- Broadcasting – random scattering of the fertilizers on the ground.
- Placement method– application of fertilizers in the planting holes.
- Side dressing – fertilizer is placed at the side of the plant within the root zone, in bands or spot-rings.
- Foliar spraying – specially formulated fertilizer solution applied on the foliage in spray form.
- Drip method – applied through irrigation water.
- Determination of Fertilizer Rates
Contents of fertilizers are expressed as fertilizer grade or fertilizer analysis.
- Fertilizer grade indicate the guaranteed minimum of the active ingredients (N, P205, K 20) in the mixture.
- It is expressed as a percentage on a weight to weight basis or percentage by weigh
Example 10:20:o means for every 10kg of the mixture there are 10kg of nitrogen, 20kg of P10 5 and 1okg of K20.
Example
A farmer was asked to apply fertilizers as follows:
- 60 kg/ha nitrogen (top dressing)
- 60 kg/ha P205 (in planting hole).
- 60 kg/ha K20. How much sulphate of ammonia (20%) would be required per hectare? How much double super-phosphate (40%) P2O5would be required per hectare? How much muriate of potash (50% K20) would be required per hectare?
Answer/Solution
Sulphate of ammonia (SA) which gives 60kg/ha N
60/20 x 100 = 300 kg SA
Double super phosphate (40% P2O5)which gives 60kg/ha P205
60/12 x 100 = 150 kg DSP
Muriate of potash (60% K20) which gives 60kg/hK2O
=60/60 x 100 = 100 kg muriate of potash
Example
A farmer was asked to apply fertilizers as follows:
200kg/ha of DSP (40% P205
150kg/ha of muriate of potash (60% K20)
150kg/ha of sulphate of ammonia (20% N)
How much P205 did the farmer apply per acre?
How much K20 did the farmer apply per hectare?
How much N did the farmer apply per hectare?
Solution/Answer
P205 applied per hectare from 200kg of DSP 40/100 x 200 = 80 kg/ha P205
K205 applied per hectare from 150 kg of muriate of potash = 60/100 x 150 = 90 kg/ha K20
N applied per hectare from 150 kg/ha sulphate of ammonia 20/100 x 150: 30 kg/ha N