BRONZE

Biochar: Fertilizer, Carbon sequestration, Heat source

Project investigates the effectiveness of biochar on plant growth. Creates biochar and compares to typical combustion of wood.
Maddy Gerlach
Grade 9

Hypothesis

Experiment #1

The goal of our first experiment was to investigate how effective biochar is, in different concentrations, on plant growth. Jasmine (my partner who is unable to participate) and I hypothesized that in order of most effective to the least effective 

1. 10% activated biochar plants

2. 40% activated biochar plant

3. 10% unactivated biochar plants

4. No biochar plants 

Experiment #2

The goal of experiment 2 was to contrast a controlled oxygen stove that produces biochar and an uncontrolled oxygen stove that produces ash. We predicted that the controlled oxygen stove would burn slower than the uncontrolled oxygen stove. We expected that the uncontrolled oxygen stove would rise to high temperatures very fast but burn out. In contrast, we predicted that the controlled oxygen stove would slowly reach higher temperatures and slowly decrease.

Research

Biochar

Biochar is a plant fertilizer, made by burning organic matter in a low oxygen environment. Biochar mineralizes quite slowly in soil, allowing it to last in soil from decades to thousands of years. Biochar can be very effective at sequestering carbon and holds carbon for hundreds to thousands of years. Biochar is able to sequester carbon by absorbing carbon through photosynthesis and slowing down the decomposition of plants.

Benefits of Biochar

  • Biochar helps microbes grow and protects them
  • Helps keep moisture and nutrients in soil
  • Help plants get nutrients from soil by increasing a process called cation exchange 
  • Makes soil easier for roots to grow and move
  • Holds carbon in soil for hundreds to thousands of years 
  • Controls soil acidity, which can help plants that who require a certain amount of potassium and pH
  • Reduces irrigation and fertilizer requirements

Variables

Variables for Experiment #1: 

Independent variables:

  •  Levels of biochar (percentages of biochar)
  •  (40% activated biochar, 20% activated biochar, 20% inactivated biochar and 0% biochar) 

Dependent variables:

  • Height of the sprouts
  • Number of sprouts 

Controlled variables: 

  •  The ambient temperature of the room (20-22˚C)
  •  The amount of water per day (1 tbsp)
  • Location (amount of light plants receive) South east facing Windows
  • Consistent interval between measurements (week)

Variables for Experiment #2:

Independent Variable

  • Stove type
  • Controlled oxygen stove and uncontrolled oxygen stove

Dependant Variable

  • Measured temperature change every 5 minutes
  • Weight of fuel before and after
  • Measured how much water evaporated 

Controlled variables

  • 1 tsp of fire starter
  • 250ml of water at 15˚C
  • Weight of fuel (low oxygen 79.46, oxygenated 79.3)
  • Ambient temperature (1˚C and 2˚C)
  • Taking temperature every 5 minutes

Procedure

Experiment #1

Procedure for Activating Biochar

We mixed biochar, worm castings, flour and degassed water in a large bowl. We then let the biochar sit for 2 days before planting our plants.

Procedure for Planting plants

40% biochar soil: 6 ½ cups topsoil and 4 ½ cups of activated biochar

10% biochar soil: 9 ½ cups of topsoil and 1 ½ cups of biochar

10% Unactivated Biochar soil: 1 ½ cups of unactivated biochar and 9 ½ cups of topsoil. 1 tablespoon of worm castings.

No Biochar: 10 ½ cups of topsoil and 1 tablespoon of worm castings.

Planting: We placed 2 radish seeds in each of the 48 soil filled compartments. We didn’t have enough bean seeds to fill all 48 compartments, so we eliminated one row of beans plant compartments. We ended up having only 40 bean seeds planted. To keep our variables Jasmine and I equally planted seeds for each condition. 

