Dry Season Decomposition of Leaf Litter from Five Common Plant Species of West Africa

Abstract

The rates of decomposition of litter from five plant species common to West Africa namely: Chromolaena odorata (Siam weed), Anacardium occidentale (cashew), Acioa batteri, Imperata cylindrica (spear grass) and Pentaclethra macrophylla (oil bean) were investigated in the laboratory and the field during the dry season using respiration and litter bag techniques. There were significant differences (P< 0.05) amongst the species in the total carbon lost due to respiratory activities and this followed the order Imperata > Chromolaena > Anacardium > Pentaclethra > Acioa. Unexpectedly, the particle size of litter (ground versus unground) did not affect the rates of respiratory activity in any regular pattern although the unground samples were in nylon mesh bags. Possibly, fungi were the main agents of decomposition since by their mycelial habit, they ramify into a substrate. Under adequate moisture conditions, the highest amount of litter decomposed—58.3%, 52.3% and 34.3% were obtained with Chromolaena, Imperata and Anacardium respectively. The corresponding percentages of 63.2, 37.0 and 35.6 under field moisture stress would suggest for Chromolaena and Anacardium a compensatory faunal contribution to the decomposition process. Chromolaena increased the soil pH by as much as one unit. In carbon cycling in our ecosystems, Chromolaena appears to have the added advantage that it could ameliorate the acidity of our soils to the advantage of most crops.