Remediation of Radiocesium-137 Affected Soil Using Napiergrass Under Different Planting Density and Cutting Frequency Regimes

Kang, Dong-Jin; Ishii, Yasuyuki; Tazoe, Hirofumi; Isobe, Katsunori; Higo, Masao; Hosoda, Masahiro; Yamada, Masatoshi; Tokonami, Shinji

Remediation of Radiocesium-137 Affected Soil Using Napiergrass Under Different Planting Density and Cutting Frequency Regimes

2017

This study investigated the use of napiergrass (Pennisetum purpureum Schum.) to remediate soils highly contaminated with radiocesium-137 (¹³⁷Cs) in the town of Namie, Fukushima Prefecture, which is located around 9 km northwest of the Fukushima Daiichi Nuclear Power Plant, Japan. Field experiments were performed to investigate the remediation effects using two sites (paddy or upland grassland) as replicates, three planting densities (low, medium, and high density), and two different cutting frequencies (cut once or twice a year) over 2 consecutive years. Napiergrass can be more efficient than sorghum for ¹³⁷Cs remediation. The maximum ¹³⁷Cs removal ratio (CR, %) in napiergrass achieved with high-density planting (11 plants m⁻²) was between 0.32 and 0.57%. However, cutting frequency did not affect the CR. Higher biomass leads to a dilution of ¹³⁷Cs in cutting frequency. Therefore, we suggest that the greatest CR could be achieved through a high above ground biomass (high-density planting).

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