Watershed nitrogen saturation

Much of the debate over whether aquatic systems are being affected by N deposition centers on the concept of nitrogen saturation of forested watersheds. Nitrogen saturation can be defined as a situation in which the... 

Lovett, G. M., K. C. Weathers, and W. V. Sobczak. 2000. Nitrogen saturation and retention in forested watersheds of the Catskill Mountains, NY. Ecological Applications 10 73-84. 

Nodvin, S.C., Van Miegroet, H., Lindberg, S.E., Nicholas, N.S. and Johnson, D.W. (1995). Acidic deposition, ecosystem processes, and nitrogen saturation in a high elevation Southern Appalachian watershed. Water, Air, and Soil Pollution, 85, 1647-1652. 

Typically, phosphorus is added in various forms to a watershed (Figure 9.1). These include fertilizers, nonhazardous wastes (animal manures and biosolids), and nutrient-enriched waters. Historically, organic wastes such as animal manures were applied to agronomic crops and pastures on the basis of the nitrogen availability, which has resulted in excessive application of phosphorus. As a result, many uplands used for land application of wastes have accumulated phosphorus in excess amounts. A major portion of the phosphorus added to uplands is retained within the soil. However, as upland soils become saturated or overloaded with phosphorus, a significant portion of the stored phosphorus can be released and transported with water during runoff events. 

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