Role of biochar on improvement of physical characteristics of re-vegetated ex coal mined soil and production of black corn (Zea mays L. var. Black Aztek)

Abstract

Ex coal mined soil generally had problem for farming activities, even though it had been re-vegetated for few years. This research was aimed to determine the effect of biochar derived from corn cob to improve the physical characteristics of ex coal mined soil and production of black corn. A pot trial was conducted in Glasshouse at Andalas University, Padang. Soil was taken from re-vegetated of ex coal mined soil in Sawah Lunto, West Sumatra, Indonesia. The soil was mixed with biochar at 4 different doses (0; 0.5; 1.0; and 1.5%) of the weight basis. The experimental units were allocated based on Completely Randomized Design. Parameters analyzed were soil texture, bulk density (BD), total soil pore (TSP), hydraulic conductivity (HC), soil organic matter (SOM), and plant available water (PAT), as well as corn production parameters. The result showed that biochar significantly increased the SOM. SOM content at 1.5% biochar application increased by 32.4% compared to the OM content of the soil without biochar (0 T ha−1). Improving SOM due to biochar application, improved the soil physical properties, especially it decreased the soil BD (r=-0.71); increased HC (r=0.65); TSP (r=0.71); PAW (r=0.86); aeration pore (r=0.54); field capacity (r=0.83); and decreased wilting point (r=-0.66). Biochar application also improved production of black corn. It linearly increased crop height (r=0.76); corn stalk dry weight (DW) (r=0.75); grain yield DW (r=0.75); shoot DW (r=0.74); and root DW (r=0.76). Biochar derived from corn cob could be used to improve physical properties of ex coal mined soil.