Growers of vulnerable crops such as sugar beet and oilseed rape should give them a helping hand to make use of available soil moisture now the region has had some much-needed rain, an eastern counties crop advisor is urging.

According to Ian Jackson of agronomy firm ProCam, achieving good soil contact of tiny oilseed rape seeds, planted during August and September, will be crucial if they are to absorb sufficient moisture for good germination.

“There’s little doubt there’s been a substantial soil moisture deficit built up over the summer,” says Mr Jackson, “particularly on lighter, freer-draining land.

“Getting oilseed rape established into a healthy crop quickly is increasingly important now that growers can no longer use a neonicotinoid insecticide seed treatment against damage from cabbage stem flea beetles.

“If you disturb the soil surface when planting oilseed rape, make sure you squeeze it back down again properly afterwards to achieve a good seed to soil contact. Use a heavy press and rolls, not just rolls. Although rolls alone may look like they are firming the soil up, they may not be firming it enough.”

Although irrigating crops such as potatoes helps in drought conditions, Mr Jackson says irrigating oilseed rape to help it establish is unlikely to be economically viable. Similarly, irrigating sugar beet on soils with a certain clay content may not be advantageous, because it can bake hard afterwards in warm weather, which is forecast, he adds.

“As well as cultural methods to boost moisture uptake, consider applying a naturally-based treatment to help stimulate root growth to give crops better access to soil moisture. Consider a seaweed extract plus micronutrient in sugar beet, or a humate treatment in oilseed rape.

“First-hand experience with this type of approach in onions over the summer showed they continued bulking up below ground even during the drought.

“There’s an opportunity to apply a seaweed and nutrient treatment in sugar beet when fungicides are applied against rust and powdery mildew in early September. In young oilseed rape, there will be an opportunity to apply a humate treatment, such as Borg, around the time of spraying off grassweeds.”

The additional problem with crops unable to absorb sufficient soil moisture, says Mr Jackson, is they are also unable to absorb sufficient nutrients, which are normally drawn up from the soil with the moisture. “Sugar beet leaves can turn yellow in just three or four days, at a time when the plant should be green and sending sugar down to the beets below ground.

“These types of treatments help to keep crops ticking over for nutrients,” he adds, “so that when moisture is available, they are in a healthier position to respond.”

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