The nutrient content of solid manures and slurries can vary considerably from the typical values presented in Defra's Fertiliser Manual (RB209), published in 2010. Given this variability and the increasing cost of manufactured fertiliser it is worthwhile analysing nutrient content of solid manures and slurries.
Over the past three years AHDB's Cereals & Oilseeds, Dairy, Potatoes, Beef & Lamb and Pork divisions have collaborated to co-fund a Defra LINK project to test the use of Near Infra-red Reflectance Spectrometry (NIRS) to analyse the nutrient content of manure (slurries and biosolids).
The project was very successful and has shown that NIRS can provide rapid and reliable analysis of:
- dry matter*
- total-N (Figure 1)
- readily available N (can be taken up immediately by the crop)
- phosphate (P2O5)
- potash (K2O)
- sulphur (as SO3)
- magnesium (as MgO)
*Dry matter content of slurry samples must be greater than 2%.