A fertilizer contains 20% nitrogen by mass. To provide a fruit tree with an equivalent of 1 kg of nitrogen, the quantity of fertilizer required is

To determine the quantity of fertilizer required, one must use the percentage of the specific nutrient present in the material. In this case, the fertilizer contains 20% nitrogen (N) by mass. This means that every 100 units of fertilizer provide 20 units of nitrogen. To provide 1 kg of nitrogen, the calculation involves dividing the required amount of nitrogen by the percentage concentration: 1 kg / 0.20 = 5 kg. This principle of calculating fertilizer rates based on nutrient analysis is standard practice in agriculture to ensure crops receive the prescribed quantity of nutrients for optimal productivity. Therefore, 5 kg of a 20% nitrogen fertilizer is necessary to supply exactly 1 kg of actual nitrogen to the fruit tree.

Sources

1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 9: Agriculture > 2. Availability of Chemical Fertilisers > p. 47