Part article taken from Crop Production Magazine, February 2018, written by Rob Jones.
Deficiency symptoms are often the triggers for foliar applications to redress the balance of some of the key elements necessary for plant growth, but this approach could be too late to salvage lost yield potential, believes Chris Martin, agronomist and technical manager for Agrovista (North and Scotland).
The 'hidden hunger' which precedes and underlies any symptomatic evidence of deficiency, is not always identified and, without regular analysis and monitoring, can often go untreated. Chris is adamant that for many of his growers on more fertile and high organic matter soils, photosynthetic ability can be dramatically reduced where unseen manganese deficiency affects the crops ability to establish and compete during the autumn and over winter.
Where our leaf tissue analysis suggests deficiency levels of manganese, a manganese product should be applied prophylactically," he advises. ""Once the symptoms have become apparent, it's often too late and the damage is done. Drip feeding small amounts of product into the crop between GS21-30 can be hugely beneficial and allows the plant to maintain vitality during the rapid growth phases.""
High organic matter
Chris explains the high organic matter soils, found on many of his farms, can naturally lock-up several different elements, especially manganese. So rather than being prescriptive, treatments are planned to ensure growth continuity and stability, with up to three applications throughout the autumn.
""As far as manganese is concerned, we generally use an FMC 15% liquid sulphate formulation for routine and frequent applications, which will suffice as a maintenance dressing and keep deficiency symptoms at bay. This is the backbone of the programme and is applied routinely with autumn herbicides and insecticides, right up to TO.""
For more severe deficiency, he recommends a higher concentration of manganese - between 300-500g/l and sometimes as a nitrate formulation for rapid uptake and activity.
""This holistic approach to crop nutrient agronomy works well for us," he continues. ""We've found regular soil and leaf tissue analyses and a prophylactic approach to treatment can make the difference between an average yield and a good one. In extreme cases areas of total crop loss, both in winter cereals and oilseed rape, may occur where deficiency is severe.""
Another potential nutrient deficiency Chris highlights is magnesium. Often overlooked where soil indices are relatively high (Mg 5-6), it doesn't necessarily mean the magnesium is available in a form the crop can readily utilise.
""We've found the regular use of a compound product, such as FMC's Multiple Pro at 1.0 I/ha, delivers the required manganese at 300g/l, but also contains magnesium at 75g/l. This ensures a ready supply of both elements to keep plants levels where they need to be, with the added bonus of 1 00g/I copper and 60g/l zinc," he says.
""This really gives us a highly efficient and cost-effective treatment that will not only ensure a healthy plant over the winter, but a stable and competitive growth platform going forward in the spring. Our growers have seen the benefits of this approach, noticing improved plant health and increased yield.""