In greenhouse experiments, the toxicity threshold limits of cadmium (Cd) were evaluated for amaranthus, fenugreek and buckwheat grown in a mollisol fertilized with varying levels of farmyard manure (FYM). The soil treatments involved factorial combinations of three levels of FYM (0, 2.23 and 4.46g kg^<-1> soil) and seven levels of Cd (0, 5, 10, 25, 50, 100 and 150mg Cd kg^<-1> soil). Increasing levels of Cd in the mollisol decreased the dry matter yields. The toxicity threshold limits of Cd for 10% reduction in the relative yields in 0, 2.23 and 4.46g FYM kg^<-1> soil were 7.3, 30.5 and 11.0mg Cd kg^<-1> dry matter in amaranthus, 2.5, 3.6 and 4.9mg Cd kg^<-1> dry matter in fenugreek and 6.4, 21.0, 16.0mg Cd kg^<-1> dry matter in buckwheat, respectively. The toxicity threshold limits of 0.1 M HCl-extractable Cd in soil amended with 0, 2.23 and 4.46g FYM kg^<-1> soil were 2.0, 4.5 and 2.2mg Cd kg^<-1> soil for amaranthus, 2.5, 5.0 and 22.2mg Cd kg^<-1> soil for fenugreek and 2.8, 12.5 and 19.0mg Cd kg^<-1> soil for buckwheat, respectively. The toxicity threshold limits of 0.005 M DTPA (pH 7.3)-extractable Cd in soil amended with 0, 2.23 and 4.46g FYM kg^<-1> soil were 1.3, 2.6 and 2.1mg Cd kg^<-1> soil for amaranthus, 1.6, 2.9 and 9.6mg Cd kg^<-1> soil for fenugreek and 1.6, 11.5 and 6.9mg Cd kg^<-1> soil for buckwheat, respectively. Based on plant tissue concentrations of Cd, amaranthus was less susceptible to Cd toxicity than fenugreek and buckwheat. Application of FYM to soil helped to reduce uptake and mitigate toxicity of Cd in leafy vegetables.
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