Soil type largely influences root distribution. Heavier or more compacted soils tend to make root penetration more difficult and limit lateral root growth. However, very little is known regarding the influence of water in the root distribution. In a study carried out in Kenya, the effect of irrigation and mulching (soil coverage) using banana rejects on the distribution of Arabica coffee roots was evaluated for 20 years (Bull 1963). It was observed that irrigation diminishes the main root deep penetration (almost 0.5 m smaller, 20% of the maximum length observed) and also the development of primary (> 5 mm of diameter) and secondary roots in the lower layers. However, there was an increase in the lateral length of secondary roots. Mulching increased both depth and lateral growth, forming a net of thin roots close to the
soil surface. The combination of both treatments provided better development of the roots, even when the main root growth decreased by 0.5 m.