By Jim Isleib, Michigan State University Extension
Thinking through the process before you start prepping a field for crop production can help avoid future problems.
Having a good understanding of the soil type, fertility, history and characteristics of your old, neglected field will help you determine the best approach for putting it into active production. Contact your local Michigan State University Extension agricultural educator for help accessing soil map information, soil testing and other important background on your site. Getting started in the late summer is usually better than waiting until spring, especially if old vegetation is to be killed with herbicide. Once you are satisfied your field preparation will be worthwhile in the long term, it’s time to decide how to go about it.
Preparation work is finished at a trial site at the MSU Upper Peninsula Research and Extension Center in Chatham, Michigan.
Here are a few example timelines for prepping that field.
If the field is to be used as permanent pasture:
- Soil test. Do this anytime, before any soil amendments or fertilizers are applied.
- Make a thorough evaluation of the existing vegetation. In many cases, it is wiser to work with the plants you have in place and invest in good fencing, watering and a practical fertilizer program. If desirable grasses and legumes are present, good grazing management will result in big improvement in the pasture mix over a few years.
- If the existing plant mix is too poor to work with, consider the preparation suggestions below and plant an appropriate pasture seed mix.
If herbicides and synthetic fertilizer use is to be included:
- Soil test. Do this anytime, before any soil amendments or fertilizers are applied.
- If the field is brushy, cut or pull woody plants as needed. Larger plants and trees may require heavier equipment. Safety is a big concern here, so take all precautions.
- Make a light nitrogen fertilizer application to promote growth of vegetation before herbicide application. Using 25-50 pounds of 46-0-0 fertilizer per acre in late summer or early spring will set up your field for herbicide application a month or so later. This is not essential, but will make your target vegetation more vulnerable to the herbicide application.
- Wait 30 days, or until you see a good flush of plant growth from the nitrogen fertilizer, then spray with a non-selective, systemic herbicide such as glyphosate. Follow all label instructions carefully. Grasses should be 6 inches tall and actively growing to achieve a good kill. If glyphosate is used, be sure to include the recommended amount of spray-grade ammonium sulfate in the sprayer tank. Tough perennials are much easier to kill with herbicide in the fall compared to spring.
- Wait seven days or more with sunny weather and over 50 degrees Fahrenheit before tillage. Longer is better. Killing the old vegetation in fall and allowing the root mass to decompose until spring before tillage is best. If lime is to be applied, it should be spread and thoroughly incorporated to the desired depth. Your tillage approach will depend on equipment available, soil conditions and other factors. If your goal is to use no-till practices, you may still need to work up the field and get it into better condition before beginning a no-till rotation. Rock and debris removal may be needed after tillage.
- Apply fertilizer if needed and lightly incorporate into the first few inches of soil. Remove additional stones and debris brought up by this final pass. You’re ready to plant.
If no herbicides or synthetic fertilizers are to be used:
- Soil test. Do this anytime, before any soil amendments or fertilizers are applied.
- A fallow period with repeated cultivations to kill perennial plants and expose, germinate and kill weed seeds will be necessary to reduce plant competition when the field is planted. The initial plowing and disking should be followed up with repeated disking or field cultivating to disturb surviving perennial plants and newly emerging weed seedlings every few weeks. This process can be continued throughout the growing season before seed is planted the following spring.
- An alternative approach is to till the field in fall or spring, keeping it fallow and tilled until early summer. A cover or “green manure” crop such as buckwheat, oats or clover can be seeded. Some cover crops are better at smothering emerging weeds than others. Check out potential cover crops for your area on the Midwest Cover Crop Council’s Decision Tools website. The cover crops must be managed appropriately to avoid unwanted carry-over into the next crops.
- Remove stone and debris as it is exposed during tillage.
- Make the appropriate additions of soil amendments and nutrients with final tillage to incorporate. You’re ready to plant.
If your soil test shows your field has poor plant nutrient levels, poor pH levels or both, you may want to consider a soil-building crop rotation including legumes and deep rooted radish, for example, for a year or more before putting the field into regular crop production. This will depend on your business plan, timeline and other resources.