Renewable fertilisers resulting from anaerobic digestion (AD) processes can increase crop yields without threatening quality or safety, according to a report by WRAP.
A five-year project ran across 22 sites in the UK. It concluded there is a “robust evidence base” to support using digestates and composts.
WRAP said food-based digestate - a product of AD - was a valuable source of readily available nitrogen, the single most important nutrient influencing crop yields.
It found that grain yields from winter cereal crops increased by 7-10%.
WRAP has also produced a series of good practice guides to help farmers predict how much nitrogen the digestate will supply their crops.
Richard Swannell, director of sustainable food systems at WRAP, said: “Digestate and compost are valuable renewable products of our food and garden waste recycling processes.
“These new findings show the benefits that using the products correctly can bring, and for the first time farmers and growers have the evidence to make informed decisions about their fertiliser use.
“This is a significant step forward for both the anaerobic digestion and composting industries and for farmers and growers.”
Martin Rogers, National Farmers Union environment policy advisor, said: “Digestate is an excellent biofertiliser which can help farmers to reduce their costs.
”With the recent rapid growth in AD infrastructure, it is becoming increasingly available to farmers across the UK.
”It is therefore important that anaerobic digestate is managed appropriately to maintain quality standards and achieve the best results.”
Resources minister Rory Stewart, said: “Sustainable farming is increasingly important for our environment and food supply.
“I welcome this report which will allow farmers to make better decisions about renewable fertilisers, helping to grow crops more smartly and efficiently.”