ABSTRACT
Phosphorus becomes the master key to agriculture because lack of available P in soils limited the growth of both cultivated and uncultivated plants. The adsorbed fraction of soil P is often considered to be the labile soil P. The earth supply of P can be divided into P that is sufficiently concentrated to be mined and the P which exists in the soil and other geologic material where the P concentration is too low to be mined but the P becomes slowly soluble for plant or other biological growth. A number of equations have been developed to describe quantitatively the distribution of P between the adsorbed and solution phases. Strongly acid soils are found in many areas of the world, including the southeastern US Fertilizer recommendations are specific to the area and crop, and only general guidelines will be given here. It is important for a farmer to have realistic yield goals when planning a fertilizer program.
