Practical advice for growers aiming to get the most out of cover crops in orchards. By Anna Mouton
Tillage – preparing soil for sowing – is as old as agriculture itself. It helps seed germination and plant growth by loosening the soil and removing weeds. This sounds like a good idea when sowing cover crops in orchards. But there is a downside, explains Matthew Addison, crop-protection programme manager at Hortgro Science.
Addison rotovated the soil in existing orchards as part of cover-crop trials. “It disrupted the whole system,” he says. “The soil carbon just flat-lined.”
Results from Addison’s cover-crop trials suggest that populations of soil micro-organisms take three to four years to stabilise after tillage. “When you plough up the soil, you disrupt the topsoil, and you’re going to lose soil,” cautions Addison. “And you’re delaying the process of getting healthier soils. Whereas, if you don’t plough it, you’re preserving the soil.”
Pome-fruit grower Craig Johnson of Nidderdale Farms acknowledges that tilling can benefit seed germination. “When we created a seedbed, we had better results. But keep in mind, how many times do you have to drive a tractor down the row to do it? Every action, every time you drive down that row, has a cost implication.”
Besides the cost, more tractor hours also equate to more diesel burned and more carbon emissions. And there are logistical issues. Johnson points out that the best time for planting cover crops overlaps with harvesting – and harvesting naturally takes priority.
“Time is money,” says Johnson, “so the more quickly and effectively I can plant my cover crops, the better.”Read More