%0 Tesis de Maestría %A Ortiz Navarro, Mar?a Soledad %E Wulf, Amelug %I Alemania / Universidad de Bonn / 2015 %D 2016 %G deu %T Delta O-18 signature and phosphate pools in selected soil groups %U http://repositorio.educacionsuperior.gob.ec/handle/28000/1995 %X Soil P-cycling is an issue that requires a great deal of attention regarding the importance of P in all living organisms. This study focused its attention in four selected soils: Ferralsols (China) and Andosols (Indonesia), which are used for paddy rice cultivation; Luvisols (Germany) covered by winter wheat cultivars and Chernozems (Russia) covered by natural steppe vegetation. The study hypothesizes that the soil-forming factors and anthropogenic influences determine the composition of phosphate pools and the ?18-O signature. The soil samples were taken from different depths and each one was processed according to Hedley et al. (1982) modified by Tiessen and Moir (1993) and to modified from Tamburini et al.(2010). Pi concentration was measured by the Molybdenum Blue method of Murphy & Riley (1962), PT content was determined using ICP-OES, and Po by the difference between P and Pi, while ?18OP was measured using TC/EA-IRMS. T