If biochar is added to the soil, then the soil will retain water for longer periods of time, and the plants will grow faster and more efficiently than the plants without biochar. This will happen because the biochar's porous carbon structure absorbs and stores water. Then it slowly releases water to the plant, providing it with the nutrients and water it needs to grow.

Background research What is Biochar Biochar is a carbon-rich material produced by heating natural materials, such as wood and plant waste, in a low-oxygen environment. This process is called pyrolysis. Biochar has a sponge-like structure that helps it retain water and is filled with nutrients. Biochar improves soil health, increases plant growth, and reduces the need for repeated fertilizer applications and watering. It also stores carbon for long periods, helping reduce greenhouse gas emissions and fighting climate change. Lastly, biochar is biodegradable and environmentally friendly, which makes it an essential material for farming and soil improvement. 

Main Types of Biochar Wood-based Made from wood, branches, or sawdust, it has large pores that help retain water, improve soil structure, and enhance airflow. Crop waste-based Made from leftover plants such as straw or corn husks. It is rich in nutrients and helps soil hold water. Manure based Made from animal manure, such as cow or chicken waste. It helps plants grow faster and more efficiently. Grass Based Made from fast-growing plants such as bamboo or tall grass. It is lightweight and very effective at retaining moisture in dry places.

Why does biochar help soil hold more water? Biochar increases water retention because its pores create a massive area that traps water and stores it in the charcoal structure. These tiny pores hold water through something called capillary action, which means the water sticks to the inner surfaces, allowing the water to slowly be released and preventing it from evaporating. This keeps the plants hydrated for long periods of time.

How does biochar reduce water loss in soil? Biochar reduces water loss by stopping evaporation and runoff. When water is added to soil, including biochar, the water enters the pores and becomes trapped instead of quickly evaporating or draining away. This reduces surface drying and helps the soil stay moist even during hot or dry conditions. Biochar also improves soil aggregation, meaning soil particles stick together better, which reduces erosion and water loss during heavy rainfall. How can Biochar help save water? Biochar improves the soil's ability to hold water. Its pores act like a sponge, trapping rain or irrigation water and preventing it from drying up too quickly. Over time, it releases the stored water to the plant, keeping the plant hydrated. This reduces how often watering is needed and helps the plant survive during dry periods. Even in dry environments, biochar prevents water loss by increasing water absorption. As well as clay soils, biochar improves drainage and reduces waterlogging. This is why biochar is useful in any environment. Research shows that biochar can increase water retention by 20%-50%, depending on soil type. This demonstrates that this can be a highly effective method for conserving water in agriculture.

How does biochar stabilize carbon capture? Biochar captures Co2 from the atmosphere through crop growth. Biochar production transforms the carbon captured by plants into a highly stable form.

Uses and Benefits of Biochar Biochar is added to soil to help improve its physical, chemical, and biological properties. Biochar increases water-holding capacity, enhances nutrient retention, and boosts microbial activity in the soil while the seeds are growing into plants. It also converts plant matter into a stable, long-lasting form and provides a way to repurpose organic waste that would otherwise decompose in landfills. Lastly, adding biochar to soil can help reduce the number of nitrous oxide emissions, another greenhouse gas related to farming.

How Biochar Affects Soil Ph Biochar often has a higher pH level (Alkaline). This can help balance acidic soils. Sometimes the soil is too acidic, because of this, plants have trouble absorbing nutrients. Biochar improves nutrient availability by adjusting pH levels. This boosts nutrients and leads to healthy roots. This is another reason plants should be grown in biochar-rich soil.

Long Term Use If plant matter decomposes or burns, the captured Co2 goes back to the atmosphere. However, biochar can remain for hundreds of years even when placed in a dry soil subject to droughts. This is a necessary carbon removal situation that is good for the climate.

Does biochar enhance soil quality and help in water and nutrient retention? When biochar is mixed with soil, it improves the soil quality. Increases crop yields. This benefits poor, dry, and acidic soils that are lacking nutrients. Biochar has an ultraporous microstructure resembling a carbon sponge. This helps for retaining soil and essential nutrients.

Reduces Fertilizer Use Biochar helps make the pH level neutral, and based on the biochar's natural high pH level, it also helps in acidic soil. This helps farmers to reduce or stop using chemical fertilizers, which have severe problems with natural biolife. This will help cut the cost of their fertilizers and help them improve their soil health. This minimizes runoff and pollution.

Manipulated Variables

1. Biochar (Amount of Biochar)

Dependent Variables 

1. Soil Moisture Retention (How long does the soil stay wet? How much water is retained during a period of time?)
2. Plant Growth (How tall or healthy the plant is over time)

Controlled Variables

1. Container with Soil (Same containers for every plant.)
2. Soil Type (The same type of soil will be used for every plant.)
3. Temperature (Room Temperature)
4. Light Exposure (The same amount of sunlight is provided to each plant)
5. Water (Same amount of water added.

1. Prepare Materials 

Gather and set up all materials. All pots and tools should be  clean.

1. Label Pots

Label half the pots with biochar and the other half without.

