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WATERSHED NITROGEN AND PHOSPHOROUS BALANCE: THE UPPER POTOMAC RIVER BASIN
Citation:
Jaworski, N., P. Groffman, A. Keller, AND J. Prager. WATERSHED NITROGEN AND PHOSPHOROUS BALANCE: THE UPPER POTOMAC RIVER BASIN. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/199 (NTIS PB93199586).
Description:
Nitrogen and phosphorus mass balances were estimated for the portion of the Potomac River basin watershed located above Washington, D.C. he total nitrogen (N) balance included seven input source terms, six sinks, and one "change-in-storage" term, but was simplified to five input terms and three output terms. he phosphorus (P) balance had four input and three output terms. he estimated balances are based on watershed data from seven information sources. ajor sources of nitrogen are animal waste and atmospheric deposition. he major sources of phosphorus are animal waste and fertilizer. he major sink for nitrogen is combined denitrification, volatilization, and change-in-storage. he major sink for phosphorus is change-in-storage. iver exports of N and P were 17% and 8%, respectively, of the total N and P inputs. ver 60% of the N and P were volatilized or stored. he major input and output terms on the budget are estimated from direct measurements, but the hange-in-storage term is calculated by difference. he factors regulating retention and storage processes are di and research needs are identified.