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The Triffa Plain is the most productive irrigated agricultural zone in north-eastern Morocco. Irrigated agriculture in (semi-)arid regions may exert different pressures on soil resources, but in northern Africa these are often poorly documented. A field survey conducted in 2005 to assess soil quality in the region focuses on the soil’s physico-chemical parameters and analyses their spatial dependency on a regional scale. As most of the soils are light-textured, with poor organic matter content and slightly basic pH, they are vulnerable to soil nutrient depletion. Multivariate analysis shows that organic matter content is well correlated to the soil’s P and K content, while the total and active lime correlate well with the alkalinity and pH, which in turn correlate negatively with nitrate content and soil electrical conductivity. The spatial structure of the soil parameters can be modelled using Gaussian semi-variograms, suggesting consistent spatial structuring of the parameters. The low nutritional status of the soils is compensated by important fertiliser supplements, leading to nutrient imbalances and further environmental deterioration. Copyright (C) 2012 John Wiley & Sons, Ltd.