Nutrient cycling, water quality, forest hydrology, fertility, acid deposition
One year of pre-harvest and five years of post-harvest water chemistry data were collected and analyzed for N03-N, TKN, TP, OP, K and Ca on nine small watersheds in the Ouachita Mountains of central Arkansas. Gross exports of all nutrients except TKN were significantly increased by cl earcutting followed by mechanical site preparation and broadcast burning of slash. Discharge-weighted nutrient concentrations were increased only for OP, K and Ca. The treatment effect was brief, lasting only one year. The first harvest of a selection system regime had no measurable effect on gross losses or concentrations of nutrients. Precipitation chemistry measurements from the region indicated that annual imports of all nutrients considered in this study generally exceed the gross losses measured. However, because of the possible threat to soil fertility by the leaching effects of acid deposition, foresters should be especially vigilant in their efforts to protect site productivity where soils are low in base cations.
Beasley, R. S.; Miller, E. L.; and Lawson, E. R.. 1987. Chemical Properties of Soils and Streams in Natural and Disturbed Forest Ecosystems in the Ouachita Mountains. Arkansas Water Resources Center, Fayetteville, AR. PUB 132. 99