9:15 AM - 9:30 AM
[HGG01-02] Land transformation and secondary succession in the case of abandoned farmland around Komado Marsh, Fukushima Prefecture
Keywords:Human activities, Topsoil removal, Reforestation, Miscanthus sinensis
Introduction
Secondary Fagus forest, which was once used for fuel woods, widely distribute in cool temperate Japan. In the area around Komado Marsh in Fukushima Prefecture, where farmers settled in the 1950s, the surrounding forest was cleared in the 1970s with intensive land transformation, then soon after resulted in as abandoned farmland. After the Komado Marsh was registered as a national natural monument in 1970, there was concern about the impact of soil inflow from surrounding farmlands, and conservation measures was strengthened. By 2000, all abandoned farmland (about 56 ha) were publicly owned, and nearly 75% of which was additionally registered and protected. Since then, activities of Fagus sapling-planting have been conducted mainly by local volunteers, but even now, more than 20 years past, Miscanthus sinensis is thriving and the planted trees are dwarfed.
Academic research on the environmental issues in this area (Komado report 2004) carried out soil environment and vegetation surveys at abandoned farmland, and proposed the use of growth of M. sinensis as an indicator for selecting preferable sites of Fagus sapling-planting for the restoration. On the other hand, in the abandoned farmland, it has become clear of the lack of mycorrhizal flora, Basidiomycetes that involve in the formation of mycorrhizal roots to help tree growth (Guo et al 2018), and field experiments are undergoing to plant Fagus sapling with fungi inoculates in their roots.
The purpose of this study is to elucidate the secondary succession in the abandoned farmland, which has been strongly disturbed by human activities, and to obtain knowledge for the restoration of Fagus forest, using field surveys and soil analysis methods.
Material & Method
The study area was defined in the abandoned farmland, in Minamiaizu, Fukushima Prefecture. Totally six sections; North, Middle, and South sections (about 2.14, 1.38, and 0.81 ha), including sub-sections of N1, N2, M1, and M2, based on different by M. sinensis cover, were arranged, together with adjacent Fagus forest (control section).
Field surveys were conducted in September 2021 and August-October 2022 to examine vegetation cover by aerial drone photography, M. sinensis height and density, and biomass (g/m2 ) (dry litter volume, 30 x 30 cm2).
A soil profile survey was conducted in each section and soil samples were collected at every 10 cm depth. In addition, surface soil samples (0 -10 cm) were repeatedly collected at 5 plots in each section. Air-dried fine soil samples were applied for the following measurements: soil pH (H2O, KCl, NaF) (glass electrode method), soil colloidal Al, Fe, Si content (selective dissolution method), and exchangeable Ca, Mg, K content (batch b method).
Results and Discussion
The results of the soil colloidal properties revealed that the surface soil in N section was equivalent to 40-50 cm of Fagus Forest soil, and those in the M and S sections were equivalent to 30-40 cm of Fagus Forest soil. It was considered that the removal of topsoil was more intensive in N than M and S. The results of exchangeable Ca content showed that the surface soil in M2 and S, where well growing of M. sinensis, had significantly higher than others. Moreover, the fact that vertical distribution of exchangeable Ca content in soil profiles differed by sections suggested the Ca-leaching and Ca-accumulation difference among sites were caused by lime fertilizers, and Ca absorption by M. sinensis roots.
Conclusion
In this study, it was revealed that the amount of topsoil removal and intensity of soil disturbance during developing farmland differed by sections. Furthermore, the response of the biological process through the thriving M. sinensis as secondary succession, was seen with the soil properties. For the reforestation in the abandoned farmland, the knowledge of soil properties based on the history of land transformation is expected to contribute to the selection of preferable sites to plant in the future.
Secondary Fagus forest, which was once used for fuel woods, widely distribute in cool temperate Japan. In the area around Komado Marsh in Fukushima Prefecture, where farmers settled in the 1950s, the surrounding forest was cleared in the 1970s with intensive land transformation, then soon after resulted in as abandoned farmland. After the Komado Marsh was registered as a national natural monument in 1970, there was concern about the impact of soil inflow from surrounding farmlands, and conservation measures was strengthened. By 2000, all abandoned farmland (about 56 ha) were publicly owned, and nearly 75% of which was additionally registered and protected. Since then, activities of Fagus sapling-planting have been conducted mainly by local volunteers, but even now, more than 20 years past, Miscanthus sinensis is thriving and the planted trees are dwarfed.
Academic research on the environmental issues in this area (Komado report 2004) carried out soil environment and vegetation surveys at abandoned farmland, and proposed the use of growth of M. sinensis as an indicator for selecting preferable sites of Fagus sapling-planting for the restoration. On the other hand, in the abandoned farmland, it has become clear of the lack of mycorrhizal flora, Basidiomycetes that involve in the formation of mycorrhizal roots to help tree growth (Guo et al 2018), and field experiments are undergoing to plant Fagus sapling with fungi inoculates in their roots.
The purpose of this study is to elucidate the secondary succession in the abandoned farmland, which has been strongly disturbed by human activities, and to obtain knowledge for the restoration of Fagus forest, using field surveys and soil analysis methods.
Material & Method
The study area was defined in the abandoned farmland, in Minamiaizu, Fukushima Prefecture. Totally six sections; North, Middle, and South sections (about 2.14, 1.38, and 0.81 ha), including sub-sections of N1, N2, M1, and M2, based on different by M. sinensis cover, were arranged, together with adjacent Fagus forest (control section).
Field surveys were conducted in September 2021 and August-October 2022 to examine vegetation cover by aerial drone photography, M. sinensis height and density, and biomass (g/m2 ) (dry litter volume, 30 x 30 cm2).
A soil profile survey was conducted in each section and soil samples were collected at every 10 cm depth. In addition, surface soil samples (0 -10 cm) were repeatedly collected at 5 plots in each section. Air-dried fine soil samples were applied for the following measurements: soil pH (H2O, KCl, NaF) (glass electrode method), soil colloidal Al, Fe, Si content (selective dissolution method), and exchangeable Ca, Mg, K content (batch b method).
Results and Discussion
The results of the soil colloidal properties revealed that the surface soil in N section was equivalent to 40-50 cm of Fagus Forest soil, and those in the M and S sections were equivalent to 30-40 cm of Fagus Forest soil. It was considered that the removal of topsoil was more intensive in N than M and S. The results of exchangeable Ca content showed that the surface soil in M2 and S, where well growing of M. sinensis, had significantly higher than others. Moreover, the fact that vertical distribution of exchangeable Ca content in soil profiles differed by sections suggested the Ca-leaching and Ca-accumulation difference among sites were caused by lime fertilizers, and Ca absorption by M. sinensis roots.
Conclusion
In this study, it was revealed that the amount of topsoil removal and intensity of soil disturbance during developing farmland differed by sections. Furthermore, the response of the biological process through the thriving M. sinensis as secondary succession, was seen with the soil properties. For the reforestation in the abandoned farmland, the knowledge of soil properties based on the history of land transformation is expected to contribute to the selection of preferable sites to plant in the future.