Stability against pyrolytic cleavage in the assessment of recalcitrant C forms in Southern African Soils

Substantial loss of organic matter (OM) as a result of clearing and cultivation is one out of the main factors contributing to declining productivity in savannah soils. Nevertheless, very little research has been carried out on the mechanisms controlling soil OM accumulation in these soils characterized by low activity clays and limited physical and chemical fertility. The present study with a characterization of the humic acids (II.As) and humins in representative savannah ems under sandy and clay soils in Northern Botswana. The main objectives are to check for distinctive features of the OM that could inform on the major C sequestration mechanisms in the site under study, and look for differences between C forms in virgin and cleared savannah fields.