Abstract
In the French West Indies, intensive crop systems such as banana (Musa sp.), pineapple (Ananas comosus), and sugar cane (Saccharum officinarum) on steep lands could seriously damage the environment through water erosion and chemical pollution, because of the use of high chemical inputs under aggressive tropical rainfalls. Therefore, on the volcanic soil or Nitisol (FAO classification) of Martinique, a field study based on 10 runoff plots (100-200 m2) located on 10, 25, and 40% slopes was established for the assessment of the effect of these crop systems and slope on the environment. In spite of an average rainfall variation, the results of 1999 and 2000 were similar and they allowed an assessment of the treatment behaviours, as well as the runoff and soil loss behaviour. Indeed, the erosion-slope relationship is a nonselective linear erosion, which could turn from a rill erosion into a creeping one when the slope increases. The study also showed that when cultivated treatments are mulched by organic crop residues, runoff and soil loss are weak, even on a steep slope. Mulching is therefore proposed in the soil management system to reduce soil erosion on this tropical volcanic soil.
