Solutions spotlighted by experts – British Potato Review
Agronomists, scientists and soil specialists share practical knowledge gleaned from trials at demonstration day hosted by Hutchinsons ...
Agronomists’ trials of potential solutions for current grower concerns were the focus of a recent demonstration day held at Worth Farms, Holbeach.
Ongoing research on wireworm, PCN management, crop safety of post emergence herbicides, nutrition trials, plus updates about root lesion nematodes were some of the topics covered at the Hutchinsons Potato Demonstration Day.
Heavy rainfall the previous day meant it was not possible to see the demonstration plots in the field so the talks took place in one of the farm’s yards.
Hutchinsons Root Crop Technical Manager Darryl Shailes highlighted some of the field trials being done by the company to assess the impact of different strategies on wireworm populations in a crop of Maris Piper.
“At the moment we are focused on the theoretical effects of these products,” said Darryl. The Hutchinsons team is also exploring wireworm populations when different cover crops are grown, separating out two different types of buckwheat, a high glucosinolate mustard and a lower glucosinolate standard caliente mustard, and a multi-variety cover crop for soil health.
To help growers understand how to reduce PCN levels, further trials are exploring the potential benefits from growing DeCyst- Prickly (Solanum sisymbriifolium) and DeCyst Broadleaf (Solanum scabrum) as cover crops.
Darryl said: “We will be comparing the final populations with those initially present (pf/ pi). These beneficial cover crops can be grown anywhere in the rotation, and are effective with PCN, reducing populations of both G. rostochiensis and G. pallida and if you get a good crop of you can achieve up to 80% reduction. “They also contribute up to 12t/ha of green manure, and may be suitable for integrating into your SFI.”
PCN tolerance and resistance trials
Simon Faulkner of SDF Agriculture said growers need to understand how to best protect and manage their land against pests such as potato cyst nematodes and stressed the importance of knowing which varieties can offer resistance and/or tolerance.
He updated delegates on the PCN varietal resistance trials assessing a mix of older and newer varieties.
“We are seeing some crisping, packing and chipping varieties that are showing both tolerance and resistance traits, which will be very important traits going forward,” he said.
All the varieties in the trial will be taken to harvest and put into store, and outcomes announced at the Hutchinsons/SDF Agriculture Results Day.
The effects of cover crops on root lesion nematode
Knowing the impact your cover crop species could have on plant parasitic nematodes is crucial to their management, according to PhD student Vongai Chekanai of Harper Adams. For example, her research has identified that French marigold (Tagetes patula) and oilseed radish cover crops can be effective at reducing soil populations of root lesion nematode (RLN) Pratylenchus spp, she revealed.
Potatoes, onions, carrots, daffodils and other narcissi are all susceptible to Pratylenchus, which is associated with potato early dying disease.
Trials undertaken on narcissi fields across different parts of the UK suggested that oilseed radish might be a poor host or a partial biofumigant. Unlike biofumigants for PCN, oilseed radish reduces Pratylenchus spp before incorporation, said Vongai.
“Our trials found, however, that Indian Mustard, which is popular as a biofumigant to suppress potato cyst nematodes (PCN), increased Pratylenchus spp. What reduces one soil pest can increase another, so knowing what you are dealing with on your own land is key to cover crop decisions.”
Crop safety herbicides
Michael Rodger of Richard Austin Agriculture updated delegates on the herbicide crop safety trials being held on 26 varieties, including some new, coded varieties provided by the breeders.
While last year’s trials were focused on metribuzin, hotter herbicide mixes have been used this year, including Basagran mixes and rimsulfuron. “Sometimes when you apply a post-emergence herbicide to a commercial crop, you do not really see a difference, but when you compare treated and untreated plots, you can really see the yellowing,” said Michael.
*Some of the treatments last year, when applied at ideal timings did not show any crop effects. However, this year, crops are water- stressed, and five days after treatment, we have observed that some of the varieties have been much more affected than last year, while others look good,” he said.
This implies that crop damage can be seasonal, as the condition of the crop and timing of application are crucial. Further observations will be made weekly for the next four weeks, to assess whether any stunting occurs.
“We will be taking these plots through to yield, and then look at tuber quality and internal characteristics.”
Foliar nutrition tailored according to plant needs
In the future, nutrition products such as foliar biofertilisers, are likely to be tailored according to how the crops are developing in the particular year, said Rob Jewers, Crop Nutrition Specialist at Hutchinsons.
This year, biological nutrition products Utrisha N, Vixeran and R-leaf are being evaluated by the Hutchinsons team. Trials are assessing their efficacy, the effects of different water volumes, and any interactions with other products if they are tank mixed.
Rob said: “Given the rise in input prices, environmental concerns and the need to improve soil health, tailored bionutrition programmes are an important way forward.”
Agroecology the way forward for soil health
Hutchinsons Head of Agroecology Ed Brown emphasised that agroecological strategies can deliver benefits for potato crops when done appropriately, and he encouraged growers to explore the principles and keep an open mind.
Minimising soil disturbance, keeping soil covered, maintaining living roots throughout the year, maximising diversity, and where possible, integrating livestock into the rotation, can make a real contribution to healthy soils, and healthy crops, he said.
“These principles can also be applied to vegetable and potato crops grown in intensive rotations, but the terminology is ‘minimise’ or ‘maximise’ but does not mean eliminate. Implement these practices in your context on your own farm, as best as you can, and you will deliver clear benefits.”
Disturbance also applies to inputs. Over applications have a negative impact on soils, impacting on the bottom line.
Other work is exploring companion cropping potatoes with legumes such as peas and beans.
“First indications are that this will work well, and we can even continue to use herbicides with these crops as many of the potato herbicides are safe to use with legumes,” said Ed.
“This brings diversity into the crop. It attracts beneficials such as pollinators, and reduces disease pressure by avoiding a potato monocrop.
“Cover crops will help you tick a lot of these boxes, and the positives far outweigh the very few negatives, but nevertheless, it is one small element in the context of a larger system of the soil food web.
“There may be some situations where we think there is an association with some pests, but, for example, if you think that slugs may become an issue, you can manage that with appropriate choices of the species in your cover crops.”
Trials exploring the use of French Marigolds around the headlands for slug control are underway, he revealed.
“Having a diverse mix is also important.”
Ed drew attention to possible reasons for why nematodes may be proliferating, such as too short rotations and lack of predators for those nematodes in the soil food web.
“We need to ensure that the soil food web is balanced, so individual species never get a chance to take hold,” he said.
Head of Soil Services for Hutchinsons, Ian Robertson, emphasised that nutrient soil indexes do not imply functionality or availability to the plant.
He explained some of the interactions of the Soil Food Web, which go from photosynthesisers, at the start, through decomposers, pathogens and root feeders, and predators at different levels and all cycling nutrients.
“Connectivity between the different levels of organisms is key, and as soon as you move soil you lose this, which allows some pests to proliferate above others,” he said.
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