BASF Funginar #1: Nitrogen and fungicides
15.03.2023
Nitrogen and Septoria levels
Dr Julie Smith, Plant Pathologist Researcher, ADAS told growers, “In academic literature a value of 8 % Septoria increase per 100 kgN/ha is widely accepted. A reduction of 50 kgN/ha, which is probably the most growers are likely to cut, would have a fairly negligible effect on Septoria levels. Our trials have shown that in both a high disease pressure situation and a low to moderate disease situation; different nitrogen rates have minimal effects on Septoria levels. This is not surprising as Septoria is a hemibiotrophic pathogen which requires living tissue for part of its lifecycle but then continues to live in dead tissue.”
Better disease control, less nitrogen: same yield
Dr Pete Berry, Head of Crop Physiology, ADAS, said, “Trials over the last few years have typically found better disease control strategies result in a higher economic optimum nitrogen rate and that’s because the disease control is driving bigger yields which in turn drives a greater requirement for nitrogen to support that yield. Conversely, in this new era of extremely costly nitrogen, you could potentially maintain your yield but achieve that with a lower rate of nitrogen, if you were to adopt a better disease control strategy.”
Effects of fungicides on nitrogen use efficiency
Dr Berry studied the effects of fungicides on nitrogen use efficiency (NUE), defined as the kg yield produced per kg of available nitrogen from soil and fertiliser. The trial in a crop of Gleam (R.L. 5.7 rating for Septoria) at ADAS Rosemaund, Herefordshire in 2022 looked at a range of nitrogen and fungicide treatments.
“In what was a low to moderate disease pressure situation, we found in the trial crop of Gleam that the fungicide programme of Revystar® XE + Comet® + Arizona at T1 and T2 produced a statistically significant increase in NUE, increasing from 34.0 kg up to 38.0 kg of yield for every kg of nitrogen which was available. 1 l/ha of Revystar XE at T2 increased the NUE by nearly 2% points, from 34.0 kg to 35.6 kg.
The increase in NUE was driven by both better nitrogen utilisation and uptake efficiencies, and again we found there were considerable increases from the untreated to the fungicide treated.
Revystar® XE significantly increased the nitrogen uptake efficiency – defined as the amount of nitrogen taken up for every kg of nitrogen available from both the soil and the fertiliser.
When we looked at fertiliser uptake efficiency, the amount in kg of N taken up by the crop per kg of fertiliser N applied, we found there was a statistically significant increase from 54% of the fertiliser nitrogen taken up without any fungicides to over 62 % with a fungicide strategy of 1.5 l/ha of Revystar® XE at T2.
It is likely that these effects can be accounted for by the fact that the Revystar® XE programme kept the crop greener for longer and allowed the crop to ‘operate’ for a longer period of time. This meant the crop had more time to take up nitrogen from the soil and fertiliser and more time to remobilise nitrogen that was in the canopy into the grain and build yield. The longer duration of the grain filling period was the main reason that these improvements in nitrogen efficiency occurred and the yield increase was achieved through increasing the thousand grain weight.”
Economic value to investing in Revystar® XE regardless of nitrogen rate
Dr Jon Helliwell, Business Development Manager, BASF used data from the same ADAS trial to explore the effect of applying Revystar® XE across different levels of nitrogen input on return on investment. He said, “As the level of nitrogen increased the yield increased right up to commercially relevant doses of nitrogen in plots untreated with fungicide illustrating there is a key role in nitrogen to build gross margin and yield, in a low to moderate disease pressure situation.
We found that for every dose of nitrogen an increased dose of Revystar® XE increased gross margin, which showed a reduction in the nitrogen rate did not have an impact on the most economical dose on Revystar XE. In this trial on Gleam, investment right up to a full label dose of Revystar® XE at T2 continued to improve economic return.
So, regardless of the rate of nitrogen that growers apply to their crops, there is a value to investing in Revystar® XE in terms of economic return. Our work over the past 2 seasons with ADAS has illustrated this. It was found that in the high disease pressure situation of 2021 there was a key benefit of stepping up to Revystar® XE over AscraXpro (bixafen and fluopyram) across all doses of nitrogen. In 2022 when disease pressure was low to moderate, there was increasing profit right up to full label dose of Revystar® XE.”
A recording of the webinar is now available to watch by clicking north_east here .
Use plant protection products safely. Always read the label and product information before use. For further product information including warning phrases and symbols refer to www.agricentre.basf.co.uk. Revystar® XE contains mefentrifluconazole (Revysol®) and fluxapyroxad (Xemium®). AscraXpro contains bixafen and fluopyram. Revystar® XE, Revysol®, Xemium®, are registered Trademarks of BASF. All other products are those of other manufacturers where proprietary rights may exist. © BASF 2023. All rights reserved.
