LU CAEHS Research Seminar
"How Manure Can Affect Soil Health and Biosecure Entry System Improvement to Support Disease Prevention"
A recent study evaluated over 15 thousand statewide soil samples collected between 2016 and 2024 for the effects of cover cropping and manure application on soil quality across Missouri. 33% of the samples were associated with cover crop practices (CCPs), while 10% had received manure applications. Soil carbon showed interannual variability, but was consistently greater under extended CCPs (≥5 yr) in multiple years. Aggregate stability responded positively to long-term CCPs, whereas bulk density remained largely unchanged.
Overall, the benefits of cover cropping on soil health were strongly time dependent, with measurable improvements emerging primarily under long-term practice. Soil chemical properties responded more strongly to manure application, resulting in higher PMN, phosphorus, and soil carbon compared with inorganic fertilizer. In manure-amended silt loam soils, aggregate stability was consistently higher across multiple years, indicating a texture-dependent response.
Collectively, these results indicate that manure primarily improves soil chemical indicators, while structural and biological responses required longer-term management. Cover crop biomass has the potential to improve soil health, but inappropriate termination could reduce overall potential, underscoring the importance of long term field studies for comprehensive evaluation of CCPs.
The most widely used biosecure entry systems to minimize the spreading of disease-causing pathogens are conventional shower-in/shower-out and Danish entry systems (DES). However, these systems can be impractical or troublesome for some farms, especially when farm staff do not always adhere to the biosecurity protocols and standards.
This study evaluated the effectiveness of multiple biosecurity interventions - including air shower (AS), disinfectant spraying (DS), disinfectant fogging (DF), and their combinations - with and without integration of the DES and hair nets. Results show that incorporating the (DES) and hair net protocols significantly improved bacterial and viral reduction.
Full-body showering remains the most effective biosecurity intervention, though its performance is highly dependent on strict adherence; even minor lapses reduce its efficacy. Alcohol-based hand sanitizer and multi-step combinations involving DES offer practical and effective alternatives in settings where full-body showers are not feasible.
The presentation will end with current workshops focusing on biosecurity and composting, and hands on activities for attendees to have improved workshop experiences.
About the presenter:
Dr. Teng Lim is an extension professor at University of Missouri and a professional engineer. His research and extension programs focus on developing and assessing practical animal manure management, on-farm biosecurity, and air quality control. Dr. Lim is an active member of the University of Missouri Swine Focus Teams. He enjoys collaborating with colleagues and farmers to work on various agricultural engineering production issues.