Is Food Digestate Safe for Land?
Digestate spreading services are increasingly popular with farmers across the UK and has a range of benefits. Despite this, there are a number of misconceptions and misunderstandings which we are going to address.
Digestate spreading services are increasingly popular with farmers across the UK. Food digestate has a range of benefits and can make a positive impact on the nutrient levels of the soil. Despite this, there are a number of misconceptions and misunderstandings about digestate spreading.
What is it, and is it safe to use on the land? Which we are going to address in this article.
What is digestate spreading?
Digestate spreading is a means by which a nutrient-rich product can be added to the soil. It’s a method of fertilisation that uses products that have been formed through anaerobic digestion. Where compost is produced through a combination of exposure to oxygen and aerobic micro-organisms, digestate is a mixture of dead microorganisms and indigestible materials.
The food digestate is applied to the land by means of a spreader. This helps to evenly distribute the material across the land, helping to ensure that the nutrient benefits are available across the growing crop.
Digestate spreading can be used to address nutrient deficiencies and as part of nutrient planning, helping to ensure that the soil is in a healthy condition for growing crops. The amount of digestate introduced to the soil will be determined by a test to ensure that the correct nutrient levels will be present after the process has been completed.
How is digestate produced?
Digestate is an efficient, practical and environmentally beneficial use of food waste. Anaerobic digestion is key to the production of digestate. This involves a series of biological processes, through which materials are broken down by microorganisms despite the absence of oxygen.
Digestate can be produced to three different specifications: fibre, liquor and whole. Fibre is composed primarily of solid material after the whole digestate has been separated. As the name suggests, liquor has most of the dry matter removed and is primarily a liquid base. Whole digestate slurry has a similar appearance to livestock slurry and is usually less than 5% dry matter.
What is it made of?
Digestate consists of a range of by-products, such as food waste, dairy produce, meat, and fish, and is governed by the Animal By-Products Regulations. Digestate fertiliser is nutrient-rich, fluctuating in the amounts used depending on the type of slurry used to create it.
Food-based digestate has around 80% of the nitrogen readily available, making it a genuine alternative to ‘bagged’ fertiliser.
Is it safe?
Digestate will undergo a pasteurisation process to ensure that digestates are safe to use on the land. However, it’s not suitable for land used by grazer livestock or for forage crops within three weeks of the digestate being applied. If pigs are to have access to the land then this time period extends to 2 months.
How should it be applied?
To achieve the maximum effectiveness of the digestate content, it should be applied to the land during periods of maximum crop growth. Digestate spreading will normally be carried out from late winter through to the end of summer. The application will usually be avoided during the autumn months, as during this part of the year, nitrogen is less effectively absorbed by crops.
As well as this general rule, there is a range of other restrictions about when and how the nutrient-rich digestate should be applied. There are restrictions related to the geography and topography of the land.
It should not be applied to land located within 10 metres of a pond, water surface or ditch. The same applies if the land is located within 50 metres of a water supply that’s used by humans or dairy farms. This includes springs, boreholes and reservoirs. Digestate spreading is not recommended where fields are located on steep slopes.
If the land does not fall into any of the restricted geographical contexts, then there are a number of conditions to bear in mind before the application process begins. Food digestate should not be applied to the land:
- During periods of heavy rainfall or if it is forecast within the next 48 hours.
- If the ground is waterlogged.
- If the ground is frozen or covered in snow.
- If the soil has cracked down to the field drains.
- If a field has been mole or pipe drained.
- If a field is sub-soiled over drains within the last year.
To find out more about food digestate and its safe use in agriculture contact BioteCH4 today.