Computers and Electronics in Agriculture 53 (2006) 113–121 Fate and transport of nitrogen compounds in a cold region soil using DRAINMOD Shaoli Wang a , Shiv O. Prasher b,∗ , Ramanbhai M. Patel b , Chun-Chieh Yang b , Seung-Hyun Kim c , Ali Madani d , Paula M. Macdonald d , Stephanie D. Robertson d a China Institute of Water resources and Hydropower Research, P.O. Box 366, Beijing 100044, China b Department of Bioresource Engineering, Macdonald Campus of McGill University, 21,111 Lakeshore Road, Ste-Anne de Bellevue, Que., Canada H9X 3V9 c Department of Environmental Engineering, Yeungnam University, Kyongsan 712-749, Republic of Korea d Department of Engineering, Nova Scotia Agricultural College, Truro, NS, Canada B2N 5E3 Received 22 August 2005; received in revised form 7 April 2006; accepted 29 April 2006 Abstract Freezing and thawing cycles in soil can have a significant effect on field hydrology, which, in turn, can have a major influence on the fate and transport of agricultural chemicals. This study was conducted to evaluate the hydrological performance and NO 3 - -N movement of the DRAINMOD 5.1 model with respect to freezing/thawing conditions. Measurements made in the years 1999 and 2000 at an experimental site in Truro, Nova Scotia, Canada on four test plots receiving inorganic fertilizer were used to test the model. Monthly subsurface drainage outflows, simulated using the original and DRAINMOD 5.1, were compared with the observed values. The results showed that the original DRAINMOD overestimated drain outflows during the colder months. The average difference between the monthly drainage outflows, simulated with DRAINMOD 5.1, and the observed values ranged from -0.35 to -1.42 mm. Since the new model predicted the timing and magnitude of drainage events quite well and also did a much better job of simulating the hydrology of a colder region, as compared to the original model, it was used to simulate fate and transport of nitrogen compounds. The model was calibrated with the data from two test plots, and validated with the data from the remaining two plots. The difference between the simulated and observed total NO 3 - -N losses over a period of 2 years were, respectively, 1.32 and 1.40 kg N/ha for the calibration plots. For validation plots, they were -1.64 and 0.97 kg N/ha, respectively. These results indicate that the DRAINMOD 5.1 model, performed satisfactorily, and may be used to estimate NO 3 - -N losses through drainage outflow in colder regions. © 2006 Elsevier B.V. All rights reserved. Keywords: DRAINMOD; DRAINMOD-N; DRAINMOD 5.1; Subsurface drainage; Freezing-thawing; NO 3 - -N losses 1. Introduction The climate in Atlantic Canada is characterized by a cool and moist spring and fall, dry summer, and cold winter in which freezing, thawing, and snow melt often occur. The snow melting process and the daily freezing-thawing cycles can have a dominant effect on the overall field of hydrology. Frozen soil surface layers often result in no or ∗ Corresponding author. Tel.: +1 514 398 7783; fax: +1 514 398 8387. E-mail address: shiv.prasher@mcgill.ca (S.O. Prasher). 0168-1699/$ – see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.compag.2006.04.005