Planting Cover Crops to Improve Clay Soil Quality Used for Pasturing Livestock

How can cover crops and annual forage crops be included in pasture re-establishment on clay soils? Should they be?
By: Jim Isleib, and Frank Wardynski, Michigan State University Extension

In recent discussions with farmers at cover crop meetings across Michigan’s Upper Peninsula region and again at the Michigan State University Forage Technology Conference in East Lansing, Michigan, the problem of incorporating cover crops to improve soil quality on clay soils used for pasturing cattle came up. Pastures and hay fields are, by nature, a type of “cover crop,” but the use of annual cover crops with forage value during the occasional pasture renovation or re-establishment period has potential to improve challenging soil conditions before the next semi-permanent stand of perennial forage is established.

What’s the problem?

Conventional tillage and planting practices, including fall plowing, are widely used on clay soils in the eastern and western Upper Peninsula. The main crops are perennial forages and small grains. When the time comes to renew hay or pasture fields, they are typically killed with herbicide in the fall, fall-plowed, then planted with a new forage seeding and small grain nurse crop, usually oats or barley. Fall rains contribute to very soft soil conditions under this management practice and livestock are kept off them until late spring when soils dry out enough to allow grazing without hoof action cutting up the soil too badly.

If spring seeded with conventional tillage practices, annual forage crops or cover crops must be utilized before soft, wet soil conditions develop in the fall. Even then, previous tillage has broken up the root structure that helps provide better footing on clay soils and disrupted the soil structure. Deep mud conditions can develop where livestock congregate or on frequently used alleys or lanes. Local farmers refer to the month or so between snow melt-off and green-up, and the month or so before winter freeze-up as the “mud season.”

Livestock farmers on low-fertility, clay soils, especially in the short-season northern parts of Michigan, maythink the effective use of soil-building cover crops in their forage systems is not a possibility. If traditional tillage practices are used, this may be true. However, if soil structure and previous plant root structure can be maintained, the wet clay soil should be better able to support grazing livestock.

What’s the solution?

There is no silver bullet! However, Michigan State University Extension educators and local farmers are thinking about it. New practices:

• Must result in improved success with perennial forage re-establishment.
• Must be practical with regard to equipment and labor requirements.
• Must be economically justifiable.
• Must provide adequate volume and quality of forage during the re-establishment period.
• Should result in improved soil condition.
• May add time to the process.

Key ingredients to a modified hayfield or pasture re-establishment plan include use of no-till planting technique and incorporation of annual forage or cover crop selections with potential for good grazing.

MSU Extension educators in the Upper Peninsula region are planning a demonstration project on clay soil in Ontonagon County for 2015 through 2018 using these key ingredients. In addition, two fertilizer rates will be included in the demonstration. These rates include a “crop removal” application meant to meet minimal crop needs and a “full” application to comply with the MSU soil test report recommendation. The full application will include additional fertilizers to build up soils with inadequate phosphorus and potassium test levels to support the crops and yield goals indicated. One-half of a small pasture field will be re-established using the trial method. The other half will be left in its undisturbed condition for comparison.

The demonstration is intended to determine if a two-year, no-till rotation of annual forages or cover crops with a new seeding of perennial forage during the third year will result in acceptable spring, summer and fall grazing throughout the rotation, improved soil quality and good re-establishment of perennial forage. Soil quality will be measured with the MSU soil test including organic matter and the Solvita soil respiration test.