|Better Farming Series 06 - The Soil: How to Improve the Soil (FAO - INADES, 1976, 29 p.)|
|Plan of work|
You may have seen labels like this on sacks of fertilizer. The first Figure shows
COMPOUND the quantity of nitrogen (N)
FERTILIZER in 100 kilogrammes
13- 10- 15 of thisfertilizer.
In this case 13 kg.
The second Figure shows the quantity of phosphorus (P) in 100 kilogrammes of this fertilizer. In this case 10 kg.
The third Figure shows the quantity of potassium (K ) in 100 kilogrammes of this fertilizer. In this case 15 kg.
We say this fertilizer has a 13- 10- 15 content.
To find the amount of nitrogen, phosphorus and potassium contained in a sack of fertilizer, we must multiply the fertilizer content by the weight of the sack and divide the result by 100, thus: content X weight of sack 100
In a 50 kg sack of 13- 10- 15 fertilizer there is: nitrogen 3 X 50 = 6.5 kg
10 X 50/100 = 5.0 kg
15 X 50/100 = 7.5 kg