Reducing nitrogen (N) was a recurring theme across presentations and demonstrations at the Groundswell Show.
At a workshop on this topic, Joel Williams, an independent plant and soil educator, pointed to the evidence showing the efficiency of N inputs ‘hovers around the 50 per cent mark’.
Mr Williams said: “There are lots of opportunities for us to do better and N is a big issue for the environment because it is reactive and is easily leachable, so can cause ecosystem degradation.
“N fixation is a critical tool to use and if we match legumes to the right crops, there are many opportunities to improve N utilisation.
“All plants can fix N via free living soil bacteria associated with their roots which will take up the root exudates produced by these roots in exchange for providing N to the plant.
“Elements such as molybdenum, iron, nickel, calcium, boron and cobalt are all vital to healthy bacteria function, so are we managing these?”
Kent farmer, Andrew Howard supported this view and explained he now uses 40 per cent less N than he did four years ago.
“I have adopted a holistic approach to create a balanced soil and healthy plants,” he said.
“N is the driver of disease and insect problems, so I have tried to encourage the soil biology.
“I grow cover crops before drilling spring cereals and these provide an extra 70kg for the spring barley and spring oat crops.
“I do not believe the cover crops fix much N, but I think they are very good at scavenging for it.
“I use species complementarity and by increasing this intercropping and the diversity in the field, the need for fertiliser disappears and it is a game-changer.
“I use an N meter and this has helped me realise there is no need for extra N after certain crops. It shows there is more N in the spring oats grown with spring beans than the crop grown following an application of 80kg of N.
“We also brew up biological additives which we add to the seed to help reduce the need for N and we are seeing a 30 to 50 per cent reduction in the incidence of fungal disease.
“I find foliar N application is six times more efficient than broadcasting N and I mix the N with boron humate, which results in less volatilisation and reduced leaching.”
Tim Parton, farm manager at Brewood Park Farm tries to ‘farm as biologically as possible’ and aims to ‘grow as much N as I can’ by establishing cover crops on half the farm, including beans, vetches and rye, prior to spring cropping.
“I have incorporated sheep into my rotation to turn the cover crops into a fertiliser and the rent from the sheep pays for the seed,” he said.
“I want to increase the species diversity in my cover cropping to 20 species and ideally establish clover underneath all the crops we grow.
“We have not used insecticides for five years and no longer apply many of the fungicides we once did. I have realised less N means less disease.”