After the final cutting for the year, it doesn't matter much if hay bales and stacks set on cut fields for a while. But when more harvests are expected off that field, delaying removal can be harmful, says Bruce Anderson, University of Nebraska agronomy professor.
Anderson says plants underneath often are killed if covered for more than a week or two, providing a great starting place for weeds. Most of the damage, however, is due to wheel traffic on the regrowth. Studies show that when fields are dry, plants driven on before regrowth occurs yield about 5-7% less at next cutting.
Even worse was waiting to remove bales. Just seven days after cutting, when regrowth shoots had started to grow, yield was reduced by more than 25% and survival of these plants also was less.
Worst of all is removing bales when fields are wet, as wheel traffic causes much more compaction, with yield loss typically exceeding 30%.
These studies emphasize the benefits of baling and removing bales from hay fields as quickly as possible after cutting, as well as minimizing driving on wet soils. They also suggest that following the same trail when removing bales or stacks from fields can reduce losses from wheel tracks by limiting the total area damaged.
Hay fields must be driven on, of course, to remove bales after harvest. But you can lessen damage by controlling where, when and how often you drive.