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Algorithm/AI Asset

This record describes an algorithm or artificial intelligence asset. It does not describe a dataset. Learn more here about how the Government of Ontario is working to grow our catalogue beyond data for greater transparency and accountability.

Phosphorus Loss (PLATO) Calculator – AgriSuite Tool

AgriSuite is the Ontario government’s agricultural and environmental suite of tools related to crop management, nutrient management and minimum distance separation.

The Phosphorus Loss Assessment Tool for Ontario (PLATO) is a calculator within AgriSuite that is used to estimate the risk of phosphorus loss from user-defined agriculturally-managed field areas of interest.

To define or characterize the field, you begin by providing the field’s county and geotownship location along with the name of the dominant soil series a description of the soil surface texture that forms the field, as well as the field’s soil test phosphorus level.

Next, to describe the agricultural practices used on the field, you select the crop type grown, tile drainage system and spacing details (if present) and provide an estimate of annual rates of soil erosion by water that result from the field practices being used on the field. Water erosion estimates can be determined quickly by entering a maximum field slope value and defining the primary tillage practices used on the field.

Alternatively, a more detailed 2-dimensional and field area average estimate of erosion can be prepared by using the new Annual Average Water Erosion Mapping feature in AgMaps.


Ontario is a partner in the international Great Lakes Water Quality Agreement, which is focussed on improving and maintaining the health of the Great Lakes. As part of this agreement, Ontario has committed to reducing both total and dissolved phosphorous loadings to Lake Erie in particular. Past studies have identified phosphorus leaving agricultural land as one of the contributors of phosphorus loads to Lake Erie.

OMAFRA experts, in cooperation with Agriculture and Agri-Food Canada scientists, developed the PLATO tool to use field specific soil, crop and nutrient application information to determine a phosphorus loss risk or index score. Farmers can use this field-specific score to evaluate the relative effectiveness of their field practices in making the best use of available phosphorus fertility while at the same time minimizing the risk of phosphorus leaving their fields. Keeping soil covered and minimizing erosion are key elements of both reducing phosphorus loss and improving soil health. Maximizing the efficiency of crop nutrient uptake and minimizing losses are also the foundation of agriculture industry’s 4R Nutrient Stewardship program.

PLATO allows farmers to quickly and easily run different crop management scenarios to assess the best course of action for meeting or exceeding 4R phosphorus stewardship goals on their land. They can try scenarios to adjust the timing and placement of fertilizer or manure applications and compare how reduced tillage practices can minimize the risk of soil erosion and phosphorous loss.


Nutrient Management regulations in Ontario apply to livestock farms in the province that have expanded or built manure storages since 2003 through the application for a building permit. Calculators in AgriSuite are used to develop both voluntary and regulatory Nutrient Management Strategies and Plans for producers needing to comply with Ontario’s Nutrient Management regulations. The PLATO calculator is a part of the AgriSuite tool set.

For many environmental cost share programs in the province, there is often a requirement that applicants have completed either a voluntary nutrient management plan (NMP) or an environmental farm plan (EFP) in order to access the cost share funds. Because PLATO is embedded into the province’s nutrient management software, if necessary, its output can be used to evaluate the relative benefits of two cost share applications to help determine the application showing the greatest potential to reach phosphorus reduction goals. Learn more about the AgriSuite tool set and the use of the PLATO calculator within the context of a Nutrient Management Strategy and Plan here.

Potential impacts

Decisions made and applied in the field that are based on the risk score and recommendations of the PLATO calculator are designed with the intent to have a minimal detrimental effect on crop yields and farm income.

Soil phosphorus test levels may see a gradual decline over multiple years if PLATO risk score recommendations are followed. This could lead to reduced phosphorus loadings to surface waters. Livestock producers may incur lower fertilizer costs as a result of taking full advantage of available nutrients in their farm manure. Winter spreading is discouraged, protecting rural water quality.

In general, field management practices employed, as influenced by PLATO risk scores, have the potential through time to reduce phosphorus loadings to the Great Lakes and other P-impacted water bodies in the province (eg. Lake Simcoe) and ultimately the health of nearby and downstream surface waters for multiple years.

Internal use policies

This tool is intended for use by agricultural producers and their representative service providers (e.g. nutrient management planners, agronomists). The input data provided by the user, used to generate a PLATO score, is not stored or accessed by the government. The tool is in the process of being set-up as an Applications Programming Interface (API) so external users such as crop input suppliers can access the PLATO algorithms for use in their own proprietary software.

The information can be saved and printed by the user. Information is not accessible to anyone beyond those selected by the user.

Government staff have access to this calculator and tool set to help support policy development and emergency management response activities. OMAFRA has developed information sheets and instruction videos describing the tool and its potential uses.

Technical description

PLATO was developed internally by OMAFRA specialists and Agriculture and Agri-Food Canada scientists. It uses internally-developed databases based on science and field and lab data collected or relevant to the province of Ontario (e.g. manure sample database, phosphorus fertility trials, field–edge P loss study findings).

AgriSuite is an on-line web browser based product that allows users to complete PLATO calculations quickly or alternatively sign in as an authenticated user to save and potentially share their work with people they choose to share the information with.

Related Tools

Additional information

Field Value
Geographic coverage Ontario
Maintainer branch Environmental Management Branch
Last Validated Date 2020-10-08

Phosphorus Loss (PLATO) Calculator – AgriSuite Tool

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