HURON — Kingsbury Conservation District & USDA Natural Resource Conservation Service will host a Cover Crop Workshop for producers on Sept. 23, at a plot located a ¼ mile north of Manchester from 9 a.m. to noon with a courtesy lunch to follow.
The Cover Crop Workshop will be an opportunity for producers to view three different cover crop mixes seeded in prevented plant acres. In addition, the workshop will cover opportunities for producers to learn about available assistance, chemical carryover concerns, crop insurance concerns, soil health and biology, and design of cover crop mixes.
Cover crops can be used to provide multiple benefits compared to tillage or chemical fallow of the ground. Considering that the weather patterns the last two springs have resulted in acres not being able to be planted to a commodity crop, planting these acres to a cover crop that has the potential to use excess water, fix nitrogen, control weeds, reduce compaction, control erosion, and/or improve soil health and biology can build considerable yield potential for following crops. With the potential “prevented planting” payment and the improved yield potential following a full season “green manure” crop, their economic potential for the whole rotation could be considerable.
Leaving a field unprotected can cause excessive rainfall runoff or flood waters to cut the field leading to topsoil loss from erosion and scouring. With the productive topsoil lost, so too are the nutrients, organic matter, and soil biology. If tillage is applied to these water-damaged fields to control weeds or smooth them out, even relatively flat soils will lose carbon, nitrogen and biomass. This, again, shows the importance of an above-ground biomass of cover crops as they can help protect the soil from further sun, wind and water damage. Selecting high bio-mass cover crop mixes will rebuild topsoil. Cover crops, especially if no-tilled, will add organic biomass both above and below ground to rebuild topsoil quicker than if left to grow weeds or especially if left with no cover.
Some fields may be so compacted that remediation activities are needed. However, cover crops, whether used alone or in conjunction with other compaction remediation activities, are essential to rebuild healthy soil structure. The roots of cover crops help to penetrate compacted zones, hold soil aggregates together, and sustain healthy organisms to restore soil structure. Growing roots are essential to re-establish the mycorrhizae in the soil and to create pathways for air and water to move through the soil profile, which are key components to restoring the soil’s functional properties and will keep the pathways more open to result in a quicker fix of the compacted layers.
Cover crops can build organic nitrogen, and/or sequester residual nitrogen in the soil. A legume or legume mix planted in early summer can easily provide 60-100 percent of the needed Nitrogen of a following corn crop. A brassica or grass, or brassica+grass mix can scavenge more than 40 pounds of residual Nitrogen from the soil, and even more in situations where manure or pre-plant nutrients have been recently applied. Additionally, this results in a more rapid gain in total soil biomass and a higher total nutrient availability for subsequent crops.
Planting cover crops in mid-summer may pose a challenge due to weather conditions; sometimes a successful stand is dependent on timing of rainfall after seeding. The other consideration in planting cover crops is what chemicals were applied for the prior year crop or pre-plant chemicals.
For the complete article see the 09-13-2013 issue.
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