Soil fertility and biogas boost
With the world seemingly headed towards water wars in the not-too-distant future, being the custodians of the Indus basin we are among those ‘elite’ countries that are not water deficient. This abundance of waters boosts up the credentials of our soil as well, with Pakistan possessing six and a half million hectares (16 million acres) of saline and alkaline soils starting from Khushab, a district of Punjab, down to regions in Sindh. Our only problem is that it is brackish.
Water is of pivotal importance to our life. It has got a myriad of uses but the major three faucets for utilisation of water are drinking water, agriculture (irrigation) and industrial use.
In an earlier article I talked about agriculture in detail and how one could pull brackish water from the soil through biogas plant to reclamate the alkaline and saline soils of Pakistan and utilise the slurry manure to improve the conditioning.
The salinity and the alkalinity of a soil is a veritable menace for our agriculture, which is one of the major factors for low crop productivity. The salt tolerance of a plant can be defined as the capacity to endure the effects of excess salt in the medium of root growth. Salinity is the concentration of dissolved mineral salts present in waters and soils on a unit volume or weight basis. The major solutes comprising dissolved mineral salts are the cations: sodium (NMa), calcium (Ca), bicarbonate (HCO2), carbonate (CO3), and nitrate (NO). Soil salinity can affect plant growth both physically (osmotic effect) and chemically (nutritional effect and/or toxicity).
Soil salinity problems can result from dry land saline seeps, improper drainage or water management on irrigated soils, or cultivation of naturally saline soils. Soil salinity is strongly linked to water movement though the soil profile. When sub-soil moisture containing salts moves upwards and evaporates, salts are precipitated at or near the soil surface. Soil amendments such as gypsum (CaSO), calcium chloride dehydrate (CaC12-2H,O) and sulfuric acid (H2SO4) have been used for the reclamation of saline-alkaline soils.
As our reservoirs of water help nourish our soils and in turn bolster our agriculture, we would be able to profit from another very promising sector that is awaiting our attention: biogas.
There are 29 million cattle and 25 million buffaloes in Pakistan; therefore, we have massive livestock dung available in our country, enough to produce a million of megawatt electricity. Biogas typically refers to a gas produced by breakdown of organic matter in the absence of oxygen. Biogas is produced by an aerobic digestion or fomentation of bio degradable material, such a manure, municipal waste, green waste, plant material and crops. Biogas comprises primarily methane and carbon dioxide and may have small amounts of hydrogen sulfide moisture and siloxanes.
This energy release allows biogas to be used as fuel, which can be used for heating, cooking or as a different engine fuel. Biogas plant is the name given to an aerobic digester that treats farm waste for energy crop. During the process, an airtight tank transforms biomass waste into methane producing energy that can be used as an internal combustion engine. By converting manure into methane biogas through millions of cows and buffalos available in the country, we would be able to produce million kilowatt hours of electricity, enough to power millions of home across Pakistan. In fact, one cow or buffalo can produce enough manure in one day to generate 3 KW hours of electricity. Only 2.4 KW hours of electricity are needed to power a single hundred watt light bulb for one day. Furthermore, by converting manure into methane biogas instead of letting it decompose, we can significantly reduce the global warming gases. Raw biogas produced by digestion is roughly 60 percent methane and 29 percent carbon dioxide. Owing to simplicity in implementation and use of cheap raw material in villages, it is one of the most environmentally sound energy sources for rural areas.
Domestic biogas plant converts livestock manure into biogas and slurry, and the fermented manure. This technology is feasible for small holders with livestock producing 50 kg per day i.e. equivalent to 5 cows or buffaloes. The manure has to be collectable to mix it with water and feed it into the plant. The slurry is a clean organic fertiliser that potentially increases agriculture productivity by solving the salinity and alkalinity of soil.
In Pakistan, presently there are many companies operating to provide the biogas plant with a range of Rs 50 to 95 thousand producing about 10 to 20 cubic meter gas every day. NARC, Ministry of National Food Safety and Research have put up an experimental biogas plant at the premises at Chak Shahzad to show and provide technology to the interested farmers. And they have divulged the nitty-gritty and the financial implications required to run a successful biogas plant.
It is high time entrepreneurs invested in the sector and provided a state-of-the-art biogas plant to the small farmers. It could help the dairy farmers meet the country’s energy requirements as well. A lot of work on biogas has been carried out in UK, India, China, USA, Brazil and information can be gathered from these countries through the Web. After getting the information one can work on learning to produce biogas in the country.
The writer is former federal minister and writes a blog for The Spokesman