Technical ArticleEvaluation of Nitrate-Nitrogen Leaching From Lysimeter-Grown Bearing Apple TreesToselli, Moreno1; Perry, Ronald L.2; Flore, James A.2Author Information 1Dipartimento di Colture Arboree, viale Fanin, 46-40127, Bologna, Italy. Dr. Moreno Toselli is corresponding author. E-mail: email@example.com 2Department of Horticulture, Michigan State University, East Lansing, MI. Received July 6, 2010. Accepted for publication March 10, 2011. This work was not financially supported by any of the following organizations: National Institutes of Health, Wellcome Trust, Howard Hughes Medical Institute, and other(s). Soil Science: June 2011 - Volume 176 - Issue 6 - p 280-287 doi: 10.1097/SS.0b013e318219db11 Buy Metrics Abstract A 2-year investigation was conducted on eight replicate plots located 30 miles east of Lake Michigan on sand to sandy-clay-loam soil, using 1.8-m-deep lysimeters (4.8 m3 of volume), consisting of an undisturbed monolith excavated from the soil and containing a bearing (2- to 3-year-old) apple tree each. The aims of this research were to study the leaching rate and migration time of nitrate-N (NO3−-N) through the soil profile and to assess the suitability of soil suction tube (SST) water samples to predict the NO3−-N leaching rate. The NO3−-N concentration in the water collected by the lysimeters ranged from less than 10 mg L−1 (in late summer) to more than 40 mg L−1 (in winter). We calculated that NO3−-N lost via leaching in a year amounts up to 141 kg ha−1, with the most potential for groundwater pollution occurring during the cold and wet season. The application of labeled N ammonium nitrate as fertilizer increased the concentration of NO3−-N in the solution collected by SST. Labeled N was found at the bottom of lysimeters 3 months after its application, leaching through the soil profile at a speed of 2 cm day−1, so that the NO3−-N concentration of SST was correlated significantly with NO3−-N concentration of lysimeters only when the time of movement was considered. The application of fertilizer did not increase the amount of NO3−-N collected by lysimeters, meaning that the NO3−-N leaching rate is mostly the result of the breakdown of soil organic matter. © 2011 Lippincott Williams & Wilkins, Inc.