Improving the availability of phosphate and key micro-nutrients in the spring can markedly improve the performance and nitrogen use efficiency of winter wheat, barley and oilseed rape on higher pH soils, according to the latest series of Green Horizon trials at the Bishop Burton iFarm in East Yorkshire. And this on soils with phosphate and potash indices of 2+ or more.

“For the second year in a row we’ve seen highly cost-effective winter cereals and OSR yield improvements from the application of a specialist soil phosphorus activator which also appears to improve the availability of a number of micronutrients,” reports Agrii northern Trials manager, Jim Carswell. “Improvements which have noticeably boosted the efficiency with which the crops use nitrogen.

“Averaged over the 17 OSR varieties we grew in the Bishop Burton demonstration plots last season, for instance, we recorded a yield increase of just over 0.2t/ha with no reduction in oil content from a single early-February spray of the activator, AgriiStart Release containing no additional nutrients.

“The response to the same treatment across nine varieties of winter barley was almost 0.4t/ha, with a lift of nearly 1kg/hl in ex-combine specific weight,” he adds. “While across 13 varieties of winter wheat we brought in an extra 1.3t/ha on average with no impact on either specific weight or protein content (Figure).

“At harvest 2022 values this gave us returns on investment of over £60/ha with the barley, £109/ha with the oilseed rape and £300/ha with the wheat.”

As well as general increases in the soil phosphorus bio-availability four weeks after treatment, detailed monitoring over the season shows these valuable performance gains were associated with clear improvements in OSR biomass and wheat ear numbers.

Grain testing also showed they were also associated with higher offtakes of key nutrients and higher calculated nitrogen use efficiencies, especially in the winter wheat.

Despite the diluting effect of higher yields, higher grain nitrogen levels were recorded in all three crops. Comparing the measured offtakes in the grain against calculated total N supply in each case demonstrated worthwhile efficiency improvements. For wheat, the single spring application increased NUE from 75.9% to 82.7%.

Interestingly too for those wishing to feed it, the treatment gave general improvements in the nutrient contents of both the wheat and barley straw.

“Essentially what we are seeing is an increased availability of phosphate in the higher pH soils at Bishop Burton leading to a better supply of phosphate to the crops, improving their ability to utilise  nitrogen,” Mr Carswell observes.

“Alongside this, the chelating properties of AgriiStart Release also appear to be enhancing the availability of a number of micro-nutrients – most noticeably zinc, boron and copper.

“Our latest findings underline the importance of the best-balanced nutrition to optimise both crop performance and nitrogen use efficiency,” he points out.

“We have long found crops on higher pH soils – known to restrict the availability of many nutrients – respond well to both fresh available phosphate and potash even where their soil indices are relatively high. Equally, we have appreciated the particular value of foliar micro-nutrient supply here.

“Two years of trial work in very different springs is now showing there is much we can do to cost-effectively improve higher pH soil cropping without having to add extra nutrients by making use of the same phosphorus-enhancing technologies we know work so well in seedbed fertiliser coatings.”

Figure: Bishop Burton iFarm Responses to a Spring 2022 Phosphate Availability Enhancer