Effects of High Nonexchangeable Aluminum on Decomposition and Nutrient Release from Chestnut Leaves

The effect of high nonexchangeable aluminum of a Cryptopodzolic soil derived from mica schist on decomposition and nutrient release from chestnut ( Castanea sativa ) leaf litter was studied in southern Switzerland using the litter bag technique. Variables studied were time (18 months), exposure (NW versus SE), and profile position of litter (L, O f and A h horizons). A site with a Haplumbrept (Al‐poor) derived from cherty limestone provided a parent material contrast. Litter decay was chiefly controlled by microclimatic of sites rather than parent material. Litter decay differed between NW‐ and SE‐exposed sites for L and O f horizons. After 18 months, initial dry matter remaining in L, O f and A h positions was 58, 34 and 18%, respectively. All factors equal, the mobility series for nutrient release was K>Mg>Ca>P>N, but site and litter position affected element release. Only K and Mg were lost more rapidly than dry matter. Because dry matter and nutrient loss were similar for Al‐rich and Al‐poor sites, we conclude that Al content of soils had no influence on decomposition.