Effect of Biochar Produced from Paddy Husk and Coconut Frond on Soil Physical Properties and Productivity of Ginger in a Laterite Soil

The effect of biochar produced from paddy husk and coconut frond on soil physical properties and yield of ginger crop was studied in a laterite soil of Kerala, India. The treatments included paddy husk biochar (PHB) and coconut frond biochar (CFB) each @ 10, 20 and 30 t ha-1 + NPK as per KAU package of practices (KAU POP) recommendation, KAU POP alone (30 t FYM + 75: 50: 50 kg NPK ha-1) and absolute control. The recovery of paddy husk biochar (PHB) was 50% and that of coconut frond biochar (CFB) was 40%. Physical properties of the soil were significantly improved by the application of biochar compared to FYM as per KAU POP application. Specific surface area (68.74 and 2.56 m2 g-1 respectively) and water holding capacity (276.33 and 256.51% respectively) were higher for PHB compared to CFB whereas bulk density was lower for PHB (0.27Mg m-3) than CFB (0.35 Mg m-3). Biochar application reduced the bulk density, increased the water holding capacity and water stable aggregates of soil. Plant height, rhizome spread, and ginger yield were calculated towards interpreting the direct influence of biochar on growth of ginger. All these parameters were positively influenced by the incorporation of biochar at different rates. The highest ginger yield was obtained for PHB @ 30 t ha-1 (13964.2 kg ha-1) which was on par with CFB @ 30 t ha-1 (13418.3 kg ha-1). From the investigations, it can be concluded that application of PHB or CFB @ 30 or 20 t ha-1 along with NPK as per KAU POP produced significantly higher yield than FYM treatment as per KAU POP can be considered as the economically viable treatments in laterite soil.