Should I harvest the Last Cutting?

Richard Leep

Department of Crop and Soil Sciences

 Michigan State University

Many producers are debating on whether to leave the last cutting in the field.  This leads to the question of what are the consequences of doing this?

First of all, there may be some benefits from leaving a cutting in the field because carbohydrates will build up in the roots and crown of alflafa plants.  This will result in larger bud and crown size when the crop is left in the field.   With additional carbohydrates and proteins in the crowns and roots, alfalfa will usually be more vigorous and yield more in the first cutting the following spring. 

There are also negative impacts from leaving the cutting in the field, especially if they’re if significant amounts of grass forage in the cutting, lodging can occur.  Lodging and the associated mold can cause damage to the alfalfa stand.  In addition, the first harvest quality in the spring can be lower if residue is left in the field.  Pure stands of alfalfa left in the fall will rarely lodge as the leave drop off the stems with frosts in the late fall. 

Flail chopping the mature alfalfa/grass onto the field in order to minimize any of the negative effects can be done as long as the tonnage is low and the crowns aren’t covered with residue.  If the cutting is left in the field it can also be flail chopped back unto the field in the spring.  Setting the rake, chopper, or bailer higher than normal can minimize the amount of old residue in the first cutting, thus increasing the forage quality of the harvest.

In summary, the best option may be to leave those older stands which are going to be plowed down anyway as the excess top growth will increase the fertilizer nitrogen value of the plowed alfalfa crop. Leaving the residue does not hurt the stand unless there is significant grass and matting occurs. Steps should be taken to minimize residue in the first harvest in the spring.