The most important nutrient on any farm is the one that is the lowest, as it restricts the rest.
N is involved in the process of photosynthesis and is responsible for protein production. It therefore has an integral role in plant growth and directly impacts the number of grains that are set on the individual ears in a cereal plant. N efficiency is improved by adequate levels of sulphur.
The importance of sulphur should also not be overlooked, particularly in western areas, where an average of 96% of tested farms were deficient in 2017.
As it plays a key role in the structure of proteins and functioning of enzymes, Sulphur is also involved in the defence of plants against stresses and pests, so often those crops which are deficient are more susceptible to disease risk.
Sulphur-based products also aid the uptake of N, which reduces the risk of leaching, which is again important for a spring crop with a short growing window.
P is involved in energy transfer within the plant, especially during periods of rapid growth. In the early stages of plant growth, it promotes root development, therefore if its availability is limited, it can affect the efficiency of uptake of all nutrients.
For this reason, I always recommend soil testing as soon as possible after harvest, to ensure that there are sufficient levels of P in the soil to satisfy the early demand of the crop after planting. If levels are deficient, they need to be topped up before the root development stage.
K is key to the transportation system within the plant. It's fundamental to many metabolic processes, through the activation of a large number of enzymes required for chemical reactions.
It controls cell sap content, which is crucial to maintain a turgid crop and has an essential role in the distribution of sugars and proteins made by the green tissue, for plant growth and grain fill.
Alongside N, K increases yield through influencing the boldness of grains, which significantly affects the profit margin.
Every field and farm is different, so for maximum impact from fertiliser applications, speak to your local Wynnstay specialist who can create a bespoke fertiliser plan.