CHANGES IN CARBON AND NITROGEN FRACTIONS OF GRAMINACEOUS STRAWS AFTER BURNING

Changes in the carbon (C) and nitrogen (N) fractions of graminaceous straws were measured after their combustion under both laboratory and open-air conditions. Volatilization of C and N increased with increasing combustion, and losses exceeded 90% when combustion was nearly complete. The small proportion of total N already present in the inorganic form in straw was not increased during the ashing process. Burning of plant residues decreases the amount of organic microbial substrates returned to the soil, and hence directly affects soil biological processes. In addition, the volatile loss of nutrients occurring during the burning of vegetation must be considered in the long-term nutrient economy of ecosystems, and hence in the full evaluation of fire as a management tool. © 1979 Martinus Nijhoff, The Hague/Kluwer Academic Publishers.