Bioslurry: the world’s brown gold – a new Hivos study

March 25, 2014

As shown in the Hivos study ‘Bioslurry: A Supreme Fertiliser – A study on bioslurry results and uses’, biogas produced from cattle, pig and buffalo dung (and other excrement) leaves a by-product called bioslurry, which not only solves various soil fertility problems, but also gives biogas projects for farmers in Africa and Southeast Asia access to modern energy services, while helping mitigate poverty and climate change.  You can download the study in the right sidebar.


When a biogas installation is filled with locally available raw materials, such as crop residues and animal (pig, poultry and cattle) and human waste, the by-product, bioslurry, can be used to improve soil fertility, soil structure and crop productivity, amongst other uses. However, not many farmers are familiar with using fertiliser to start with, which makes it all the more important to educate them on the use of biogas digesters and the advantages of bioslurry.

The composition of bioslurry depends upon several factors: the kind of dung (animal or human), water, breed and age of animals, types of feed and feeding rate. But in general, bioslurry contains phosphorus, potassium, zinc, iron, magnesium and copper, some of which some have become depleted in the soil. Bioslurry also contains readily available plant nutrients and higher amounts of nutrients and micronutrients than farmyard manure and composted manure. As such, bioslurry can form a serious alternative to expensive chemical fertilisers.

But the many amazing properties of bioslurry do not stop at being a great source of nutrients.  

When used to treat seeds, bioslurry results in higher germination, better yields, improved coloration of fruits and vegetables and greater tenderness and taste of leafy vegetables, as well as fostering disease resistance. It can increase the feed value of fodder with low protein content and helps the production of vitamin B12 and amino acids for animal growth. The enzymes it contains stimulate hunger in animals, resulting in more food intake and better nourishment.  By boosting the availability of nutrients for soil micro-flora, it increases the quality and quantity of organically grown flowers and vegetables.

Not only does bioslurry reduce wastewater, water pollution, greenhouse gas emissions and noxious odours – it even acts as an insect repellent and reduces weed growth that attract these insects. No wonder that some call it the world’s “brown gold”.