Soil fertility and crop nutrition research at an international center in the Mediterranean region: achievements and future perspective.

The Mediterranean climate allows for rainfed cropping in the relatively moist cool period from autumn to late spring/early summer. Drought has a constant influence. Soil fertility was partly maintained by fallowing, nitrogen-fixing plants, and animal manures. Considerable changes have occurred due to land use pressure, i.e. decreasing fallow and increasing crop diversification, irrigation, and chemical inputs, especially chemical fertilizers. Generally, N use has increased about 20-fold, while phosphate has also increased significantly. Due to adequate reserves in the soils, there is a limited potassium fertilizer use. Awareness of the significance of micronutrients has developed. This presentation gives a broad overview of nutrients in relation to soil properties and crops, emphasizing nutrient dynamics in agroecosystems and nutrient use efficiency. Chemical fertilizers have contributed significantly to increasing crop output in the Mediterranean region. Fertilizers and nutrients are considered in the broadest sense, i.e. agricultural production, human and animal health, and the environment. Attention is given to the potential contribution of soil and cropping systems to the emission of greenhouse gasses and how soil management is likely to need to respond to the likelihood of climate change. Projections about future changes related to soil resources of the Mediterranean region are seen in the light of global trends. [ABSTRACT FROM AUTHOR]