Soil Solution Chemistry at Different Positions on Slope in a Conifer Plantation Forest

概要

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It is known that soil property varies along the slope. It suggests that soil solution chemistry also differs topographically. To determine the variation in soil solution chemistry within one watershed, soil solution chemistry at the different positions of the slope was investigated. Soil N transformation changed along the slope. NH_<4^-> ratio to inorganic N (NH_<4^->+NO_<3^->) increased upslope. The tendency was verified by laboratory incubation. After incubation most of the mineralized N was nitrified at the lower part of the slope, while little nitrification occurred at the upper part of the slope. At the ridge and the backslope Inorganic N form in soil solution was concomitant with inorganic N form by incubation. At the ridge NH_<4^-> was predominant form in soil solution, at that time major anion was sea salt originated Cl^-. From this, soil solution chemistry seems to be regulated by the external nutrient source at the ridge. In the second year of lysimeter installation NO_<3^-> concentration increased in both sites and the ratio of NH_<4^+> to inorganic N decreased. It was considered due to the effect of lysimeter installation. The lag time and the magnitude of NO_<3^-> increase were different between the ridge and the backslope. It would he related with soil N transformation in pre-disturbance. The influence of disturbance were shown in other solute concentrations of soil solution.
一般社団法人日本森林学会の論文
1999-05-16