Inorganic and suspended/dissolved-organic nitrogen in Sierra Nevada soil core leachates

• Published in: Journal of environmental quality 1998-07, Vol.27 (4), p.755-760
• Main Authors: Marcus, J.A. (University of Nevada, Reno, NV.), Miller, W.W, Blank, R.R
• Format: Article
• Language: English
• Subjects: Applied sciences; BASSIN VERSANT; Biological and physicochemical properties of pollutants. Interaction in the soil; COMPOSE ORGANOAZOTE; COMPUESTO ORGANICO DEL NITROGENO; CUENCAS HIDROGRAFICAS; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; LEACHATES; LESSIVAT; LIXIVIADOS; NEVADA; Organic nitrogen; ORGANIC NITROGEN COMPOUNDS; Pollution; POLLUTION DE L'EAU; Pollution, environment geology; POLUCION DEL AGUA; Soil and sediments pollution; WATER POLLUTION; WATERSHEDS
• ISSN: 0047-2425; 1537-2537
• DOI: 10.2134/jeq1998.00472425002700040005x

Watershed disturbance has been suggested as a possible mechanism for accelerated nutrient input into Lake Tahoe, California/Nevada. However, little is known regarding how nutrient discharge is coupled to physicochemical watershed processes. Recent investigations in the Lake Tahoe Basin have suggested that suspended/dissolved-organic nutrient transport may play an important role in lake and tributary water quality. The mobility of inorganic and suspended/dissolved-organic N in soils of a Lake Tahoe watershed was assessed using constant head permeameter leaching experiments with intact soil cores. We evaluated the interaction of plot condition (riparian, nonforested, and forested) and soil depth (0-15 and 15-30 cm) on magnitude and form of N discharge. Incremental leachate discharge was analyzed for concentrations of inorganic (NH4-N and NO3-N) and suspended/sissolved-organic N. Leachate from the riparian soil cores had significantly higher (P 0.05) concentrations and total discharge NO3-N than that from the nonforested or forested areas. Loading of NH4-N was more consistent among vegetative cover types, but the riparian leachate again contributed a significantly (P 0.05) greater amount. Suspended/dissolved-organic N was mobile and the most dominant form of N for nonforested and forested soil cores with discharge loading ratios (suspended/dissolved-organic:inorganic) of 17:1 and 7:1, respectively. Although the loading ratio was approximately 1:1 for the riparian soil cores, the amount of suspended/dissolved-organic N discharged was greatest. The mobility and presence of significant amounts of suspended/dissolved-organic N indicate that this once unrecognized nutrient form is an important component in at least one Sierra Nevada watershed, and should be more fully investigated elsewhere