Daily and seasonal variations of soil respiration and contributions of above-and below ground litter in the rain forest of south western Cameroon in Central Africa

Soil respiration in plots either with natural litter or without but on which was added above ground litter was examined in order to evaluate its periodic variability and the contributions of above and below-ground litter to the total soil respiration. This work was conducted within a one year period in the South western region of Cameroon. During the day, the mean soil respiration reached a seasonal peak rate (917 ± 19 mg CO_2 m^(-2) h^(-1)) in May (rainy season) and a trough (345 ±96 mg CO_2 m^(-2) h^(-1)) was observed in February (dry season) indicating a clear relation with soil moisture. The maximum diurnal values of soil respiration appeared in May between 8 and 10 am and in February between 14 and 16 pm. This evolution was proportional to air and soil temperatures. The contribution of aboveground litter to the total soil respiration was in average 34 to 43% while that of below ground litter was 57 to 66% in which is included probably about 10 to 20% of labile carbon pool. The exclusion or addition of litter to the soil surface thus modified the total soil respiration.