Using a computer model to help environmental stewardship
Saturday, October 3, 2015
Computer models can help evaluate best practices both on individual farms and on a watershed scale. Given realistic expectations, it is one way to bring data and knowledge together
by JACQUI EMPSON LAPORTE
I had the opportunity to see a University of Guelph beta version of a computer program which modelled the environmental effectiveness and cost/benefit analysis of various best management practices (BMPs) in a study watershed (Gully Creek, near Holmesville) in Huron County.
A model is a computer program that is designed to simulate what might or what did happen. We take past events like storms or erosion and input the data, and then the model tells us how to fix it. We in the agriculture ministry also have an erosion model (called RUSLE2) and an agronomic model (called NMAN3). Farmers have limited budgets to spend on stewardship initiatives, and the stewardship programs have limited budgets to assist. We need to try to make the best and most efficient choices for our money, so we can use a model to help guide our choices. Monitoring and data collection can be complex and expensive, so properly calibrated models are often the choice to explore different scenarios.
Modelling programs have two important components – science and education. The science component takes the data and research that we have at hand, and helps us attempt to make our best science-based decisions. Soil and water samples might provide data, but information also comes from the farmers, who are integral to the process. They provide the agronomic, agricultural and historical data that provides context to the science. Every model includes assumptions, so we must acknowledge the limitations of a computer program and be careful not to raise unrealistic expectations of the results.
Successful BMPs are defined by the parameters that we choose — environmental or financial. What BMP works for phosphorus might be different for nitrogen. The University of Guelph computer program considers environmental parameters such as sediment, phosphorus and nitrogen, and economic factors such as cost, revenue and crop return. The model lets us run different scenarios to see what impact our actions might have and how much it might cost.
We may not see the effects of a BMP this year, but we might in five, 10 or even 20 years. The effectiveness of a BMP might change by season, land use change, cropping practices or during storm events. A model can help us understand the potential effects of these variables when the time between BMP adoption and the idea of "success" is long.
The education component is how the results are displayed, which is important to whoever is trying to interpret them. A modelling program can help us visualize an environmental problem, when we can't actually see it. Soil erosion can be insidious and, until you see the rill or gully, you may not know the extent to which it's occurring.
The effects of point or non-point source nutrient pollution may not be seen unless the algae bloom occurs miles away. Each person interpreting the model has different tools and resources to respond. A farmer can change an agricultural practice or install erosion control devices, whereas a policy analyst can influence the choices in a funding program.
The model helps us examine the cost and benefits to the farmer of various BMPs on a field scale at a particular farm. We can also look at them on a watershed scale. What are the costs and benefits to the farmer and cumulatively to the entire area? These scales of perspective show us that, although every BMP is good, BMP effectiveness is not equal in every location. Sometimes the greatest environmental benefit occurs through BMPs implemented on a select number of properties. We may need to adapt our stewardship programs to address this inequity.
Most of all, we need to balance expectations, given environmental factors out of our control and the resources farmers and stewardship initiatives may have available. Stewardship is not easy, and there are no magic solutions. We need to use the tools and resources we have available, incorporate whatever data and knowledge we all can bring to the table, and we need to work together. Using computer models is one way that we can bring that data and knowledge together. BP
Jacqui Empson Laporte is an environmental specialist with the Ontario agriculture ministry in Clinton.