Protecting Farm Streams Near Horticultural Crops

Planting protective buffers along natural watercourses gets most attention in agriculture that is associated with pasture and livestock production. Providing vegetative buffers for streams is equally important for all types of agriculture. Vegetative stream buffers help protect water resources. They provide shade to moderate stream temperatures and promote healthy aquatic ecosystems.

Stream buffers should be as naturalized as possible. A naturally vegetated width of three metres to the water's edge can provide an effective buffering distance. In fact, the Nutrient Management Regulations require a permanent vegetated buffer at least three metres wide on any farm that is required to complete a nutrient management plan. Once established, buffer plants are typically self-sustaining native species that require little maintenance. Widening vegetative buffers beyond 3 metres to the water will provide additional protection of water resources and increase the amount of diverse naturalized area.

Catching crop nutrients

Preventing unintended movement of agricultural nutrients can be difficult where excessive rain or random heavy downpours can wash nutrients out of the rooting zone of crops. At the soil surface, rainwater can carry valuable soil and nutrients by overland flow. Trees, shrubs and grasses planted along streams as buffers will act to catch eroding sediments and can effectively absorb nutrients that may be escaping from the field. Farm windbreaks and shelterbelts not associated with stream buffers will also help to purify ground water by taking up nutrients from soil moisture.

Spray drift and wind management

Efforts should be made to prevent spray drift of fungicides and insecticides from contacting vegetation in natural stream buffers. Drift of herbicide can kill or burn naturalized vegetation in buffers and should be prevented. Horticultural plants, for example orchard trees should not be used as stream buffer vegetation where pest-controlling sprays, fertilizers and herbicides are going to be applied. Best management practices for horticultural crops are not the same as BMPs of protective stream buffers.

Figure 1. Fruit trees are planted right to the edge of this stream bank, compromising the protection of the waterway. A wider buffer plus addition of conifers and taller shrubs would improve protection for this stream from nutrient applications and orchard spray drift. All spray applications should be directed away from protective stream buffers.

Having a protective buffer established will create a separation distance and a barrier between agricultural activities and natural waterways. Mature vegetated buffers can also act as windbreaks to protect developing crops from turbulent wind to boost crop yields and reduce wind erosion of exposed soils. Orchard situations may require taller and thicker vegetation along stream buffers than vegetable crop situations due to the difference in the types of sprayers used to apply pest control products.

Vegetation within stream buffers however, should not be so thick that air movement is blocked. Too little air movement can lead to formation of frost pockets and freezing injury to sensitive adjacent crops during spring. Good air drainage will lead to faster drying of horticultural crops after rains to reduce crop disease problems. Excessively thick vegetation can be thinned as necessary to promote better airflow through natural vegetation of stream buffers.

Buffers can grow useful products

Stream buffers can be utilized in unique ways to provide useful products. For example, eastern white cedar can be grown and harvested for posts and rails in a sustainable fashion. Other hardwoods that are tolerant of wet soil or prefer drained low lands such as black maple or in southern regions, tulip-tree and black walnut, can also be grown long term for specific wood markets.

Stream buffers can provide plant cuttings that can be used for decorative purposes. Foods of wild berries or wild edible herbs can be collected for personal use. There is nothing wrong with utilizing stream buffers in innovative or profitable ways on private land as long as water quality and protection of the aquatic ecosystem is given a high priority.

Native vegetation for stream buffers

Unprotected streams usually need a bit of help to get new buffers established and will require planting. It is ideal to have a diverse selection of native plant species in vegetated stream buffers. Eastern white cedar, black spruce and white spruce are good stream buffer conifers that will provide a barrier of evergreen foliage. Buffers may also include species like red osier dogwood, highbush cranberry, willows, speckled alder, silver maple and other tree and shrub species that associate naturally along streams and ditches.

In wild settings, herbaceous species include northern bugleweed, common skullcap, purple-stemmed aster, lance-leaved aster, spotted joe-pye weed and many more. Grasses, sedges, aquatic plants, horsetails, clubmosses, ferns, bryophytes (liverworts and mosses) also contribute to create highly diverse interactive plant ecosystems within stream buffers.

Figure 2. Five years since planting, a vegetative stream buffer with diverse species of eastern white cedar, spruce, grasses, shrubs and hardwood trees. Winter road salt damage from a nearby highway can be seen in white cedar as foliar browning.

Conservation Authorities and local MNR Stewardship Councils can provide a wealth of knowledge and experience and they are always eager to share ideas. Ask a few experienced farmers for some well-rounded insight into the benefits of having healthy stream buffers.

| Top of Page |