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Evaluation of spatial management practices for non-point source pollution prevention
Abstract
This research addresses the non-point source (NPS) contamination problem by developing a methodology for spatial management of production agriculture while incorporating the inherently complex issue of soil spatial variability. The methodology can assist programs which focus on the management of crop production according to localized conditions and the protection of groundwater from NPS (or diffuse) nitrate pollution. The work utilizes accessible information in characterizing the spatial variability of related soil and crop parameters. The research assimilates spatial variability of various soil and crop parameters in estimating groundwater contamination potential from typical production fields. It employs a combination of geostatistical simulation and unsaturated zone transport modeling. Uncertainties related to the spatial variability of input variables and their impact on results are characterized with an application of geostatistical and Monte-Carlo simulation techniques. Results of simulations are then used as input into a transport model in a quasi 3-D framework to predict contaminant loadings to the groundwater. Various application scenarios are developed and evaluated to predict the potential environmental impact of spatial production. Hence, the methodology is shown to be able to give quantitative estimates of the effectiveness of spatial application practices on the basis of sustaining production agriculture and preventing environmental pollution. The methodology is applied to three situations, differing in extent of spatial variability of soil parameters. The results indicate that while spatial management is beneficial, the spatial application system may not be warranted for fields exhibiting low variability. However, it is shown that the spatial application is very effective under medium and high variability field conditions where it can lead to meaningful reductions in both nitrogen inputs as well as groundwater contamination while maintaining appropriate yield conditions. The degree of variability of controlling parameters is found to be a functional indicator for evaluating the suitability of spatial management. There appears to be a break-even point between the benefits of spatial application technology and the amount of information used in implementing this technology for various degrees of spatial variability. This methodology provides an important tool for: (1) producers in evaluating the effect of spatial application from a given field, (2) performing a risk-based analysis on nitrate loadings that would result from each spatial application scenarios, (3) engineers and decision makers in deciding whether or not an action should be taken to reduce the groundwater pollution, (4) use with other NPS anthropogenic pollutants in estimating groundwater contamination potential.
Subject Area
Civil engineering|Agricultural engineering|Environmental engineering|Soil sciences|Geography|Hydrology
Recommended Citation
Goderya, Farida Shaukat, "Evaluation of spatial management practices for non-point source pollution prevention" (1996). ETD collection for University of Nebraska-Lincoln. AAI9703776.
https://digitalcommons.unl.edu/dissertations/AAI9703776