About 11km from Kutus town along the Kutus-Kimunye Road adjacent to Githage Primary School sits Daipo Farm on two acres.
The farm hosts 12 cows (six that are lactating and the rest are heifers), 600 chickens (350 which are layers), a 12 cubic metres biogas plant and various fodder crops.
Sammy Nyaga, a 62-year-old retired agriculture teacher, is busy mixing cow dung and water in the ratio of 1:1, and, thereafter, adds the slurry in the bio-digester.
“I add over 100 litres of slurry into the system every day for continuous biogas production,” Nyaga explains.
What he does with the waste his animals generate is what has made all the difference in his agribusiness.
Nyaga, however, does not only use cow dung to generate biogas, the waste from chicken too ends up in the bio-digester and the resultant energy is used mainly for cooking at home.
“I use the biogas for cooking in my house and warming water to clean the cowshed and cow towels, saving me a huge sum of money that I would have spent on fuel,” says Nyaga, who started farming in 2008 with his wife Shelmith soon after retiring and installed the biogas system in 2012.
Ending up with the right quantity and quality of cow dung, according to Nyaga, which in turn generates the fuel all depends on how one feeds the animals.
“Cows must be fed the right quantity and quality of feeds for them to produce good cow dung, and in turn milk. I feed my cows mainly on silage that I make from fodder maize and ensile to last my animals for up to six months.”
He feeds his dairy animals three times a day after every milking, that is, at 5am, 12pm and at 6pm.
Every cow is fed on 10kg of silage, 5kg of green matter and 2kg of concentrates enabling him to get 150 litres of milk that he sells to Kirima co-operative where he is a member at Sh36.
HIGH MOISTURE CONTENT ENCOURAGE WRONG FERMENTATION
Other fodders he grows, which complement silage, are napier grass, lucerne, calliandra, desmodium, sweet potato vines and mulberry.
“To make the silage. I start by cutting the maize at the dough stage, then wilt it to remove any extra moisture. High moisture content will encourage the wrong fermentation producing poor quality silage.”
“I normally test the moisture content in the chopped fodder by squeezing a handful and if water oozes out, I know it has a high moisture content,” he adds.
Thereafter, he pours on the chopped fodder some Beneficial Macro-Organisms (BM). These are bacterium that help in fermentation and are sold in agrochemical shops.
About 200ml of BM is diluted in five litres of water and sprinkled on the fodder to hasten the fermentation process by producing lactic acid while at the same time preserve the material.
When ensiling napier grass, which is low in sugar content, Nyaga further adds some maize germ that is rich in sugar and some soya bean cake that helps in improving the nutrition value as it is high in protein content.
Nyaga also uses dry maize stovers, otherwise considered waste, by many farmers who burn them due to their low digestibility.
“I chop the fodder into smaller pieces and sprinkle urea on them to help breakdown the stover making the feeds palatable to the animals and later I put in the silage chamber for 21 days.”
He also makes his own dairy meal as trained by officials from the Kenya Agricultural and Livestock Research Organisation in Naivasha in 2014.
“I use 33 per cent of maize germ, 64 per cent of poultry waste, 2 per cent of minerals, 1 per cent of premix and 100g per 100kg and another 100g per 100kg of toxin binder.”
Toxin binder is incorporated to prevent the growth of aflatoxin, which is lethal to both humans and animals.
These are the feeds that the farmer offers his animals to end up with about 100kg of cow dung each day.
From the dung, he generates a maximum of 5.5 cubic metres of gas per day, an equivalent of 5,500 litres of biogas.
CHICKEN WASTE HIGH IN CRUDE PROTEIN
According to Edward Mugambi, an engineer with Green Energy Revolution, biogas production depends on quality of feeds.
“If the cows are fed on high quantities of green matter, which are high in water content, this reduces quality of dung produced. But if fed on high quantities of dry matter, they produce solid waste that is good for quality biogas.”
Mugambi says a kilo of cow dung produces about 40 litres of biogas while a kilo of poultry waste can offer up to 60 litres. From the chicken farm, where he keeps Rainbow Roosters, Kuroiler and Kenbro varieties, Nyaga collects three 70kg bags of manure after about a week.
“I do not use the chicken waste directly to make biogas. I collect it from the poultry house, pile it at a spot on the farm and wait for three to one month and sieve it to remove the saw dust. I then dilute the residue with water, mix with cow dung and put it in the bio-digester,” says Nyaga, who started his farming venture with Sh150,000, part of his retirement package.
The chicken waste is also used to feed the dairy animals after it is dried in the sun to remove excess moisture and sieved to extract foreign material.
George Muriithi, a senior livestock production officer in Kirinyaga County, recommends the use of poultry waste in formulating dairy meal noting that chicken waste is high in crude protein content and minerals and that ruminant’s need.
Nyaga, who invested about Sh120,000 in the bio-digester, says the system should be installed near the cowshed to collect the slurry, which should flow into it by gravity.
“It should always be away from the homestead to keep off the odour produced.
One should observe high standards of hygiene and sieve the poultry mixture to avoid blocking the bio-digester, which is expensive to unclog,” says the farmer, who adds that generating his own biogas saves him at least Sh10,000 a month, which he would have used on electricity bills, cooking gas and buying of fertiliser as he uses the mixture from the bio-digester to grow crops.
His next project is to install a bigger bio-digester to enable him light his home and poultry unit using the biogas.