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

Abstract

AbstractAgriculture 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.