Cropland Management With Wildlife in Mind
A large portion of the United States is covered with crop fields that produce food and fiber for use by people throughout the World. Unfortunately the increased use of pesticides, herbicides, removal of fencerows and other odd areas has reduce the value of these fields for wildlife. In the early 20th century the nature of farming practices in its self created wildlife habitat. Farm fields were small and crops were rotated. There were no herbicides or pesticides being used so field were weedy and had an abundance of weed seeds and insects. The nature of farming now and the high cost of producing with little return, means productivity of crop fields needs to be as high as possible in order for a farmer to survive. Although we may never see farming practices go back to the way they were in the beginning of the 20th century, there are a number of steps a landowner can take to improve their cropland for wildlife while still maintaining profitability.
Direct mortality, nest abandonment, and nest destruction in crop fields often occurs and is more likely to happen the more often equipment passes over the field. Some species of waterfowl, shorebirds, songbirds, and upland game birds use crop fields. Primary tillage, disking, rotary hoeing, herbicide, and fertilizer applications occur during the nesting season increasing the likelihood of causing problems for wildlife. Therefore, any tillage system that reduces equipment passes and leaves standing residue should increase the benefits of the crop field for wildlife. Farming practices that increase wildlife use, but also increase wildlife mortalities create an "ecological trap" for wildlife because residue on reduced tillage fields appears more attractive than conventionally tilled fields, but high frequency of disturbance from equipment passes increased mortality. These problems often occur in row crops such as corn and soybeans and in areas where summer fallowing of wheat is done. No-till appears to be the only tillage system that reduces disturbance enough to have a positive influence on wildlife due to the low frequency of disturbance that occurs in the field.
If you are not already doing it you should consider using conservation tillage on croplands because aquatic resources are improved by the soil protection and water quality benefits of increased crop residue. The benefits are accrued only if the producer shifts from a more intensive tillage system to one that leaves more residue on the surface (e.g., conventional tillage to ridge till or ridge till to no-till). To better help wildlife, using no-till provides the most benefits to birds and mammals because of the cover and food it produces and the reduced disturbance during nesting season. Some forms of reduced tillage, although they provide many benefits, can be an ecological trap for birds due to the frequency with which the equipment passes over the field which is about the same as conventional tillage. Wildlife will generally benefit from any tillage system that leaves standing residue after harvest in the fall until spring planting.
A cover crop, also called "green manure," refers to any annual, perennial, or biannual plant that is grown as a monoculture or polyculture. Cover crops help to improve soil fertility, water infiltration, reduce weeds, pests, and diseases. Cover crops hold soil particles in place and additional organic material is added to the soil. Deep rooted cover crops can also increase water infiltration and reduce soil compaction. Cover crops can help smother and compete with weed seedlings reducing the number of weeds found in a field. They have the ability to reduce disease and pest issues. Predatory insects and pest insects will utilize the cover crop. With increased number of predatory insects pest species can be reduce in the field.
The best overall benefit of cover crops for wildlife is for fish and other aquatic species due to the reduced runoff and nutrient loading caused by fertilizer runoff. Cover crops can also provide some food in the form of insects and seed for wildlife. Depending on the cover crop some species of wildlife may utilize the cover crop for nesting, brood rearing, or as escape cover.
Many farmers no longer rotate their crops like they once did. Now soybean is often followed by corn and then soybeans followed by one or two years of corn or soybeans. This limited rotation increases the need for fertilizer, herbicides, and pesticides. Soil compaction and organic matter is also reduced in these types of limited rotation. A good crop rotation will reduce need for fertilizer, herbicides, pesticides, improve soil organic matter, and provide wildlife habitat. In the past rotations typically followed a 4 to 10 year cycle. A good rotation will included a legume (clover, alfalfa, or soybeans), a small grain crop, fallow period, grain crop (corn), and/or a grass rotation.
A good rotation for wildlife includes a year or two of fallowing. Although a fallow field to most farmers looks to be nothing more than a bunch of "weeds", it creates food and habitat for wildlife for nesting, brooding, and potential winter cover. Weeds like common ragweed provide an abundance of seeds for quail and songbirds to feed on during the fall and winter. Numerous insects are also found feeding on the "weeds" which farther provides a high protein snack for quail and songbird chicks.
These weeds also do other things for farm production. The deep roots of many "weeds" loosens hard packed subsoil. These roots create spaces for water to penetrate deeper into the soil. The organic materials left behind builds up the soil. The deeper roots of "weeds" can also improve the nutrient composition of the soil by bringing to the surface micro-nutrients found deeper in the soil profile and other nutrients as the plant decomposes.
