Tuesday, 18 July 2017

Improving the eating quality of Potatoes

Use of nitrogen and the effect on dry matter

By Knowledge Exchange Manager, Anne Stone 

At the first field walk of SPot SW on July 4th, sixteen visitors looked at the Electra crop in Joe-S field, together with Ollie Blackburn, farm manager of Dillington Estates, Ben Mitchell and Merren Lewenden of Branston Ltd and Marc Allison of NIAB CUF.  
The topic for the demonstration arose from the experience of growers of Electra for Branston last year. As Ben Mitchell explained, 18 growers on 350ha achieved 60t/ha on average. The crop ranged from 15-22% in dry matter, and at the lower end of this range, the eating quality was poor.  Data collected by Merren Lewenden in the graph below showed how dry matter development over the season was affected by the rate of nitrogen fertiliser.

It appeared that excessive nitrogen resulted in too low dry matter percentage. Not enough nitrogen can also be damaging, as in one case on a sandy, gravelly soil where70kg/ha N was applied. The resultant tubers had 22% DM and dehydrated in store. About 19% DM is ideal and, with that target, Branston Ltd recommended 100kg/ha N for the 2017 season.

% dry matter / no. days after planting & harvest / nitrogen rates

The rebels at Dillington

In spite of that recommendation, Ollie Blackburn revealed that the Dillington Electra has received 120kg/ha this year. Nobody commented, but I’m sure we all like it when  people don’t give the ‘right’ answer.

Not so simple.

Relationship of N with dry matter is affected by moisture in the soil and varies from year to year. As Marc Allison said, in NIAB CUF research on 25 crops around the country with differing nitrogen rates, reduction of 30kg N only increased dry matter by 0.3%.  Knowing that a tidy correlation can’t be relied on each year led Dillington Estates and NIAB CUF to look at both irrigations and fertiliser as in the plan shown below. A base rate of 90 kg/ha N was applied to the whole field, with top dressing sprayed to achieve 120kg and 150kg/ha. Irrigation was scheduled for July 6th, and one side of the field will always receive less than the other.


There was a small snag setting up the demonstration. Practical problems led to spraying the top dressing later than on the rest of the farm, on June 24th.  Due to risk of scorch, Ollie chose an Omex product at 18% N, rather than the 26% N product originally planned. Still there was some scorch, especially where 60kg/ha had been applied, as the photo (right) shows.

Cheapskate Marc

In response to the question of whether sulphate of potash would help raise dry matters Marc replied that in NIAF CUF experiments there had been little difference between the results of using the sulphate or the muriate form of potash. There is a big difference in price between the two forms, making potash about twice as expensive if applied as sulphate.

 It is sometimes thought that keeping the crop green until burndown, with more fertiliser than required for yield, can protect against black dot. Marc Allison asked if those present had found that N fertiliser rates which led to yellowing of leaves from early August was associated with black dot or any other disease. No one had that experience, which encouraged Marc in his view that the low N strategy was sound.

Matt Hallett and Ben Mitchell
Whether to apply foliar nutrition was another query put to our visiting scientist. Marc thinks that although petiole tests for N are commonly used in America there is a lack of understanding of how the results relate to any benefit of nitrogen subsequently applied. He suggested that although growers are seduced by the low cost of adding foliar feed to a blight spray, these small costs add up. Similarly with trace elements, there is rarely an economic response. So his advice if you feel you really have to use a foliar feed is to leave an unsprayed strip to convince yourself over time that it doesn’t work.

With every question, Marc favoured the cheaper option. If he applies the same approach to family holidays the Allisons must have a nice time paddling at Felixstowe and Clacton on Sea.


Much of the discussion was about the end of crop life and whether there would be an effect on dry matter content of tubers if diquat is lost. A range of approaches were suggested by different visitors:

·         Flail first, one day, diquat (Reglone)at 1l/ha, followed by carfentrazone-ethyl (Spotlight) at 1l/ha

·         If lush crop: diquat at 0.5l/ha, 7 days, diquat at 1.0l/ha, 5 days, flail

·         If a senescing crop: Flail, 2 days, diquat at 2l/ha, 7 days, carfentrazone-ethyl (Spotlight) 1l/ha

·         cyazofamid (Ranman) and diquat together

·         If blight or blackleg; diquat before flailing

Delayed skin set can be a problem in Electra and two of those present mentioned times when it had taken 7-8 weeks after burn down. This is another reason for not using too much nitrogen.

