Effect of application timing of potassium fertilizer on root uptake of Cs-137 in brown rice

摘要

We investigated the optimal timing and quantity of K to reduce radiocesium in brown rice. The concentration of Cs-137 in brown rice was reduced from 32 Bq kg(-1) without K fertilizer to 2.0 Bq kg(-1) with 16 g m(-2) of basal K. The concentration of exchangeable Cs-137 in the soil decreased from 234 to 25 Bq kg(-1) with increasing application of K fertilizer from 0 to 57 g m(-2). Hence, heavy application of K fertilizer in the early growing period can decrease the uptake of Cs-137 by rice plants and the concentration of exchangeable Cs-137 in the soil.