Nutrition – Validation and 'Micronomics” - Tim Kerr - Agronomist & Arable Farmer

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- Agronomist & Arable Farmer

One of the biggest challenges facing growers and advisers is how to respond to each season appropriately. Tim Kerr, Hutchinsons fertiliser manager, explains.

tim kerr of hutchinsons (2)

Time and again, we are told that the biggest area of uncertainty in responding to the seasonal conditions is how to get the best from crop nutrition. It was with this in mind that Hutchinsons decided to try to put more certainty where there may be doubt and – particularly with regard to micronutrients – provide agronomic justification for the use of trace elements and, just as importantly, show that the products work.

The validation process
Hutchinsons has introduced a new validation process for all new foliar feeds or biostimulants that we are asked to handle. We are conscious that new products and suppliers require rigorous screening to ensure that they meet exacting standards. The process we have introduced covers many aspects, including the supplier's approach to research and development, the production standards and - most obviously - the efficacy of products agronomically and economically.

Fundamental to the process is our ability to rapidly test products under laboratory conditions - using trials protocols that can quickly and accurately evaluate product efficacy. In short, we can verify whether a product performs within weeks rather than years.

In order to gain the final level of validation each product would then be expected to perform consistently in field trials over a number of seasons. This means our advisers and customers can have confidence in products that are given the green light through the validation process.

The greater challenge we face is to define the need and time to use micronutrients or biostimulants.

We define this as micronomics - providing the agronomic and, importantly, the economic justification for applying trace elements.

For example, we know that there are 16 essential elements and rightly focus on the importance of nitrogen in building yield.

However, nitrogen does not function as a lone nutrient - it works in combination with others and requires micronutrients in order to be efficiently metabolised by plants. Phosphate and sulphur are both macronutrients that are key to nitrogen use efficiency - P helps to provide the energy needed and S is a vital component of protein forming compounds. Plants also need magnesium (Mg), boron, manganese and molybdenum to effectively synthesise nitrogen.

Understanding this, we can build a picture of when these micronutrients could become limiting factors to nitrogen utilisation. We also know that pH can limit the availability of boron, manganese and molybdenum. Therefore, knowing the soil pH is essential. Soil tests are a reliable indicator for magnesium and boron - less so for manganese and molybdenum. Simply as a consequence of a basic soil test, we can quickly get an idea of the risk of certain deficiencies.

In order to build on these foundations, we would recommend tissue testing in early spring to identify any potential shortfalls in nutrition - often that the naked eye would not see. Remember, it is not possible to see nitrogen use efficiency: under-utilised N is neither visible or easily measurable.

Trace element shortages are quantifiable and importantly – if measured pre-emptively – manageable.

It is important to learn from each different season and adapt our knowledge accordingly.

Last year, most areas suffered from drought conditions. We know that certain nutrients are less mobile than others - and some rely solely on active transpiration for the plant to acquire them.

Magnesium was a prime example last year - where it was obvious that the dry conditions were reducing the amount of Mg reaching the plant - with visible deficiencies seen in many crops. As a consequence, we are researching the benefits of early applications of magnesium and the quickest way of getting Mg through the leaf.

Breaking yield plateaus will be less about applying more nitrogen and more about the finer details - getting the correct balance of micronutrients, so the N that is applied will be used more efficiently.