Effect of biochar on Chinese kale and carbon storage in an agricultural area on a high rise building

Abstract

Supplementation of agricultural soil with biochar can positively affect growth and yield of crop plants. In this study, a mixture of different amounts of rice husk biochar (RHB) at 1.5%, 2.0% or 2.5% by weight (wt.%) and 20 wt.% vermicompost were used to grow Chinese kale in a soil on a high rise building in Bangkok city. The effect of this mixture on yields of Chinese kale and the level of carbon storage in the soil and plants were evaluated, since this could contribute towards urban food security and reduce greenhouse gas emissions. Eight treatments were evaluated as (i) the soil alone (TC), and soil supplemented with (ii) 20 wt.% vermicompost (TM20), (iii–v) RHB (TB1.5, TB2.0 and TB2.5), or (vi–viii) vermicompost with RHB (TMB1.5, TMB2.0 and TMB2.5). Treatment TMB2.0 gave the highest yield of Chinese kale shoots, followed by TMB2.5, TM20 and TMB1.5, respectively. In addition, TMB2.5 gave the highest carbon storage in the soil plus plants, followed by TMB20, TM20 and TMB1.5. Thus, adding the appropriate amount of RHB and vermicompost mixture in the soil led to a higher yield of plant products, including an increased level of soil carbon storage. Applying RHB in urbanized agricultural areas is an alternative way for metropolitan areas to boost the yields of crop plants for food sustainability and long-term urbanized environmental management.