Cacao Developmental Pattern, Soil Temperature and Moisture Variation as Affected by Shade and Dry Season Drip Irrigation

Abstract

Field experiments were conducted in Akure and Oda communities in Ondo state within the rain forest zone of Nigeria between 2010 and 2012. Single and combined effects of shade and irrigation were investigated on soil temperature, soil moisture variations and cacao seedling development and establishment on the field. The treatments involved included plantain shade alone, dry season irrigation alone, plantain shade + dry season irrigation and the control. Seedling vigor in terms of plant height, number of leaves and basal stem girth were significantly higher under no shade + irrigation compared to those obtained in the control plots. No significant difference in the basal stem girth of the cacao seedlings and the number of leaves produced between no shade +irrigation and shade + irrigation at the first nine months of the experiment. Soil temperature was significantly higher in the unshaded plots compared to other treatments. Shade alone and the combination of shade + irrigation was found to significantly reduce soil temperature and enhanced seedling survival compared to the non-shaded control plots. The results indicated a significant difference between the irrigated plots with shade and the unshaded control. Shaded plots + irrigation enhances soil temperature maintenance within the range of 26-32ºC throughout the four months of dry season and also improve percentage seedling establishment from less than 61.5% under the control plots to 99.12% under irrigation alone and irrigation + shade. Percentage seedlings survival was highest under irrigated plots with no record of stand mortality as they suffer less of moisture stresses during the dry season as recorded under non irrigated plots.