How To Work Out How Much Nitrogen, Phosphorus and Potassium Has Been Applied Per Hectare In Your Fertiliser Application

So you’ve spent the morning applying granular fertiliser to your tees. How do we work out how much of each ingredient has been applied?

The reasons for keeping track of how much Nitrogen has been applied to a specific area has great benefits. If you asked 10 Course Managers how much Nitrogen should be applied per hectare per year, you’ll get 10 different answers. The catch? They’re all right!

As a greenkeeper at any level on a golf course, or a groundsman at a soccer pitch, it’s important to know the climate, and microclimate that you’re working with and work with what you’ve got, and not against it. What matters isn’t how much your next-door neighbour is applying, but if what you’re applying is doing what you want it to. A soil test and an agronomist’s report are the best way to determine exactly what your turf requires.

So, you want to apply fertiliser to your tees at 35g/m2. You know your area is 8000m2  so;

•   8000m2 x 0.035kg = 280kg of fertiliser required.

To work out exactly what rate you have applied you will need to know exactly how much product you have applied. Let’s say you only used 264kg;

•   264kg ÷ 8000m2 = 0.033kg/m2 or 33g/m2

With 264kg or 33g/m2 of fertiliser applied we can work out how much of each fertiliser constituent we have applied. Let’s say we applied a ratio of 15-5-12. We know from this that 15% is Nitrogen, 5% is Phosphorus and 12% is Potassium. This is true if you have one prill, or one tonne of the fertiliser, it’s still 15%-5%-12%.

As above, we applied 264kg/ha over the tees, so to find out the Nitrogen input we need to find 15% of this;

• 264kg ÷ 100% x 15% = 39.6kg Nitrogen over 8000m2

• 39.6kg ÷ 8000m2 x 10,000m2 = 49.5kg Nitrogen over 10,000m2 or 1ha