Example Rotation 1
Example Rotation 2
Herbicide and Pesticide Use
Reduction or elimination of the use of herbicides and pesticides is one way to not only increase profitability of your operation, but also to improve crop field value for wildlife. Although a nice clean field may look good, the added cost of herbicides and reduced value of diversity of the field excludes wildlife from using the field. In the 1930s and 1940 farm fields had weeds that provided seeded, insects, and cover. Present day fields which are treated heavily with herbicides and pesticides have a very limited value to wildlife. They may be used for cover during the summer, but the food value of these crop fields is very limited.
Although you probably cannot eliminate herbicides and pesticides completely from your operation unless you plan on going organic, there are some practical steps that you can take. First consider setting up an Integrated Pest Management (IPM) system. An IPM is an ecological approach to dealing with pest which includes insects, weeds, and pathogens. In an IPM system you have 6 basic principles. They include: acceptable pest levels, preventive cultural practices, monitoring, mechanical control, biological control, and chemical control. By setting up an IPM system you will be able to reduce your use of herbicides and pesticides. This will not only make your operation more profitable, but it will improve the value of your crop fields for wildlife. An IPM will also help in reducing the potential of insects and weeds becoming resistant to pesticides further increasing your cost by requiring you to use more and stronger ones.
Another option is to leave an unsprayed buffer along field edges and ditches. In this unsprayed buffer no herbicides or pesticides are used on the crop. The buffer should be from 20ft to 60ft wide. Pesticides can be used in the buffer, but should not be used after April 1st. Spot spraying of noxious weeds should be done in order to keep them from becoming established. The conservation buffer will allow predator insects to thrive and move further into the crop field. The No spray zone will also keep insects and weeds from becoming pesticide resistant. From a wildlife standpoint these areas will provide insect and weed seeds for food and additional cover along travel corridors.
When harvesting your crop to protect wildlife you should either start at one end of the field and harvest back and forth across the field (fig.1) or start in the middle of the field and harvest from the center out (fig. 2). Harvesting around the field until reaching the center forces wildlife to move toward the center of the field. This can cause them to hold longer and be killed easier by your harvesting equipment. Also it does not give wildlife cover to escape to as you harvest closer to the center of the field. You should never harvest at night if you are interested in protecting wildlife. Harvesting at night increases the potential of killing more wildlife because they are more likely to hold longer or flush wildly into the path of your harvesting equipment.
Another option for harvesting crops that will benefit wildlife is to raise the picker or combine head higher. If you plant grains such as oats and wheat consider getting a stripper header for you combine. The stripper header leaves more stubble behind compared to a conventional combine head. If you plant corn consider picking it just below the ears. This will leave more cover for wildlife during the winter. Although you may miss some ears, these ears can provide food for wildlife during the winter particularly if snow or ice storms occur. Harvesting higher will also reduce damage to equipment tires from the sharp ends of the harvested corn stalks. Cutting low often leaves very sharp stiff stalks which can easily puncture tractor and vehicle tires. If you are no-tilling and are concerned that the higher stalks will interfere with planting consider mounting a stubble bar on your no-till drill. A stubble bar made of strong angle iron or tube steel is attached on the tongue of the drill 2 to 3 ft in from of the drill parallel the planter. As the drill is pulled forward the stubble bar will knock down the tall corn stalk. Another option is to mow the stalks down prior to planting.
Grassed Terrace/Contour Strip
You can reduce erosion prone fields by either installing grassed terraces or contour strips. Grassed terraces and contour grass strips can benefit wildlife in two ways. The reduce erosion of fields which keeps nutrients and sediment from washing into streams, lakes, and wetlands. Another way to benefit wildlife is to install native grass and forb terraces or contour strips. Very rarely are contour terraces established to grasses. One reason for this is it that it is often believed that the terraces can be maintained easier if they are allowed to be planted to crops. The exact opposite is true. When terraces are planted to crops the operation of disking, planting, and harvesting slowly wear down the terraces. This means that over time the terraces will lose their effectiveness as they become compacted, soil displaced by tillage and erosion. Depending on the construction of the terrace this loss and deformation will mean that you will need to rebuild them in order to maintain them.
Planting native grasses and wildflowers on terraces over time will reduce you need and cost to maintain them. The deep roots of the native grasses and wildflowers will bind the soil and help build organic matter and reduce erosion. Grassed terraces also act as filters to reduce erosion and movement of nutrients from the field. For wildlife these strips can act as corridors for movement.
Field edges, grassed waterways, and drainage ditches along and within crop fields can be very important for wildlife. These areas also act as filters to runoff from the crop field. Field edges, grassed waterways and drainage ditches should not be mowed. Mowing removes cover for wildlife. Mowing creates a thick thatch layer which makes movement difficult and smothers out beneficial vegetation. When possible consider using fire to manage vegetation on a rotational basis of 2 to 4 years. Additional information on managing using fire can be found HERE. Always plant field edges, grassed waterways, and filter strips in diverse mixes of native grasses and wildflowers, a divers planting provides both cover and food for wildlife (Native Grass For Wildlife). Exotic grasses like fescue have very little benefit for wildlife.
