2008 Annual Report
1a.Objectives (from AD-416)
Determine dominant environmental parameters and processes involved in the fate and transport of manure-borne coliform bacteria at field and watershed scales in a hydrological context. Develop predictive models of the fate and transport of manure-borne coliform bacteria at field and watershed scales.
1b.Approach (from AD-416)
An integrated laboratory research, field research at hillslope and watershed scales, and mathematical modeling will be used. The experimental research will include evaluating effect of manure particulates on transport of coliform microorganisms in soil, relating partitioning of coliform microorganisms between sediment and runoff to soil texture, manure properties and flow rate, establishing dependencies of coliform release rates from manure on rain intensity, manure type and composition, and manure application method, evaluating predictive efficiency of laboratory data on manure-borne coliform survival data for the field conditions, assessing phosphorus as a tracer of manure-borne transport in runoff; determining effect of background coliform populations and field manure application on coliform concentrations in runoff from fields and in a perennial creek in a riparian zone. Modeling research will include determining dominant mechanisms of manure-borne coliform transport at pedon, field, and watershed scales; develop and test models to simulate those mechanisms, performing uncertainty analysis to evaluate the reliability of coliform transport model predictions given available data on variation in input parameters, transforming model computers codes to make them compatible to existing and under-development user-friendly decision support tools.
An experimental site at the OPE3 experimental watershed at the Beltsville Area Research Center (BARC) has been instrumented with replicated multiple capacitance probes, multilevel sampling wells, tensiometers, rainfall simulation system, and runoff flume to infer runoff flow and fluxes of soil water carrying bacteria and manure particulates. The four-month experiment was carried out to investigate the breakthrough of E. coli and chemical tracer from surface-applied manure to ground water and subsequent lateral transport. In addition, E. coli concentrations were monitored in the creek water and in the runoff from manured fields at the OPE3 site. The creek was grab-sampled weekly, and refrigerated samplers were used on the event basis.
The Cove Mountain Creek Watershed in Southern Pennsylvania was instrumented and monitored year-round to provide datasets for validation and improvement of the bacterial transport submodel in the ARS watershed model SWAT. Concentrations of both generic and potentially pathogenic E. coli were measured. Support and participation of local school and watershed community groups were established. The preliminary calibration of the SWAT model was performed.
The Patuxent lysimeter site was re-instrumented to simulate the edge-of-field input of manure-borne E. coli to vegetated buffer strips. A series of runoff experiments on clay loam and sandy loam soils was carried out to evaluate the efficiency of the vegetated filter strips to retain manure-borne E. coli, phosphorus, and manure particulates, and to provide the validation data for the mechanistic sub-model of surface transport of manure-borne coliforms at field scale.
A new laboratory setup was designed and implemented to evaluate the effect of manure particulates on soil water retention and evaporation from soils. A series of experiments has been carried out that has demonstrated that manure application may bring favorable changes to soil evaporative water losses.
A mechanistic sub-model has been developed for the USDA-ARS runoff and erosion model KINEROS to simulate the surface transport of manure-borne coliforms at field scale. Surface release, dispersion in the overland flow, attachment, size exclusion, and straining in soils and vegetation are included as the possible transport mechanisms. The submodel has been verified with the series of experiments at the Patuxent lysimeter site.
With the objective of obtaining experimental data to estimate pathogen transport characteristics, this research is aligned with Research Component "Pathogens and Pharmaceutically Active Compounds (PACs)" of the National Program 206 Action Plan in its Problem Area 2a. “Inactivation Rates and Transport Characteristics of Pathogens from Animal Agriculture.”
The submodel to simulate the surface transport of manure-borne coliforms at field scale.
Mechanistic models simulate the surface transport of manure-borne coliforms at field scale are currently absent. The submodel has been developed for the USDA-ARS runoff and erosion model KINEROS to simulate the surface transport of manure-borne coliforms at field scale. The submodel integrates knowledge on major processes of transport and retention of manure-borne microorganisms at the field scale. The submodel has been verified with the series of experiments at vegetated buffer strips. The submodel has been used to predict the vegetative strip efficiency in retention of manure borne E. coli transport from manured fields and to evaluate the inherent uncertainty in such predictions. This accomplishment aligns with the Component IIIg “Modeling Fate and Transport of Manure-borne Pathogens from “Pedon” to Watershed Scale” of the NP 206 “Manure Byproduct and Utilization.”
The effect of manure particulates on soil hydraulic properties. The agronomic importance of manure application is usually attributed to supply of nutrients whereas the effect of manure particulates on soil water balance and availability of water to plants is mostly unknown. The significant effect of manure particulates on soil hydraulic properties was demonstrated in laboratory experiments. Soil water retention decreased, and evaporative soil water losses decreased as manure particulates were introduced in soil. This result poses a new research question whether manure application substantially improves water economy of soils. This accomplishment aligns with the Component IIIg “Modeling Fate and Transport of Manure-borne Pathogens from “Pedon” to Watershed Scale” of the NP 206 “Manure Byproduct and Utilization.”
5.Significant Activities that Support Special Target Populations
Guber, A.K., Gish, T.J., Pachespsky, Y.A., van Genuchten, M., Daughtry, C.S., Nicholson, T.J., Cade, C.S. 2008. Temporal stability of soil water content and soil water flux patterns across agricultural fields. Catena. 73:125-133.
Pachepsky, Y.A., Karns, J.S., Yu, O., Shelton, D.R., Guber, A.K., Van Kessel, J.S. 2008. Strain-dependent variations in attachment of E. coli to soil particles of different sizes. International Agrophysics. 22:61-66.
Pachepsky, Y.A., Gimenez, D., Lilly, A., Nemes, A. 2008. Promises of Hydropedology. CAB Reviews: Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources. 3(40):19.
Lamorski, K., Pachepsky, Y.A., Slawinski, C., Walczak, R. 2008. Using support vector machines to develop pedotransfer functions for water retention of soils in Poland. Soil Science Society of America Journal. 72:1243-1247.
Rawls, W.J., Nemes, A., Pachepsky, Y.A., Saxton, K.E. 2007. Using the NRCS National Soils Information System (NASIS) to provide soil hydraulic properties for engineering applications. Transactions of the ASABE. 50(5):1715-1718.
Nemes, A., Roberts, R.T., Rawls, W.J., Pachepsky, Y.A., Van Genuchten, M.T. 2007. Software to estimate –33 and –1500 kPa soil water retention using the non-parametric k-Nearest Neighbor technique. Journal of Environmental Modeling and Software. 23:254-255.