(ii) Fixed dome type: The gas plant is dome shaped underground construction. The masonary
gasholder is an integral part of the digester called dome. The gas produced in the digester is
collected in dome at vertical pressure by displacement of slurry in inlet and outlet. The entire
construction is made of bricks and cement. The models available in this category are Janata and
Deen-Bandhu.
Selection of Size:
The size of the biogas plant is decided by the number of family members and the
availability of dung. One cubic meter capacity plant will need two to three animals and 25 kg of
dung. The gas produced will meet the requirement of a family of 4-6 members. It would suffice
to have a 2 cubic meter plant to cater to the needs of a family of 6-10 members.
Biogas slurry:
Slurry is obtained after the production of bio-gas. It is enriched manure. Another positive
aspect of this manure is that even after weeks of exposure to the atmosphere, the slurry does not
attract fleas and worms.
Factors influencing the selection and size of components in farming systems
1. Climatic conditions - Rainfall, temperature, solar radiation, wind, humidity, etc.
2. Soil type
3. Farmers preferences
4. Size of the Farm
5. Knowledge, skill and technology
6. Storage, transport and marketing
7. Resource mobilizing power of the farmer
8. Credit facilities available
9. Socio-economic condition
10. Customs, sentiments and believes
IFS for different agro-climatic zones (India)
1. High altitude cold deserts: Pastures with forestry, goats, angora rabbits and limited settled
agricultural crops like millets, wheat, barley and fodder.
2. Arid and desert region: Centering mainly in animal husbandary with the camels, sheep and
goat and with moderate cropping components involving pearlmillet, wheat, pulses, gram and
fodder crops.
3. Western and central Himalayas: Horticultural crops as major component have less intensive
agriculture mainly on the hill terraces and slopes with maize, rice, wheat, pulses and fodder
crops.
4. Eastern Himalayas: Primitive crop husbandry with rice, millets, pulses etc. Agro- forestry
system is also common. Piggery and poultry are the chief livestock activity.
5. Indo-Gangetic plains: Intensive crop husbandry involving rice, wheat, maize, mustard, pulses
and livestock inclusive of dairy cattle and buffaloes.
6. Central and southern highlands: Cotton, sorghum, millet, pulses with dairy cattle, sheep and
goats and poultry are the secondary livestock and animal husbandry enterprises.