The application timing for biofertiliser is from mid-January to the end of September if the agricultural land is located within a Nitrate Vulnerable Zone (NVZ), such as at Westwood. However the biofertiliser can be used on grassland as well as arable crops, which significantly increases the spreading opportunities beyond just a spring and summer application.
At Westwood biofertiliser is spread on Bedfordia Farms land as well as land belonging to neighboring farms. The product is transferred from the plant to the fields by two systems. The first is via a combination of underground and over land pipes which form the distribution network. Spreading is then carried out with a 24m dribble bar system attached to an umbilical cord pipe delivering up to 130cu.m per hour. The second system used for more distant fields operates with a tanker system transporting the digestate directly to a field based applicator. This machine can apply the digestate to the soil surface or directly into the soil depending on the requirements.
Application rates are typically between 25 and 50cu.m per hectare.
The application of biofertiliser must take account of Nitrate Vulnerable Zone (NVZ) regulations, Animal by-product regulations where appropriate and Codes of Good Agricultural Practice for Soil, Water and Air.
There are two options to enable spreading: under a mobile deployment with the Environment Agency where the biofertiliser is still classed as a waste; or under PAS110 where the biofertiliser has to meet certain audited standards to be classed as a product.
At Westwood the application of 42,000m3 of biofertiliser spread annually on the farm makes a significant contribution to utilised crop nutrients supplying around 231,000kg of nitrogen, 10,000kg of phosphate and 60,000kg of potash.
The savings in purchased crop nutrients is the equivalent of 670t of Ammonium Nitrate, 22t of triple super phosphate (TSP) and 100t of muriate of potash (MOP). At current prices this has a value of approximately £270,000. In the future as energy costs and fertiliser prices increase this is expected to be more significant.
In addition to the above input savings, there have been yield benefits of up to 15% particularly in dry years where nutrient uptake is challenging.