The importance of getting your cattle slurry analysed has been highlighted to farmers as the results can show a large variation in the value of nutrients, according to the College of Agriculture, Food and Rural Enterprise (CAFRE).
Knowing the nutrient value of the slurry can, according to CAFRE, allow farmers to plan the type and the rate of chemical fertiliser to apply which turn can deliver financial and environmental benefits on farm.
According to CAFRE dairying development adviser, Elizabeth Calvin, many factors will influence the variety of nutrients within slurry.
“The variation is due to the type of livestock it comes from, the diet fed to those animals and the way in which it is handled and stored,” she added.
Nutrients in slurry
Calvin said when the largest volume of slurry is available there is “likely to more divergence from quoted nutrient content in slurry”.
She added: “Having got your analysis report, it is important to understand and use it to ensure efficient use of this valuable product.
“Take regard of any soil analysis to target slurry to low K (potassium) and P (phosphorus) fields, consider the crop requirements, weather conditions and method of application, alongside the nutrient content of slurry to determine application rates.”
An organic analysis of cattle slurry will show the dry matter, pH, total nitrogen (N), ammonium N and nitrate N, P, K, Mg, Cu, Zn, S, and Ca, contained in the sample.
Calvin added: “An analysis can be carried out at any time of year, just prior to spreading but is particularly useful in early spring, ahead of the main slurry spreading period for first cuts.
According to CAFRE, a more diluted slurry has a lower N content which must be considered when adjusting application rates.
Diluting the slurry will thereby improve the N uptake as the slurry will enter the soil faster when compared to thick slurry.
Using a more diluted slurry will also reduce grass contamination as it is more easily washed off the grass by rain, ensuring grass is palatable to cattle and sheep when applying slurry between grazing.