East Anglian farmers missing out on soil benefits of recycled material30 March 2017
East Anglian farmers could be missing out on the benefits of a simple recycled material that could improve sticky, clay soils, says a crop expert in the region. According to Ian Jackson, who advises farmers in Norfolk and Cambridgeshire for agronomy firm ProCam, gypsum, which can be obtained from recycled plasterboard, makes a valuable soil conditioner, yet it remains under-utilised.
“Use of gypsum on some heavy clay soils can render them more friable,” explains Mr Jackson. “The soil starts to fracture, as if it’s been frosted, so the clay opens up.
“It may take four to six weeks to bring about noticeable soil changes, and they will depend on the amount applied, but a more open and friable soil can lead to a number of benefits.
“These include soils being easier to work, for example becoming workable earlier in spring or after rainfall, and improved drainage as rain can percolate deeper. Roots are also able to penetrate deeper, accessing more nutrients and water, and the problem of ‘capping’ may be reduced.”
Mr Jackson says gypsum works by displacing sodium from clay, effectively precipitating finely-dispersed clay particles that can otherwise block small soil pores and hinder the drainage of water. “Improving pore volume also improves aeration and provides volume for occupation by roots and root hairs.
“Also, foot rots, which cause the base of crops to rot away, can be reduced because roots aren’t sitting in airless mud.
“With a finer crumb structure on the soil surface, it is also noticeable how soil-applied herbicides work better. It can also allow drilling to be delayed because the land is less sticky, which can also help with blackgrass management,” he adds.
As rain percolates deeper into the soil, Mr Jackson says it carries gypsum with it, and the process continues with the depth of reaction related to the amount applied. However, it is important to know where and how to apply gypsum correctly, he stresses. He also urges the use of a quality source that has been recycled from new boards, such as those damaged during manufacturing, rather than from old buildings.
“Because gypsum consists of calcium and sulphate sulphur, it can also contribute to the nutrition of the crop.
“Using techniques such as applying gypsum can form part of a wider conservation agriculture approach to farming that benefits the crop, saves on resources and benefits the environment. We are keen to help farmers with this type of strategy.
“The benefit of gypsum was established by the then HGCA, which found soils required 14% less fuel and power to work them.