Converting Agricultural Waste into Biochar for Improving Physical Properties of Soil

Abstract

Biochar is a carbon-rich, fine-grained, porous material obtained from pyrolysis process, in which biomass is subjected to thermochemical conversion in the absence of either oxygen or very little oxygen. India is currently facing an acute problem of management of large quantities of agricultural waste which is either partially utilized or unutilized due to certain constraints. One of the indiscriminate uses of crop residues adopted by Indian farmers in the states of Punjab, Haryana and Uttar Pradesh is direct burning in open fields (in the form of Parali) which causes emission of greenhouse gases in the atmosphere. It is one of the sources of air pollution being faced every year during winter in the national capital region of Delhi. One of the recent advancements to combat this problem is the conversion of agricultural waste into biochar and applying it back into the soils to improve soil properties. Although biochar is not a new product, it has recently drawn attention of researchers because of its usefulness in improving the soil properties and as a means of carbon sequestration, thereby reducing greenhouse gas emission. Direct burning of agricultural wastes in fields cannot be called an environmental-friendly approach as it causes loss of biomass as well as introduces harmful gases into the environment. So converting agricultural wastes into biochar may be a better solution. In India, not much research has been carried out so far on biochar application in soils. The process of making biochar and the effects of utilizing biochar on the physical properties of soil have been presented in this paper, which will prove useful for Indian context where large quantities of agricultural waste are produced that creates environmental air pollution when directly burnt in fields.