A Study on Rural Biomass Energy Scenarios in Haor Ecosystem

Biomass is biological material from living, or recently dead organisms, most often referring to plant or plant derived materials. As a renewable energy source, biomass can either be used directly or indirectly-once or converted into another type of energy product such as bio-fuel. Biomass is the overall plant matter created by photosynthesis. It constitutes man’soldest and most fundamental source of renewable energy. It includes new plant growth, plant residues and wastes. The available forms are: wood, short duration trees, herbaceous plants; residues such as agricultural and forest residuese.g., straw, husks, bagasse, cobs, forest or wood based materials like bark, sawdust, roots and even animal droppings, waste comprising garbage, night soil, sewage solids and industrial refuse (Sharma, 1985).

In Bangladesh, biomass is generally used as food, feed, fuel, fodder, organic manure, building material and as the raw material for cottage industries including ploughs, fishing requirement, bullocks, carts and country boats (ESCAP, 1989). The primary production of living biomass on the earth surface is around 172 × 109 t (dry) year-1 of all the biomass resources, the greatest quantity of which is known as phytomass is formed by plant (Aziz and Jalal, 1982).

In the haor area, biomass plays an important role. Crop grains, pulse, vegetable, spices, etc. are used as human food, bran, straw, leaves, weed, etc. are used for feed, the best portion of straw is used for fodder and the rest is used as fuel or bio-fertilizer/organic manure or for housing materials, etc. About 90% of the fruits, vegetable, fodder and biomass fuel requirement are met by home gardens (Hossain and Bari, 1996). Davidson (1984) observed that over half of the fruits, vegetable and spices grown in home gardens are sold to meet family expense.

In Bangladesh, the forest productivity is very low. It is only 0.5-2.5 m2 ha-1yr-1 in both plantation and natural forests (ADB, 1993). It cannot meet the country demand. According to FAO (1982), in Bangladesh 48% of saw and veneer logs and upto 70% of fuel and 90% bamboos come from villages. Extraction rate from village forests is 8.9% and increment rate is 5% (FAO, 1982). At present the dominant source of biomass in the rural areas is field crops, vegetable, trees, livestock etc. from village forests, roadside and homestead plantation. Home gardens along with marginal wastelands and non-forest lands supply more than 80% of fuel wood in Bangladesh (Gujral, 1990). If not properly managed this reserve will be diminished in the near future. So the village forest resources need to make more productive.

Biomass is closely linked to biodiversity which is dependent on mankind or any living species that lives on earth. The mass of living organisms is as biomass which described population in unit area or a volume of the earth surface. It is more précised that the amount of living matter incorporated into a circulatory system of plants (producer), animals (consumer) and micro-organisms (decomposer) in unit area or volume of habitat. Biomass, therefore, can be trees, grasses, crops, aquatic flora and fauna, agricultural residues, fish, etc. (Hossain and Hossain, 1985). Around the homestead area different varieties of tree including crops, shrubs, herbs and aerial plants are grown in nature. Small poultry and livestock production is also apart of home production system.

According to FAO (1986), home gardens are one of the most elaborate systems of indigenous agro-forestry, found most often in tropical and subtropical areas where subsistence land use systems predominate. According to Linda (1990), the high diversity of plant species in village home-gardens assures continuous production of fruits and vegetable, fuel woods, timber and medicinal and cash crops. Michon et al. (1983) noted that the ecological value that they represent in items of genetic diversity and preservation of species in areas when original forest resources have been largely depleted.

Biomass is the principal source of domestic energy in the country. It has been the primary source of energy for cooking, heating and other basic needs since pre-historic time (Sarhandi, 1985). About half of the population in the present world use biomass for cooking at a rate of 1.3 to 2.5 m3 capita-1 yr-1. In Bangladesh contribution of biomass to meet the total energy demand is nearly 63% (Islam, 1991), as compared to only 37% commercial resources. In rural areas the share of biomass is overwhelming. Biomass resource is now being depleted very quickly due to population pressure and intensive cropping with the use of high input high output technology. Actually basic information on biomass production and utilization at the community and national level are very scarce and limited. It needs to initiate micro level studies in Bangladesh to generate information and suggest policy to address the existing situations of biomass production and utilization by adopting appropriate techniques and technologies in haor farming systems and other means. Therefore, it is needed to investigate about biomass production and their utilization in haor areas of Bangladesh. With the above discussion, the present study was undertaken into micro level, concentrated on rural biomass energy scenarios in haor ecosystem.

The general objective of the study is to assess the biomass production and its utilization in haor ecosystem. The specific objectives of the study were: a) To identify the source of biomass energy in the study area. b) To assess the biomass utilization pattern in the haor ecosystem. c) To identify ways and means of increasing the biomass energy fuel.