New technology expands options for cover crop establishment in northern climates
Innovative interseeding equipment allows cover crop establishment prior to fall harvest.
Cover crops are traditionally grown between harvest and planting of commodity or feed crops for the production of biomass and the various agroecological benefits this additional biomass can provide. Cover crops contribute to crop production through improvement of soil health and fertility, pest management and water availability. A 2012 survey conducted by North Central Sustainable Agriculture Research and Education (SARE) found that under drought conditions, corn and soybeans planted after cover crops yielded 10.6 percent more, on average, than fields without covers. Cover crops can also reduce soil erosion and increase nutrient cycling on farmlands, thereby decreasing the soil and nutrient loads entering our lakes and waterways.
In northern climates, cover crop establishment is often compromised by short growing seasons. Growers attempting to maximize crop yields select corn and soybean varieties that mature later in the year. When summers are cool, as the last two seasons have been, harvest may not occur until mid-November. Even if cover crops can be seeded following grain harvest, few species have the capacity to germinate and grow as temperatures dip below freezing. With a cost of $25-$40 per acre for seed and establishment, a cover crop that fails to produce represents a significant loss and quickly discourages future investment in the practice.
Producers can overcome the limitations of late season establishment by interseeding cover crops into standing corn and soybeans before harvest. According to Michigan State University Extension, the primary challenge to this approach is getting cover seed into the field without damaging the existing cash crop. In the past, dropping seed from an airplane was the only viable way to achieve this. Aerial seeding can work well in large, open fields with few tall obstacles nearby. However, many fields in Michigan are small, irregular in shape and scattered among woodlots. Aerial seeding in this environment often produces less than adequate results.
Fortunately, new technologies are expanding the suite of interseeding options available to growers. One option currently being commercialized by a number of manufacturers is highboy interseeders. These modified sprayer chassis include air seeding equipment in place of spray tanks and drop tubes hanging from the boom to guide seed down between crop rows. Highboy interseeders improve the accuracy of seeding rates and seed placement over aerial seeding. The new Hagie Cover Crop Interseeder (CCI) was recently showcased in Iowa, seeding into standing corn at 8-14 mph carrying 80 ft3 of seed (see photo).
In the near future, another technology may make even the latest highboy interseeders obsolete. At only 22 inches wide and 7 feet long, the “RowBot” may not look very impressive, but this GPS-guided automaton has the ability to broadcast seed and fertilizer into standing corn and soybean crops 24 hours a day without the need for a human operator. Its small size eliminates the potential for crop damage during interseeding operations and reduces costs associated with hardware, fuel and labor. Aside from efficiency, automated terrestrial vehicles like RowBot have the potential to bring unprecedented precision to modern agricultural operations. Much like the farmer of old walking fields, robots can use multimodal sensory equipment to make real time decisions that optimize the yield potential of each plant in the field.
With new establishment technologies on the horizon, cover cropping will soon be more realistic and profitable for Michigan producers than ever before. Those interested in learning more about cover crops are encouraged to visit the Midwest Cover Crops Council website.