Why every farmer should have a biogas unit

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Biogas is a cheap source of energy that also reduces the destruction of trees while producing high quality organic fertilizer that farmers can use to improve crop yields. It is a clean source of energy. It's use both environmental and human health benefits.

Biogas is a gas produced when bacteria break down organic material such as cow dung, farm waste, garbage and even sewage material in the absence of oxygen. The gas is a mixture of methane (60%) and carbon dioxide (40%). Indeed, methane is what makes natural gas, which is colourless, odourless and burns in a clean way that does not pollute the environment.

The methane gas produced when organic material decomposes is captured and used in cooking, heating and even lighting in homes. If methane is not captured through biogas production, a lot of it ends up in the atmosphere where it causes great damage to the ozone layer, a shield that protects the earth from harmful ultraviolet (UV) rays of the sun.

Protects the environment

The damage of the ozone layer is a major cause of global warming and climate change. Therefore, by using farmyard manure in biogas production, farmers help to protect the environment. A lot of farmyard manure produced in farms in Kenya often goes to waste. If the manure was used in the production of biogas, many homes in the country would have a good source of energy for cooking, which would in turn save a lot of trees that are cut down for firewood.

Benefits of biogas

Organic fertilizer: Biogas production has many benefits in organic farming. The main product of biogas production is slurry, a high quality fertilizer that is higher in nutrients than compost or farmyard manure.

The slurry (organic fertilizer or biogas manure) has great potential especially in organic farming systems where crop rotation is practiced and nutrients recycled to improve agricultural productivity. Research has shown that the slurry can increase crop yields in organic farms by up to 30 per cent.

Clean energy: The majority of farmers in Kenya as in the rest of Africa uses firewood, charcoal or crop residue for cooking. In Kenya, more than 70 per cent of the population relies on wood fuel for their energy requirements. This has caused a lot of deforestation and even desertification across the country. The increase in population makes it unsustainable to continue with the use of wood fuel as a source of energy. Biogas is therefore the most suitable alternative source of energy that farmers in rural areas need to use to protect their environment and increase crop production.

Human health: The other reason why more people need to use biogas is the health benefits they stand to gain; the firewood used in most rural households is responsible for air pollution and gases that damage the atmosphere.  Indoor air pollution poses great danger to the health of women and young girls who perform most of the household chores such as cooking and even household sanitation.

How does biogas work?

A biogas production system uses a simple technology. The system consists of a large tank (also known as a digester). When organic matter such as cow dung and chicken waste is put into the digester, a number of bacteria in the material to convert the organic waste into methane gas. This can only take place in an environment where there is no air (anaerobic digestion).

Every day the farmer has to feed the bacteria with more cow dung, kitchen waste and other organic material for the digestion process and methane gas production to continue. A family that has a 6 cubic metre biogas system can meet their daily cooking needs, use it for lighting and also for other purposes such as heating chicken brooders or incubators while saving money that they would have used to buy charcoal or even firewood.

Biogas has many advantages

It is a renewable source of energy (the production of organic matter is continuous and cannot be exhausted as is the case for fossil fuels such as petroleum and other sources of energy). It cuts down the cost of importing petroleum products such as kerosene for lighting and energy for cooking.A fixed dome biogas system under construction

The slurry (manure) from a biogas digester biogas is odourless and does not attract flies. The manure from a biogas digester repels termites and other pests when used in the shamba. The slurry reduces weed growth by up to 50 per cent.

Major plant nutrients such as nitrogen, phosphorus and potassium are preserved during the fermentation process, making them readily available to the plants.

When mixed with water at a ration of 1:1, biogas manure can be applied directly to vegetables or fruit crops in the shamba.

How to preserve biogas manure

 1. Spread it under shade on the flat surface and dry for 3-4 days depending on the weather.

2. Put the dried manure in bags or drums and store in a dry place for future use.

3. Farmers can also add biogas manure to other material while making compost to enrich further.

To be continued....

>>Tell us how useful this information is to your farming enterprise. Share your experience by email to admin@theorganicfarmer.org, leave a comment below this article or SMS 0715 916 136.

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