, with a mean and SD of 3,060 +/- 300 kg/ha. While variation between years was relatively small but significant (P<.01), the effect of stocking rate or grazing system (seasonal, yearlong) was smaller and not significant. It is concluded that the attained level of herbage production of Mediterranean grassland on relatively shallow basaltic protogrumosols is not sensitive to total precipitation over a very wide range or to grazing system. It may be dependent on the availability of nutrients, especially nitrogen, and the seasonal distribution pattern of available soil moisture in a restricted rooting zone.