Farmers discuss black-grass, cereal fungicides and precision farming

Jess Townsend of BASF.

Jess Townsend of BASF. - Credit: Archant

Arable farmers in East Anglia met up for one of a series of events being organised by BASF’s agronomy team across the country.

Jess Townsend, BASF’s agronomy manager for Cambridgeshire, brought together a set of presenters who covered the latest thinking in black-grass control, cereal fungicide trials and precision farming.

John Cussans of NIABTAG kicked off with a presentation entitled “Understanding the influence of agronomy on black-grass”. He challenged the audience by stating that black-grass has been building up especially in the last few seasons, yet there have been relatively few changes in agronomy to head off the problem.

“The main historic reasons why black-grass is such a problem is the switch from spring to winter cropping, earlier drilling and less ploughing,” he said. “Now 25% of crops are drilled before September 20, whereas in 1970 the figure was 0%. Crops pick their own weeds!”

Mr Cussans said that HGCA-funded work showed herbicide performance was influenced by delayed drilling and advised farmers not to establish wheat crops with a high density of black-grass. “Use stale seedbeds, delay drilling or whatever to reduce black-grass density,” he advised. “Very high populations of black-grass are much harder to control than lower density ones.”

He also pointed out that the pattern of rainfall in September and October had a profound influence on herbicide performance. “The solution is multifaceted,” he said. “Plough strategically, using it sparingly and well. Apply residuals at true pre-emergence timing following the drill. Stack residuals but use at least 4 modes of action into the programme. “Take up resistance testing so you know exactly what you are dealing with on your farm. Grow a competitive crop species at a higher seed density. You must also focus on effective herbicides in non-cereal crops as part of the rotation.”

Mr Cussans warned however that, although the cultural control methods add to the weed management solution, they can be very variable. “For example ploughing on average reduces black-grass by 67%, but the range from 25 trials was a 20% increase in the weed population up to a reduction of 96%,” he said. “It depends on getting a proper inversion of the soil and using ploughing at the most appropriate place in the rotation. Similarly delaying drilling gave a mean reduction of black-grass of 37%, but the range from 16 trials was a weed population increase of 64% to a reduction of 83% – massive variation!

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“Cultural control doesn’t mean less herbicide should be used,” he added. “We’re in an era where cultural control is necessary to close the gap between the level of herbicide control we can reliably achieve and the level of control required to make rotations sustainable.”

Steve Dennis, BASF regional sales manager for the south, took farmers through the latest cereal fungicide trials. “Last season yields were good but prices not so,” he said. “Rainfall was average but conditions milder with significant sunshine in June and July – good for grain fill. Overall conditions were good for yields, but equally good for disease! In 2014 a robust disease approach was needed. Most farmers were able to apply their four fungicides at the right time and within the right spray intervals.”

Reporting on fungicide trials at Rawcliffe Bridge, a major trials site for BASF, Mr Dennis reported that all wheat varieties responded to fungicide inputs, with an average of 4.24 tonnes per hectare (t/ha) response, giving a Margin over Input Cost (MOIC)of £352/ha. The lowest response to fungicides was 3t/ha, giving a MOIC of £216.

He advised that, with Septoria being the top target and most varieties having low Septoria resistance, a full programme starting with a T0 treatment will give good results. “When it comes to growth stage 32 (the so called T1) when Leaf 3 is emerging, eyespot should be treated,” he said. “This disease is difficult to see, but early diagnosis is important, even in first wheats. Tracker is still the best fungicide for eyespot and high responses of 1t/ha can be achieved through controlling this disease.

“I would advise sticking with Tracker and only moving away from it in known low risk eyespot situations where Septoria infection is very high. At T2 AICC independent trials showed Adexar + chlorothalonil producing the best results, with treated crops yielding 12.6 t/ha (and a MOIC from the T2 of £118). I would advise the use of chlorothalonil at T0 through to T2 to help mitigate against resistance development. At just a few pounds per hectare it is well worth it. When used in mix with Adexar at T2, the MOIC of adding chlorothalonil was £45.”

Mark Jarman of Ursula Agriculture, an expert in precision technology and unmanned aerial vehicles (UAVs), described the many ways that crops can be monitored by UAVs and satellites.

“We can survey crops using multi-spectral sensors (cameras) to precisely identify and quantify problems in the crop,” he said. “For example, this means we can map the exact location, extent and density of black-grass patches in the field, for control this season as well as for longer-term management.

“We are in a technology revolution in agriculture, which will continue to develop. Problems will arise from data overload and farmers being flooded with data, so the skill lies in being able to interpret and act upon that data. Ursula Agriculture’s focus is on informing management decisions, rather than just providing measurements.”

This view of echoed by farmer and Nuffield scholar Andrew Williamson who farms 900 acres in Shropshire and has been keen on precision farming for many years.

“In 2007 it was yield mapping and soil sampling,” he said. “In 2008 it was variable P and K rates: 2010 auto-selection and boom height control on sprayers: 2013 variable seed rates and electrical conductivity measures. Any future technology will have to increase production, manage resources sustainably, assist in technology development and interpret data to the greatest benefit.”

He illustrated a number of examples of farmers in other countries using precision technology to their benefit. A farm in New Zealand was using variable rate irrigation where every part of the field had a moisture probe. Telemetry was introduced so that readings were taken every 15 minutes and this helped inform irrigation decisions.

“Data is king but it needs to become more mobile and based on good agronomy,” he added. “It is the analysis that is challenging, so that the cause of variation is determined, not just measured. The UK is perfectly suited to more sophisticated precision farming.”

Farmers interested in attending future BASF meetings, or local demonstrations and trials, can call Jess Townsend on 07771 815699 or email .