When can we get an idea of the results?

Wednesday, 28 June 2017

Water, water, not everywhere  – water use and conservation at SPot East this season

By Teresa Meadows, KE Manager, SPot Farm East

With the hot, dry weather experienced across the country and in particular in East Anglia, thoughts at the first SPot East meet of the 2017 season turned to the mitigation of the impact of the dry weather on the potato crops and the social responsibility that comes with managing irrigation.

Andrew Francis, Farm Manager at Elveden Farms, takes water seriously and that is water in all respects. Andrew manages everything, from the accurate timing of water to the crop, through to ensuring that this water is used efficiently to minimise risk of common scab and does not cause soil erosion and diffuse pollution through loss of N or other actives from the site.

Of the five demonstration areas at SPot East for 2017, three are concerned with water use. There is more detail on each below:

N and Irrigation

Developing the findings of the trials that took place at Elveden Estate last year is the focus of this demonstration in 2017. Key questions include:

• What is the best rate of N to use to maximise efficacy of take-up and reduce loss of N through the soil profile? 
• What irrigation scheduling should be used in order to avoid drainage events?  
The replicated trials are beginning to show the effects as the season starts.

At the field walk on 22nd June, there were differences in colour between the trials beginning to show between the standard (18mm at 18mm deficit) and over-watered (25 mm at same deficit) demonstrations.

• Will this difference develop through the season?
• Can we use remote sensing applications or aerial technology to look at how this difference develops?

Follow the blog to find out more as the season develops.

The sensors through the soil profile will also show how the N has moved through the profile and whether that is related to irrigation or rainfall events through the season.   Ideally, the data from this trial will allow for a more predictive system to be developed, answering many potato growers’ burning question of…”do I need to top up after this heavy rain?”

One treatment in this trial has also received only 160kgN/ha.   Even for this late variety, Brooke, there is the thought that this might be insufficient to get it through to the end of September.  However, will further N need to be applied for yield later on in the season?   There is the possibility that this lower rate might compromise longevity later in the season, though it does not appear to have had an effect on expansion to-date.  A decision on whether to top-up this base amount will be made in early July.

Common Scab Control

2017 looks to be a ‘good’ season for testing irrigation regimes and their link to common scab control!  Building on the work at SPot East last year, this year a range of varieties are being used to look at two different irrigation treatments for scab control to find the ideal irrigation response on different soil types per variety.   The two treatments which are being trialled at SPot East this year include:

 1. Standard: 15 mm doses at 12-15 mm soil moisture deficit
 2. Infrequent: larger (25 mm) doses every alternate application of ‘Standard’

Owing to the shorter emergence period in 2017 compared with 2016, this season is looking likely to require a shorter scab control period than the normal 4 weeks for maincrop varieties.    This highlights the essential need to know your emergence dates and tuber initiation timings.

Attendees on the June Farm Walk asked: “When is your scab period over?”  Dr Mark Stalham shared that this is typically when the majority of the crop reaches 35-40mm in diameter, then the risk is significantly reduced.    The recommendation is to ensure that the soil in the ridge is wet from 1 week to 3 weeks after tuber initiation, since this is the critical period when pathogen populations build up rapidly in dry soils.  Irrigating outside of this critical period will still improve scab control in most varieties but the key target period should be kept in mind in hot weather and when irrigation application capacity is stretched.

Run-off Trial

The desire to keep soil and water in the field has led to a partnership being formed between a large range of organisations this year, to look at ways to ensure no diffuse pollution occurs when growing a potato crop.   With the Elveden Estate situated in the Cam and Ely Ouse catchment and with a number of Safeguard Zones across the Estate, ensuring no diffuse pollution takes place is a key consideration for Andrew and the team.

Using a field with a 4° slope on the Elveden Estate, three pieces of machinery have been trialled this year to act as tramline disruptors and contain water between the rows and allow for filtration back into the soil.   The Creyke, Wonderwheel and Briggs machines have all been trialled in two locations – one that has had controlled wheelings (only had the de-stoner and planter through) and another that has been trafficked four times to mimic the sprayer passes.

These have then also been irrigated to two different ways – firstly with an intense boom event (18mm single pass) and the second with a rain gun (18mm but over a longer period of time).
Early signs of this work look like the treatments are inhibiting the flow of this water down the slope – come along to our Open Day on 6th July to see the treatments in action under irrigation and compare their effectiveness.

Keep an eye out for the next blog post, looking at the results as they develop from our herbicide programme post-linuron and manipulating tuber numbers trial.

