While low boron can have a negative impact on wheat yields, attitudes to its application vary
Tissue analysis is showing more winter wheat samples with very low boron levels in crops this year, most likely as a result of wet winter conditions leaching it from the soil and a cold spring slowing uptake of the micronutrient.
Of 388 winter wheat samples submitted to Yara-owned Lancrop Laboratories, 91 per cent were classified as deficient in boron with 48 per cent classified as very low which compares with previous years when about 20 per cent were classified as very low.
Jez Wardman, Yara digital marketing and agronomy manager explains: “Boron behaves similar to nitrate and sulphate; it is mobile in the soil and leached out easily. Given the heavy rainfall [over winter] it is no surprise that it is low.
“Low spring temperatures meant root growth was slow and transpiration slow. Boron tends to go in through transpiration so if this is slow the amount of boron going into the plant is low.”
Boron is important in the flowering period for anther set and grain set and Bedfordshire-based grower Andrew Robinson believes applying it has a positive impact on wheat yields.
“We have been tissue testing since 2009. While we had boron deficiency before it was quite sporadic and not top of the agenda. It was significant in 2012, a wet year, but not bad in the last two years.
“This year we are applying it to all crops. Wheat has had its first dose and will have its second dose at T3. With boron you have to be careful as it can be toxic. We apply no more than 75g/hectare.”
Mr Robinson tests wheat, barley, beans and oilseed rape on his farm four times in a season, applying micronutrients according to test results. “It is important for general plant health and one of the factors why we are seeing higher yields. Plants are in the best shape to fight off disease and maximise their genetic potential.”
Conducting trials on wheat micronutrient levels throughout this year’s growing season in response to micronutrient applications, including boron, Agrii regional technical manager, East, David Felce questions whether existing testing protocols and guidelines are appropriate to modern varieties.
“The concern has been applying too much but I think we are a long way off this and maybe need to put on more.”
However, Yorkshire-based Agrovista technical manager Chris Martin says he has not seen any cases in his area this season where applying boron to cereals can be justified. “With cereals it is a fine line between deficiency and toxicity. Applying boron can have a negative impact.”