1. Prepare Soil Mixtures

2. Without Biochar: Fill pots with soil

3. Biochar Group: Mix 10 grams of biochar with the soil.

4. Plant the Seeds

Plant the same number of seeds at the same depth in each   pot.

1. Watering

Add the same amount of water to each pot using a measuring cup. 10 grams of water in each pot every day.

1. Daily Monitoring

2. Measure soil moisture using a soil moisture meter and a pH level meter. Weigh the pot on the kitchen scale.

3. Record data for 10 Days and make observations

4. Measure Plant Growth and Weight

Record plant growth and weigh pots every day.      10. Analyze Results

• Compare moisture retention times
• Compare plant growth between groups
• Graph the results for moisture and plant height

1–2 Days

• No visible differences in plant height.
• Soil with the biochar is still damp and has a higher soil moisture than the ones without biochar.
• Soil pots without biochar show in the moisture detector that percentages are dropping. 
• Plants without biochar soil are slowly drying out.

3-4 Days

• Plants without biochar begin to dry around the edges of the pot.
• Biochar soil is still damp, leaving consistent moisture level
• Plants in both groups have sprouted but the ones with biochar have more sprouted than the ones without biochar.

5-6 Days

• A growth difference begging to appear as the one in the biochar are already getting taller than the ones without.

7-8 Days

• Biochar plants show greener leaves compared to the ones without biochar.
• Plants without biochar begin having big dry spots in the soil.
• Soil texture is different with the plants with biochar being more damp than the others.

9-10 Days

• The height difference is significant as the plants with biochar are way taller than the ones without it.
• Plants with biochar seem healthier having deep green leaves and plants without having slightly yellower leaves.

The results support the hypothesis that adding biochar improves water retention and plant growth. Throughout the 10-day experiment, the soil with biochar stayed moist longer than the soil without biochar. Moisture levels in the control group dropped more quickly, and the soil began drying around the edges earlier. By Days 5–6, plants grown in biochar soil were noticeably taller. By the end of the experiment, the biochar plants had greener leaves and stronger growth, while the plants without biochar showed some dryness and slight yellowing. This suggests that biochar’s porous structure helped store water and release it slowly to the plants, improving hydration and nutrient availability. Although minor sources of error may have affected the results, the overall trend shows that biochar positively impacts soil moisture and plant growth.

The results of this experiment show that adding biochar to the soil improves water retention and plant growth. This is because of biochar's porous structure, which stores water and maintains stable soil, and improves nutrient availability. Our results show that using biochar helps with plant growth and water retention. Plants grown in soil with biochar showed better growth and retained water longer than those without biochar, confirming our hypothesis. These results show that biochar can be a valuable tool for farmers, especially in places with less water and drought. Further studies could explore the effects of different types and amounts of biochar on plant growth and soil conditions.

Biochar helps farmers conserve water by increasing the soil's ability to retain moisture, which is especially useful in dry seasons or places where there are droughts. It also improves soil fertility and can lead to healthier, faster-growing crops. Biochar keeps nutrients in the soil longer, which can reduce the need for chemical fertilizers and lower farming costs. Further research could investigate the effects of different amounts of biochar on soil retention and plant growth in different plants.

• Uneven Mixing of Biochar The biochar may not have been mixed evenly into the soil. Some pots could have had more concentrated biochar in certain areas, affecting water retention and plant growth.
• Inconsistent Water Distribution Even though 10 grams of water were measured each day, the water might not have been poured evenly into each pot. Some soil may have absorbed water differently depending on how it was poured.
• Measurement Tool Accuracy
  • The soil moisture meter may not be perfectly accurate.
  • The pH meter may not have been calibrated.
  • The kitchen scale may not measure small changes precisely. Small measurement errors could affect recorded data.
• Light Exposure Even if all plants were placed in the same room, some pots may have received slightly more sunlight due to window angle or shading from other pots.
• Seed Not all seeds grow at the same rate. Some seeds may naturally grow faster or slower regardless of soil conditions. This could influence plant height results.
• Environmental Changes Room temperature and humidity may have changed during the 10-day period. Warmer days could increase evaporation and affect moisture levels.
• Pot Differences If pots had slightly different drainage holes or soil packing, water retention could vary independently of the biochar.

Agriculture and Agri-Food Canada. (2022). Biochar can turn plant waste into healthy soils and improve the environment. https://agriculture.canada.ca International Biochar Initiative. (n.d.). Biochar. https://biochar-international.org Carbon Direct. (2025). What is biochar? A carbon removal solution gaining ground. https://www.carbon-direct.com/insights/what-is-biochar-a-carbon-removal-solution-gaining-ground Regeneration International. (2018, May 16). What is biochar? https://regenerationinternational.org/2018/05/16/what-is-biochar/ RIT Sustainability Institute. (n.d.). What is biochar and how it is made. https://www.rit.edu/sustainabilityinstitute/blog/what-biochar-and-how-it-made Wakefield Biochar. (n.d.). Does biochar raise soil pH? https://wakefieldbiochar.com/learning-center/does-biochar-raise-soil-ph Springer. (2025). Biochar as a green solution to drive the soil carbon pump. https://link.springer.com/article/10.1007/s42773-025-00432-8

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