Pig slurry is a valuable nutrient resource but constitutes a waste disposal problem in areas of high animal density. In the semiarid area of Pla d'Urgell, in the Ebro Valley, North-East Spain, irrigated crops receive large amounts of nutrients in the form of manure and mineral fertilizers. We studied the effect of pig slurry and additional side-dress mineral fertilizers on irrigated wheat, Triticum aestivum L., on a coarse loam soil, with high soil P and K levels. Yields increased by 62.3% when using pig slurry. The application of ammonium sulfate nitrate sidedress did not significantly increase wheat production. The average apparent recoveries were higher for potassium (88.7%) than for nitrogen (51.3%) and phosphorus (36.3%). Greater amounts of soil NO 3 -N were measured over the four growing seasons, which was consistent with the amount of N applied. Macronutrient and micronutrient uptake was significant higher for pig slurry treatments, but only small differences were found between the pig slurry and pig slurry plus ammonium sulfate nitrate treatments. The unfertilized treatment showed significantly lower soil P, K, Cu and Zn content than pig slurry treatments; 34%, 21%, 34%, and 26% respectively. These findings could be used to develop a nutrient management plan based on knowledge of soil test results and crop nutrient removal. This could help to improve the use of pig slurry and mineral fertilizers on limited available land areas and prevent the accumulation of potentially toxic elements in soils and the export of nutrients through agricultural drainage. over-fertilized soils / irrigated wheat / nutrient uptake / nutrient recovery / pig slurry * Corresponding author: jmvillar@macs.udl.es Article published by EDP Sciences and available at

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The effect on greenhouse potted Dieffenbachia maculata 'Camille' growing on 80% unfertilised blond peat (pH 6.0) and 20% perlite (v/v) of different fertilization methods has been studied. The fertilization treatments were: F (control) -Standard fertigation (9,7 meq N L -1 ; 10% NH 4 + -N; 1,4 meq P L -1 ; 4,3 meq K L -1 ); CF-30% of total N applied as soluble complex 17-8-14 (11,1% NH 4 + -N and stabilized with DMPP) and 70% of total N like F; BF -Basacote Plus (16-8-12; 3,0 g L -1 ) + 50 % of total N equal to F; C-70% of total N as soluble complex 17-8-14 (11,1% NH 4 + -N stabilized with DMPP). The experimental design was unifactorial with 29 pots per treatment. During the experiment nitrogen concentrations (nitrate and ammonium) in the leached solution were analysed; finally, height, leaf area, dry matter content and total concentration of nitrogen, phosphorous and potassium were determined. The fertilization method had a significant effect on the crop vegetative and bioproductive parameters, showing the treatments with complex fertilizers (CF and C) highest values of leaf area, plant height and dry matter production. Plant N concentrations were lower in treatments CF and BF than in control treatment. Treatment C had similar results than those of F; however, and due to higher biomass production, treatment C showed higher N extraction index and uptake efficiency. The control treatment (F) showed the highest rates of N lixiviation losses, the slow release fertilizer treatment (BF) the lowest. Complex and slow release treatments showed low rates of ammonium lixiviation losses.