Streamside Management Zones Effectiveness for Protecting Water Quality after Forestland Application of Biosolids

Abstract

Biosolids, materials resulting from domestic sewage treatment, are surface applied to forest soils to increase phosphorus (P), nitrate, and ammonium availability. Retaining streamside management zones (SMZs) can limit nutrient pollution of streams. We delineated 15-m SMZs along three intermittent streams in an 18-yr-old Pinus taeda L. plantation. We applied biosolids at a rate of 1120 and 629 kg ha(-1) of total nitrogen and total P outside the SMZ on one side of each of the streams while maintaining the other side of the stream as control. We collected water samples from the three treated and six reference streams and from the perennial stream upstream and downstream from the intermittent streams for 12 mo after treatment. Along transects perpendicular to the treated streams, we collected overland flow samples, soil solution samples at 60 cm, and extracts from ion exchange membranes (IEMs) placed in the surface soil. We observed significantly elevated P concentrations adjacent to the stream in overland flow during one period on the treated side of the stream. We found significantly elevated nitrate concentrations outside the SMZ in the treated-side soil solution samples, in which concentrations remained below 1.5 mg L(-1). Phosphorus, nitrate, and ammonium concentrations outside the SMZ in treated-side IEM extracts showed significant increases after biosolids application, returning to near control levels after 1 yr. Phosphorus, nitrate, and ammonium concentrations in IEM extracts were not different adjacent to the streams. Stream P, nitrate, and ammonium concentrations showed few differences downstream from the treatment with concentrations below 1.5 mg L(-1). Our results indicate that at 15 m, SMZ protected streams from P, nitrate, and ammonium pollution for the first year after biosolids application to adjacent loblolly pine plantations in the Virginia Piedmont.

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

“…These values are higher than the total N removal levels of 60 -80 found in the Allegheny Plateau (Kochenderfer and Hornbeck 1999) and Cumberland Plateau (Arthur et al 1998) and are six times higher than those reported by Wynn et al (2000) for the Coastal Plain. The higher NO 3 Ϫ removal efficiencies found in this study are suspected to be partially caused by the dry conditions, but Pratt and Fox (2009) also found Ն90% NO 3 Ϫ removal efficiencies from subsurface water in SMZs located adjacent to biosolid applications in the Virginia Piedmont. NH 4 ϩ removals between the fertilized stands and stream edge ranged from 68.7 to 92.8 in surface waters and 87 to 97.4 for near-surface waters (Table 6).…”

“…Their nutrient analyses were based on limited samples, because of drought conditions, but the authors speculated that the 15-m SMZ, with or without harvest, appeared to be sufficient for minimizing NO 3 Ϫ and P movement to the stream. Pratt and Fox (2009) evaluated the effectiveness of 15.2-m-wide SMZs for minimizing movement of N and P to streams after applications of biosolids in the Virginia Piedmont. The biosolids were applied to an 18-year-old loblolly pine plantation at rates of 1,120 kg ha Ϫ1 for N and 629 kg ha Ϫ1 for P. After 1 year of monitoring, their results indicated that the 15.2-m buffer was adequate for nonpoint source pollution protection, although they did find one period of elevated stream P after overland flow.…”

“…For the near-surface movement of NH 4 ϩ and NO 3 Ϫ , cation and anion transfer membranes were inserted in the Oa and Ap horizons as described by Cooperband and Logan (1994), Subler et al (1995), and Pratt and Fox (2009). These transfer membranes provide an index of nutrient movement across their surface, but they are reported in milligrams per square meter per day for the nutrient rather than concentrations.…”

U.S. Billion-Ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

“…Wood ash, created during wood combustion for energy, can be safely used to replace calcium and other basic cations removed through biomass harvesting (Pitman, 2006). Concerns related to the impact of forest fertilization on water quality have generally been unfounded (Binkley et al, 1999), even in intensively managed systems (McBroom et al, 2008) or when biosolids are applied (Pratt and Fox, 2009). …”

Economic Analysis of a Pine Plantation Receiving Repeated Applications of Biosolids

“…Forest land application, rather than applying biosolids to agricultural land, can reduce the risk of contaminants entering the human food chain [8]. In addition, forest application can increase tree growth and subsequent economic returns [9], [10], [11], [12]. However, few studies have been conducted to quantify the economic return of forests associated with land application of biosolids.…”