Hope to see you on the 6th July at our SPot East Open Day,
Teresa Meadows
AHDB Knowledge Exchange Manager

Monday, 12 June 2017

Demonstration programme at #SPotEast 2017

I’m Teresa Meadows and I am a Knowledge Exchange Manager for AHDB in East Anglia. This year, I am delighted to have the opportunity to work with Elveden Farms on the SPot Farm East initiative. I typically work within the Cereals and Oilseeds sector and so I am looking forward to being involved in SPot East and seeing what we can learn from a different part of the arable sector.
Spot Farm activity at Elveden this season
This season we have expanded some of the work we were doing last season and brought in some new focus areas for the trials and demonstrations.
Farm Manager, Andrew Francis, is interested in and has supported the areas being demonstrated this year as they are all relevant to the long-term sustainability of the Elveden business.  And if they’re important to him then you will probably find they’re relevant to you and me as well.
The direct relevance of the SPot East trials for growers and farm businesses, combined with a ‘can do’ innovative attitude is what the initiative is known for and I’m really looking forward to sharing the outputs of this research with you and enjoying the challenging discussions.
This year, the demonstrations will include:
Potato common scab control
This trial will build on the work last year and explore the latest knowledge of irrigation requirments to control common scab with minimal resourse in a challenging environment.
Nitrogen use efficiency under differing irrigation regimes

This was an area of great debate last year. There were many different perspectives on the approproiate nitrogen rate and how effectively it was used.    This year, the trial is looking at applications of N (220kg N/ha) applied in three ways (standard split N, all in the seedbed and placed N) along with different irrigation regimes (standard and over-watered) to see which is the most effective for N uptake in the plant and the minimum losses through the soil profile.   N sensors are in place across the trial to track N movements through the soil and the results will be shared as to the best combination from this research. 

Herbicide demonstration
This is a large scale demonstration of different residual herbicide programmes as applicable to ca. 20 different potato varieties. The demonstration has been redesigned from last year to explore the effects on the potato crop as well as the level of weed control.   With the imminent loss of the widely used residual herbicide, linuron, this trial will be important for future planning future herbicide programmes.  There’s bound to be something for everyone here.

Manipulation of potato tuber numbers
Producing the correct crop specification, including tuber size is essential for grower profitability.  This demonstration, new this year, is looking at ways of manipulating the number of tubers per plant in three different varieties.

Reducing soil run-off and associatated pollution.
We’ve teamed up with a range of partners to look at ways to minimise soil run-off from potato production.   An important aspect of farming within the Cam and Ely Ouse river catchment on the Elveden Estate, this trial will look at ways to minimise diffuse pollution and prevent in-field soil movement.  The tramline disturbance treatments have been applied and it looks to be a really interesting demonstration and trial. Collection and assessment of the soil run-off for each treatment will start soon and we look forward to sharing the results with you.

SPot Farm East Events
Please come along to our events over this season – click on the links below to book your place:

22 June, SPot (East) Elveden Farms, Suffolk - Field Walk
6 July, SPot (East) Elveden Farms, Suffolk - Open Day
3 August, SPot (East) Elveden Farms, Suffolk - Field walk
7th September, SPot (East) Elveden Farms, Suffolk - Field Walk

And if you have a group that might be interested in arranging their own visit to the trials at Elveden Farms, then please do get in contact with me on 07387 015465 or at: teresa.meadows@ahdb.org.uk.
 Looking forward to seeing as many of you as possible over the coming season,

Teresa Meadows

Friday, 2 June 2017

Varieties, cattle and experimental design, it’s a busy demo field at SPot West

Knowledge Exchange Manager, Anne Stone has the latest from Heal Farms

A month after planting, emergence of most varieties is now nearly complete, though Royal has been rather slow to come through. There’s a slight metallic click across the field as irrigation pipes are fitted together, but more prominent is the sound of the resident cuckoos here at Heal Farms.

PCN and key processing varieties

The main demonstration at SPot West 2017 explores the tolerance of and resistance to Potato Cyst Nematode (PCN). 

Farm Manager, Matthew Wallace chose Maris Piper and Maris Peer varieties as part of this demonstration as they both have a commercial interest at Heal Farms. 

