Variation of interception loss with different plant species at the University of Agriculture, Abeokuta, Nigeria

Abstract

Interception studies of six plants groups were carried out at the campus of University of Agriculture, Abeokuta in Nigeria, using three different sample sites. These sites were the Arborea plantation, cashew plantation and College of Environmental Resources Management premises of the University. The field work was carried out between 15^th June and 28^th September, 2009. Of the 22 rainfall events recorded for each plant species, at least 13 produced measurable through fall and stem flow and a maximum of 18 measurable records. Through fall showed a very strong linear correlation against daily rainfall for different plant species. The r² values varied between 0.841 (Teak) to 0.963 (Gmelina). This trend also followed for stem flow since without rainfall no stem flow. This was not the case for interception loss which showed only a moderate correlation against rainfall amount for each plant species with r² value ranging from 0.058 (Teak) to 0.716 (Neem). This implied an inverse relationship between interception rate and rainfall amount. Interception ratio for coniferous plants was more than deciduous plants, both having average values of 32.01 and 26.54% respectively when interception loss was considered per storm or event. But when considered at the end of observation, deciduous plants had more interception ratio than the coniferous plants with average interception values of 26.54 and 32.01% respectively. At the end of the observation, the interception loss for each plant, Pinus leuceana sp, cashew, Neem, Gmelina and Teak were 18.77, 21.04, 31.96, 26.16, 11.1 and 38.05% respectively. The values changed when considering average interception loss per storm and the values for the plants species as arranged above were 28.60, 30.18, 31.96, 37.26, 17.78 and 29.89% respectively. This showed that interception loss varied from one plant species to another. With these, one will know which can best be used for conservation purpose.

Key words: Through fall, stem flow, canopy.