The above-ground net primary production was estimated for two areas of campo sujo of cerrado, one unburnt and the other initially burnt. Production was estimated by using diferences in the above-ground biomass which was sampled at quarterly intervals. The study was planned to coincide with the wet season, between october 1980 and april 1981. The above-ground net primary production of the herbaceous layer in the burnt area (176 ± 33 g m-2) was higher than in the unburnt area (108 ± 26 g m-2). The efficiency of the conversion of solar energy into dry matter was 0,12 ± 0,0,03% for the unburnt campo sujo and 0,19 ± 0,04% for the burnt campo sujo. The quartely production figures had significative correlation with precipitation and soil water, showing that the water is a limiting factor to the herbaceous layer primary production in campo sujo of cerrado.
primary production; fire; savanna