Farm-Scape, Episode 1579

Computer models developed at the University of Manitoba are helping determine the capacity of Manitoba soils to absorb phosphorus and to calculate how much of that capacity is being used.

A department of soil science phosphorus management study, funded by the Manitoba Livestock Manure Management Initiative, was completed in June.

Its goals were to determine the ability of Manitoba soils to absorb phosphorus, to develop mathematical equations to calculate that ability and to determine the degree of saturation.

Associate Professor Dr. Wole Akinremi says the biggest factors affecting phosphorus absorption capacity are soil properties and management practices.

"What we find is that the ability of Manitoba soils to retain phosphorus differs from soil to soil.

The clay soils have high ability to retain phosphorus where as the sandy soils, both in the wet sand and in the dry sand have very low ability to hold phosphorus.

The advice to farmers is to know their soil because this boils down to phosphorus management, manure management, fertilizer phosphorus management.

If we are dealing with soils that are course texture, we have to watch how much phosphorus and how much manure we put on those soils because the ability of those soils to retain that P is very limited.

It doesn't take much to exceed the ability of those soils to retain phosphorus so the risk of loss on those soils is very high.

For clay soils, the capacity of those soils to take in phosphorus and retain phosphorus is high.

Those soils have better capacity to receive phosphorus and manure and phosphorus fertilizer without undue risk of phosphorus loss."

Dr. Akinremi says, based on the results of the study, scientists have created mathematical equations to calculate the soil's ability to absorb phosphorus based on its properties and to calculate the amount of absorption capacity that is already being used.

For Farmscape.Ca, I'm Bruce Cochrane.