Owens et. al. report that the critical time for pastures, in the eastern United States, is during the dormant season, which falls from November through April, typically. This is when conditions are wet and soils are partially thawed, making them extremely vulnerable to the effects of trampling and compaction, thereby reducing vegetative cover and infiltration, and increasing runoff and sediment yield. Annual runoff was more than 10% of precipitation during Period 1 and less than 2% during Periods 2 and 3. The decrease in annual sediment loss was even greater with the change in management. Over 60% of the soil loss during Period 1 occurred during the dormant season. In response to weather inputs, there was considerable seasonal and annual variation in runoff and soil loss within management periods. Low amounts of runoff and erosion from three adjacent watersheds, with summer-only grazing, supported the conclusion that the increased runoff and erosion during Period 1 resulted from the non-rotational, winter feeding on pastures. When the management was changed, the impacts of the previous treatment were not long lasting, changing within a year.
Runoff and sediment losses resulting from winter feeding on pastures