**1. Introduction**

Agriculture plays an important role in shaping the global economy. Now-adays, food security is a major issue. Despite remarkable refinement of agricultural practices after World War II, the global food supply is yet incapable to fulfill the actual demands. Further, emerging issues of soil pollution, climate change and-Desertification still remains to be iron out for the agriculture sector [1]. The global food demand is anticipated to increase by 70% till 2050 with the burgeoning population [2] and meeting up this demand without compromising soil health and agroecosystem has turned into a big challenge in the agriculture sector. To meet the pressing demand for food; indiscriminate use of fertilizers, plant growth regulators, pesticides etc. has become a general practice. Their excessive use is a serious concern because of their adverse impact on the environment and the entire food chain.

Depletion in soil organic matter and soil nutrients, decline in agricultural productivity due to excess use of chemical fertilizers and changes in climate due to anthropogenic activities are posing great threats to the sustainability of agricultural production in the tropical regions. So it is becoming important to use organic fertilizer along with inorganic fertilizer for improving sustainability and maintaining soil health. Along with organic manures and composts, the use of biochar is quite

a novel approach having potential benefits to both environment and agriculture as the former is a source of calcitrant carbon and the later contains recalcitrant form of carbon. Application of biochar to soil as a technique to improve the quality of soil has emerged in recent years. A common characteristic of biochar is that it comprises mainly stable aromatic organic carbon that cannot readily be returned to the atmosphere [3, 4]. The decomposition rate of biochar is 0.03% per year. Once it is applied, it is able to help in water and nutrient retention for next 5–8 years. Furthermore, biochar can reduce the risk of environmental pollutants (organic and inorganic) from soils by forming complexes or through sorption of organic compounds like herbicides [5].
