Tailored winter OSR and wheat nutrition is showing excellent returns on investment from the strategic use of foliar nutrients well beyond traditional programmes at the Bishop Burton iFarm in East Yorkshire.

Additional autumn copper and early summer calcium applied to the Agrii team’s extensive OSR and wheat demonstration crops respectively both resulted in yield improvements of over 0.20t/ha last season (Figure).

Averaged over all 23 OSR varieties and seed treatments in the field-scale plots, the return
on investment at harvest prices and actual costs was just over £166/ha while across the
13 wheat varieties it averaged £50/ha.

“Despite soil analyses indicating more than adequate levels of both minerals, we were prompted to focus on these nutrients in 2022 by imbalances identified in our post-harvest grain analyses of the preceding crops,” explains Agrii northern trials manager, Jim Carswell.

“So, we were particularly keen to see what the regular tissue analyses we always take to key performance-based growth stage benchmarks showed. And, low and behold, they revealed very low copper levels in the OSR at six leaves and relatively low calcium contents in the wheat in early May.

“Responding to these, we included extra foliar copper in our normal OSR spray programme in mid-October, mid-November and mid-March on top of our standard stem extension treatment. With the wheat we added a single application of foliar calcium in May. In each case we left a cross-section of plots without further treatment as controls.”

Detailed monitoring showed the foliar sprays increasing and maintaining higher leaf copper levels in the oilseed rape through to flowering, with a slight dip in late-February coinciding with the start of stem extension.

Applying approximately 10 times the standard level of copper led the average seed yield to increase from 4.65t/ha to 4.86t/ha with no effect on oil content. Despite the diluting effect of the higher yield, copper and a number of nutrient levels in the seed were noticeably higher too, suggesting overall improvements in nutrient use efficiency.

Lifting average wheat yields from 14.66t/ha to 14.90t/ha, the single mid-May application of calcium at Bishop Burton also increased specific weights and nitrogen contents slightly. While there were no obvious improvements in grain nutrient levels here, the nutrient content of the straw was consistently higher across the board.

“In just the same way that Agrii trials first identified the particular value of extra boron for wheat, if we hadn’t seen it with our own eyes we wouldn’t have believed oilseed rape would respond so positively to so much more copper,” reflects Mr Carswell. “And on high pH soils like those at Bishop Burton it’s counter-intuitive to believe a crop needs extra calcium.

“It all comes down to availability, though, especially when a relatively high pH soil is also  high in phosphate which is also antagonistic to copper and calcium, amongst other nutrients.

“Long-experience teaches us that what’s really vital in optimising nutrient use efficiency – increasingly so, at today’s prices – is ensuring our crops have the best balance of all the nutrients they need throughout the growing season.

“But it’s not just a matter of ladling on extra micro-nutrients just in case,” he insists. “Instead, we have to know which ones actually make the difference on our ground and, equally importantly, at what stage in the season they are most needed. Otherwise, we risk adding to our costs for little, if any, benefit.

“That’s where the carefully tailored approach we follow comes into its own. Soil analysis every three years or so sets the base for our nutritional planning, alongside later winter soil mineral nitrogen assessments.

“Post-harvest grain analysis of crops from key areas of concern tells us what to watch out for in the following crops.  Then tissue testing in them to established performance level and growth stage benchmarks alerts us to what is actually going on and the best balancing action to take.

“The results of our latest field-scale trialling under the strictly commercial farming regime at Bishop Burton may be surprising to many, but they are great proof of this particular pudding,” concludes Jim Carswell. “They are a good illustration of the increasing precision we need to put into our crop nutrition in the face of growing economic and environmental pressures.”

Figure: Response to Tailored Nutrition at Bishop Burton 2021/22

And Extra Titanium ?

One thing Agrii’s tailored nutrition approach cannot cater for is the possible value of non-essential nutrients like titanium which are known to influence a number of plant flowering and other metabolic processes.

Which is why, as part of his 2022 Bishop Burton trial work, Jim Carswell took the opportunity to include a novel titanium-based biostimulant in the OSR’s mid-flowering spray.

Interestingly, this gave a 0.18t/ha yield increase with no effect on oil content for a return on investment of over £100/ha.  Higher levels of nitrogen and phosphate in the grain suggested an improvement in the use of these nutrients, in particular.

“This may have something to do with helping the crop tolerate the July heat better,” suggests
Mr Carswell. “Unlike our tailored nutrition work, however, this is only a single season’s result. So, we are treating it with caution as well as interest. If we continue to get economically positive responses to titanium in future trials then it could be valuable addition to our NUE improving armoury.”