2017 Volume 88 Issue 3 Pages 339-349
Cattle manure compost (less than 400Bq/kg per wet weight) polluted with radioactive cesium was applied to a rice paddy field for two years and its effect on growth and the radioactive cesium level of the cultivated rice and rice straw were investigated. The application rate of the cattle manure compost was 1t/1000m2 per wet weight. One rice paddy field (approximately 2200m2 ; soil type : andosol ; radioactive cesium level of plowed soil layer before investigation [before cattle manure compost application] : 1,821±230Bq/kg per dry weight [mean±SD]) was divided into three parts and rice was grown in each section. The three examined sections were as follows : 1) no cattle manure compost, 2) cattle manure compost polluted by radioactive cesium (less than 400Bq/kg per wet weight), and 3) non-polluted cattle manure compost. The polluted cattle manure compost was prepared by mixing highly polluted cattle manure compost with normal cattle manure compost. As a result, the polluted cattle manure compost did not influence the radioactive cesium level of the rice or the rice straw. There is the possibility that cattle manure compost (less than 400Bq/kg per wet weight) can be used on rice paddy fields. When the potassium concentrate of a rice paddy field is above 25mg/100g per dry weight, the effect of radioactive cesium on rice and rice straw has been reported to be restrained. When cattle manure compost is applied to a rice paddy field that meets that potassium concentration requirement, there is the possibility that transference of radioactive cesium to rice and rice straw is more restricted than in past reports.
