In year three, Bob plants a spring grain with a lower nitrogen requirement such as soft white wheat, buckwheat or barley, and underseeds it with alfalfa. If the alfalfa survives the harsh Montana winter, he manages it as a hay crop for a year to help control wild oats and other weeds. It also provides an alternate cash crop, helps prevent soil erosion, and improves the soil. Bob incorporates the hay regrowth in April of year five for early soil-building and to provide organic matter for the fall wheat crop. If the alfalfa does not survive, he plants peas in the spring of the fourth year followed by winter wheat in the fall.
Every year is different.
You begin to see patterns. Learning how to respond to the differences is the biggest challenge, but that's also half the fun. Volunteer plants are also a problem with some crops. Again, Bob minimizes the nuisance of volunteers through his planned rotations. Crops that are prone to produce volunteers in the following season are never followed by similar grains.