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Effects of Chemical Defoliation of an Abies grandis Habitat on Amounts and Chemistry of Throughfall and Stemflow
Author(s) -
Tiedemann A. R.,
Helvey J. D.,
Anderson T. D.
Publication year - 1980
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1980.00472425000900020032x
Subject(s) - throughfall , stemflow , chemistry , nutrient , ammonium , precipitation , environmental chemistry , nitrogen , zoology , acid rain , hydrology (agriculture) , environmental science , soil water , soil science , biology , physics , geotechnical engineering , organic chemistry , meteorology , engineering
Amounts and chemistry of gross precipitation, throughfall, and stemflow were measured before and after chemical defoliation of a coniferous forest stand in eastern Washington. Throughfall ( T ) in the natural stand is related to gross precipitation ( P ) by the equation T = 0.842 P − 0.182 with a coefficient of determination ( R 2 ) of 0.972. Throughfall and stemflow increased significantly after defoliation but the actual amounts were small. Gross precipitation before defoliation contained 0.47 mg/liter total nitrogen (T‐N), 0.06 mg/liter total phosphorus (T‐P), and 0.7 mg/liter total cations (Ca, Mg, Na, and K). Total inputs between 24 Aug. 1975 and 1 June 1976, were 0.84, 0.07, and 0.90 kg/ha for T‐N, T‐P, and total cations, respectively. Approximately 80% of the total annual precipitation is normally received during the period sampled. Concentrations of chemical constituents were increased up to 15 times in throughfall and up to 48 times in stemflow compared to gross precipitation. Ratios of nutrient delivery (kg/ha) before defoliation as gross precipitation/throughfall/stemflow were 1.00:1.01:0.02 for T‐N, 1.00:3.78:0.15 for T‐P, and 1.00:7.57:0.20 for total cations. Defoliation reduced concentration of ammonium‐N and increased concentration of T‐P in throughfall. Concentrations of other measured constituents were not changed. Delivery of all nutrients to the forest floor, however, was greater after defoliation because of increased amounts of throughfall and stemflow. Comparisons of summer with winter storms and dry fallout with precipitation indicated that (i) T‐P and K are of local origin; (ii) N probably originates from passage of air masses over urban and industrial areas, automobile exhaust, and agriculture (fertilization); and (iii) Na and Mg are of marine origin.