Location: Agroecosystem Management ResearchTitle: Wheat strip effects on microbial transport following variable applications of beef cattle manure
|MARX, DAVID - University Of Nebraska
|THAYER, CHANCE - University Of Nebraska
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/25/2018
Publication Date: 4/4/2019
Citation: Durso, L.M., Gilley, J.E., Marx, D., Thayer, C., Woodbury, B.L. 2019. Wheat strip effects on microbial transport following variable applications of beef cattle manure. Transactions of the ASABE. 62(2):263-270. https://doi.org/10.13031/trans.12940.
Interpretive Summary: The effectiveness of a 1.4-m long wheat strip in reducing microbial transport following manure application was examined in this study. Beef cattle manure was applied to 0.75-m wide by 4.0-m long plots established on a silty clay loam located in southeast Nebraska. Manure was added at rates required to meet none or the 1, 2 or 4-year phosphorus requirements for corn. The transport of phages, total coliforms, E coli, and enterococci was measured for three 30-minute simulated rainfall events. The narrow wheat strip did not reduce counts of any of the measured microbes. For the plots that received manure, no significant differences in the transport of phages or enterococci were found among the three manure application rates. Rainfall simulation run significantly affected measurements of phages, total coliforms, E. coli, and enterococci. The introduction of water during the initial rainfall simulation run appeared to enhance microbial growth since counts for each of the measured microbes were significantly greater for the 2nd than the 1st rainfall simulation run. The transport of E. coli was significantly correlated to selected nutrient loads and electrical conductivity. In contrast, enterococci transport was not significantly correlated to any of the measured water quality constituents. A 1.4 m long strip of wheat did not significantly reduce microbial transport following variable applications of beef cattle manure.
Technical Abstract: Vegetative filter strips (VFS) consisting of perennial vegetation have been successfully used to reduce the transport of contaminants in runoff from land application areas. The effectiveness of a winter wheat strip, which may be more acceptable to producers, in reducing microbial transport was examined in this study. A 1.4 m wheat strip was used to allow direct comparison with experimental results obtained in previous studies. Beef cattle manure was applied to 0.75 m wide by 4.0 m long plots established on an Aksarben silty clay loam located in southeast Nebraska. Manure was added at rates required to meet the 0- 1-, 2-, or 4-year phosphorus requirement for corn. The transport of selected microbes was measured for three 30 min simulated rainfall events separated by 24 h intervals. The narrow wheat strip did not significantly reduce counts of any of the measured microbes. The application of manure to meet the 4-year P requirement resulted in E. coli and enterococci loads that were significantly greater than the 1-year P requirement. Rainfall simulation run significantly affected measurements of phages, total coliforms, E. coli, and enterococci, with measurements during the three runs varying from 9.35 to 10.9 log plaque-forming units (PFU) ha-1, from 11.5 to 12.1 log colony-forming units (CFU) ha-1, from 12.1 to 12.5 log CFU ha-1, and from 11.1 to 11.4 log CFU ha-1, respectively. The transport of E. coli was found to be significantly correlated to selected nutrient loads and electrical conductivity of runoff. The presence of narrow wheat strips did not reduce microbial loads in runoff.