Manage farm waste as you generate animal feeds and fertiliser

Friday May 01 2020
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Farmer Caleb Karuga attends to black soldier flies which he keeps in his farm in Kiambu. Recent research has indicated that black soldier flies are instrumental in closing the loop between animal waste and animal feed. PHOTO | FILE | NATION MEDIA GROUP


More solid waste is being generated in urban areas the world over due to rapid urbanisation.

The amount of waste generated per year currently stands at over four million tonnes, and is expected to double by 2030.

The rise, however, has not been accompanied by an increase in the capacity to handle the challenges of solid waste management.

We can kill two birds with one stone by using biodegradable waste to produce animal protein and in the process help manage it thus keep our towns cleaner.

This will involve the production of black soldier flies, which are considered as one of the best animal proteins.

Known scientifically as Hermetia illucens, they are small, harmless insects that have the potential to provide promising solutions to two of modern agriculture’s growing problems


These are high cost of animal feed and the disposal of large amounts of animal waste. Many farms now operate as linear systems, purchasing animal feed and then paying to eliminate waste from farm animals.

Recent research has indicated that black soldier flies are instrumental in closing the loop between animal waste and animal feed.


Black soldier fly larvae eat nearly all kinds of organic waste, ranging from animal refuse from pigs and poultry to dirt from kitchen, slaughterhouses, markets, food factories and spent grain from beer makers among others.

With a decline in animal protein sources to make livestock feeds occasioned by the plummeting supply of omena (fish meal), black soldier flies offer the best alternatives.

Protein sources are the most expensive feed ingredients, thus, we should utilise available solid waste to rear high quality black soldier fly protein, which has 40-45 per cent crude protein.

The insect in the process of breaking down the waste generate good bio fertiliser (frass) thus not only reducing the cost of feeding animals but also growing crops.

This means therefore a farmer ends up with more money in his pockets. This insect frass has the following benefits for plants and crops.

It promotes early plant growth and seed inoculant, has low carbon to nitrogen ratio that promotes rapid mineralisation and faster nutrient release, has long shelf-life of over a year and has no odour.

Egerton University is currently running black soldier fly larvae production and multiplication programme, where interested farmers can learn the best way to manage waste, rear high quality protein for their animals and get bio fertiliser for their farms as they make the environment clean.

The writer is based at the Department of Animal Sciences, Egerton University.