2021 Volume 92 Issue 2 Pages 182-191
Increased soil carbon content exhibits an ameliorating effect on global warming. Grassland soil has a high soil carbon content and functions as a carbon dioxide absorption source. Therefore, we investigated the long-term effects of grassland renewal and fertilization on soil carbon content. The survey area included 14 grasslands in Nemuro, Hokkaido, Japan. The vegetation in each grassland was investigated, and soil samples were collected for physical and chemical analyses. The soil A0 layer thickness was measured, and the chemical properties and eukaryotic microorganism community characteristics were examined. The data, analyzed considering grassland management implications, showed that the total soil carbon content was positively correlated with the A0 layer thickness, whereas it was negatively correlated with the soil pH (H2O). The A0 layer thickness increased with the number of years after grassland renewal; however, it decreased with increased nitrogen input. Reduced nitrogen input and increased number of years after grassland renewal were associated with increased soil carbon content. Increased soil exchangeable calcium increased the soil pH (H2O) and reduced the soil carbon content, while increased soil pH (H2O) increased the grass canopy coverage and soil eukaryotic microbiota diversity. These results suggested the possibility of identifying the optimum quantity and application method of calcium material, which fosters a high diversity of eukaryotic microflora while maintaining a high soil carbon content.
