This summer we’ve heard several reports of fertiliser prills being visible in silage aftermaths.

When very dry at application fertiliser is going to struggle to have any benefit to grass growth.  However, even in a good growing year the same is true, the crop will respond to the nutrient it needs but applying more than this is just wasteful.  This applies regardless whether you’ve purchased fertiliser directly (i.e. in bags from a fertiliser company) or indirectly (in every load of feed and bedding that comes onto the farm).

Nutrient budgeting is a practical exercise allowing you to identify the quantity of nutrient required in any given field, and then identify the most appropriate and cost-effective way to deliver this.  Normally the first choice is to provide home-produced nutrient, i.e. dungs or slurries.  An up to date soil analysis will identify where P and K levels in soil are low or very low (and where an economic plant response could be achieved by applying extra) or are already high (in which case you can save money by applying less).

Preparing a nutrient budget for the whole farm will identify exactly how much purchased fertiliser is required, what type of fertiliser/blend would be most appropriate, and when you’ll need it.

Slurries and dungs have the potential to replace a significant quantity of purchased fertiliser, however to rely on this form of nutrients you need to have an analysis.

Remember when doing any nutrient budgeting that where available you should always use the Scottish data, i.e. SAC technical notes or PLANET Scotland as these contain application rates most relevant to the Scottish growing environment and are research-backed.

Chloe McCulloch, SAC Consulting

This article from Farming for a Better Climate was funded by the Scottish Government as part of its as part of Scotland’s Farm Advisory Service www.fas.scot