Enhancing acquisition and utilization of applied phosphorus by crops will help to conserve limited rock phosphate reserves and minimize off-site transport of applied phosphorus. Understanding plant root growth and the release of substances that can solubilize mineral and organic phosphorus in response to phosphorus deficiency will enhance crop recovery when phosphorus is applied. Improved technologies to quantify plant-available phosphorus from mineral and organic soil phosphorus reserves will enhance the accuracy of fertiliser and manure phosphorus recommendations. This chapter discusses interactions between phosphorus management (phosphorus rate, source timing, and placement) and diverse cropping systems and climate and how these interactions are essential to efficient utilization of phosphorus resources.