Photo: A diversion terrace breaking up surface runoff from the upper field to the lower one. Diversion terraces, grassed waterways, surface inlets, and hedgerows are the most common structures used for soil conservation by Island farmers. A drive by many fields will show abundant use of these methods. Diversion terraces are used where the slope length of a field is greater than the accepted limit for cross slope farming or strip cropping. Terraces break up long slopes into a series of shorter ones. Diversion terraces will transport substantial amounts of runoff and must be permanently vegetated.      Photo: A good example of a grassed waterway Grassed waterways are broad shallow channels that are protected against erosion by a permanent grass cover. They are used to control gully erosion where water collects and flows through natural depressions in the field. The may also serve as outlets for diversion terraces. Ideally grassed waterways are gently sloped to control water flow speeds. Occasionally, grade control structures are required to ensure the stability of the waterway.      Grassed waterways are the least expensive method of gully erosion control but they do reduce the amount of land in production. A surface inlet and underground piping system is an option that minimizes the loss of land and avoids some of the inconveniences associated with waterways. Earthen berms or dams can be constructed at strategic locations within fields to intercept heavy runoff. The water can then be discharged through a surface inlet and underground piping system to a safe and convenient outlet location.      Hedgerows are treed windbreaks that protect fields from wind erosion. They control soil erosion by reducing wind speed at ground level and by trapping snow, leaving soil less exposed during the winter months. Well established windbreaks can reduce wind speed downwind for a distance equal to twenty times the height of the windbreak. Snow drifting can be controlled for a distance of ten times the height. Hedgerows should be planted at right angles to the prevailing winter winds. However, they should not be planted up and down slopes where they may hinder cross slope farming. Photo: Hedgerows on the Eric Robinson property      Photo: A buffer zone of trees protects a nearby stream from field runoff Vegetated riparian buffer strips can be extremely effective in reducing the level of contaminants reaching the watercourse. The term riparian buffer strip refers to a permanent vegetated zone bordering streams, ponds and estuaries that serve to filter and assimilate contaminants from runoff water as it passes through this area. The appropriate width of a buffer zone will vary depending on slope, crop cover and other factors. Buffer widths in the ten to thirty metre (thirty-three to one hundred feet) range are a general rule of thumb.

Some photos and technical information courtesy of the P.E.I. Department of Agriculture and Forestry