Livestock production under Northern European conditions can affect water, air and soil. Examples of the possible environmental effects on water are fish kills or microbial contamination, if solid manure, slurry, “dirty water” or silage effluent are collected, stored, handled or spread inappropriately. Examples of the possible environmental effects on air are emissions of ammonia (which can lead to acidification and, after subsequent deposition, to eutrophication), the greenhouse gases methane and nitrous oxide, odours and particulates.
In the case of water pollution, good management practices using existing technology are usually adequate for preventing most environmental impacts. This often requires storage during periods when conditions are unsuitable for spreading, followed by carefully controlled application. However, for relatively dilute effluents (such as dairy farm “dirty water”), it may be more cost-effective to use different approaches, such as waste minimisation and/or continuous treatment and land spreading. Recent research results are reviewed and compared in this paper, to identify ways in which farmers can prevent water pollution at least cost. The potential implications of such measures on further reductions in the annual numbers of pollution incidents are discussed in conjunction with the impacts of different regulatory and punitive approaches.
In the case of preventing air pollution, although good management can achieve much, there is a need for new technology to back it up. Existing ammonia abatement techniques are mostly expensive and farmer-unfriendly. In the longer term, changes to the animals' diet should hold the greater potential for abatement, not only of ammonia emissions but also of methane emissions. Reducing one form of pollution can often increase another, so an integrated approach to solving pollution problems is necessary.