Ontario Grain Farmer April/May 2021

FIELD LEVEL Farmers’ experience working, tending, and observing the land will help explain the subsurface. Areas in the field that dry out first, are mushy, soft, or retain water give hints about the subsurface. Areas of Ontario with large drainage ditches compared to others with no roadside ditches, or thick lush vegetation compared to sparse vegetation, help to explain the soil and water movement through it. To explore further, start with where a field is located in the watershed. Source Water Protection Assessment Reports were completed for Southern Ontario several years ago and are available on line at https://www.ontario.ca/ page/source-protection or by contacting your local Conservation Authority. The reports describe the soils and subsurface geology of each watershed and include figures of soil type, thickness, bedrock, groundwater flow directions, and recharge areas. In many cases, the reports describe how the soil and rock were deposited over time and why they change with location. The scale of the maps may mean fields will be the size of a pinpoint which can make it difficult to interpret. County Agricultural Soil Surveys provide detailed soil mapping of the upper one metre of soil and in some cases include cut away sections or cross-sections of typical subsurfaces in the area. The soil maps should confirm observations on the surface when working the field and the cross-sections will provide an idea of what conditions could be like in the subsurface (Figure 3). The reports can be found at https://sis.agr.gc.ca/ cansis/publications/surveys/on/index.html and a sample cross-section is shown in Figure 3. Some of the most detailed subsurface data in the province is provided by water well records. Water well records are required to be submitted to the Ministry of Environment, Conservation and Parks (MECP) for every water well constructed in the province. The well records describe the soil, rock, and water conditions from land surface to the bottom of the well. They also provide information on the depth to water, water found at (aquifer), quantity available, and quality. Most water 20 well records will be located near a home or livestock barn. Water well records for your area can be viewed and accessed through the MECP website at https://www.ontario.ca/ environment-and-energy/map-well-records. Construction activities on your farm or in the local area can yield valuable subsurface information. Consider asking local well drillers, excavation contractors, drainage tile installers, and old timers about their experience with the subsurface. Post hole augers or backhoes allow easy and quick observation of the subsurface. Keep records of the investigations that are done, even handwritten notes can be helpful to refer to in the future. Getting a better understanding of how water is moving in the subsurface can help farmers better manage their crops and local water resources. It is important to understand that water moves under adjoining properties and protecting water resources is a shared responsibility of landowners, tenants, and the public at large. FINAL THOUGHTS This article is the final in our series on water management. We conclude with a discussion of groundwater because it is a shared resource and a shared responsibility. Groundwater is beyond our individual fields and farms. While we are dependent on groundwater to support our crops and other parts of our farms, others are reliant on the same resource. From a water management standpoint, we need to ensure the protection of groundwater in quantity and quality. From this series it is important to understand that the way we collectively manage our crop production and soils can impact us and our neighbours, sometimes a great distance away. Cropping practices that enhance soil health prevent soil erosion by reducing overland flow of rainfall, promote infiltration which slows down water movement and provides filtration, recharges groundwater supplies and builds the water holding capacity of our soils. Farmers are blessed today with high yield potential genetics. High yields require high inputs and more water to achieve their yield potential. Ensuring water and soils are well managed ensures our best opportunity to optimize crop potential. Optimizing production means achieving the highest profitability while minimizing the environmental risks associated with the production practices. The stewardship of water resources is a shared responsibility. l continued from page 19 FIGURE 3 (BELOW) SCHEMATIC LANDSCAPE CROSS-SECTION SHOWING THE RELATIONSHIP OF DRUMLINS TO THE BEDROCK AND OVERLYING DEPOSITS NEAR CAYUGA. ILLUSTRATION COURTESY OF OMAFRA. *FROM SOILS OF THE REGIONAL MUNICIPALITY OF HALDIMAND- NORFOLK, VOLUME 1, REPORT NO. 57, ONTARIO INSTITUTE OF PEDOLOGY 1984.