Saturday, 15 July 2006
137-21

Numerical Simulation of Atrazine Leaching at Field Scale During Summer Maize Growing Season under Meteorological Condition.

Meng Mao and Li Ren. Dept of Soil and Water Sciences, China Agricultural Univ, No. 2 West Yuanmingyuan Road, Haidian District, Beijing, 100094, China

Atrazine is an herbicide commonly used in summer maize throughout the North China, while the growing period of summer maize happens to be the main rainfall period in the Northern portion of China. Therefore, the assessment of leaching risk of atrazine at the filed scale is of importance to the protection of groundwater environment. In this study, soil samples were taken from a small agricultural plot (40×40 m2), which located at Yucheng experimental station, Shandong province. By running ROSETTA code, van Genuchten type's hydraulic parameters were generated from the measured soil particle size fraction and soil bulk density, the dispersivities of atrazine were indirectly obtained from the water retention curves, and the adsorption coefficients of different samples were estimated by the measured soil organic carbon contents. Based on these field data and the meteorological data for the year of 2003 of Yucheng experimental field, on the assumption of column model, numerical simulations of the spatial distribution of atrazine leaching at field scale were carried out and the spatial variability of soil hydraulic parameters, the transport and adsorption parameters of atrazine were considered. In addition, geostatistical analysis was applied to analyze the special variance structure of soil water potential, water flux and atrazine concentration at 20-cm depth during the growing stages of summer maize. Results showed that, most variograms of the variables were no-sill models, some variograms had ranges about 25 to 30 m, which had significant meaning to design the layout of monitoring network for water movement and atrazine transport at field scale.

Back to 2.1B Soil Hydrology, Structure, and Micromorphic Propoerties (Soil Porous System) - Poster
Back to WCSS

Back to The 18th World Congress of Soil Science (July 9-15, 2006)