Panama disease leaves and progresses to younger leaves until the entire plant dies. Gros Michel was the only type of banana eaten in the United States from the late 19th century until after World War II. From the beginning, however, a serious disease was present in the banana plantations of Central America. The problem was first diagnosed in Panama after which it was named. Over several decades, the fungus spread from Panama to neighboring countries, moving north through Costa Rica to Guatemala and south into Colombia and Ecuador. The banana industry was in a serious crisis, so a new banana thought to
Crop residue above-ground plant in the first year. There is some residual benefit of fertilizers as the crops take up a small amount of the nutrients two and three years later. Fertilizer placement can significantly affect the efficiency of crop uptake. The impact of residue placement (buried by tillage or left on the surface in zero tillage) on nutrient cycling and efficiency is under study. Thus, the practice of calculating the fertilizer equivalent value of the nutrients in crop residue is a reasonable guide to estimating the partial value of crop residues. Crop residue There are two types of agricultural crop residues.