Planting green manure cover crops over the winter before potatoes could save growers up to £60/ha through reduced fertiliser needs and benefits to soil quality, according to new ADAS research.
Furthermore, such green manures can be more effective at reducing soil loss via erosion than overwinter stubbles, adds ADAS senior soil crop and water researcher Martyn Silgram.
He calculates that growers could save up to £20/ha in nitrogen in the potato crop from nutrients released back into the soil by green manures, with a further £40/ha worth of N contributing to soil organic matter over the medium term. A range of innovative management options have been assessed at sites in England and Scotland.
There is evidence of soil nutrient loss this year through leaching during the incredibly wet spring, which so disastrously delayed potato planting and disrupted the season. “Protecting soil reserves is essential for all potato growers, both economically in the search for more cost-effective production, and legally to comply with soil management plans,” he warns.
“The techniques that are being developed will help growers conserve nutrients, and cope with the extremes of weather that are becoming more commonplace. It is vital growers are aware of the risks and the opportunities to save costs and reduce losses,” he says.
Dr Silgram’s research has also identified ways to conserve water loss from potato fields in a more typical season. During 2011, run-off losses totalling up to 18% of rainfall or costly irrigation were observed down stone rows in potato crops. Novel management techniques successfully reduced these losses to just 1%, conserving water in the potato bed and avoiding erosion and run-off down stone rows – which prevented fertile topsoil from being lost from fields.
Full details will be presented at the The Potato Conference and Exhibition, organised by ADAS/Syngenta in partnership with the Potato Council, being held at the Newark Showground, Nottinghamshire, on 22 November.