"Integrated farming and indicators
Can Sustainable Devlopement be measured ?"

A necessary prerequisite to encourage implementation of sustainable agricultural systems are indicators and indicatorsystems. This will enable scientists, farmers and administrators to monitor the changes in land-use systems. The first step is to choose a set of indicators, which have to comply with a number of requirements  :

• indicators should be based on high quality statistics and have a high level of differentiation with regard to time and space

• the parameters should be scientifically sound and reflect the current state of scientific knowledge

• indicators should be monitored at regular intervals and over long periods

• indicators should be user friendly and relevant for the agri-environmental situation

• indicators should have a reasonably cost-benefit ratio

Following the OECD classification of indicators in "driving force", "state" and "response" indicators, the current approaches in agriculture research focus mainly on "driving force" and "state" indicators, whereas "response" indicators are used to a smaller extend. The second step is to develop a complete system of indicators. This is necessary, because the different indicators are interrelated and therefore the relation between the different indicators has implications for the interpretation of the results. In general, the following other requirements for an evaluation of indicator sets are important :

• target (control, administration, optimisation of husbandry, marketing)

• scale (country, region, catchments, farm or field)

• interactions between indicators

• model (modelling of energy and material flows)

• regional requirements (modelling or basic data sets)

• aggregation of single indicators

• time requirement for evaluation

• practical use (PC, internet)

In order to draw scientifically sound conclusions, the consideration of the interactions between indicators is a crucial point. One example: In the case the indicator nitrogen balance gives a high positive result, the consequences of such a finding without interactions would be to lower the nitrogen fertilization. This might be a completely wrong conclusion because a high positive nitrogen balance might weil be caused by a suboptimal application of pesticides and a low yield for that reason. The consequence in this case would be not to lower the nitrogen fertilization, but to improve the pesticide management. Another very important classification, which relates closely to the example mentioned above is the actual target of a indicatorsystem. An indicatorsystem designed to control or to administer payments etc. might be very simple and complex considerations like interactions between single indicators seem to be unimportant, although conclusions might be wrong. If, however, the optimisation of husbandry, fertilizer or pesticide management on the farm level is the target, those interactions must be considered.

Conclusions
Sustainability is currently and will continue to be a major challenge for agricultural research. Given the complex nature of this challenge, integrated and long-term projects based on interdisciplinary research have to be strengthened, which will also require a change in funding policies. A major focus for future research should be the development and implementation of indicators and indicatorsystems. The best chances for a widespread use have indicatorsystems, which combine the different dimensions of sustainability. Only if sustainability as complex system, is measurable with indicators the concept will eventually have consequences for the management of farms or regions.
 

O. CHRISTEN
Institute of Agronomy and Crop Science, University of Ha/Ie-Wittenberg, D-O6099 Ha/le (Saale), Germany

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