A Massey University soil scientist Professor Michael Hedley says resting wet farmland is the best way to avoid soil compaction by dairy herds.
The government's State of the Environment Report, released yesterday, says soil compacted by heavy animals and machines can lead to run-off and soil erosion.
Professor Hedley said the combination of compacted soil and rain caused problems.
"Theoretically compacted soils will generate more runoff if the compaction takes the soil to a point where the rate at which water can move into the soil is slower than the rate at which water is falling on the soil.
"Generally we find that runoff occurs when soils are saturated anyway so if your soil has serious compaction the time at which runoff can occur might be slightly prolonged."
Pugging damage is caused by animal hooves, and Professor Hedley said avoiding it required keeping an eye on the weather forecast.
"What we're trying to work on are solutions to avoid getting severe pugging damage or compaction in the first place.
"That's like recognising when climate events are coming and your soil is likely to be pugged or severely compacted and having the ability to stand cows off while its raining, when soils are saturated and allowing them periods to drain for half a day, a day before you put them back on. So it's really looking at standoff during wet events."