Submitted to: Ecological Modeling
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2013
Publication Date: 8/5/2013
Publication URL: http://handle.nal.usda.gov/10113/56890
Citation: Guber, A., Pachepsky, Y.A., Dao, T.H., Shelton, D.R., Sadeghi, A.M. 2013. Evaluating manure release parameters for nonpoint contaminant transport model KINEROS2/STWIR. Ecological Modeling. 263:126-138. Interpretive Summary: Microbiological quality of non-potable surface waters can affect human health, since these waters are used for recreational purposes and for irrigation of fresh produce. Animal waste and manures are potential sources of pathogenic microorganisms which can be released and transported with overland and infiltration to surface waters. Consequently, one factor in evaluating the risks of surface water microbial pollution, is an understanding of how microbes are released from animal waste under rainfall. Existing release models-rely on assumed, rather than observed, time series of microbe concentrations to estimate release rates. We used actual time series of concentrations measured in our multi-year experiments, and established a microbial release model that appears to be very robust and reliable. Results of this work will be useful in environmental predictions of microbial quality of waters in that they substantially improve the accuracy of estimating microbial loads.
Technical Abstract: Release of manure components is an important component of modeling applications in environmental water quality. The scarcity of experimental data and the multiplicity of the approaches for modeling release kinetics of the manure components introduce uncertainty and reduce reliability of overland flow and contaminant transport models. The objectives of this work were to evaluate reliability and robustness of the manure release parameters estimated based on individual and grouped release kinetics of soluble, particulate and combination of particulate and soluble materials from surface applied manure. The parameters of Bradford-Schijven model were evaluated from the experimental data on release of chloride, water-extractable phosphate-P, total bioactive P, organic carbon, enterococci and E. coli from surface applied manure measured in the runoff-box and runoff-plot experiments. The results showed that release of different manure components from surface applied manure can be reliably predicted with just a single set of parameters characterizing the kinetics of manure mass release. We demonstrated that the manure release parameters could be estimated more reliably when the model fit was performed using data for different manure components pooled together, while the model fit to a single release curve produced correlated parameters. The model parameters appeared to be robust and transferable from the calibration to validation datasets without any or with only minor losses of the model accuracy. Better transferability of the model parameters was associated with a large number of replications in the runoff-box experiments. The results of this study provide an improvement in parameterization of KINEROS2/STWIR model developed for pathogen risk assessment associated with livestock operations.