The Great bustard (Otis tarda) is a vulnerable species which is declining due to the loss in habitat quality throughout its range. In Europe sizeable populations exist in Hungary, Portugal, Russia and Spain. The bird is one of the heaviest extant birds capable of flight. The average weight of an adult male is about 13.5 kg, with circa 1 m length and 2.4 m wingspan. The female bird is much smaller and half the weight. The bird's habitat is open grassland and agricultural land. The birds feed on seeds, insects and other small creatures, including frogs.

To assess different crop production practices regarding their impacts on the Great bustard the following assessment parameters were taken into account:

1. the suitability of the crop type to provide beneficial habitat conditions for this bird species,
2. the time- and operation-related risk disturbance potential of single operations during the reproduction period,
3. the risk associated to the application of nitrogen fertilisers influencing height and density of the vegetation and therewith microclimate, coverage and freedom of movement within the crop stand when looking for food and
4. the number of insecticide and herbicide treatments affecting the availability of food resources such as seeds and insects.

All alternative production practices of all crops defined for the model were assessed by their goal achievement levels using a fuzzy logic tool with the optimum being a zero risk for the great bustard to get negatively affected by agricultural activities.

Best results were calculated for set aside due to the low disturbance potential. Alfalfa and grassland got medium scores. The worst ratings were given to corn and sunflower as these crops are intensively managed.