Influence of biochar on soil properties, soil health and crop productivity- a review

Abstract

India achieved a spectacular growth in agriculture since 1966, but for meeting the needs of current growing population, food grain production has to be increased at least 70 per cent by 2050. Over more the present-day agriculture is challenged to fulfill the objectives of achieving food, fodder, fibre and fuel security as well as environmental sustainability to restoring soil resources, improving water quality and mitigating climate change. Therefore, it is crucial to maintain the threshold level of organic matter for maintaining physical, chemical and biological integrity of the soil and also to perform its agricultural production and environmental functions (Segun and Oladele, 2019). For managing these issues, addition of organic amendments and biochar to mitigate climate change and ensures food production at global scale. Biochar (commonly known as agri char) is a carbon rich product derived from slow pyrolysis process of several kinds of waste biomass. Application of biochar at the rate of 5 t ha^-1 favourably influenced the soil bulk density, pH, OC, microbial carbon and CEC in the soil and positive changes in increasing nutrient availability. Further application of biochar may offer additional carbon-negative benefits though avoiding burning in field and bioresource recycling, which have been a great concern with air pollution of Indian agriculture and climate change mitigation (Segun and Oladele. 2019). Application of biochar at low doses (3–6 t/ha) with low rate of nitrogen fertilizer (30 kg/ ha) notably improved N fertilizer use efficiency, grain biomass yield of upland rice and soil physicochemical properties.

The results of Snekapriya and Jayachandran (2018) concluded that application of 100 per cent recommended dose of NPK along with 2 t of bio-char + Azospirillium @ 10 kg ha^-1 recorded higher benefit cost ratio of 1.96 for sugarcane seed cane production. The digested-enriched biochar treatments significantly improved soil quality as it provided higher soil organic matter and macronutrients. Application of green waste biochar improves soil physical properties and reduce tensile strength and increases the field capacity (Naresh Kumar et al., 2018). Recent studies have demonstrated that soil pH was a main factor affecting soil microbial community and stability of biochar. Little information is available for the micro biome across different soil pH and subsequently CO₂ emission. However, the decreased bioavailability of SOC via adsorption of biochar resulted in higher abundance of oligotrophic bacteria in Phaeozems, leading to the decrease in CO₂ emission.