HYDROLOGY AND CHEMICAL-QUALITY OF FLOW FROM SMALL PASTURED WATERSHEDS .1. HYDROLOGY

Surface runoff, soil loss, and subsurface flow were measured from four rotationally grazed summer pastures. One of these pastures was also used as a winter-feeding area. Surface runoff volumes and peak rates from the three pastures used only for summer grazing were generally less as compared with values for earlier years when the fields were in meadow and light pasturing; however, runoff from the winter-feeding area was markedly increased. Both before and after the initiation of grazing, the areas used only for summer grazing had but a trace of soil loss. More soil was lost from the winter-feeding area, particularly during the dormant season. Water-balance studies indicated that during the growing season surface runoff and subsurface outflow were higher and evapotranspiration (ET) was less from the winter-feeding area than from areas summer-grazed only. During the dormant season, surface runoff was higher and subsurface outflow was lower from the winter-feeding area than from the summer-grazed areas, whereas ET was similar.; Surface runoff, soil loss, and subsurface flow were measured from four rotationally grazed summer pastures. One of these pastures was also used as a winter-feeding area. Surface runoff volumes and peak rates from the three pastures used only for summer grazing were generally less as compared with values for earlier years when the fields were in meadow and light pasturing; however, runoff from the winterfeeding area was markedly increased. Both before and after the initiation of grazing, the areas used only for summer grazing had but a trace of soil loss. More soil was lost from the winter-feeding area, particularly during the dormant season. Water-balance studies indicated that during the growing season surface runoff and subsurface outflow was lower from the winter-feeding area than from the summer-grazed areas, whereas ET was similar.