ZLV Online

Forest floor and topsoil properties of two 50-year-old stands (larch and spruce, alder and spruce) were compared under conditions of former agricultural land in the Orlické hory Mts. (East Bohemia). The results showed, that amount of forest floor did not differ between larch (75 t.ha-1) and spruce (66 t.ha-1) whereas forest floor of alder origin showed significantly higher weight (121 t.ha-1) compared to spruce (77 t.ha-1). The upper layer of forest floor of larch origin was higher in both Ca (2,543 mg.kg-1) and Mg (296 mg.kg-1) than under spruce (Ca – 1,056 mg.kg-1, Mg – 103 mg.kg-1). Lower larch forest floor layer (FH) and topsoil showed lower concentrations of K (155 and 44 mg.kg-1 respectively) whereas topsoil was higher in P (17 mg.kg-1) compared to spruce (7 mg.kg-1). The topsoil under larch was also significantly lower in percent of both total C (3.3%) and N (0.2%) and in C/N ratio (14). Topsoil was higher in Ca (152 mg.kg-1) under alder. Both K (4,142 mg.kg-1) and P (209 mg.kg-1) were found to be significantly higher in the upper forest floor (LF) compared to spruce (K – 659 mg.kg-1 and P – 102 mg.kg-1). The trend of higher K was confirmed also in topsoil under alder. The LF horizon of alder origin consisted mainly of N-enriched leaves having significantly lower C/N ratio (15) compared to spruce (27). The topsoil had lower C/N under alder as well. It can be concluded that both larch and alder are able to form the nutrient-enriched forest floor; the lower C/N, the higher risk of nitrate leaching. The C/N ratio was significantly lower in alder topsoil (12; p≤0.01) though the value under spruce seemed to be similar (13).