Resistance to
Resistance to G.rostochiensis
Maris Piper

Maris Peer

Not resistant
Data from breeder

Improving the PCN calculator
On the AHDB website a calculator can be found, to predict numbers of nematodes and guide planting and treatment decisions. This calculator could be more useful if the model in the background contained better information on:

·         variety tolerance and resistance,
·         effect of Brassicas in the rotation,
·         effect of action taken before the crop; nematicides, trap crops, biofumigation

Harper Adams University has a separate experiment at SPot West, which forms part of a SARIC (sustainable agriculture research and innovation club) project to improve help the PCN calculator.

Bill Watts, a Research Associate at Harper Adams University manages the field experiment.

Bill’s knowledge of biofumigation will be familiar to those who visited SPot West at James Daw’s ilast yearor you may recognise him as the star of AHDB’s biofumigation video. You can view the video by clicking here

This year Bill is helping to systematically assess PCN tolerance of the most widely grown varieties of potatoes.

Which statistics are best for PCN?
Trial design is not a topic   that would usually make our hearts beat faster in excited anticipation, however the SARIC trial will be set out in a neat way to tackle a problem PCN trials often face.

Nematode numbers vary across a field, sometimes with ‘hot spots’ which sees dramatic changes over a short distance.

The AHDB trial in the same field has four replicates of each treatment, randomly allocated within blocks, each next to each other in a row across the field: 1,2,3,4.

The SARIC trial will use ‘stratified blocks’. Each block will be of plots which are not necessarily next to each other, but which share similarity in numbers of PCN eggs. So the varieties will be tested fairly against each other.

Shocking egg numbers
When Bill counted egg numbers on his plots the results were a nasty shock, both to him and to Heal Farms. They ranged from 28 – 304 eggs per gram. The four blocks are linked to 

PCN density:

0 - 75eggs/g
75 -150 eggs/g
150 - 225 eggs/g
225 eggs/g

It will be a test of tolerance under really tough conditions.

PCN experiment has to fit in with calving
On April 22nd Bill Watts was busy. He had spent the night at home with a cow struggling to calve, came to mark out the trial, then rushed back home to help with calving again.
As you can see, all ended happily

On May 15th when quietly working in the field, sowing trap crop seeds, I looked up in surprise to see a group of  eight young cattle, which had broken into the field. I tried to encourage them away from my working area, which of course was more interesting to them than anywhere else. They followed me steadily for a while, then abruptly turned and rushed right through the trial!

Fortunately It didn’t do much harm.

On a more serious note, the Invasive Species Compendium by CABI reports that PCN cysts can pass unharmed through the guts of animals. Anecdotal evidence from this country suggests that places where cattle have dunged heavily after feeding on PCN infected potatoes become new hot spots of infection

Come and see for yourselves.
 Our first field walk is planned for next week, Tuesday 6 June: Where you will be see the latest from our PCN trials and hear first-hand knowledge from Dr Matt Back, who will be on hand to answer all of your question.

If you’re interested in the this event, you can register by clicking here

Monday, 15 May 2017

Looking forward to another successful season at SPot Scotland with Knowledge Exchange Manager, Claire Hodge:

Planting is now complete on our commercial scale demo plots. We recently reported on successful cultivations demonstrations held at Bruce Farms last season, which showed that reduced cultivation depths resulted in lower costs and a higher yield. The excellent current conditions are perfect for reduced cultivations, we have used them at Bruce Farms and I would hope that this becomes standard practice.

Early signs are that our current work on cover crop use is also producing positive results. The aim when planting cover crops, in this instance, was to improve soil structure, reduce lying water over winter, and therefore make the soil easier to cultivate. While the ground did not get a serious challenge this winter, we could notice a difference between the land that had benefitted form cover crops and the land that had not. It will be interesting to monitor this as the season continues.
Overall things are going well and we are ahead of where we were this time last year. I expect there may be one or two growers who are challenged by dry conditions and looking forward to the forecasted showers over the next few weeks.

It is particularly beneficial to talk to other farmers at our events or when we are out and about. This season we are acting on advice given from local growers and are introducing a triple tiller.  The hope is that it will further reduce costs and increase yields. We will watch with interest and report on what we find.

I am looking forward to catching up with growers the Open Day at Bruce Farms on the 18th July. I am happy to contribute to discussions on the triple tiller, cultivations depths or our other on-going trial areas such as nutrition and seed rates.

We have morning and afternoon sessions available for our Open Day on 18 July, you can register for either session by clicking here 

It would be great to see you all there!

Friday, 5 May 2017

2017 season kicks off at SPot East, Elveden

Read the first blog from SPot East by guest blogger and AHDB Potatoes Knowledge Exchange Manager, Phil Burgess.

