The annual Association of Independent Crop Consultants conference drew around 300 independent agronomists and manufacturer representatives to Whittlebury Hall in Northamptonshire last week.
The presentations included Professor Andy Whitmore of Rothamsted Research’s correlation between increasing levels of organic matter in the soil and crop yield.
Penetrometer readings show that most agricultural soils are compacted, he observed. Adding organic matter reduces the bulk density, with the benefit that better structured soils are less expensive to manage. Less phosphorus in needed when organic matter levels are higher, probably because roots are freer to move towards the nutrient in the soil. The lighter, fluffier soils are also easier to work, with a 15% fuel saving measured when ploughing.
While this is not a quick fix – yield increases are measured two years after adding organic matter – it appears that it encourages earthworm activity which in turn helps drainage, root movement and encourages beneficial soil micro-organisms.
Rothamsted is working on a tool to identify the breakeven point of adding organic matter to different soil types, Prof Whitmore advised, a similar tool to the Nitrogen break even tables in the RB209 Fertiliser Manual.
Nuffield scholar Kate Speke-Jones said that many UK farmers were “too input and machinery-focussed”, with the danger that they were losing touch with the soil. She added that this was made worse by the fact that most R&D effort goes into arable inputs, with insufficient attention paid to soil health in agricultural education.
Her travels had shown other regions were starting to pay more attention to the soil – in Australia there is an initiative to link the value of agricultural land to organic matter levels, while in Kenya there is a programme to link soil health to farm credit availability. She also identified a growing movement for consumers to link soil health and nutritive value attributes to their food-buying choices in many countries.
Professor Adrian Newton of the James Hutton Institute addressed the subject of elicitors – products derived from yeast cell walls that have been shown to keep crop leaves greener for longer in cereals and tomato plants.
It is believed the material “fools” the plant into thinking it is being attacked, so priming natural defence mechanisms and preparing a faster response to an actual pathogen infection.
The effect is not guaranteed, and research work to understand the effect of environmental factors such as weather, pH and mineral status is ongoing. It seems elicitors are effective against some bacterial and fungal diseases in keeping the leaf green, but there appears to be no advantage on seed germination and early growth.
Derek Cornes, global integrated weed technology lead for Syngenta, updated delegates on research into alternatives to herbicides at the Jealott’s Hill R&D centre. The cost of getting a new molecule to market, especially in the face of Europe’s difficult regulatory system, meant a more holistic approach to weed control would be needed in future, he argued.
There are promising new technologies, such as global positioning, drones, genetic advances such as gene editing, sensor technologies, big data analytics and robotics allied with imaging technology. Combinations of these would allow more precise and automated mechanical weed control, or the targeted application of herbicides to substantially reduce the volumes of active applied to reduce cost and better protect the environment. He even discussed the use of lasers in weed control.
NIAB weed expert John Cussans explored the role of synergists in making existing actives more active in the weed plant, along with nanotechnologies to enable lower doses of product with the same efficacy. However, he warned that such new technologies might be restricted by regulatory concerns. He is also investigating machinery to physically destroy weed seeds as crops are harvested – an expensive option, but possibly a last resort in situations with high populations of weeds with resistance to available herbicides.
Turning to pest control, crop protection consultant Alan Dewar blamed growing pesticide resistance in the Cabbage Stem Flea Beetle (CSFB) in oilseed rape to overuse of sprays, a position made worse by the withdrawal of neonicotinoid seed treatments.
Too many farmers and agronomists had failed to assess threshold levels of the pest, he advised, and used sprays that were not needed, contributing to pesticide resistance. He has seen very high larvae counts this autumn, and predicted adult CSFB populations would be “off the scale” for harvest 2016.
Control measures included early rapeseed drilling; higher seed rates; better control of volunteer plants and planting trap crops around the main oilseed crop. Growers could also use oilseed rape less frequently in rotations, keep blocks of the crop separate and possibly graze overwintered crops with sheep to remove leaves with developing larvae.
Mr Dewar suggested the situation could become bad enough to limit oilseed growing to the north and west regions of the UK where CSFB is less of a problem.
• The AICC’s training academy (AICCA), launched in mid-2014, has seen the eight inaugural members complete their first training modules. The trainees are working with established groups of independent agronomists around the country.
“As 78% of AICC members are now part of a group, they are better placed to take on a trainee, with the trainee benefitting from the experience of established agronomists with different areas of expertise,” says AICC chief executive Sarah Cowlrick. “Also, by adopting this approach, each trainee is appointed their own mentor.” The industry partner training modules have included input from ADAS and NIAB TAG on soil fertility, cultivations and managing rotations.