Soil nutrient management should be a focus on every farm, particularly this year, as chemical input costs are at an all-time high.
To ensure that you are getting maximum forage production from your soils, nutrients such as phosphorus (P); potassium (K); magnesium (Mg); sulphur (S); and soil pH, all need to be at optimum levels.
The key to soil nutrient management is to apply nutrients to enhance the soil’s fertility and support crop growth at locations where it is required, and in the correct amounts.
Soil nutrient management
An indication of soil nutrient status can be obtained by collecting soil samples from fields every 4-5 years and analysing them for the main plant nutrients P; K; Mg; S; and pH.
Regular soil analysis will improve overall nutrient use efficiency, save money on unnecessary fertiliser, reduce the loss of excess nutrients to the environment and eliminate nutrient deficiencies.
Research from Agri-Food and Biosciences Institute (AFBI) has shown that grass yields can be improved by as much as 2t dry matter (DM)/ha if nutrients or soil pH are optimal.
Understanding the nutrient requirements of farms, and how they change over time, can be achieved through regular soil testing and a carefully balanced farm nutrient management plan.
Sulphur
In the past, S was overlooked as an essential nutrient to include in a fertiliser plan, but farmers are beginning to come to the realisation that S is just as important as N to the grass plant.
S and nitrogen (N) go hand-in-hand when it comes to maximising grass production and sward quality during the grazing season.
In addition to N, S is involved in protein synthesis in the grass plant. Both elements are the building blocks of the amino acids which form plant proteins.
If you feel you are not getting as much of a response from your N fertiliser as you should be, this may be a clear sign of S deficiency in the soil.
In addition to this, pale yellow leaves – similar to what is observed when there is a N deficiency – are an indicator to an S deficiency. Although, this is usually more visible in younger plant leaves when associated with S.
The most effective way of assessing the S content of your grass is through a herbage analysis.