5 July 2018

Effective digestate management

The use of digestate on farms has increased in popularity in recent times, due to the overarching benefits to the land which can lead to accelerated crop production and the cost-efficiency that it offers farmers in comparison to artificial fertilisers.

Digestate spreading, slurry injection and long-term storage of digestate have all been adopted by farmers up and down the UK in order to get the most out of recyclable materials and waste to produce their own fertilisers and store them effectively. This allows them to ensure they are applying the product at the most effective time, both in terms of seasonality and in terms of where the crops are in their growth cycle.

Scientific developments

The Nutrient Mangement Centre at Agri-Food and BioScience Institute (ABFI) have recently been commissioned to explore further opportunities for improved nutrient management within slurry and digestate. Working with advanced technologies to establish ways to improve the effectiveness of the digestate, those working on the project are looking at the best ways to remove large quantities of solids from the slurry.

By doing this, the product can become more economical in terms of transportation and can remove some of the high levels of phosphorus (P) present in the material. Where a high level of P is present, farmers can run the risk of increased run-off into water sources, resulting in pollution to the local water supplies and nearby environments.

Equally by separating the solids, these can then be distributed to areas where P supply is low, whilst the liquid fraction can be applied to grassland and used as an effective bio fertiliser.

Utilising digestate effectively

One of the key benefits of utilising digestate for agricultural services whether its spreading or injection purposes, is that it can significantly reduce the need for bagged fertiliser and therefore should be utilised as a valuable resource.

Using digestate means that you often can reduce the amount of resource that you’re actually spreading or injecting due to the increased amount of nutrients compared to non-organic fertiliser application.

Alongside the ability to produce digestate through the use of recycled material and byproducts, it can also offer significant savings to farmers. Through both understanding the nutrients available in your digestate and spreading or injecting at the right time in the year, farmers can see significant economic benefits.

Testing your digestate

Digestate management not only requires farmers to understand when and how to best apply the product to their land and crops but also involves gaining a deeper understanding of the nutrients that exist in their soil and those that are available in the digestate.

With all manures different from one another, it is important to ensure that it is not brazenly applied to your land. Aligning the nutrient values in the soil with those available in the digestate will allow you to ensure that you do not over saturate the soil with excess nutrients or create run-off of excess phosphorus or nitrogen, which can result in pollution to the local water, land and air. Understanding the nutrient composition of the digestate and how much your crops will take-up will mean that you can regulate the application more effectively.

Digestate storage solutions

It is important to ensure that your store your digestate product effectively and without risk of causing pollution or watering down the product. Where you opt to install a lagoon to house your product, it should be regularly stirred allowing for the product to harmogenise. Ahead of spreading, samples should also be taken, alongside periodic tests, which will ensure that you have the best understanding of the nutrients available.

Storing your digestate also allows you to apply it at the most optimum times and at the most effective point during the growth period. This can reduce pollution and increase the effectiveness of the product.