The Podzol has been elected "Soil of the year 2007" in Germany. This article reviews the present knowledge on the development, functions, and threats of Podzols. The main theories on mobilization and transport of organic matter, Fe, Al, and Si are (1) metal-organic migration, (2) metal reduction, and (3) inorganic sol migration. Immobilization theories include precipitation or polymerization due to increasing pH/ abundance of base cations with depth, mechanical filtering in soil pores, oxidation of metal-organic complexes, biodegradation of the organic part, decreasing C-to-metal ratios during translocation, adsorption to soil particles, and flocculation at the point of zero charge. Podzolization is discussed also on the catena scale, where vertical and lateral translocation processes (across pedon boundaries) need to be considered to understand Podzol patterns in landscapes. Chronosequence studies show that incipient podzolization usually becomes visible between 100 and 500 y and mature Podzols develop in 1,000-6,000 y. The occurrence of Podzols worldwide is concentrated mainly on the boreal zone and mountain regions within the humid temperate zone. Smaller Podzol areas are found in some perhumid tropical and subtropical regions. In Germany, Podzols occur in the Alps, in the glaciofluvial valleys and heathlands of N Germany, and in the mountain ranges. They fulfil several ecological functions, especially for groundwater recharge. Main threats for these mostly sandy soils are wind erosion and surface mining of sand. Two pedons which were chosen to represent the "Soil of the year 2007" are presented. Finally, some conclusions about podzolization processes are drawn, which may explain the diverse observations reported in the literature.

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Soil characteristics and methanogenesis were investigated in Fluvisols of the Balandra lagoon mangrove in Baja California, Mexico in March/April 1995.The grain size distribution was dominated by the silt fraction (54-92%), sand and clay contents were 6-44% and 0-19%, respectively. Bulk density was 0.6-1.5 g cm -3 , the water content 290-690 ml 1 -1 and the air content 38-200 ml 1 -1 . The soils always showed saline conditions (30-70 g kg -1 ), mostly negative redox potentials (down to -202 mV), P contents from 0.8 to 16.0 g kg -1 , Corg contents from <2 to 140 g kg -1 and neutral pH values. In one soil the pH dropped < 2,5 after peroxide treatment indicating, together with low carbonate/pyrite ratios (mostly < 3) sulfidic properties. The relative distribution of the porewater canons was always 74% Na, 17% Mg, 6% Ca, and 3% K. For the exchangeable and water soluble cation fraction it was 28-59% Na, 22-34% Mg, 12-32% Ca, and 2-5% K, with increasing Na-and decreasing Ca-concentrations in the transect from sea to land.The methane concentrations were mostly lower than 2 µM. Methane production rates were between 1 and 23 nmol ml -1 d -1 . Methane emission was not detectable. This indicates, that methanogenesis is balanced by methane oxidation processes within the soil. Higher methane concentrations (33 µM) and production rates (100 nmol ml -1 d -1 ) in one of the investigated soils were attributed to anthropogenic impact. Consequently, in case of human manipulation the potential of mangrove soils to emit methane seems to be high, thus mangroves are sensitive with respect to methanogenesis.