|MENDONCA, E - UNIV. OF VICOSA, BRAZIL
Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 9/30/1998
Publication Date: N/A
Technical Abstract: Agroforestry systems have been introduced in the Brazilian tropical highland areas to increase erosion protection and soil fertility. There is a lack of data about the chemical and physical characteristics and decomposition rates of pruning residues from the systems' main plants. The objectives of this study were to (i) characterize prunings from the main plants of an agroforestry system; (ii) determine the characteristics effects on the prunings' decomposition patterns; (iii) assess the effect of mixing leaves of different species on decomposition rates; and (iv) propose a decomposition index for the residues studied. The pruning materials have high polyphenol and lignin contents, high C:P ratio, and low Ca, Mg and K contents. The projected surface area-to-mass ratio and water sorption characteristics of the prunings need to be considered when choosing the plant species to be introduced in an agroforestry system. The low decomposition rates of the prunings were related to the (lignin + polyphenol):N ratios and the Ca, Mg and P contents. The decomposition rate may be increased by mixing leaves of some species. The study also highlighted the capability of CENTURY to simulate the decomposition of tropical pruning species as measured in the laboratory.