The effectiveness of streamside management zones in controlling nutrient fluxes following an industrial fertilizer applicationThis article is part of a larger document. View the larger document here.
Many State best management practice programs recommend streamside management zone (SMZ) widths based on limited or inadequate data with regard to nutrient fluxes from silvicultural activities. Diammonium phosphate and urea were applied to subwatersheds of 2- to 3-year-old loblolly pines (Pinus taeda) upslope from 12 SMZ study areas in Buckingham County, VA. Three replications of four SMZ treatments (30.5 m, 15.2 m nonthinned, 15.2 m thinned, and 7.6 m) were studied using ionic exchange membranes. Our hypothesis is that nitrogen and phosphorous levels will decrease in a forested SMZ setting as distance from the harvest boundary to the creek increases. Furthermore, we hypothesize that wider, unthinned SMZs are more likely to prevent nutrients from reaching the creek than narrower and/or thinned SMZs. Preliminary results indicate stream water quality is unaffected by fertilization at all SMZ width treatments. Nutrient movement in the upper soil and litter layer through the various SMZ widths will be discussed.