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Moist‐ and Dry‐Season Nitrogen Transport in Sierra Nevada Soils
Author(s) -
Burcar S.,
Miller W. W.,
Tyler S. W.,
Blank R. R.
Publication year - 1997
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1997.03615995006100060032x
Subject(s) - soil water , environmental science , surface runoff , macropore , andesite , nutrient , hydrology (agriculture) , soil horizon , agronomy , soil science , chemistry , geology , ecology , biology , volcanic rock , volcano , mesoporous material , biochemistry , geotechnical engineering , seismology , catalysis
Characterization of ion mobility is a first step in the understanding of nutrient flux relationships in alpine forested watersheds. Our purpose was to: (i) investigate the transport dynamics of inorganic N in Sierra Nevada soils by applying unspiked source water as a control, and a 1 mmol c L ‐1 NH 4 NO 3 spiked solution to two soil types (granitic and andesitic) under forest and meadow conditions via artificial rainfall during moist (spring) and dry (late summer‐early fall) seasons; and (ii) evaluate the presence of macropore or preferential matrix flow from characteristic profile distributions of the two N forms. Peak concentrations in surface flow discharge (runoff) of both N forms from control treatments occurred early for both soil types and were highest from the meadow areas (1.6–0.4 mg NO ‐ 3 ‐N L ‐1 meadow to forest for granitic soil and 0.3–0.1 mg L ‐1 meadow to forest for andesitic soil; 0.75–0.37 mg NH + 4 ‐N L ‐1 meadow to forest for granitic soil and 0.25–0.18 mg L ‐1 meadow to forest for andesitic soil). Both soils exhibited NH + 4 ‐N adsorption, but only the soil of andesitic origin appeared to sorb NO ‐ 3 ‐N. Andesitic soils of the Sierra Nevada may thus serve as a temporary sink for NO ‐ 3 ‐N deposition, whereas meadow areas of both soil types appear to serve as a source. Higher initial soil moisture for the spiked treatments generally resulted in the transport of NH + 4 ‐N to greater depths in both soils of forested cover (≈ 40 compared with 20 cm from spring to late summer‐early fall), and for NO ‐ 3 ‐N (≈ 50 compared with 40 cm) as well. Wet‐season (spring) mobility must therefore be considered an important groundwater nutrient transport mechanism in Sierra Nevada watershed soils.