Using electromagnetic induction technology to identify atrazine leaching potential at field scale

Authors: ALVES DE OLIVEIRA, LUCIANO - Luiz De Queiroz College Of Agriculture (ESALQ); Woodbury, Bryan; HONORIO DE MIRANDA, JARBAS - Luiz De Queiroz College Of Agriculture (ESALQ); STROMER, BOBBI - Former ARS Employee

Submitted to: Geoderma
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/5/2020
Publication Date: 9/1/2020
Citation: Alves de Oliveira, L., Woodbury, B.L., Honorio de Miranda, J., Stromer, B.S. 2020. Using electromagnetic induction technology to identify atrazine leaching potential at field scale. Geoderma. 375:114525. https://doi.org/10.1016/j.geoderma.2020.114525.
DOI: https://doi.org/10.1016/j.geoderma.2020.114525

Interpretive Summary: Herbicides are applied to crops to improve production. These herbicides can infiltrate into the soil and contaminate groundwater or erode with the soil to contaminate surface water. Certain physical and chemical characteristics of a crop field can impact how fast herbicides can infiltrate soil. Many times, these physical and chemical characteristics cannot be identified visually. A method was developed using a geological instrument to identify areas of a field that may be prone to leaching herbicides faster than other areas. Once these areas were identified, soil samples were taken from these areas and taken to a laboratory to determine how fast herbicides moved through the soil. The herbicide transport rates determined in the laboratory correlated very well with the values measured by the geological instrument. Based on this, a computer model was used to estimate herbicide movement in the soil based on overall field average properties or properties that were determine based on zones measured by the geological instrument. The method using the zones based on measurements determined by the geological instrument provided a much better estimate of movement.

Technical Abstract: Atrazine is an herbicide commonly used to control weeds in corn crop. Atrazine becomes an environmental concern when it moves off-site to surface and ground waters. Understanding how atrazine moves in the field is important for developing management controls. Electromagnetic induction (EMI) has been used to map certain contaminant transport at the field scale. This study was developed to evaluate the efficacy of EMI technology for identifying surface soil atrazine concentration in a corn crop field. The research was conducted in a corn silage field with silt, clay and loam soils at the U.S. Meat Animal Research Center (USMARC), Clay Center, NE – USA, and it was divided in three stages; i) EMI data collection and a response surface sampling design for collection of bulk soils and soil core samples, ii) atrazine transport parameters were obtained by Breakthrough Curves using the bulk soil and numerical adjustments using STANMOD (HYDRUS package), and iii) Modeling atrazine parameters through EMI signal data with posterior atrazine’s movement simulations through the soil using HYDRUS 2D. Atrazine’s retardation factor, partition coefficient, and transfer coefficient were strongly correlated with EMI signal exhibiting a strong correlation with apparent electrical conductivity (ECa). The low values for RMSE and RRMSE and the high values for Willmott and Pearson coefficients indicate EMI technology can be used to predict atrazine movement parameters. HYDRUS 2D quantitatively simulates the atrazine concentration leaching and how the temporal scale of this contamination would be. Combining EMI technology with HYDRUS 2D modeling provides researcher with additional information for developing better management practices for controlling atrazine movement to surface water; however, further studies are needed determine the effectiveness of this approach for other soil types.