Nitrate sorption in the profile of an acid soil

Sorption of NO _inf3 ^sup– by different horizons of a highly weathered, acid tropical soil was measured in laboratory batch experiments. Sorption was found to increase with depth, ranging from small amounts in the 0–15 cm layer to amounts that would be roughly equivalent to 25 to 50% of the NO _inf3 ^sup– in the 90–120 cm layer at water and NO _inf3 ^sup– contents commonly found under field conditions. Calculations, based on sorption isotherms, demonstrated how sorption may be important for managing N in a tropical acid soil. Sorption of Cl^– was also found in the range of 0.1 and 2.0 mol m^–3. In this range of concentrations sorption of NO _inf3 ^sup– and chloride were found to be independent, suggesting that anion exchange sites were far from saturated.Contribution from the Department of Soil, Crop and Atmospheric Sciences, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853. SCAS paper No. 1726. This research is part of the TropSoils program.Contribution from the Department of Soil, Crop and Atmospheric Sciences, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853. SCAS paper No. 1726. This research is part of the TropSoils program.