The importance of essential mineral nutrition on plant growth and development is indisputable. Plant productivity and yield quality depend to a great degree on plant nutrition (Marschner, 1995; Fageria, 2009; Fageria et al., 2011a). In  nutrient-de‰cient soils (like Brazilian Oxisols and Ultisols), the supply of an adequate amount of essential nutrients increases crop yields of important crops like rice, dry bean, wheat, corn, and soybean by about 40% (Fageria, 2009; Fageria et al., 2011), provided other factors of production (cultivar, soil moisture, control of diseases, insects, and weeds) are at an optimal level. Figure 7.1 shows upland rice response to N fertilization grown on a Brazilian Oxisol. It is clear from Figure 7.1 that nitrogen-de‰cient plants had yellow leaves without tillering. Plant growth was also reduced compared with plants that received adequate rate of nitrogen (right). Similarly, upland rice response to phosphorus is shown in Figure 7.2. Growth and tillering of upland rice was signi‰cantly increased with increasing P rate from 0 to 175 mg kg−1 soil. In Figure 7.3, the root growth of upland rice also improved with the addition of phosphorus to a Brazilian Oxisol. Figures 7.4 and 7.5 show the response of lowland rice and dry bean, respectively, to K fertilization grown on a Brazilian Inceptisol. The growth of lowland rice as well as dry bean was signi‰cantly improved in a quadratic fashion with the addition of K. Similarly, root growth of upland rice was also improved with the addition of potassium compared with control treatment (Figure 7.6). These ‰gures show the importance of nitrogen, phosphorus, and potassium fertilization for the growth of rice and dry bean crops grown on a Brazilian Oxisol and Inceptisol, respectively.