“Custom-made organic fertiliser” means that biogas plants can combine phosphorus and nitrogen nutrients in the exact quantities needed for a specific holding. In other words: The organic fertiliser can be tailored to contain a specific formulation of nutrients. 

“There is significant potential in this, which will only result in winners if we succeed in producing custom-made organic fertiliser: It is good for the environment, it is good for agriculture, and it is good for the biogas producer,” says Lars Villadsgaard Toft who is Bio CFO at SEGES, the knowledge and innovation house for agriculture. 

SEGES is at the forefront of the project, which has received aid from the Ministry of Environment and Food of Denmark. The specific tests will take place at Nature Energy's biogas plant in Videbæk with a group of local farmers as key players. 

Custom-made organic fertiliser is an example of sustainable development in the agriculture and energy sectors. The project supports the green development in agriculture for the benefit of the individual farmer, the agricultural and biogas industry as well as society as a whole. The project, which aims to identify the possibilities, will run over the next three years. Custom-made organic fertiliser is expected to become available to the suppliers of Videbæk Biogas at the end of the project.

As much natural fertiliser as possible

The farmer and the farmer's crop consultant are already today calculating the nutrient requirements of the individual agricultural parcels and developing a fertiliser plan for the total holding via an IT programme. The aim is to be able to send an order directly from Mark Online to the biogas plant, which then customises the digested organic fertiliser to the individual holding.

“In this way, the organic fertiliser is optimally formulated, and the farmer can limit or perhaps completely avoid having to supplement the natural fertiliser, which organic fertiliser is, with commercial fertiliser. In other words, there are benefits for both the farmer and the environment. That is why we in the agriculture sector have taken the initiative to demonstrate how we can make the technique work in all stages of the chain, so that we can make custom-made organic fertiliser a reality,” says Lars Villadsgaard Toft.

The digested organic fertiliser from biogas plants is currently a one-size-fits-all fertiliser. This means that the full potential of the natural fertiliser is not utilised. In some cases, the standard organic fertiliser from the biogas plant will also contain so much phosphorus that the farmer is unable to utilise the fertiliser’s potential, as the digested organic fertiliser reaches the limit for how much phosphorus may be applied to the fields. Adjusting the ratio between nitrogen and phosphorus makes the organic fertiliser much more attractive to the farmer - and can therefore displace the use of commercial fertiliser.

Local farmers are the current suppliers of livestock manure to Videbæk Biogas, which is one of Denmark's largest biogas plants. Approximately 80 farmers in the area purchase the digested organic fertiliser for fertilising agricultural parcels. The project will demonstrate and quantify the amount of commercial fertiliser that can be saved by using the custom-made organic fertiliser. 

Part of the green transition

There is also significant potential for Nature Energy in being able to supply custom-made organic fertiliser to the agriculture sector. 

“We look at the project as being part of a whole, in which biogas production is both an important part of Denmark's green transition and we form an intelligent part of the circular economy. It will be a fantastic gain for both the farmer and aquatic environment to be able to supply the various agricultural parcels with a digested organic fertiliser with the precise amount of phosphorus and nitrogen - and no more - that the crops need and are able to absorb,” says Nature Energy's CEO Ole Hvelplund.

Facts

The project will analyse the residual nutrients in the organic fertiliser after degassing. It will look at how the organic fertiliser is separated into nutrients and recombined. Measurements of the nutrient content will be made for each separate supply of digested biomass. Another major task lies in ensuring an automatic flow between the farmer's agricultural holding and fertilisation accounts and the biogas producer, with specifications of the desired nutrient ratios.

• The farmer benefits by getting digested organic fertiliser containing the precise amount of nutrients needed for each holding. This means that the consumption of commercial fertilisers can be reduced and the farmer's yield and economy improved.

• The biogas plants will be able to supply fertiliser products to match the nutrient requirements. In other words, it will be possible to supply a specially designed product with added value.

• Society will gain an increased respect for the environment through improved utilisation of the digested livestock manure. The utilisation of nutrients is therefore optimised and the procurement of fertilisers and phosphorus can be reduced. A larger proportion of digested livestock manure will reduce CO2 emissions from agriculture.