When harvesting alfalfa, minimize wheel-traffic damage by avoiding unnecessary trips across the field, advises Eric Young, agronomist and soil scientist at the Miner Institute, Chazy, NY.

University of Wisconsin research revealed that the amount of damage is related to the amount of regrowth when the crop is driven on. It showed a 4-6% yield reduction when alfalfa was driven on one day after mowing, and 20% when wheel traffic happened five days after cutting.

“Soil compaction from tractors and manure spreaders also reduces alfalfa productivity and persistence,” says Young. “Compacted soil reduces pore space and hinders fine root growth.”

Lower field areas usually are most susceptible to compaction because the soil is wetter and tends to have more silt and/or clay compared to higher areas.

He lists five management practices that can help minimize alfalfa damage caused by wheel traffic and compaction:

1) Harvest as quickly as possible after mowing, using wide swaths to speed drying, to avoid traveling on alfalfa regrowth.

2) If applying manure, apply it as soon as possible following harvest, always before regrowth, and avoid spreading on wet fields.

3) Utilize controlled-traffic patterns to minimize the field area traveled on. For example, utilize the same area of the field to the extent possible when entering and exiting the field with trucks or forage wagons.

4) Consider planting traffic-tolerant alfalfa varieties.

5) Avoid using dual-wheel tractors on alfalfa fields, and try to utilize lighter-weight tractors when merging, raking, etc.