Effect of Biochar and Compost Amendments on Soil Biochemical Properties and Dry Weight of Canola Plant Grown in Soil Contaminated with Heavy Metals

Soil contamination with heavy metals has resulted in a reduction of crop productivity and soil quality. We studied the effects of rice straw biochar (RB), rice straw compost (RC), and their mixtures at rates 0.5% and 1.0% on soil biochemistry and dry weight of the canola plant (Brassica napus)grown in contaminated soil with heavy metals. The results showed that the addition of the RB or RC alone or their mixtures together significantly increased contents of soil exchangeable cations, microbial biomass carbon (MBC), organic matter (OM), cations exchange capacity (CEC), availability of nutrients, NPK uptake, and dry weight of the canola plant. Soil microbial biomass carbon increased by 20.2% and 59.3% for RB, while it increased by 69.5% and 79.8% for RC with the addition of 0.5% and 1.0%, respectively, compared to the control. The results of this study reveal that the co-application of biochar with compost can be a promising strategy for improving soil productivity and soil quality in soil contaminated with heavy metals.