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Phosphorus Losses from Four Agricultural Watersheds on Missouri Valley Loess
Author(s) -
Schuman G. E.,
Spomer R. G.,
Piest R. F.
Publication year - 1973
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/sssaj1973.03615995003700030032x
Subject(s) - watershed , surface runoff , loess , hydrology (agriculture) , environmental science , phosphorus , soil loss , erosion , geology , ecology , chemistry , paleontology , geotechnical engineering , organic chemistry , geomorphology , machine learning , computer science , biology
Abstract Phosphorus losses from four field‐size experimental watersheds at Treynor, Iowa, were measured during 1969, 1970, and 1971. A contour‐planted corn watershed and a pasture watershed were fertilized at the recommended P rate (39 kg/ha). A level‐terraced and a second contour‐planted corn watershed were fertilized at 2.5 times this rate. At the high level of P fertilization, phosphorus loss by surface runoff from the contour‐planted corn watershed was 0.495 kg/ha in 1969, 1.034 kg/ha in 1970, and 2.130 kg/ha in 1971. Level terraces greatly reduced P loss by reducing runoff and erosion. Water samples for all runoff events taken above the overfall of each watershed gully contained considerably more inorganic P in solution than samples taken at the weir site, 70 to 230 m downstream. This reduction in solution P was caused by the adsorption of P by the additional suspended soil material entering the stream from gully erosion.