Assessment of Potassium Status of Soils-recent Developments

The field of soil fertility deals mainly with the mineral nutrition of plants in which both the supplying power of the soil and the ability of the plant to absorb nutrients, are of importance. The soil may be considered as. the rooting medium which provides water and mineral nutrients necessary for plant growth. Ionic equilibria play a fundamental role in fertility relationships because they govern the ability of the soil to supply a particular nutrient. Nutrient uptake is the resultant of the reaction of the plant to a given nutrient supply and is influenced by both biological and soil factors as illustrated in Figure 1.