Lab Report: Investigations on Plant Growth and Soil pH Effects
Introduction
This lab report summarizes two investigations conducted to examine factors influencing plant growth: the effect of light exposure on plant height and the effect of soil pH on plant health. The goal of these investigations was to understand better how environmental conditions affect plant growth and development.
Investigation 1: Effect of Light Exposure on Plant Growth
Objective
To determine how varying amounts of light exposure affect the growth of bean plants.
Materials
- 30 bean seeds
- Peat pots
- Potting soil
- Measuring tape
- Grow lights
- Timer
- Watering can
- Ruler
- Data recording sheets
Method
- Setup: Thirty bean seeds were planted in peat pots filled with potting soil.
- Grouping: The pots were divided into three groups of ten, each receiving different light conditions: full light (16 hours/day), partial light (8 hours/day), and no light (dark).
- Watering Schedule: All pots were watered equally every two days to maintain consistent moisture levels.
- Data Collection: Over four weeks, plant height was measured weekly using a ruler, and data was recorded for each group.
Data
| Week | Full Light (cm) | Partial Light (cm) | No Light (cm) | |------|------------------|---------------------|----------------| | 1 | 3 | 2 | 0 | | 2 | 6 | 4 | 0 | | 3 | 10 | 6 | 0 | | 4 | 14 | 8 | 0 |
Conclusion
The data indicate that light exposure significantly affects plant growth. The plants in full light grew the tallest, while those in total darkness did not grow at all. This suggests that light is a crucial component for photosynthesis and overall plant health.
Investigation 2: Effect of Soil pH on Plant Health
Objective
To assess how different soil pH levels affect the growth and health of tomato plants.
Materials
- 30 tomato seeds
- Peat pots
- Potting soil
- pH testing kit
- pH adjustment products (lime and sulfur)
- Measuring tape
- Watering can
- Data recording sheets
Method
- Soil Preparation: Three peat pots were prepared for each of the following pH levels: acidic (pH 5), neutral (pH 7), and alkaline (pH 9). Soil pH was adjusted using lime (to increase pH) or sulfur (to decrease pH).
- Planting: One tomato seed was planted in each pot, resulting in 30 pots with 10 seeds for each pH level.
- Growth Conditions: All pots were placed in the same location with equal sunlight exposure and were watered consistently.
- Data Collection: Over six weeks, plant health was assessed based on height, leaf color, and general vigor.
Data
| pH Level | Average Height (cm) | Leaf Color (Scale 1-5) | General Health (1-5) | |----------|----------------------|-------------------------|-----------------------| | 5 | 8 | 3 | 3 | | 7 | 14 | 5 | 5 | | 9 | 6 | 2 | 2 |
Conclusion
The results show that tomato plants thrive best in neutral pH conditions. Plants in acidic and alkaline soils exhibited stunted growth and poor health. This indicates that soil pH significantly influences nutrient availability and plant health.
Overall Conclusions
Both investigations demonstrate the importance of environmental conditions in plant growth. Sufficient light is critical for growth, while the pH level of the soil can affect nutrient absorption and overall plant health. Future investigations could explore additional variables such as water quality and temperature to further comprehend factors affecting plant growth.
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