Because of the differences in the content of digestate and slurry, it’s not as simple as saying one is better than the other, instead they both work best on different types of soil. Digestates may be better fertilisers for heavier soils with high clay and carbon content, while manure or slurry from livestock works best in lighter, sandier soils that contain fewer organic carbon elements.
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Across the UK, we have seen an increase in demand for farmers seeking digestate spreading services. At AWSM Farming, we specialise in digestate spreading, offering our customers a highly effective and professionally completed fertilisation system. If you are unsure if digestate spreading is the right farming service for your requirements, we’ve provided some key information to support you in making the right decision.
What Is Digestate Spreading?
Digestate spreading is a method of fertilisation which involves the application of a nutrient-rich product, formed through anaerobic digestion. Differing from compost which is produced through aerobic micro-organisms and requires oxygen, digestate is made up of a mix of indigestible material and dead microorganisms.
This product is then applied to the field using a spreader, which is used to evenly distribute to the digestate and ensure an even spread across the ground. Digestate spreading can be used to treat nutrient deficient soil and ensure the effective growth of crops going forward. The process and amount of digestate are determined by a test to ensure that the correct level of nutrients is inputted into the soil.
Digestate is produced through a process called anaerobic digestion, which involves a series of biological processes. During this process, microorganisms break down materials during the absence of oxygen. The materials that can be used for AD fertiliser production include biodegradable products such as food remainders, livestock slurry and waste crops, including grasses.
Digestate can be produced to three specifications; whole, liquor and fibre. Whole digestate slurry is typically less than 5% dry matter and is often described as similar in appearance to slurry produced from livestock. Liquor is primarily a liquid base, with most or all of the dry matter removed and fibre is more comparable to compost and composed of primarily a solid material with the whole digestate separated.
Digestate is typically made up of by-products, such as food waste, dairy produce and meat and fish and governed by the Animal By-Products Regulations, ensuring that all products used are pasteurised. Pasteurisation ensures that digestates are safe to be spread on the land, however, it is not suitable to grazer livestock on the land or forage crops, within three weeks of the application. This time period extends to 2 months for pigs and ensures farmers are aligned with legislation and good practise requirements, in terms of using organic materials on their land.
What are the Benefits of Digestate Spreading?
Digestate spreading has become a popular choice for farmers seeking an alternative to slurry spreading. Opting for digestate spreading ensures that your fields are subjected to a product which is proven to be a great organic fertiliser, improves soil and yields better crops overall.
Digestate fertiliser contains a number of nutrients, which can fluctuate in amounts dependant on the type of slurry; food-based, pig or cattle. Within food-based digestate, around 80% of the total nitrogen is readily available, which means that digestate is the ideal replacement in place of ‘bagged’ fertiliser, or alternatively, livestock slurry can increase the availability of nitrogen in the soil by up to 10%.
Phosphate and potash are two other highly important nutrients that are present in digestate, accompanied by further small amounts of nutrients and trace elements which create a composite soil that is highly fertile. When considering the availability of nutrients, typically 50% of the phosphate and 80% of the potash, is available to the crop. This better allows for nutrient planning, that measures the current nutrients available in the soil and the ability to manipulate the fertiliser required accordingly.
Many farmers have seen their annual costs spent on fertiliser, decrease drastically by adopting the use of digestate fertiliser. Even factoring the cost of the application, many farmers believe that digestate application is overall the most economically friendly option.
Digestate Spreading Restrictions
In order to ensure the optimum effectiveness of the digestate content, including the absorption of nitrogen, the application should be carried out during periods of maximum crop growth. The application of digestate spreading is carried out from late winter through the end of summer, avoiding application during Autumn months. During these months, nitrogen will not typically be absorbed effectively by crops or will not have a nitrogen requirement at this time. It is also advised to avoid spreading during the following conditions:
- On waterlogged soil or land
- During periods of heavy rainfall or when this is forecast within 48hours
- On top of the frozen ground or during periods of snow covering
- Where soil has cracked down to the field drains
- Where a field has been pipe or mole drained
- When a field is sub-soiled over drains within the past 12 months
Equally, farmers should carefully assess their land ahead of an to check for the following, ensuring digestate is not applied in any of the following scenarios:
- Where the land is located within 10 metres of a ditch, pond or water surface
- Where the land is located within 50 metres of a water supply used by human or dairy farms, including springs, boreholes or reservoir
- The application is not recommended where fields are located on steep slopes
AWSM Farming Digestate Spreading
If your fields require a digestate spreading service, get in touch with AWSM Farming today to find out how we could improve your crop yields and provide you with this economically friendly option.
Do I need a digestate spreading contractor?
Digestate has a wide range of benefits and has long been used to improve the soil quality and workability. For all it’s benefits working with digestate can be difficult if you’re unused to it or don’t have the proper equipment. For many, it’s cheaper and easier to hire a digestate spreading contractor to make the most of digestate and it’s beneficial properties. Knowing which type of digestate to use can also requires in-depth knowledge, which only your contractor will have.
What are the digestate spreading rules?
As of March 2022, the rules around digestate spreading have changed, becoming more restrictive in order to protect underground water courses. For farmers this means applying strictly only what’s necessary to nourish the crops on their land in the spring and autumn. Excessive digestate can lead to increased levels of nitrate and phosphate leaching into the water sources.