Quantitative Relationships Among Nutrients Leached From Soils

Abstract This study was undertaken in an attempt to quantify relationships among anions (An) and cations (Cat) leached from soils. Several sets of published data on leaching of ions from acid and nonacid soils were evaluated by linear regression calculations based on the chemical equivalency of Σ Cat and Σ An leached. Calcium, Mg, K, and Na comprised most of Σ Cat, and NO 3 , SO 4 , and Cl, most of Σ An. Bicarbonate (HCO 3 ) is also leached from nonacid soils; H is assumed to account for most of the excess of Σ An over Σ Cat in leachates from acid soils. The regression coefficient for each cation on Σ An indicates its contribution to anion leaching and that for each anion on Σ Cat indicates its contribution to cation leaching. Amounts of each ion leached from a given soil depended largely on amount of soluble ion present and amounts of leachate. Calcium and NO 3 tended to dominate Σ An and Σ Cat leached if these ions were applied or were abundantly present in a soil. Magnesium, Na, SO 4 , and Cl were increasingly important as the proportionate supply of each increased. Potassium was not leached in amounts appreciable enough to influence amounts of anions lost, and HCO 3 , although present in appreciable amounts in nonacid soils, apparently was not related to Σ Cat leached. Amounts of ions leached were much more closely correlated with leachate volumes among soils and time periods than with leachate volumes from various treatments for a given time period.