**2. Agricultural residues**

**1. Introduction**

72 Agricultural Waste and Residues

the demand and supply of biomass [2, 3].

the nation's reliance on coal as a major energy source.

As at 2012, world basic energy supply touched 560 EJ, corresponding to about 19,000 Mtce [1]. Of this energy supply, more than two-third is made up of fossil fuels, nuclear power was made up of 5% while 3% was renewable energy comprising hydropower, geothermal, solar, wind, and tidal. The balance is made up almost entirely of biomass and waste, which amounted to 10% of the world market. This portion of the energy considerably provided about 56EJ/y of the energy supplies; an amount, which is equal to three times the energy contributed by all other renewable energies in totality. However, considering resource report and reserves, biomass did not comparatively attract desired interest and data are not as extensively available as those for oil, gas, and coal, although reasonably good data are available for

Of importance is the renewable energy resources meant for locomotion and generation of electric power to curb the menace of climatic, economic, environmental and political concerns associated with the combustion of fossil fuel. Bioenergy, which is the utilization of bio-based materials, including plant materials and manure, to produce renewable fuels for transportation and to generate electricity sustainably. This fuel is characterized with low-carbon emission compare to fossil fuels while communities also stand to benefit immensely from the sale of this local resource [4]. Bioenergy is among the various policies put in place to reduce the dependence on the use of fossil fuel and it has been propose to cut US. oil use in half by 2030, and consequently, this practice will ensure the propensity of phasing out coal as electricity producing feedstock. An important key to exploring biomass resources sustainably is to focus on the right ones, and to develop them in holistic ways and at appropriate measures [5].

Cellulosic biomass may be derived from agricultural sources, such as crop residues and perennial energy grasses, as well as forest sources, such as forest residues and woody biomass. Crop residues mainly include corn stover, wheat straw, and rice straw. Because these resource is by-products of crop production, their collection and utilization ensures sustainable practice and does not result in food energy feud and land competition. Therefore, the negative effects of cellulosic biomass production from crop residues on food prices can be expected to be negligible. Although cellulosic feedstocks differ significantly in their environmental performance [5], they can provide commensurate advantage and prospect for various environmental benefits when compared with the coal they will substitute [6]. China is a major producer of corn, wheat, and rice. It produced about 20% of the world's corn and wheat, and 26% of the world's rice, in 2010 [7]. Therefore, China is among the nation that can ensure universal practice of potential production of a large amount of crop residues, which can reduce

The union of concerned Scientists evaluated the magnitude of biomass resource potentially feasible from the united states production capacity in a bid to possibly comprehend the main biomass feedstock as well as the operational scales in order that the synthesized biofuel carefully balances the energy and environmental trade-offs. It was discovered that the nation could harness nearly 680 million tons of biomass resources annually up to 2030 [8]. This resource was sufficiently observed to be suitable to generate well above 10 billion gallons of Agricultural residues are carbon-based materials generated as a byproduct during the harvesting and processing of agricultural crops. Agricultural residues which are produced during harvesting are primary or field-based residues while those produced along with the product during processing are secondary or processed based residues. Agricultural residues are heterogeneous, varying in bulk density, moisture content, particle size and distribution relative to operational handling. They are usually fibrous, low in nitrogen and vary with geographical location [12]. These field residues are occasionally utilized as fertilizer, for erosion control and as fodder for livestock. Almost half of these resource are combusted on the farm prior to the commencement of another farm season.

Process residues offer high prospect as an energy source. Chemical composition of any crop residue varies depending on several factors among, which may include species, age of residue or period of harvest, physical composition including length of storage and harvesting practices [13, 14]. Agricultural residues are produced as a waste product from food crops such as maize, wheat, sunflowers, and so on. Currently, only small proportion of these residues are being used by farmers as feed for livestock and the rest of these are plowed back into the soil or burned to get rid of the huge volumes of biomass before planting the next crop. The biggest advantage of utilizing agricultural residues is that it does not compete with the production of food, and if it can become a by-product that can be utilized economically for the production of energy, it will result in lower food prices. It is estimated that roughly one ton of residue is produced for every ton of grain harvested [15].
