The 2018/19 AHDB Recommended List sees several high yielding varieties introduced, including Elicit and RGT Gravity. For maximum
potential yield to be achieved, crops need to be provided with the correct balance of essential nutrients throughout the growing season.


Importance of a fertiliser plan

An effective nutrient plan should consider current N, P and K levels. However, with considerable variation in nutrient levels between
fields, soil testing is recommended to enable development of bespoke fertiliser plans. The results provide a soil index for that field, calculating the P, K and Mg levels on a mg/kg dry soil basis. Although a good starting point for forming a nutrition plan, there is a large variation in the nutrient levels within each soil index, as seen in table 1.

Soil test results could indicate a soil index of 2, but within this index there is a broad range in nutrient availability, so fields could still end up being deficient or even over supplied. Therefore, it is advised to look at the milligrams per litre in more detail and make necessary adjustments if required. It is important to note that unlike nitrogen, P and K doesn’t readily leach from the soil, so if over supplied for the current crop, reserves will be available and can result in improving the overall soil index if required.

Implementing a fertiliser plan

The amount of P and K applied ahead of autumn drilling should consider the offtake required by the crop, along with the amount
needed to maintain or build the soil to the ideal index level. Table 2 shows the amount of each nutrient which would be needed for
winter wheat and winter barley crops, based on a yield potential of 8 T/ha. If a higher yield than expected has been achieved from
the previous crop, or if a high yielding variety is going to be planted this year, the nutrition would need to be altered accordingly. Crops
with a potential average yield of 8 T/ha could achieve 10 T/ ha if the weather conditions are favourable, but in achieving this, more P and K will be taken up, so soil reserves will need replenishing. Consideration should also be made to whether straw is being
removed or ploughed back in, as this can impact soil health and structure. Ploughing straw back in will reduce the amount of P and
K removed and is good for soil structure. However, the process of breaking down the straw in the soil does use N reserves, which
means less N will be available for the subsequent crop.

For high yielding varieties, requirements would be greater. This can be determined through a calculation that takes into account
the expected grain yield figure, which your local Wynnstay arable specialist can help with calculating and can then be used to provide
advice on the most suitable fertiliser plan to correct any deficiencies.