Soil fertility and crop nutrition in the mediterannean region: retrospects and prospects

Ryan, John; Sommer, Rolf

Soil fertility and crop nutrition in the mediterannean region: retrospects and prospects

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2010-04-20

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2010-04-20

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Ryan, John

Sommer, Rolf

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John Ryan, Rolf Sommer. (20/4/2010). Soil fertility and crop nutrition in the mediterannean region: retrospects and prospects. Syrian Arab Republic: International Center for Agricultural Research in the Dry Areas (ICARDA).

Abstract

Oral Presentation in International Conference on Soil Fertility and Productivity Humboldt Universitaet, Berlin, Germany 17-20 Mar 2010. The lands surrounding the Mediterranean, particularly the Near East, are where settled agriculture began over 10, 000 years ago and are a major center-of-origin of many of the world’s food crops, notably cereals and pulses, as well as livestock (sheep and goats).The semi-arid and arid conditions prevailing in the Mediterranean region have influenced the type of soils that have evolved there and are a major determinant of the type of cropping systems practiced in the region. The Mediterranean climate allows for rainfed cropping in the relatively moist cool period from late autumn to early summer, and even then drought has a constant influence. Fallow has been traditionally practiced as a hedge against drought. Fertility was partly maintained by nitrogen-fixing plants and the recycling of animal manures. During the long dry season, cropping is only possible with irrigation. Cropping over the millennia has influenced not only the landscape, but the intrinsic features of the soils. Nevertheless the past 3 decades or so have witnessed considerable changes due to land –use pressure induced by population growth rates, notably increased mechanization, decreasing fallow, increasing crop diversification, irrigation, and chemical inputs, especially chemical fertilizers. In most countries of the region, N use has increased about 20-fold from a very low base while phosphate (P) has increased to a lesser extent. As the region’s soils are well supplied with potassium (K), this element is used only to a limited extent. Only recently has an awareness developed of the possible significance of micronutrients. This presentation gives a broad overview of what has been achieved in terms of our understanding of nutrients in relation to soil properties and crops, with specific emphasis on nutrient dynamics in agro-ecosystems and nutrient use efficiency. 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 soils resources of the Mediterranean are seen in the light of global trends.