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Nitrate loss in soil drainage waters in relation to by‐passing flow and discharge on an arable site
Author(s) -
SMETTEM K. R. J.,
TRUDGILL S. T.,
PICKLES A. M.
Publication year - 1983
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1983.tb01051.x
Subject(s) - nitrate , drainage , nitrogen , soil water , leaching (pedology) , hydrology (agriculture) , saturation (graph theory) , water content , penetration (warfare) , arable land , environmental science , water flow , soil science , geology , chemistry , geotechnical engineering , ecology , mathematics , organic chemistry , combinatorics , operations research , engineering , biology , agriculture
Summary In a well‐structured soil at or close to pedal saturation, rainfall intensity in excess of pedal K sat is predicted to result in by‐passing flow through well connected structural voids. The depth of solute penetration (tracer dye and nitrate) under by‐passing flow has been predicted by D f =( P‐C p )/θ f , where D f is the depth of penetration of the leading edge of solute in by‐passing flow, P is gross precipitation, C p is the input volume transmitted through the soil peds and θ f is the operational volumetric moisture content in by‐passing. The timing of surface applied nitrate arrival at a channel bank is demonstrated to be related to by‐passing flow rather than uniform displacement. The relationship between nitrate load in soil drainage waters ( Y , mg s ‐1 ) and water discharge ( X , dm 3 s −1 ) was Y ∼ 6X after nitrate fertilizer application but subsequently declined to Y 0. 5X It is deduced that the decline resulted from inefficient leaching under by‐passing conditions once surface applied nitrate had become relocated within the soil peds.