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Field Study of Solute Movement in a Highly Aggregated Oxisol with Intermittent Flooding: I. Nitrate
Author(s) -
Balasubramanian V.,
Kanehiro Y.,
Rao P. S. C.,
Green R. E.
Publication year - 1973
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/jeq1973.00472425000200030012x
Subject(s) - nitrate , environmental science , macropore , leaching (pedology) , soil science , hydrology (agriculture) , field capacity , chemistry , soil water , geology , geotechnical engineering , mesoporous material , biochemistry , organic chemistry , catalysis
Abstract Movement of applied nitrate (a concentrated solution sprayed uniformly over the soil surface) under intermittent flooding was investigated in Molokai silty clay (Typic Torrox), an important soil for sugarcane ( Saccharum officinarum L.) and pineapple ( Ananas comosus ) production in Hawaii. Nitrate distribution in the profile was characterized under an extended irrigation scheme by in situ sampling of soil solutions with suction probes 1 week after each water application. The nitrate peak moved only one‐third as far as would have been predicted by a piston displacement model. Equilibration of applied nitrate solution with the aggregated surface soil for 1 week prior to flood irrigation further retarded nitrate leaching. Apparently, equilibration involved bulk flow and diffusion of nitrate into aggregate micropores where the solute was less susceptible to transport in water being conducted mostly in the macropores during and soon after irrigation. Prediction of nitrate distribution based on dispersion (diffusion plus convection) equation approximated experimental results for successive irrigations reasonably well when equation parameters were obtained by fitting one set of experimental data. The drawback of this theoretical model is discussed.