Effluent irrigation - an environmental challenge for soil science

With the growth of concern for the impact of humankind on the environment, soil scientists have increasingly shifted the emphasis of their work towards the effect of agricultural and other land management practices on the environment. This shift has required some changes to the way soil science is practised. The example of land application of wastes, an increasingly popular practice, is used to illustrate the role of soil science in the complex web of scientific, social, and economic aspects of environmental issues, and the need to influence community thinking and the policy debate. The issues often most likely to be limiting to effluent irrigation are excessive nitrate leaching, poor salt management, and the effects of increasing soil sodicity on current and future land uses. The scientific challenges that these pose are discussed, together with some broader issues including those associated with implementation of effluent irrigation, and socioeconomic and environmental considerations that should influence the decision to select effluent irrigation as the means for disposal or reuse.