Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2001
Publication Date: June 1, 2002
Citation: NOVAK, J.M., HUNT, P.G., STONE, K.C., WATTS, D.W., JOHNSON, M.H. RIPARIAN ZONE IMPACT ON PHOSPHORUS MOVEMENT TO A COASTAL PLAIN BLACK WATER STREAM. JOURNAL OF SOIL AND WATER CONSERVATION. 2002. V. 57. P. 127-133. Interpretive Summary: Riparian zones are common landscape features forming a natural border between agricultural fields and surface water systems. These zones can reduce the entry into these stream systems of nutrients lost from the agricultural fields during storm runoff events. Excess nutrients in surface water systems may exceed the ability of the stream system to function in a healthy manner. Plants and other organisms that live in the riparian zone are efficient at using these nutrients for growth and reproduction. However, if the quantity of nutrients is higher than the amount consumed by these plants and organisms, then some leakage into the stream system may occur. It is important for the maintenance of high water quality to determine the effectiveness of these zones to filter out excess nutrients. Our concern was to study the ability of a forested wetland to reduce nutrient input into a local stream system from a field that has been used for animal waste disposal. The concentrations of phosphorus, a plant nutrient contained in the manure, were measured in soil and in ground water wells in areas receiving manure and in areas within the riparian zone. We also measured phosphorus concentrations in a stream that receives drainage from the field and riparian zone. Very low P concentrations were measured in soil and ground water in riparian areas close to the stream and also very low concentrations were measured in stream water. Our results demonstrated that this riparian zone was effective at reducing the entry of phosphorus into the local stream thus preserving stream water quality.
Technical Abstract: Riparian zones are an important conservation practice because they can reduce the entry of sediments and nutrients into sensitive aquatic ecosystems. We evaluated the effectiveness of a Coastal Plain riparian zone to reduce the movement of phosphorus (P) into a local stream from an overloaded swine manure spray field. Soil P concentrations (Mehlich 3 P, M3P; and total P, TP) were measured along four transects consisting of a spray field, grass strip, mid-riparian, and stream edge area. Dissolved P (DP) was measured in ground water wells located in the spray field, grass strip, stream edge, and in-stream grab samples. The spray field and grass strip area had high surface and subsurface M3P concentrations. Low M3P concentrations were detected in surface and subsurface soils in the mid-riparian and stream edge area indicating effective retention of P by the grass strip area. Elevated DP concentrations were detected in the spray field and grass strip wells, while stream edge wells were low. Furthermore, stream grab samples were consistently low in DP concentrations. The riparian zone contributed to a reduction in DP concentrations between the grass strip and stream edge wells. This confirms that a riparian zone can effectively limit the movement of P-enriched sediments and reduce DP-enriched ground water from entering a local stream even in a heavily loaded situation.