Spring Green Manure
Featuring Burkey Farms • Dorchester, Nebraska
Sometimes full season row crops, adverse fall harvest conditions, or lack of manpower limit opportunities for good fall cover crop establishment. All is not lost as some producers are taking a “Plan B” approach and planting a diverse cover crop mixture in the early spring when soil temps reach the low 40’s. This approach still has good growth potential PLUS a spring planting gains extra plant diversity with many spring annuals to choose from. One caution is that if you get caught in a wet early spring weather pattern, spring planting can be a challenge but most years timely establishment is possible.
A good example of this concept in practice is Burkey Farms, an organic farming operation in Southeast Nebraska. They have found that their best irrigated organic corn yields come when living covers are utilized to fix organic N in conjunction with their applied hog manure. To achieve organic N fixation, Burkey Farms will typically fall plant a heavy rate of hairy vetch following bean harvest. However, when fall planting does not get done, diverse spring planted covers heavy in spring annual legumes such as 4010 spring peas and chickling vetch are also utilized.
They report planting these covers about the same time that oats would normally be planted in the region. Burkey Farms told us that they see similar corn yields when using this spring planted system as long as they are patient and allow the covers to grow long enough to do their job. Letting the covers get at least 18-20” tall before termination allows them to make a lush cover averaging 80-150# N on the spring planting and 100-170# N on the overwintered hairy vetch.
Although the primary goal of the Burkey operation is N fixation, spring planted covers offer increased diversity. The Burkey’s have observed the benefits of this diversity using plants such as phacelia, mustards, oats, and flax.