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The Contribution of Phosphorus Leached from Crop Canopy to Losses in Surface Runoff
Author(s) -
Sharpley A. N.
Publication year - 1981
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/jeq1981.00472425001000020007x
Subject(s) - surface runoff , environmental science , leaching (pedology) , leachate , agronomy , soil water , phosphorus , nutrient , canopy , chemistry , soil science , environmental chemistry , biology , botany , ecology , organic chemistry
Simulated rainfall (6 cm/hour) was used to leach P from growing cotton ( Gossypium hirsutum ), sorghum ( Sorghum sudanense ), and soybean ( Glycine max. ) plants as a function of soil type and time interval between rainfall events. The relative contribution of plant material and surface soil to the transport of soluble P in surface runoff was estimated. The amount of soluble P in plant leachate, collected before contacting the soil surface, was found to increase with plant age and soil‐water stress when changes in leaf area index were accounted for. A period of at least 1 day between rainfall events was needed for P to reaccumulate on the leaf surface. The contribution of soluble P in plant leachate to that transported in surface runoff was estimated as the difference in runoff concentration between planted and bare soil. When plants were subject to a soil P stress, canopy leachate contributed the major proportion (90%) of that transported in surface runoff. With an increase in plant age from 42 to 82 days, the contribution of plant leachate to surface runoff increased from approximately 20–60%. The possible sorption of leached P is discussed along with estimating leaching losses in improving the predictive ability of nutrient models.