Developing a fertiliser to reduce the need for pesticides

Dr Christian Laycock

The University of South Wales is working with industrial partner RecoTech Ltd to develop a unique material that can be applied to land as an advanced slow-release fertiliser.

The multi-functional advanced soil conditioner is rich in nutrients and will be able to be delivered exclusively to plant roots without excess leaching into soil or groundwater. Initial laboratory work and field-scale trials were conducted in the spring and summer of 2020 by researchers at the University’s Sustainable Environment Research Centre (SERC) and RecoTech Ltd. 

The initial field-scale trials indicate that the new soil conditioner can increase crop yields with less use of pesticides, insecticides and fungicides. The material is intended to alleviate nitrate pollution and soil degradation whilst helping to restore degraded soils.

The soil conditioner is produced from digestate, which is a by-product of anaerobic digestion processes for biomethane production and has been a key research area for SERC and USW for several decades. Digestate consists of a mixture of materials and liquids produced by the digestion process and is rich in organic and mineral nutrients. It is already applied to agricultural land as an organic fertiliser, however, the window for land application is limited by crop requirements and weather conditions.

In addition, excessive application of digestate leads to excess minerals permeating into ground water, contributing to soil degradation, nitrate pollution, water contamination and the decline of aquatic ecosystems. These are significant and well-known global public health issues, since they are also caused by conventional soluble mineral fertilisers, which have been routinely applied to land excessively as part of intensive farming practices for the last 50 years. Annually, there are now 450 million tonnes of synthetic soluble mineral fertiliser produced worldwide, causing the degradation of billions of tonnes of soil every year.

The advanced soil conditioner developed by SERC and RecoTech embeds and retains the nutrients and organic matter of digestate within a bio-available substrate, which binds the nutrients and enables their slow release to land. Over time, the material slowly decomposes, enabling targeted release of nutrients to crops and therefore preventing excess release into soil and groundwater.

The substrate also serves as a source of bio-available plant health enhancing elements, which enhance resistance to pests and pathogens. Once taken in by the crop, the beneficial elements become deposited in the plant structures and inhibit aphids from penetrating cell walls, which in turn prevents sap leakage and associated fungal diseases and leads to improved yields through better photosynthesis and greater resistance to disease. In addition to functioning as a fertiliser, the soil conditioner could potentially lessen the need for the application of insecticides, fungicides and pesticides.

“Research and field-scale trials conducted so far have shown the material can be made using commercially available equipment and materials that are already routinely applied to agricultural land," said SERC's Dr Christian Laycock.

"The soil conditioner has been shown to have significant potential on a range of crops including spring barley, potatoes, maize and sugar beet. Future work and field trials scheduled for the autumn and winter of 2020-21 will focus on further optimisation and modification of the soil conditioner, to enable easy land application using existing farming machinery.”

“We are delighted to have joined with SERC to further develop this exciting product, which has already demonstrated its potential in trials on our home farm," said Roger Pauli, Director, RecoTech Ltd.