King’s AgriSeeds tests cover crop mixes (also known as “cocktails”) that incorporate very different species to achieve maximum benefit in a rotation. Depending on the species, many needs may be fulfilled in a single crop cocktail.
This fall, King’s planted over 50 small plots for research and demonstration of cover crops, showing mixtures of various species, as well as the effects of varying seeding rates and planting dates. Plots showcase creative variations of grass and legume mixes, as well as some brassicas, all of which were formulated with attention to the agronomic attributes of each species.
Crimson Clover-Manure Treatment for Corn
One of our research fields contains corn plots, in which the benefits of the preceding cover crop management were apparent – both visually and in the numbers. These plots included 21 hybrids that all grew vigorously, maintained plant health, and excelled in both grain (181 to 283 Bu/A at 15.5% moisture) and silage yields (26.97 to 39.5 tons/A at 65% moisture). The plots had received no additional fertility other than a preceding crimson clover cover crop that had been grown to the full bloom stage, then had been sprayed and killed. The clover was then spread with semi-solid manure. Following this, the corn plots were no-till planted into this nitrogen-rich mulch mat, which provided a steady slow release fertilizer as the nitrogen in the biomass and manure mineralized over the course of the corn’s growth. The cover crop/manure mat formed a plaster-like consistency as it dried and provided excellent weed control until it began to break down. Post-emerge herbicides were also sprayed to enhance and complete the weed control. During our cover crop field day we uncovered and showed our earthworms busily working and feeding on the remains of the cover crop mat and pulling it down into their holes, digesting it and leaving nutrient rich worm castings in our plots, improving soil quality even more. Our research agronomist pointed out that because of the ecological health of our system and our year-round ground cover, the worms were alive and well and feeding profusely.
Hairy Vetch-Oats-Crimson Clover Treatment for Corn
An adjacent field was planted in a mixture of hairy vetch, oats, and crimson clover, in preparation for 2015 corn research plots. This cover crop will be managed in a similar manner to last winter’s crimson clover, – sprayed and plastered with manure prior to the no-till corn planting next spring. Because of the prolific, viny nature of the hairy vetch in the mix, the cover crops will be rolled down to flatten them into a mulch with a packer, after being sprayed and before the no-till planting of corn. The 3-species mix provides nitrogen from the legumes, a certain degree of other nutrient cycling, as well as a diverse, weed-suppressing canopy.
Clover-Radish-Oat Cool Season Forage and Treatment for Corn
A production field on this farm intended for twin rows of short-season silage corn in 2015 had been planted in a mix of 3-Way Clover, crimson clover, radish and oat. This crop gave an excellent example of a late summer-planted, multi-purpose cover. The crop was criss-cross seeded (in two perpendicular directions across the field) for maximum biomass production and canopy. It provided several crops in one. The oats and radish played double-duty – they scavenged and held onto nitrate nitrogen early in the fall, then were cut for forage in mid-October, opening up the canopy to allow the lower- and slower-growing clover mix to take off as a winter cover crop. The oats and many leafy radish tops also began to regrow. The clover will fix nitrogen for the following corn crop, and though the radish regrowth will winter kill, the tuber growth has penetrated and broken up soil, and the decomposing radish tissues hold scavenged nitrogen for the following crop. As we head into winter, though, the frost-killed radishes give nitrogen back to the roots of the clover as it establishes more fully.
Two Crops in One
An additional advantage to this mix is that it allows us grow two crops in one, as we would not have enough time to create a triple-crop scenario in which corn was followed by fall oats and radish, and THEN ESTABLISH a winter clover cover crop, yet the combination allowed us to reap the advantages of both within the season’s time constraints, as combined cover crop and forage.
Many farmers turn to cover crops because their primary concern is erosion and topsoil conservation, and growing a winter cover to be harvested as a forage still fulfills this and many other traditional cover crop functions, including fixing and scavenging nitrogen and boosting soil organic matter with root biomass.
This is the key to creating a successful mix – considering the role of each species and being very intentional about the addition of each component.
Swapping Species By Plant Function
A mix like this is also fully flexible – various species with similar agronomic properties and plant structure can be interchanged to perform similar functions. Ryegrass and triticale could be grown in place of oats and radish with the clover, for example, to provide both the nitrogen scavenging function as well as that upper story of forage growth that can be harvested while leaving a clover understory.
Mixes for Forage, Too
A look at King’s Farming Systems plots further illustrates the adaption of various roles of each crop in rotation, as well as the overall goal to maximize forage production per acre on the farm. The double- and triple-cropping systems used in each sample rotation include warm season annuals, cool season annuals, and perennials. Here again are mixes whose merits were considered for both cover crop and forage use and contain the potential for a relay-type succession within a single planting to stretch across multiple growing windows, such as King’s- Double Play (triticale, annual ryegrass, and oats) and Trit-Oats (triticale and oats). These mixes give us the opportunity for both a fall and spring harvest, as they include a fall annual and a winter annual(s). Groundcover can be maintained for most days of the year, along with nutrient retention and a habitat for diverse soil fauna and microbial life.
Not only does forage and cover crop value have to be considered (there’s overlap here, but also marked differences), but growing window of each species is also a key point in choosing a crop for the rotation. King’s research carefully emphasizes mixtures for forage and cover crops in the context of rotation, timing, and future farming goals.
Penn State is ramping up extensive and in-depth research on cover crop cocktails as well, and King’s works in collaboration with them. Their goals include
- Investigate the benefits and tradeoffs of using winter cover crop mixtures, or “cocktails,” instead of monoculture cover crops
- Collaborate with farmers in Pennsylvania to conduct on-farm participatory research within realistic management constraints
- Complete extension and outreach on farms across Pennsylvania, especially to benefit farmers working in organic feed and forage systems
Please see their Cover Crop Cocktails Newsletter for research findings and more information about projects underway.