Carbon material as a sustainable alternative towards boosting properties of urban soil and foster plant growth

Highlights: • Usage of carbon-based material for enhancement of urban soil properties • Biochar and plastic char for soil reclamation towards sustainable farming system • Char application increases the plant growth response. • Reduced metal ion activity enhanced AP concentration from 412.16 to 586.88 kg h⁻¹. • Both the chars are efficient as growth stimulator and soil quality enhancer. Addition of carbon-based byproducts in urban soil is gaining popularity as a plant growth stimulator, soil quality enhancer and fostering green land vegetation. A 60-day trial experiment was carried out for investigating the impacts of sugarcane, neem and bamboo mixed biochar and polyvinyl chloride (PVC), polyethylene (PE) and polyethylene terephthalate (PET) mixed plastic char (1:100, 2:100 and 4:100 char: soil ratio) on physico-chemical properties of soil and growth of Dendrocalamus strictus saplings. It was found that available phosphorus increased from 412.16 to 586.88 kg h⁻¹ which could be attributed to reduced metal ion activity due to increase in the soil pH (7.75–7.81) and CEC (98.07–131.04 mEq 100 g⁻¹). The application of both the char enhanced the quality of soil and thereby helped in achieving higher crop yields. Both biochar and plastic char increased the soil pH, total organic carbon, available phosphorus and nitrogen in the soil. Additionally, the results showed an entirely positive influence of the chars on plant height thereby making it more suitable for the improvement of agricultural system and reducing the dependency on market-based fertilizers.