Ecological Characteristics of Para Rubber (Hevea brasiliensis Muell. Arg) Productivity in the Niger Delta Region of Nigeria

Abstract

The Niger Delta region is the rubber belt of Nigeria, and rubber production in the area which is dominated by smallholder plantations, is characterized by low latex yield, due mainly to ageing plantations, unsuitable agronomic practices and high cost of labour. Differences in soil and weather attributes of the area require that farmers adopt location-specific management practices in order to increase yield. Consequently, the relationship between medium-term latex yield of rubber and soil and weather attributes were studied in three rubber growing areas of the Niger Delta, with a view to assessing the fertility status of soils supporting rubber and determining the critical weather factors so as to make recommendations on best management practices. Weather data for estate plantations located in Calabar (latitude 5º 7’N and 8º 18’ E), Nko (latitude 5º 5’ N; 8o 11’ E), and Uyo ((latitude 5º 0’ N; 7º 10’E), spanning a period of 20 years (1993-2012), were obtained from the Nigerian Meteorological Service (NIMET) and subjected to multiple linear correlation and regression analysis with archival latex yield data from the various estates covering the same period. The minimum amount of rainfall received was 2148.7 mm/annum spread over a period of 135 days at Nko, while a maximum of 3968.7 mm/annum of rainfall spread over 143 days was received in Calabar. Rainfall intensity varied widely across the three locations, while the relative humidity was high, but similar across the locations and the highest ambient temperature of about 32ºC was at the Nko plantation. There was high correlation between weather variables and latex yield. The high negative correlation of latex yield with rainfall in Calabar and Uyo suggest that these areas experience excessive rainfall which might result in the prevalence of fungal diseases and frequent disruption of tapping operations. Maximum temperature correlated negatively with yield at Nko implying that measures to reduce evapo-transpiration such as mulching the base of trees and cover cropping should be adopted in this area. The soil texture was sandy loam in Calabar and Uyo, and sandy clay loam at Nko, and although the pH across the estates was within the recommended range of 4.0 - 6.5, the soils at Calabar and Uyo requires liming for sustained high productivity.