Coffee husk mulch on soil erosion and runoff: experiences under rainfall simulation experiment

The high erosion rates found in the agriculture land make valuable the use of mulches to control the soil and water losses. Coffee husk (<i>Coffea canephora</i> var. <i>robusta</i>) can be one of those mulches. This paper evaluates how to apply the mulch in order to obtain the best effectiveness. An experimental factorial design 4 × 3 × 2 with two replicates was designed in a greenhouse with a total number of 48 cases. All the samples were deposited in trays of 0.51 m² and applied a simulated rain of 122 mm h⁻¹ during 21 min. The factors examined were the following: four soil classes; three treatments – buried (B), surface (S) and non-residue (C) – and the presence (WC) or absence (WOC) of the soil surface crusting. The coffee husk residue (S and B treatments) reduced runoff by 10.2 and 46% respectively, soil losses by 78.3 and 88.7% and sediment concentration by 77 and 84.4%. The infiltration rate increased on average by 104 and 167%, and time to runoff by 1.58 and 2.07 min respectively. Coffee husk is an efficient mulch to reduce the soil and water losses, although it could not completely cushion the influence of crust