Nitisol, one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO). Occupying 1.6 percent of the total land surface on Earth, Nitisols are found mainly in eastern Africa at higher altitudes, coastal India, Central America, and tropical islands (Cuba, Java, and the Philippines). They are perhaps the most inherently fertile of the tropical soils because of their high nutrient content and deep, permeable structure. They are exploited widely for...