I am in the process of building a roller and would like information
on the cover crop that I can roll the soonest in the spring
in order to get corn in the ground by May 10.
You just asked the million-dollar question. Almost every farmer
would like a cover crop that supplies enough nitrogen to grow
a good crop of corn and be ready to roll down by the 10th
of May. The reality, as it stands today, is that this cover
crop doesn't exist for us in northern climates. In the southern
states where the winter is more mild, crops like crimson clover
work very well. For us here in Pennsylvania, hairy vetch is
a better choice, but it often can't be rolled till the last
week of May or even June 1—not what we'd prefer.
In my mind, this prompts the question we need to pose to
seed breeders: Can you breed earlier flowering into our selected
cover crops? The answer has been “yes.” Dr. Tom
Devine at the USDA research station in Beltsville, Maryland,
has developed a variety that flowers at least 10 days to 2
weeks earlier. I seriously believe this could be done with
many other cover crop species.
There are of course other cover crops that can be rolled.
Rye, wheat or barley could work and be rolled earlier but
aren't legumes. Winter peas, radish and many other annuals
could work. Some trial and error is bound to take place on
the learning curve. I will tell you that it is critical to
the system that one is patient and wait till the optimum time
to roll to prevent re-growth. While this isn't always easy,
it seems to be very important to the success of the operation.
So, in reflecting on your question, there is no “wonder
plant” that will work everywhere with every crop or
that will do exactly what you want. But, if you are willing
to compromise on some points, I believe the system will work
for you. You may want to contact Dr. Steve Zwinger at North
Dakota State (701-652-2951), who is a partner on our project
and may have some information from a site closer to you.