ABSTRACT
AS. AZEVEDO and R.S. KANWAR Agricultural & Biosystems Engineering Dept, Iowa State University, Ames, USA L.S PEREIRA Department of Agricultural Engineering, Institute of Agronomy, Technical University of Lisbon, Portugal
Abstract A study conducted during the corn cropping season for a silty loam alluvial soil and a sandy eutric soil in Sorraia Valley, Portugal is reported. Soil, water, and atrazine concentrations through the soil profiles were observed. Result indicate that hydraulic properties of the alluvial soil do not favor atrazine transport, without evidence of heavy leaching by irrigation. For the coarse soils, where overirrigation is practiced irrigation water plays a role in leaching atrazine. Keywords: Atrazine transport, herbicide, irrigated soils, leaching, soil water movement
1 Introduction
Groundwater pollution from non point sources is an important concern The often excessive rates of fertilizers and pesticides applied to crops contribute to surface and subsurface water contamination, affecting drinking water supplies and the natural habitats. Herbicides represent the main class of pesticides for groundwater contamination. A review on pesticide occurrence in groundwater [1] shows that 32 herbicides have been reported to be present in groundwater. Triazines are the most frequently detected, the atrazine having the highest frequency in contamination of groundwater (38%).
