Decomposition and nutrients release pattern of leaves, stems/vines and roots of selected leguminous and non-leguminous plant species

Decomposition and nutrients release pattern of leaves, stems/vines and roots of leguminous plants (Pueraria phaseoloides and Centrosema brasilianum) and non-leguminous plants (Chromolaena odorata and Panicum maximum) were examined for a period of 98 days. The decomposition rate declined in the order R maximum> C. odorata > R phaseoloides > C. brasilianum. On the 98 day, between 63% and 71 % of stems/vines only had decomposed. The % mass of the remaining materials were in the order of C. odorata > R phaseoloides > C. brasilianum > R maximum and the decomposition rate was in the reverse order. The mass loss and decomposition rates of the parts of the plant species followed the initial N concentrations of the residues in the order of leaves > roots> stems/vines. The initial N contents in plant residues varied from 0.42 to 3.19 g/kg and P from 0.03 to 0.27 g/kg. The pattern of N remaining in the stems/vines of the species at 98 days after placements (DAP) was in the order R phaseoloides (49%) > C. odorata (42%) > C. brasilianum (41%) > R maximum (36%). The chemical composition of the residues shows that the leaves are richer in N and P than the roots and least in stems/vines in the order C. odorata > C. brasilianum > R phaseoloides > R maximum. A direct relationship was observed between the initial N contents of the residues and initial polyphenol contents (r = 0.72, P < 0.01), but no relationships with the P content of the residues. The data reported in this study shows that the decomposition patterns of above and below -ground residues of leguminous and non-leguminous plant species could have positive effect on nutrients requirement of crops. (author)