Nitrogen Uptake and Release in a Forested Watershed, Lake Tahoe Basin, California

作者：Robert N. Coats, Robert L. Leonard, Charles R. Goldman · 发表于：Ecology · 年份：1976 · DOI：10.2307/1941064 · 被引用次数：63 · 研究领域：Soil and Water Nutrient Dynamics、Hydrology and Watershed Management Studies、Peatlands and Wetlands Ecology

Inorganic nitrogen supply is an important factor limiting primary productivity in Lake Tahoe, Californai—Nevada. To estimate the influence of a watershed ecosystem on nitrogen input to the lake, samples of precipitation, soil water and stream water were collected and analyzed for NO_3—N, NH_4—N and, with less intensity, dissolved organic nitrogen. Factors controlling nitrification in selected plots were studied using a soil perfusion technique. Inorganic nitrogen input by precipitation to the watershed is 1—2 kg° ha(—1)°yr(—1). Output of inorganic nitrogen from the watershed to the lake is 10 to 33% of the precipitation input. Inorganic nitrogen is removed from snowmelt water almost completely by well—developed conifer stands, but less efficiently by poorly developed or disturbed stands. Alder stands release NO_3—N to soil water especially in fall and early winter. Nitrification does occur in some coniferous forest soils in the watershed and is closely associated with NO_3—N release. The occurrence of significant nitrification in the watershed is related more to the C:N ratio and stand basal area than to either pH or release of toxic substances by decaying litter.