Adsorption and desorption of phosphorus and nitrogen by immersed stalks

Authors: Gilley, John; EGHBALL, BAHMAN; MARX, DAVID - UNIV OF NEBRASKA - LINCOL

Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2009
Publication Date: 3/1/2009
Citation: Gilley, J.E., Eghball, B., Marx, D.B. 2009. Adsorption and desorption of phosphorus and nitrogen by immersed stalks. Transactions of the ASABE. 52(2):429-436.

Interpretive Summary: Surface residue affects runoff water quality by contributing or removing constituents from overland flow. A laboratory study was conducted to measure leaching and sorption by residue materials immersed in solutions containing several nutrient constituents. Experimental variables included type of residue material (corn, soybean, and wheat), inorganic nutrients in solution (PO4-P and NO3-N; PO4-P and NH4-N; NO3-N and NH4-N; PO4-P, NO3-N, and NH4-N), solution concentration (0, 6, 12 and 24 'g g-1 residue), and residue immersion period (25, 250, 2500, 25000, 86400 s). Corn residue leached PO4-P and NH4-N, and the quantity of PO4-P leached consistently increased as residue / solution contact time varied from 2500 to 86400 s. The presence of inorganic NO3-N and PO4-P in solution significantly reduced the quantity of PO4-P and NH4-N that was leached from the corn residue. Corn residue also leached NO3-N but the quantity leached was not significantly affected by the concentration of inorganic nutrients in solution. Soybean and wheat residue either leached or sorbed NO3-N depending upon the type of nutrients in solution and solution concentration. Wheat residue sorbed significant amounts of NH4-N. As the concentration of inorganic NH4-N in solution became greater, the quantity of NH4-N sorbed by wheat residue increased. The presence of nutrient constituents in solution can influence leaching and sorption by crop residue materials. Wheat residue appears to have the potential to sorb substantial quantities of NH4-N. The type of nutrients in solution, solution concentration, and residue / solution contact time can affect nutrient concentrations of solutions in which crop residue materials are

Technical Abstract: Leaching and sorption (nutrient movement from solution into residue materials) of nutrients by crop residue may influence nutrient concentrations in runoff. A laboratory study was conducted to measure leaching and sorption by residue materials immersed in solutions containing multiple nutrient constituents. Experimental variables included type of residue material (corn, soybean, and wheat), inorganic nutrients in solution (PO4-P and NO3-N; PO4-P and NH4-N; NO3-N and NH4-N; PO4-P, NO3-N, and NH4-N), solution concentration (0, 6, 12 and 24 'g g-1 residue), and residue immersion period (25, 250, 2500, 25000, 86400 s). Regression equations were developed relating leaching and sorption of nutrients to the length of time the residue materials were immersed. Corn residue leached PO4-P and NH4-N, and the quantity of PO4-P leached consistently increased as residue / solution contact time varied from 2500 to 86400 s. The presence of inorganic NO3-N and PO4-P in solution significantly reduced the quantity of PO4-P and NH4-N that was leached from the corn residue. Corn residue also leached NO3-N but the quantity leached was not significantly affected by the concentration of inorganic nutrients in solution. Soybean and wheat residue either leached or sorbed NO3-N depending upon the type of nutrients in solution and solution concentration. Wheat residue sorbed significant amounts of NH4-N. As the concentration of inorganic NH4-N in solution became greater, the quantity of NH4-N sorbed by wheat residue increased. The type of residue material, inorganic nutrient in solution, solution concentration, and residue submersion period can all influence nutrient concentrations of solutions.