Assessing spring alfalfa stands (Stan McGraw)
Fall and spring are the best times to assess alfalfa stands and evaluate the stands for yield potential in the cropping system. Fall is a great time to decide if alfalfa field needs to be replaced or left for another year. During spring, we try to assess winterkill, potential damage from cold temperatures, ponding of freezing water, and disease prevalence in alfalfa plants.
Do some digging
Pick several spots in the field and dig up all the plants within a square foot. Look at each plant and count the stems on each root. You can determine action based upon how many stems are found.
- More than 55 stems: Yield is not limited.
- 40 to 45 stems: Yield is probably okay, but needs to be monitored.
- Less than 39 stems: Action is likely required.
Next, slice the root in half. Check for discoloration, firmness and general appearance. By checking the roots, you can get an idea of disease that may be present. Browning or softness of the root may indicate poor root/crown health and some sort of action may be needed for the field.
Make a plan
Setting an action plan for an alfalfa field depends on a lot of variables. Tons of forage needed, rotation in the cropping system, and availability of other fields to plant alfalfa are all factors that will help you determine whether a particular field needs to be terminated. Can cool-season grasses be interceded in this field or is a high percentage of alfalfa preferred? Evaluating the field now is a priority versus waiting until the first crop cutting.