NDSU Extension Service, Published August 02 2012
Volunteer crops can provide additional animal feedThere are reports of hay shortages, especially in western North Dakota, because rainfall has been sparse this growing season.
"However, there may be some opportunities to grow some animal feed after the early season crops, such as wheat and peas, are harvested," says Hans Kandel, North Dakota State University Extension Service agronomist. "Of course, the opportunities depend on the availability of rainfall and residual soil moisture."
Dry peas are being harvested and some fields are tilled just after the harvest or may receive a late chemical burn-down to prepare the field for the next growing season. There are opportunities to utilize these fields for a volunteer pea feed crop.
At harvest, a small percentage of the dry field pea seeds will have dropped to the ground, even when combines are well-adjusted. These seeds may be stimulated to germinate and start growing. However, it may require a light harrowing of the field to incorporate the seed.
Soil moisture is essential for germination to take place. As the stimulated volunteer plants are following the main crop of field peas, there will be high numbers of Rhizobium leguminosarum bacteria (inoculum) in the soil, so nodulation typically is excellent.
The growing pea plants will provide a cover to protect the soil from erosive forces. This system can make use of the remaining growing season because field peas are tolerant to minor frost.
The total amount of biomass produced depends upon the pea plant's density, timing of regrowth, soil moisture, rainfall and the date of a killing frost.
The volunteer pea crop can be used for grazing.
"Research at the Carrington Research Extension Center in 2008 found that fall- produced dry pea biomass reached 1,500 to 3,000 pounds per acre," Kandel says "After grazing, the leftover pea stubble can be worked into the soil as a green manure or left through the winter. However, there is not enough time left to expect to harvest a second dry pea crop for seed."
Similarly to dry peas, residual small-grain seeds (wheat, barley or oats) could be worked into the soil with a light harrowing to assure good seed-to-soil contact. Sufficient moisture in the topsoil is needed for germination.
The volunteer grain will take up some of the residual nitrogen. However, because it is following a main crop just harvested, there may not be sufficient nitrogen available for the plants to maximize productivity.
If there is enough rain, some additional nitrogen applied after emergence and establishment to stimulate crop growth may be beneficial.
"The risk of this system is when winter wheat is planted in the neighborhood of the volunteer small-grain crop," says Joel Ransom, NDSU Extension Service agronomist. "The volunteer crop forms a green bridge for wheat curl mites that vector the wheat streak mosaic virus, which is a disease that can survive on grassy weeds, corn and volunteer grain. The mites might move from the growing volunteer crop to the newly seeded winter wheat plants. This would put the winter wheat crop at risk."
Under good growing conditions, a volunteer wheat crop can produce about 3,100 to 3,500 pounds of dry matter.
The dry peas or other small-grain volunteer systems will use soil moisture that may deplete the reserves for next year's crop.
Other options to increase the chances of getting a good, well-established crop stand is to broadcast some additional small-grain seeds or other species that develop well in the fall, such as radishes.
"The systems described will work best with grazing because there usually is not enough tonnage to justify haying," Kandel says.