Streamside Management Zones Affect Movement of Silvicultural Nitrogen and Phosphorus Fertilizers to Piedmont Streams

Abstract

Forestry best management practices (BMP) recommendations for streamside management zones (SMZs) are based on limited data regarding SMZ width, partial harvests, and nutrient movements after forest fertilization. Agricultural fertilization is commonly linked to increased stream nutrients. However, less is known about effectiveness of SMZ options for controlling nutrient movements after silvicultural fertilization. Diammonium phosphate and urea were applied to 12 subwatersheds in 3-year-old loblolly pine (Pinus taeda L.) plantations in the Virginia Piedmont. Three replicates of four SMZ treatments were superimposed on 12 subwatersheds in a previous SMZ harvest sediment study . Surface, near-surface, subsurface, and stream water samples were collected monthly for 1 year and analyzed for nitrate (NO 3 Ϫ ), ammonium (NH 4 ϩ ), and orthophosphate (ortho-P). Transected measurements from streamside to fertilized plantations allowed interpretations of spatial nutrient measurements across SMZs. When compared with wider SMZs, 7.6-m SMZs had 3-10ϫ surface water NO 3 Ϫ , 3-6ϫ near-surface water NO 3 Ϫ , and 1-2ϫ more stream water NO 3 Ϫ . No significant differences were detected for NH 4 ϩ for any SMZ treatment. The 15.2-m SMZ thin had small but significant increases (2-8ϫ) in surface runoff for ortho-P relative to other SMZ treatments, perhaps because of increased surface water movement along thinning corridors. Across all SMZ treatments, comparisons of stream edges with fertilized stands indicated NO 3Ϫ reductions of 33-98%, NH 4 ϩ reductions of 68 -97%, and ortho-P reductions of 70 -98%. A 39% rainfall deficit during the study influenced results, but conventional SMZs Ն 15.2 m protected streams from fertilization nutrient increases. This article uses metric units; the applicable conversion factors are: meters (m): 1 m ϭ 3.3 ft; millimeters (mm): 1 mm ϭ 0.039 in; milliliters (mL): 1 mL ϭ 0.061 in. 2 (dry) ϭ 0.27 fluid dram (liquid); milligrams (mg): 1 mg ϭ 0.015 gram; kilograms (kg): 1 kg ϭ 2.2 lb; hectares (ha): 1 ha ϭ 2.47 ac.

Increased growth rates of stream salamanders following forest harvesting

“…Following timber harvesting, the amount of dissolved nutrients leached from soil to the stream may increase until vegetation becomes reestablished, though riparian buffers minimize overland flow of water into streams (Swank, 1988 ; Swank et al, 2001 ; Webster et al, 1992 ). Fertilizer application to newly planted stands may further increase nutrient inputs to streams (Binkley et al, 1999 ), although riparian buffers can minimize inputs (Kastendick et al, 2012 ; Secoges et al, 2013 ). Similarly, disturbance to the upland overstory may add a brief pulse of nutrients in the form of organic matter to streams after harvest.…”

“…For (Swank, 1988;Swank et al, 2001;Webster et al, 1992). Fertilizer application to newly planted stands may further increase nutrient inputs to streams (Binkley et al, 1999), although riparian buffers can minimize inputs (Kastendick et al, 2012;Secoges et al, 2013). Similarly, disturbance to the upland overstory may add a brief pulse of nutrients in the form of organic matter to streams after harvest.…”

Clearcutting and pine planting effects on nutrient concentrations and export in two mixed use headwater streams: Upper Coastal Plain, Southeastern USA

“…Wynn et al, 2000;McBroom et al, 2008). A recent study of nutrient release after timber harvest with modern BMPs (Secoges et al, 2013) also found minor increases in nitrate concentrations, in the range of a few tens of μg L À1 , less than the increase of 67-340 μg L À1 observed here, but all a tiny fraction of increases observed without BMPs (Likens et al, 1970). The lack of changes to P concentrations is probably because of the previously observed lack of response of sediment concentrations (Terrell et al, 2011), because P tends to move with small sediment particles (Barling and Moore, 1994).…”

Environmental effects of short‐rotation woody crops for bioenergy: What is and isn't known

“…The effects of forest fertilization on water quality can be greatest when fertilizers are applied: (a) repeatedly; (b) as ammonium nitrate; (c) to nitrogen‐saturated forests; (d) directly to streams; or (e) shortly before rainfall events (Beltran et al, ; Binkley, Burnham, & Allen, ; McBroom et al, ). Streamside management zones (SMZs) can reduce nutrient inputs to adjacent water bodies (Perrin, Shortreed, & Stockner, ; Secoges, Aust, Seiler, Dolloff, & Lakel, ), but SMZs may be less effective at retaining nutrients traveling via subsurface flow paths than overland flow (Edwards & Willard, ), and stream water nutrient concentrations can increase after fertilizer application even when SMZs are implemented (McBroom et al, ).…”