📘 Combined Science Project
Title: The Effect of Different Fertilizers on Plant Growth at
First Choice Private School Garden
Stage1: Problem Identification
Problem Description
*At First Choice Private School, there is a vegetable garden that is
often used for teaching and food supply. However, the vegetable
yield has been low. There is debate about whether to use
chemical fertilizers or compost manure. There is a need to
scientifically determine which fertilizer supports the best plant
growth under the school’s environmental conditions.
Statement of Intent
*This project intend to investigate the effect of different types of
fertilizers (compost manure vs chemical fertilizer vs no fertilizer)
on the growth rate and yield of leafy vegetables such as spinach.
Design Specifications
*This project aims to:
Use equal-size plots
Same type and amount of seeds
Same watering and sunlight exposure
Weekly measurement of plant height, leaf number, and
growth rate
Experiment duration: 4 weeks
Stage 2: Investigation of Related Ideas
✅ Existing Idea 1: Use of Chemical Fertilizers (e.g.,
Ammonium Nitrate)
Advantages
1. Rapid nutrient supply.
2. Increases yield quickly.
3. Easy to apply and measure.
4. Promotes lush green growth.
5. Widely available.
Disadvantages
1. Can cause soil acidity.
2. May kill beneficial soil organisms.
3. Expensive in the long term.
4. Risk of water pollution.
5. Overuse can damage crops.
✅ Existing Idea 2: Use of Compost/Organic Manure
Advantages
1. Improves soil structure.
2. Adds organic matter.
3. Low-cost or free.
4. Encourages beneficial microorganisms.
5. Long-term soil fertility.
Disadvantages
1. Slower nutrient release.
2. Needs large amounts.
3. Can carry weed seeds.
4. Bad smell if poorly decomposed.
5. Requires time to prepare.
✅ Existing Idea 3: No Fertilizer (Control Group)
Advantages
1. Cheapest method.
2. No chemical exposure.
3. Easy to maintain.
4. Natural plant resistance develops.
5. No water pollution risk.
Disadvantages
1. Lowest yield.
2. Plants grow slowly.
3. Weak plants more prone to disease.
4. May not meet food production needs.
5. Cannot support nutrient-depleted soils.
Stage 3: Generation of New Ideas
✅ New Idea 1: Mixed Use of Chemical and Organic
Fertilizers
Mathematics: Ratios and proportions to mix fertilizers.
Advantages
1. Balanced nutrients.
2. Improved yield and soil quality.
3. Cost-effective.
4. Better water retention.
5. Reduces chemical use.
Disadvantages
6. Requires knowledge to mix.
7. May react negatively in soil.
8. Storage complexity.
9. Risk of overdose.
10. Application time-consuming.
Idea 2: Liquid Fertilizer from Composted Kitchen Waste
Advantages
1. Eco-friendly.
2. Cheap and accessible.
3. Fast absorption.
4. Reduces food waste.
5. Encourages recycling.
Disadvantages
6. Requires storage containers.
7. Smell can be bad.
8. Difficult to know exact nutrient levels.
9. Needs regular application.
10. May attract pests.
Idea 3: Use of Biofertilizers (Nitrogen-fixing bacteria)
.
Advantages
1. Eco-friendly and sustainable.
2. Improves nitrogen supply.
3. Boosts long-term yield.
4. Improves soil health.
5. Reduces chemical dependency.
Disadvantages
6. Rarely available locally.
7. Needs scientific knowledge to apply.
8. Sensitive to climate.
9. Costly startup.
10. Works better with specific crops.
Stage 4: Development of New Idea
Selected Solution: Mixing Compost Manure and Chemical
Fertilizer
Reasons for Selection:
Simple and safe for school environment
Easy access to manure and chemicals
Demonstrates clear contrast between natural and artificial
methods
🛠️Refinements to Idea:
Use equal volumes of fertilizers
Measure weekly using a ruler and record in a data table
Use same crop (spinach) and plot size
🌱 Benefits:
Improved yield in school garden
Teaches students about soil health
Encourages scientific thinking
⚠️Disadvantages:
Weather may affect results
Limited time frame
Requires consistent watering and care
Step-by-Step Implementation Plan
1. Planning: Select garden space, prepare three equal-size
plots.
2. Gathering Resources: Obtain seeds, manure, fertilizer,
ruler, notebooks.
3. Planting: Plant same number of seeds in each plot.
4. Treatment:
o Plot A: Compost manure
o Plot B: Chemical fertilizer
o Plot C: No fertilizer
5. Data Collection:
o Water all plots equally
o Measure plant height and number of leaves weekly
o Record data for 4 weeks
6. Evaluation:
o Compare growth rate, number of leaves, and plant
health
7. Reporting:
o Plot graphs, draw tables, write conclusion
Stage 5: Presentation of Results
*Here are findings and statistical data of results after
implementing the project:
Stage 6: Evaluation and Recommendations
📊 Evaluation of Project Outcome:
Compost manure promoted healthy, stable growth. Chemical
fertilizer gave faster early growth but needed more watering. The
control group had the lowest growth.
✅ Successes
Data was easy to measure
Students worked well in teams
Plants visibly showed differences
⚠️Challenges
Rain affected one plot
Difficulty in getting equal manure amounts
Time was too short for full harvest
➕Mathematical Observations
Used averages and growth rate = (Final height - Initial
height) ÷ Time
Graphs helped compare progress visually
Calculated % increase in height
💡 Recommendations
Extend study to 8 weeks
Test more types of fertilizer
Include fruit-bearing vegetables for comparison
Repeat the experiment in dry season