Planting has been completed on all trial and demonstration areas, other than one small area, which has been delayed in order to test our herbicide programmes to the limit and provide the best demonstration when it comes to our open day visits.

Dr Mark Stalham and his team have been busy implementing some complex studies on the timing and fate of Nitrogen. The biggest challenge has been trying to find the balance that keeps the trials scientifically robust and keeping the irrigation regimes workable in a commercial setting, but they’re all in place now, so far so good!

We all know it’s been very dry so far this spring. Which should provide a really robust test of the irrigation regimes on the full range of varieties. At least I’m pleased!

Increasing tuber numbers is a subject of much discussion at Elveden, and as the onsite agronomist the onus lays with Graham Tomalin. Graham and his team have been working hard, planning small plot trials aimed at manipulating tuber numbers. But like on most farms, they’re always asked to produce more! So this demonstration aims to show what can be achieved in both salad and processing crops.

Farm manager, Andrew Francis is as you would expect, always in the thick the action. This year he has brought a number of machines on to the farm, which are designed to reduce run-off. An area that we hope to include in the Spot farm activity this season.

So it’s all action at SPot East. See here or here 

We look forward to seeing you at Elveden during the summer. All the events for SPot farm East are listed below, to register simply click on the link.

SPot farm East - Field Walk - 22 June 2017 

SPot farm East - Open Day - Thursday 6 July, 2017 
Morning session
Afternoon session

SPot farm East – Field Walk – 3 August 2017

Thursday, 27 April 2017

Planting at new SPot West, Heal Farms 2017

Read the first blog of the 2017 season by Knowledge Exchange Manager and SPot West lead, Anne Stone:

Heal Farms in Shropshire grow 500ha per year of a range of processing varieties. 
Lodge 1 Field, on the A53 near Shrewsbury is infested with PCN and the Farms Director, Matthew Wallace, chose the crisping variety Arsenal because it is resistant to Globodera pallida, as well as to G.rostochiensis.  

Arsenal has limited tolerance to PCN, so Nemathorin has been applied with the aim of maintaining yields while varietal resistance prevents reproduction of the pest and reduces eggs left in the soil at the end of the season.

Lots of PCN – Jolly good!

A few billion potato cyst nematodes are not normally seen as a desirable soil constituent. To test and demonstrate methods of control such a feature is ideal, especially if they are uniformly distributed, so this field has become a magnet for trials. It gives a chance to compare varieties, for both their resistance and tolerance. The site will also be used to demonstrate other methods of PCN control.

The 60 acre field was prepared and planted in three days with the following stages:
  • ·   ·     Ploughing,
  • ·         Shakerator cultivation
  • ·         Bedtilling/bedforming
  • ·         De-stoning,
  • ·         Planting (with application of fertiliser and Amistar)
            Bedtiller/bedformer at Lodge 1, with Nemathorin applicator

     Planter in Lodge 1. CERC staff helped themselves to 
   some seed to plant bed ends tidily around the trial plots.
   Two of the de-stoners working in Lodge 1 on April 22nd.

A fair spread of machinery was displayed on Saturday 22nd April., Two Shakerators, one bedtiller/bedformers, five de-stoners and two planters all majestically maneuvered in a performance orchestrated by Mr Wallace.

From a distance the staff of CERC (trials arm of Harper Adams University) looked like crazed ants, scattering in all directions. Close up they could be seen running with white flexicanes and long tape measures, making 3:4:5 triangles to work out where the beds would fall, ahead of the advancing machinery. Marking out of potato experiments is usually done after the beds are in place, giving nice parallel lines. 

There was no such luxury in this case, because Nemathorin was being applied with the bedformer. The difference in a variety yield between treated and untreated with nematicide provides a measure of varietal tolerance, so Nemathorin had to be kept off the trial sites, enabling it to be applied precisely on a plot basis within the trials.

The CERC team needed to match the trials to areas in the field known to have suitable PCN counts. They measured where the beds would run, and where tram lines would be in place, meanwhile comparing with maps of PCN test results, in order to mark out before the bed former arrived. 

Pythagoras proved reliable and soon plots were marked and planting underway.

   Gary Weston, CERC mechanic, leaves his 
   machinery to help hand plant PCN control demonstrations

Life and death struggle
Read this blog to follow the fortunes of the crops in Lodge 1. Each variety has its own fight between the ravenous hunger of myriad nematodes and the defence strategies of a well bred potato.