ABSTRACT
E¬ciency of nutrient application is one of the major factors a¦ecting the overall e¦ectiveness of a fertilizer program. ¤ere are a number of ways that the e¬ciency of fertilizer use can be measured, such as the percent of the applied nutrient taken up by the plant or the increase in crop yield per unit of applied nutrient. But regardless of the measure used, a number of interacting factors determine the e¬ciency of a given fertilizer application. ¤e relative mobility of the nutrient of concern in the soil is foremost in importance. Nitrogen (N) is an excellent example of a nutrient that is mobile in the soil and easily lost from the root zone. Devising an application system that can provide N to the crop when it is needed is the challenge in many cropping situations. Sulfur, B, and Cl are other nutrients considered to be mobile in soils. Compared to N usage, uptake of these nutrients is rather small. However, management decisions regarding time and method of application may still be needed to ensure optimum utilization.
