Question 1
The diagram below illustrates a bag of compound fertilizer. Study it and answer the questions that follow.
(a) Write the chemical formula of the fertilizer illustrated. (1 mark)
(b) State three conditions that would make a farmer use the illustrated fertilizer. (3 marks)
(c) Name four other inorganic fertilizers that contain the same active ingredient as the illustrated fertilizer. (4 marks)
(d) Mention three tractor-mounted implements that could be used to apply the illustrated fertilizer to the soil, on a large scale. (3 marks)
(e) If the illustrated fertilizer contains 20.6% nitrogen, calculate the amount of nitrogen in the bag. (2 marks)
(f) If maize requires 250 kg of the illustrated fertilizer per hectare of farmland, calculate the quantity of fertilizer required for the cultivation of 25 hectares of farmland. (2 marks)
Observation
This question was poorly attempted by candidates. Many candidates could not write the chemical formula of sulphate of ammonia in Question 1(a) as well as perform the calculations in Question
1(e) and 1(f); thus recording poor marks.
The expected answers include:
1. (a) Chemical formula of the illustrated fertilizer (Sulphate of ammonia)
-(NH4)2SO4
(b) Conditions that would make a farmer use the illustrated fertilizer
- Low soil fertility / Decrease in yield
- When soil pH is high/soil is alkaline
- Leaching of soil nutrients
- Erosion of top soil
- Specific nutrient requirement/replenishment by plants
- Depletion of soil nutrients as a result of continuous cropping
(c) Other inorganic fertilizers that contain the same active ingredient as sulphate of ammonia fertilizer
- Sodium nitrate
- Anhydrous ammonia
- Ammonium nitrate
- Di-ammonium phosphate
- Potassium nitrate
- Urea
- Ammonia liquor
- Calcium ammonium nitrate
(d) Tractor-mounted implements that could be used to apply sulphate of
ammonia to the soil on a large scale
- Fertilizer spreader
- Disc plough
- Combine drill
- Boom sprayer
