The plant rhizosphere should be treated as an indispensable plant organ in influencing an avalanche of crop plant physiological processes. The overall appearance of the rooting system of a plant is referred to as root system architecture (RSA). Soil scientists and plant breeders have made significant efforts in manipulating, inter alia; the structure, depth and functions of plant roots in order to boost the productivity of crops by withstanding both biotic and abiotic stresses. Morphological root characterisation together with other growth and yield parameters under irrigated conditions in a field trial was done using sandy loam soil occupied by a yellow/orange dent maize genotype SC402. Dolomitic lime (calcium magnesium carbonate) was used in the 9 treatments to determine the chemotropic response of maize plant roots to different levels of lime and nitrogen fertilisers. Maize has a moderate terminal root depth of ±30cm with a root divergence angle of ˃ 180⁰. SC402 is an early maturing maize genotype of the 400 series suitable for low rainfall areas of Zimbabwe. It is one of the best yielding variety in terms of above ground biomass as well as kernel yield under both rainfall and soil nutrient – marginal conditions. Its organoleptic orange /yellow colouration due to presence of carotenoids has created a demand for culinary and livestock uses. A linear relationship was observed in the measured agronomic parameters of soil type, texture, depth, type and amount of lime applied in abiotic acidic soil stress conditions induced largely by nitrogen fertilisers. The findings of the study have revealed that morphological markers are more applicable in phenotypic root characterisation under field trials. A linear association was noted to exist between root density and maize growth and yield parameters under the influence of different lime and nitrogen regimes.

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