An Analysis of Vegetation as a Resource in South-Eastern Nigeria
Proceedings of an International Symposium organized by the Laboratory of Soil Fertility and Soil Biology, Katholieke Universiteit Leuven (K.U. Leuven) and the International Institute of Tropical Agriculture (IITA) and held in Leuven, Belgium, 4-6 November 1991
A long-term study was initiated in 1988 in two fallow systems: a planted Dactyladenia (Acioa) barteri system at Mbaise and a natural bush fallow at Umuahia in south-eastern Nigeria. The planted fallow systems consisted of rows of D. barteri spaced 2m apart and lengths of fallow periods ranged from 1 to 3 years. The natural bush fallow periods ranged from 1 to 5 years old. Analysis of the natural bush fallow showed that Dactyladenia barteri, Anthonotha macrophylla and Dialium guineense dominated the vegetation. Stems with a girth of over 20cm contributed most to the stem basal area in the natural bush fallow in all fallow periods. In the planted fallow, a stem basal area of 20 m2/ha was observed only in the 3-year-old fallow. Girth class distribution in the D. barteri field after the second year of fallow was more uniform than in the natural fallow, indicating less interference with the vegetation in the former. For the same fallow length, the amount of litter produced and the nutrient composition were identical in the two systems. Soil analysis showed that pH, soil organic C and total N content in the soil under planted fallow did not change, but extractable P increased with fallow length. The authors concluded that the two fallows systems are potential means of restoring soil fertility through litterfall and pruning application.