The role of riparian buffer management in reducing off-site impacts from grazed dairy systems

Abstract

Agriculture in general and intensive animal production in particular can degrade the environment, especially as a consequence of the overuse of nutrients. Intensively grazed dairy systems, defined by the presence of foraging animals in the landscape, are often considered a more benign approach to dairy production with perceived smaller impacts due to the reduced requirement for manure disposal. However, grazing dairy cows contribute nutrients and pathogens in excreta, and sediment through landscape deformation. These impacts can dramatically increase in parts of the farm such as feeding, watering and sacrifice areas, laneways and night paddocks where animals are concentrated and spend a disproportionate amount of time. Other practices such as the disposal of dairy shed or dairy factory effluent and cultivation of fodder crops can also pollute the environment. A common approach to reduce nutrient, pathogen and sediment losses from dairy farms is to establish buffer zones in riparian areas that act as an interface between upland land use and waterways. This is generally done by fencing riparian areas to exclude stock and revegetating with understory and overstory species, with the aim of increasing infiltration, trapping sediment and decreasing contaminant losses from upland pastures. However, poorly designed and managed riparian areas may themselves contribute to further environmental degradation. Rarely is an integrated approach, including factors such as animal behavior and dairy farm management practices, as well as an analysis of landscape and riparian hydrology used in developing riparian management recommendations for individual farms. This paper reviews the threats posed by intensively grazed dairy systems, approaches to improve riparian zone management and recommends future research needs.

Cross-Validation Indicates Predictive Models May Provide an Alternative to Indicator Organism Monitoring for Evaluating Pathogen Presence in Southwestern US Agricultural Water

“…Since, in the current study, the relationship between natural cover and Salmonella presence and EHEC marker detection is weak, additional research is needed to fully characterize the role wildlife plays as a source of enteric pathogen contamination for southwestern canals. Given the need for additional research, and the important ecosystem services provided by natural cover (e.g., water filtration) and wildlife (e.g., pest control, pollination), the authors want to emphasize we are not advocating the removal of natural cover or wildlife from growing areas (Aarons and Gourley, 2012;Allende et al, 2018;Navarro-Gonzalez et al, 2020).…”

Bacteria, viruses, and parasites in an intermittent stream protected from and exposed to pasturing cattle: Prevalence, densities, and quantitative microbial risk assessment

“…Billington et al (2011) suggest that uncontrolled stock access to waterways results in elevated public health risks from pathogens based on hazard identification, exposure assessment, dose-response analysis, and risk characterisation of stock accessing waterways upstream of drinking water off-takes. Aarons and Gourley (2012) suggest improved riparian zone protection approaches and strategies are needed, and Miller et al (2010) indicate that not all water quality endpoints are improved with riparian zone fencing. A complicating factor in the assessment of the water quality benefits imposed by riparian zone protection (a beneficial management practice (BMP)), is that pasturing systems, regardless of whether they are fenced or not, are variably susceptible to livestock, wildlife, and human fecal inputs .…”

Persistence of biodiversity in a dryland remnant within an intensified dairy farm landscape

“…Our findings suggest that a buffer zone would be of value around native vegetation remnants adjacent to dairy farms, and this should be at least 10-20 m wide to reduce the input of irrigation water and nutrients (effluent, urea, lime and superphosphate). Applying fertilisers only during periods with favourable winds, and planting buffer zones around remnants with native species would also be likely to help conserve the native plants and invertebrates within (Aarons & Gourley 2012).…”