Fertilizer equation??? Help!

How much Ammonium Sulphate (21-0-0) is required to apply 3 pounds of Nitrogen to 2000 square metres?

 

Hi,

The 21 stand for 21% nitrogen....so 21% of the bag is nitrogen. So to get 3 pounds of nitrogen you need to use 3 x 100 / 21 = 14.28 pounds of fertilizer.

Boa Sorte
Brian

 

Gracias from one beautiful country to another!

 

Where does the calculation for the 2000 square metres come in?

 

Hi,

yes, this looked starnge to me because you are mixing imperial units (pounds) and metric units (square metres). I'm not sure if this will help.... but:

1 square metre = 1.196 square yards.

Therefore 2000 square metres = 1.196 x 2000 square yards = 2392 square yards which is near enough 49 yards x 49 yards. i am wondering if 2000 square metres is really just an approximation for "half an acre" which is 2420 square yards.

So you could say use 14 pounds of fertilizer per half acre (to provide 3 pounds of nitrogen) and you'd be about right.

I don't know how big an area you want to fertilize, but assuming it is smaller it might be easier to think in ounces per 10 square yards. the calculation is:

14.28 x 16 / 239.2 = 1.14 onces of fertilizer per 10 square yards

...it sounds very little to me.

I hope this has not confused matters for you !!
Sorry I will not be able to reply again soon as I am off to Spain early tomorrow morning hunting for mushrooms and chestnuts. Won't be back for a few days. I am sure that others here will be able to help.

Good luck
Ciao
Brian

 

(10-2-5)
So the 10 is nitrogen the 2 is ?? and the five is ??

 

First Number is "N" = nitrogen (For the leaves)
Second Number is "P" = Phosphorus (For the Roots)
Third Number is "K" = Potassium (For the stem etc.)

These three numbers/letters are on all fertilizer bags

 

Thanks.