Green cover to protect and restore uncropped land
Sowing green manure seed mix on uncropped arable fields and headlands, left where growers just managed to muddle in landwork in the autumn, could help to restore soil structure and build fertility, and play an important role as an ecological asset.
Research and growers’ experience with the Syngenta’s Operation Pollinator Green Headland Mix cover crop has highlighted the opportunity for soil improvement and to capture nutrients for following crops, reported Syngenta Sustainable Farming Manager, Belinda Bailey.
“The techniques involved could now prove equally applicable for arable fields where land has been left, or are unviable after the wet winter,” she advocated.
“Growers’ priority will clearly be on establishing their crops in the spring, but once completed there will still likely be time after to sow a fast growing Green Headland Mix cover crop, at relatively low cost. That can help to reduce field soil losses, capture nutrients and, with the deep root systems, support soil structure and reduce moisture to help restore the land ready for autumn sowing,” she advised.
Belinda advised the Green Headland Mix, developed with seed specialist Kings Crops, contains predominantly oil radish and phacelia, along with common vetch, buckwheat and berseem clover.
It can be planted from late April through to June, once the soil has dried out and warmed up sufficiently to encourage a quick establishment. The easy to establish seed mix is best shallow drilled at 15mm, or broadcast and rolled in, at a seed rate of 20 kg/ha. An application of up to 30 kg/N/ha could prove beneficial to aid establishment.
Richard Barnes of Kings Crops (below) added: "The Green Headland mix would be the best option for short-term establishment of around three months, resulting in significant biomass and rooting activity. The green manure would be destroyed prior to cereal harvest, before stems lignify or plants set seed," he pointed out.
Trials have shown that a Green Headland mix can typically create up to 6.8 tonnes of biomass dry matter per hectare to enrich soils, as well as having the potential to capture around 100 kg/ha of N along with other nutrients for the following crop. It will also help protect soils from tractors and sprayers turning during fieldwork and harvest.
For headlands intended to remain growing for more than three months, farmers may consider using a legume mix, including clovers, which will fix nitrogen and increase soil fertility. The flowering mix can also produce an extremely valuable supply of pollen and nectar for bees and pollinating insects.
Bedfordshire, onion and potato growers, F B Parish & Son, have been pioneering the use of the Green Headland Mix over recent seasons, based at Lodge Farm, Chicksands, near Shefford. Farm Manager, Adrian Baker (below), reported protecting soil structures around the vegetable crops is one of the most important elements of the Green Headland mix.
“The margins have become much more resilient to farm traffic where we need to travel through them in the season.” The farm produces around 160 hectares of onions and 50 hectares of potatoes.
Adrian also believed that improvement in soil organic matter from the incorporation of the green material, along with the nutrient capture and retention in the cover, could be important factors in the improved vigour in the following crops on the covered margin areas.
“In the past we would have expected to see a negative impact on headlands after root crops in the following crop,” he recalled. “Now we are actually seeing an improvement; that’s a radical change."
He has also noted reduced erosion of soil from both the margins and the main body of the field, along with less susceptibility to water pooling on capped surfaces in the areas sown with the Green Headland mix.