Phosphorus Loss Assessment using PLATO – AgriSuite’s newest calculator

May 27, 2020

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Introducing to your mobile device or computer, the newest in a series of on-line calculators. The phosphorus loss assessment tool for Ontario, nicknamed PLATO, will help determine the risk of phosphorus (P) loss from nutrient applications at a field scale.
PLATO takes both field characteristics, such as erosion risk and soil test level, as well as P application practices into account, and can help to verify improved phosphorus management.
PLATO confirms in numbers what consultants have been promoting for years when it comes to phosphorus management. Timing and placement are critical factors in reducing the risk of phosphorus loss. For example, the P index for manure surface applied on frozen soil will almost always trigger a high or very high risk while the same manure applied just ahead of spring planting or to a growing crop will often have a low to moderate risk.
In a summary screen displays the relatively low risk of P loss given the input data for the field used in this example. Information icons provide further breakdown of how P is most likely lost from a field and provides some management strategies/suggestions to consider for reducing the chance of P loss from field characteristics and/or from material applications. These suggestions do not consider what practices may already be occurring in the field.
Impact of soil test P:
The possibility of surface water contamination by phosphorus cannot be based on soil-test phosphorus level alone.  Phosphorus binds tightly to soil particles (particulate P) and the movement of eroded soil from a field by runoff (overland or through surface inlets and, in some cases, soil macropores to drainage tile) is a major factor in determining the likelihood of surface water contamination.   
When soil test results indicate that no additional phosphorus is required to achieve maximum economic yield, the risk of dissolved phosphorus movement increases in both overland and tile drainage waters.  
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