James DeYoung and Richard Leep
Michigan State University, Department of Crop and Soil Sciences
One of Michigan’s most precious resources is its water. Implementing good grazing techniques can positively influence our water resources in the form of the Great Lakes, our rivers, and streams. Rotational grazing can play a big part in the conservation of our waters, if it is done right. Streamside grazing can have a powerful effect on water quality in a very short time. Unrestricted grazing increases erosion in streams and damages the sod that makes up the stream banks. Through improved grazing management, streamside pastures can be grazed and provide a good source of forage during hot summer months when other pastures are not producing.
What happens upstream in a river, affects everyone who uses the water downstream from plants, fish, birds, and animals, to people who use the water for irrigation and recreation. A polluted headwater affects fish species like trout that use streams and rivers for nesting. If silt and soil are washed into a stream, the eggs of the trout will be covered and will die. Nutrient runoff from cattle manure also affects water quality. Nutrient runoff in streams affects the types of plants that grow there. A body of water with high nutrient levels will encourage the growth of weeds, choking out native water plants and fish. Water with high nutrient levels will also encourage plankton blooms that deplete the water in ponds and lakes of oxygen that fish need to breath.
These problems can be avoided through proper management of buffer strips along streams running through the farm. Rotational grazing would be one of the ways to manage the buffer strips. These buffer strips filter the nutrients and sediment from runoff before it reaches the stream. Those buffers can also provide a great source of pasture. The goal of streamside grazing is to develop and maintain a healthy sod on stream banks that will hold the soil in place. Overgrazing will damage the sod so it does not hold during floods or heavy rain.
There are certain times of the year when streamside grazing is not recommended, but during those times other sources of pasture are usually available. Avoid grazing stream and riverbanks during wet weather, as they can become unstable and more susceptible to damage. Soils around streams are usually wet year round, so when wet weather comes along, it does not take much for cattle walking around to make a muddy mess. Cattle will also trample the plants and crush them into the ground during wet weather; this will reduce the water holding capacity of the soil, as well as increase erosion into the stream, not to mention damage the sod. During droughts or hot weather, cattle may be tempted to stand in the stream if they have access to it. Also, hot weather or droughts make it harder for plants to recover after grazing events.
Careful planning when developing a pasture will save a lot of headache later. A good sturdy fence is usually a good place to start. When fencing around a stream or river, remember that rivers and streams tend to flood each spring. When planning the fence, ask yourself how will the stream or river behave in a flood situation? Remember that floods differ from year to year, last spring’s small flood might have not been typical. A good plan for fencing will keep you from having to rebuild the fence every year. If an electrical fence is being used and will be crossing the stream, plan for good sturdy locations to anchor it to on either side of the stream high enough so that it will not be torn out by debris.
Pastures can be stream inclusive or stream exclusive where a separate streamside paddock is created. Stream inclusive pastures are ones where each pasture includes a part of the stream. These types of pasture tend to be more damaging than a stream exclusive pasture since cattle have access to more of the stream bank, but they will provide cattle with water in each pasture. An exclusive pasture system would have only one paddock with stream in it. With this separate streamside pasture, a farmer could graze it only when conditions were right. This will reduce problems such as grazing when stream is flooded, or banks were unstable after periods of heavy rain. During those times, that paddock could be removed from the rotation until conditions improve.
Fig.1. Stream exclusive paddock design. Fig.2. Stream inclusive paddock design.
Another important aspect to creating good pasture is the plants in the sod. Traditional forage plants will not perform well in extremely wet areas surrounding streams. Many plants have developed a tolerance for the wet conditions found along streams. They can hold the sod in place and will not drown when soils are wet. But many of these plants do not stand up too well to grazing. Plants adapted for grazing and the wet conditions along streams can be planted. These include Reed canarygrass, Switchgrass, Smooth Bromegrass, Red clover, Italian ryegrass, Timothy, Alsike clover, and Ladino clover. Care should be used with Reed canarygrass and Smooth Bromegrass since they tend to be aggressive competitors and will take over if not grazed intensively. (This is especially a concern in areas with fragile plant communities like fens, bogs, or springs where intensive grazing is not an option.)
Water quality is important for cattle if they are going to be drinking from the stream. If the stream is polluted, cattle will drink less and that will cause a drop in milk production or it could lead to cattle becoming sick. Always test water before allowing cattle to drink from any water source. The cause of pollution in a stream could be any number of things, from other cattle upstream muddying the waters to industrial pollution with chemicals that are harder to see. If water quality in the stream is poor, an alternative water source should be provided.
Controlling access to the stream for the cattle can greatly impact water quality. A stream with only one access point will limit the damage to that area, while a stream with unlimited access can soon become a muddy trough. Covering the streambed with rock at least 2 inches in diameter will discourage animals from standing in the stream. Monitoring streamside areas used for drinking will show areas that are being damaged by the animals. Those areas can then be closed off to access to allow the sod to recover.
A stream crossing allows you to control where the cattle cross and where they drink. If grazing a streamside pasture, the cattle have probably already decided where to cross. This is generally a good place to put the crossing. Improving the crossing with a focus on livestock convenience will encourage them to use it. Livestock need two things when crossing or drinking; a firm bed to walk on, and they like to be able to see the bottom. The bed may be rock or a fiber cloth, but it must be able to stay put in the stream. This can become a problem in faster moving streams as smaller stones tend to be washed downstream.
Technical assistance to help plan and design stream crossings is available from your local NRCS office or from the DNR. They can also help with shaping or stabilizing stream banks that are too steep, or tend to erode easily.
No article or brochure can tell you everything you need to know about any subject. Check with your local extension agent, NRCS office, or DNR before starting a project like this. They will probably have insights and some good advice on grazing streamside pastures.