EFFECTS OF SELECTED BIOCHAR AMENDMENTS ON IMMOBILIZATION OF BIOAVAILABLE CADMIUM (Cd) IN ETHIOPIAN KALE (Brassica carinata) GROWN IN ARTIFICIALLY CONTAMINATED SOIL YORDANOS KIROS G/TSADIK Addis Ababa University, 2018 Biochar has attracted research interest due to its ability to reduce the bioavailability of heavy metals in contaminated soils and reduce their risk of entering the food chain. This study aims to evaluate the potential use of Stinging Nettle (SNB), Parthenium (PB), Brewery Sludge (BR) and Bamboo (BB) derived biochar as a soil amendment for reducing Cd availability and uptake by Brassica carinata in pot experiments. The soil used for these experiments were moderately fertile silty loam and slightly basic (pH= 7.76). All the biochar treatments were pyrolyzed at 500 and sieved with mesh size (0.5mm). They were applied at the rate of 4% w/w on cultivars grown on artificially Cd spiked soil. The addition of biochars to the soil significantly (p < 0.05) increased the dry weight of edible part of Brassica carinata (Ethiopian kale) by 216% in SNB, 335% in PB, 228% in BR and 35% in BB. The bioavailable Cd concentration was measured by CaCl2 extractable procedure was significantly lower (P < 0.05) in all selected biochar treated soil than soil without biochar treatment, followed the order: BR > PB > SNB >BB. This was contributed for significant reduction in Cd accumulation in the edible part of the plant in treated soils. The amount of Cd reduction in soil and accumulation in plant were significantly higher in BR and SNB than PB and BB derived biochars, at 0.05 significant level of Post Hoc ANOVA. Particularly, with the increasing soil available phosphors (AP), pH and Cation Exchange Capacity (CEC) of BR and PB biochars significantly reduced Cd bioavailability in soil by (86% and 44%) and accumulation in shoot of Brassica carinata cultivars by (93% and 79%),respectively. The Effects of biochar treatments on heavy metal bioavailability varied with the nature of the feedstocks. The result indicates that BR and PB derived biochars are most effective to promote Cd immobilization and Ethiopian kale growth than the SNB and BB derived biochars. Therefore, these biochars could be used as effective treatments to reduce contaminated agricultural soil and efficient disposal of agriculture and industrial wastes.