Effectiveness of medium pruning on the reduction of radioactive cesium concentration in new shoots of tea plants in Ibaraki Prefecture, Japan

摘要

Tea (Camellia sinensis (L.) Kuntze) plantations in the northern part of Ibaraki Prefecture in Japan, approximately 100km southwest of the Fukushima Daiichi Nuclear Power Station (FDNPS), were contaminated with radioactive cesium (Cs) released from the power station during the Fukushima Daiichi Nuclear Disaster in 2011. Radioactive Cs concentrations in new shoots were monitored over the 3years since June 2011. The use of conventional skiffing management resulted in 64% lower radioactive Cs concentration in October 2011 compared with that in June 2011, and the concentration continued to decrease gradually thereafter. Medium pruning to approximately 40cm from the ground decreased radioactive Cs concentrations in the first tea crop of 2012 and 2013 by 24-25% more than conventional skiffing management.