Effect of mound-building termites on soil physicochemical properties and sugarcane stalk heights

Abstract

This study investigated soil factors responsible for localised patches of enhanced sugarcane growth on the remains of termite (Macrotermes natalensis) mounds observed on predominantly coarse-textured soils (weak sands) of KwaZulu-Natal province, South Africa. Soil samples (0–20 cm depth) were collected and sugarcane stalk heights determined from termite-mounds and their immediate surrounds located in the North Coast and Midlands South regions (three per location). Mean clay and total carbon levels were 45 and 3.9 g kg⁻¹ higher, respectively, in the termite-mounds relative to the immediate surrounding soils. In addition, termite-mound soil had lower acid saturations and higher pH, calcium, magnesium, zinc, nitrogen and silicon contents than surrounding soils. Although interactions between sampling regions and position (termite-mounds vs surrounds) showed no signifi- cant differences, a greater impact of termite activity associated with higher clay content was observed on the North Coast. These results suggested that increasing organic matter facilitated by activity of termites may improve the fertility of the ‘weak sands’ and thus increase the growth of sugarcane.