The effects of applying lime materials and composts on the bioavailability of metals in the contaminated soils are complicated while both inhibiting and enhancing effects may be occurred.In addition,the interactions between Cu and Zn affecting their bioavailability in soils and accumulation in brown rice were not clarified.The objectives of this study are to understand(1)the application of soil amendments to reduce the bioavailability of Cu and Zn in the soils and to reduce the Cu and Zn uptake by brown rice,and(2)also to understand the reaction of Cu and Zn in the Cu and Zn contaminated red soil.The Pinchen soil with acidic and high iron content of top soil(0-20 cm)was collected from rice-growing soils in Taiwan.The soil was cross-spiked with different rates of Cu/Zn in soil as: 0/0(control),75/0,150/0,0/200,0/400,75/200,75/400,150/200,and 150/400(mg/kg),respectively.Three treatments were conducted including control,apply compost(60 tons/ha),and apply lime material(calcium carbonate,to increase soil pH value to 7.0).Each treatment were 3 duplicates.The cross-spiked Cu/Zn-treated soils were incubated for 3 months by 3 cycling of wet and dry processes,followed by pot experiments with recommended chemical fertilization for rice cultivation.The pH value,organic matter content,EDTA,DTPA and aqua regia extractable amount of Cu and Zn in soils and concentrations of Cu and Zn in brown rice were determined.The results indicated that rice yields and Zn concentrations of brown rice were not affected by lime or compost applications,while the Cu concentration of brown rice was significantly decreased with both applying lime and compost(p <0.05).The extractable amounts of Cu and Zn in soils were not significantly different among different treatments.The interactions effects between Cu and Zn on their availability and accumulation in brown rice were observed.The addition of Zn can enhance the Cu accumulation in brown rice and this effect can be inhibited by compost or lime application(p<0.05).On the contrary,the addition of Cu did not enhance the Zn accumulation in brown rice whether compost or lime were applied or not.In this study,Cu and Zn concentrations of brown rice were below 10 and 45 mg/kg,respectively,which were in the food safety level by risk assessment for rice grown at the soil total concentration of Cu and Zn reached 150 and 400 mg/kg,respectively.