Pakistani Soils are calcareous in nature and about 90% Pakistani soils are deficient in phosphorus. Most Crops, including maize, grown on such soils suffer from phosphorus deficiency with severe yield losses. Moreover, phosphorus requirement of recently introduced maize hybrids differ from that required by indigenous maize varieties of Pakistan. This book describes the phosphorus adsorption characteristics of a calcareous soil. Critical internal and external phosphorus requirements are also illustrates. Conclusively, this book is useful for researchers and students of soil fertility and plant nutrition in planning and conducting research trials on related topics.