Computer models developed at the University of Manitoba are helping determine the capacity of Manitoba soils to absorb phosphorus and to calculate how much capacity is being used. A study was done to determine the ability of Manitoba soils to absorb phosphorus (P), to develop mathematical equations to calculate the ability and to determine the degree of saturation. The biggest factors affecting P absorption capacity are soil properties and management practices. Clay soils have a high ability to retain P where as the sandy soils, both in the wet sand and in the dry sand, have a very low ability to hold P. Soils with a coarse texture have a limited ability to retain P. It doesn’t take much to exceed the ability of those soils to retain P so the risk of loss in those soils in very high, while clay soils can receive P and manure and phosphorus fertilizer without much risk. Scientists have created mathematical equations to calculate the soil’s ability to absorb P based on its properties and to calculate the amount of absorption capacity that is already being used. It is important for farmers to know their soil because this affects phosphorus management, manure management and fertilizer phosphorus management.