MEASURING SUSTAINABILITY IN AGRICULTURAL SYSTEMS

Sustainability is often discussed but rarely defined and even more rarely measured. In the farming context, a useful working definition may be borrowed from physicians’ Hippocratic oath: ‘First, do no harm’. However, as agriculture has harmed ecosystems, perhaps ‘Identify and rectify harm’ should be added to the definition. In practice in New Zealand, projects which are attempting to measure sustainability, or the lack of it, have begun. Biological, physio-chemical, biochemical and social aspects are all involved in the new ‘Selwyn Stewardship Monitoring Scheme’ in Canterbury. These indicators include a suite of invertebrate species, two bird species, (skylark and starling), soil organic carbon and aggregate stability, nutrient leaching, ‘energy audits’, biochemical markers of sublethal effects, and productivity, among others. The way these indicators are used, interpreted and the extent to which they are accepted by the farmers involved is outlined.