If you have limited cover or trees along your field edge consider planting native warm season grasses and forbs as a field border. The abrupt zone between the crop field and tall mature trees creates what is termed a hard edge. This hard edge does two things it limits the value of these areas for wildlife and it reduces crop yields through shading and competition for moisture and nutrients. Two options for helping improve wildlife habitat along these edges is to either plant a field border or to soften the edge with edge feathering or border edge cut.
The best field borders are planted in native grasses and wildflowers. To get the maximum value for wildlife field boarders should be at least 50ft wide with 120ft or more being ideal. Wider buffers provide more habitat and decrease the possibility of predators finding nest, young, or adults. Also ider buffers provide more of the essential habitat components need for the daily life of wildlife. If you have an interest in early successional species like quail, rabbits, field sparrows, etc. consider planting 10% of the field in 0.1 to 0.25 acre thickets of plum, silky dogwood, rough-leaf dogwood, raspberry, or sumac.
Edge feathering and border edge cut are two techniques for softening the edge between crop fields and wooded edges. In both techniques the idea is to cut down trees along the field edge allowing shrubs and herbaceous vegetation to grow creating a transition zone. Edge softening should be no less than 30 ft with 150ft being ideal. In an edge feathering, cutting results in a more softened edge by creating 3 zones. In the first zone a minimum of 75% of the canopy is removed. The second zone has 50% of the canopy removed, and the third zone has 25% of the canopy removed. In a border edge cut all trees with in a 30 to 75ft zone are cut. Small trees and shrubs are left. As succession occurs after the cut it creates a transition zone of sapling and shrubs. For additional information see our section on Edge Softening Techniques.
The edges of ditches that are allowed to become brushy can act as travel corridors and escape cover through the field. Consider putting a 20ft to 120ft native grass filter strip along the ditch to improve filtration of soil and nutrients from entering the ditch. A diverse filter strip of short native grasses and wildflowers can provide habitat for a number of wildlife species. The wider the filter strip the better. Filter strips from 60ft to 120ft will be used more use by wildlife including quail and rabbits.
If you have an area that is prone to erosion and channeling consider putting in a grassed waterway. The grassed waterway can act as a channel to filter soil and nutrients out. It can help reduce erosion by channeling water from the field. Grassed waterways planted to a mix of native grasses and wildflowers can provide additional habitat for rabbits, quail, and a variety of other wildlife species. The reduction of soil and nutrients flowing into streams and wetlands will improve water quality not only for game fish, but also a number of other wildlife species that rely on clean water.
Often times there are area adjacent to or in close proximity to crop fields on your property that cannot be farmed. These little odd areas and fencerows although usually very small can be managed to provide escape cover. Small odd areas will not provide all the essentials for wildlife species, but they can be managed so that wildlife can use them as corridors or small pockets of cover as the move across your property from one area of good quality habitat to another. If the small odd area contains fescue or noxious weeds or fescue these areas should be sprayed with glyphosate, imazapic or other appropriate herbicide.
The easiest way to deal with small odd areas is to manage them as an old field by setting back succession with fire, disking, or herbicides. Mowing is not an effective means for managing habitat as it leaves thick layers of thatch and does not control woody plants. By managing these small areas you will be able to control noxious weeds and keep the area from reverting back to trees. Small weedy areas not only provide escape cover, but they do provide small pockets of food that wildlife can eat while moving across your property to better large blocks of habitat.
In the modern agricultural landscape fencerows have either been completely removed or ignored to the point where the trees are no 40 to 60 years old and have very little wildlife value. The most important aspect of fencerows is that they can provide travel corridors from one field of good habitat to another. Historically fencerows were maintained in as a mix of herbaceous vegetation and shrubs. Trees that grew in fencerows were cut for firewood or fence post. With the advent of the steel T-post and other ways of heating homes fencerows were ignored. Large trees began shading and competing with crops on the edge of the field and new larger farm implements made it justifiable in landowners minds to remove fencerows. Another issue that has resulted from the neglect of fencerows is that fescue, honeysuckle, and other invasive species with little wildlife value have invaded them.
If you have old fencerows thick with trees and shrubs consider renovating them by cutting the trees and shrubs. For information on how to renovate a fencerow see our section Fencerow Renovation. If you have no fencerows strategically establishing them to act as wildlife corridors can be an important step in making your property more wildlife friends. An example of when a fencerow/wildlife corridor would be best is if you have a well managed block of habitat on part of your field and either you or your neighbor has another block of good habitat, but it is separated by a large crop field. Creating a fencerow/wildlife corridor will connect those two areas of good habitat increasing their benefit for wildlife by allow individuals to safely move from one block of habitat to the other. For more information on design and establishment see our section on Fencerow and Wildlife Corridor Establishment.