Efecte de la topografia en la variabilitat espacial del contingut de carboni total i d?òxids solubles de ferro i alumini a l?horitzó B del sòl a una catena forestal a Suècia

The object of this study is the spatial variability of and the effect of the topography on the accumulation of soluble iron and aluminium oxides togethen with the illuviated the organic matter in the Bhs horizon of the soil. The spatial variability has been analysed geostatistically. This has been done with 96 samples where total carbon has been measured using the elemental analysator LECO. The soluble oxides of iron and aluminium complexed to the organic matter were extracted in 0.1N Na-pyrophosphate and determined by ICP. A one-way ANOVA analisys of variance between the three series showed that there are significant differences (P-value: 0,0000), but if we compare the soluble oxides there are significant similarities (P-value: 0,1839). The influence of waterlogging was studied by ANOVA; the results are that all three variables are affected, but especially the soluble iron oxides (P-value: 0,0000). The relationship between the variables are well correlated as the total carbon and the the soluble oxides of aluminium (R2 = 0.74, P0 = 0.001). When the theoretical semivariogram is fitted, the parameter with the highest spatial variability is the soluble iron oxides content. This has a good spatial correlation in a range of 20 meters. The high spatial variability is due to the effect of the waterlogging on the iron, 26 of the 96 soil samples being waterlogged. Iron is more easily reduced and leached than the carbon or the aluminium sesquioxides.