Atrazine and nitrate-nitrogen leaching through undisturbed soil columns as affected by lime application

摘要

Farm operators need information that enable them to select a combination of farming systems that minimizes the movement of agricultural chemicals into water sources. Agricultural lime (CaCO3) applied to the soil to reduce soil acidity, can affectthe movement and fate of agricultural chemicals in the soil. A laboratory study was conducted to determine the effects of three application rates of lime (0, 5 and 10 Mg ha{sup}-1) on atrazine (2-chloro-4-ethylamino-6-isopropylamino-1, 3,5 triazine) andnitrate-nitrogen (NO{sub}3-N) transport through undisturbed-unsaturated soil columns. Urea (H{sub}2NCONH{sub}2) and atrazine were applied on the surface of soil columns one month after mixing lime in the top 20 mm of surface soil of these columns. Fivedifferent irrigations, totaling 36.5 cm of distilled deionized water, were used in this study. The results indicate that lime application had no significant effect on the leachate depth and pH. An increase in lime application rate increased theconcentrations of Ca and NO{sub}3-N in the leachate. The concentration of N03-N in the leachate increased with increased irrigation events for limed soil columns. The concentration of atrazine in the leachate increased significantly with increased limeapplication rates and decreased with subsequent irrigation events.