Phosphorus cycling in conservation cropping systems of the Canadian Prairies

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Sustainability of agricultural production on the Canadian prairies requires that the nutrients that are applied to soils are effectively recycled rather than lost to the environment.  Fertilizers also represent a significant input cost to farmers and greater efficiency in their use contributes to better economic returns. Cropping systems on the prairies today are moving towards reduced or zero-tillage, and more land is also receiving application of animal manures.  The forms and transformations of phosphorus in zero-till and manured soils of the Canadian prairies is not as well documented as for nitrogen.  Producers have reported less need for nitrogen fertilizer in these cropping systems and some are now reporting less requirement for added phosphorus. It is hypothesized that phosphorus cycling through organic fractions is more important and needs to be better understood to make appropriate P fertilization decisions in these new systems. The research will identify the important pools of phosphorus present in long-term no-till and manured lands, and the factors controlling phosphorus turnover and bioavailability.