Experiment #2

To create the two ovens, we did the following:

We first ensured that both the outer and inner tins met the requirements for height and width (0.8mm to 10mm difference)

1. We then drilled X number of holes at along the bottom of the outer tin.

2. For the inner tin, we drilled holes at a height based on holes drilled in the outer tin.

3. We then cut a hole in the lid of the outer tin that was ½ of the diameter of the inner tin.

 

To light the stove, we did the following 

1. Filled the inner tin with enough to fill it up to reach the line of drilled holes.

2. We placed 1 tsp of gel fire starter on top of the fuel.

3. We inserted the inner tin inside the outer tin.

4. We lit the fire starter.

5. Once the fire was lit, we covered the tin oven with the lid and placed with tin with later on top of the lid.

Observations

Observations Experiment #1

Bean Plants: Total number of bean plants planted is 40 seeds

40% Biochar bean plants

  • #1 sprouted at week 1 and grew to be 20.5 cm tall
  • #2 sprouted at week 1 and grew to be 7 cm tall
  • #3 sprouted at week 1 and sprouted to be 14 cm tall 

10% Biochar bean plants

  • #1 sprouted at week 1 and grew to be 17.5 cm tall
  • #2 sprouted at week 1 and died during week 4

10% unactivated Biochar Bean plants

  • #1 sprouted at week 1 but did not grow upwards to properly be measured

No Biochar Bean plants

  • None of the bean plants sprouted

Radish Plants: Total Number of Radish plants is 48 seeds

40% Biochar Radish plants

  • 10 40% Biochar radishes sprouted at Week 1
  • 1 40% Biochar radish sprouted at Week 2
  • 1 40% Biochar radish sprouted at Week 3

12 Radish Plants in total sprouted with 40% biochar soil

10% Biochar Radish Plants

  • 1 10% Biochar radish sprouted at week 1
  • 2 10% Biochar Radishes sprouted at Week 2
  • 1 10% Biochar radish sprouted at Week 3

4 Biochar Radish plants sprouted with 10% biochar soil

Unactivated 10% Biochar Radish Plants

  • 0 unactivated 10% biochar radish plants sprouted

No Biochar Radish Plants 

  • 2 no Biochar radish plants sprouted at Week 1
  • 2 no Biochar radish plants sprouted at Week 2
  • 1 no Biochar radish plants sprouted at Week 3

5 Radish plants sprouted with no Biochar soil

 

Observations Experiment #2

Controlled Oxygen Stove

  • Measured temperature every 5 minutes 
  • Ambient temperature 1˚C
  • Put 250ml of water in a tin which we then glued wood blocks on and placed on top of our stove to measure how much heat is produced between the controlled oxygen stove and the uncontrolled oxygen stove. 
  • Water temperature was 15˚C before experiment began
  • Weight of fuel placed in the stove was 79.46 grams 
  • Afterwards fuel weighed 14.56 grams
  • Water afterwards 240ml

Water began at 15˚C 

Started lowering after 78.8˚C

Ended at 30˚C

Uncontrolled Oxygen Stove

  • Measured temperature every 5 minutes 
  • Ambient temperature 1˚C
  • Put 250ml of water in a tin which we then glued wood blocks on and placed on top of our stove to measure how much heat is produced between the controlled oxygen stove and the uncontrolled oxygen stove. 
  • Water temperature was 15˚C before experiment began
  • Weight of fuel placed in the stove was 79.36 grams 
  • Afterwards fuel weighed 0.28 grams
  • Water afterwards 200ml

Water began at 15˚C 

Started lowering after 95˚C

Ended at 30˚C

 

Analysis

Experiment #1

For the radish plants, 12 40% biochar radishes sprouted, 4 10% biochar radishes sprouted, 0 unactivated biochar radishes sprouted, and 5 no biochar radishes sprouted. For the beans, 3 40% biochar radishes sprouted, 2 10% biochar radishes sprouted, 1 unactivated biochar bean plant sprouted and 0 no biochar bean plants sprouted.

Experiment #2

The uncontrolled oxygen stove reached 95˚C within 20 minutes, but lowered to 30˚C in 25 minutes. This stove left ash and dust at the end of the experiment. Around 50ml of the water evaporated. In contrast, the controlled oxygen stove reached 78.8˚C within 25 minutes, but lowered to 30˚C in 70 minutes. This stove yielded 14.56 grams of homemade biochar. Around 10ml of water evaporated.

Conclusion

Experiment #1

The results of this experiment indicate that a mixture of 40% biochar was most effective at promoting plant growth for both the radishes and the beans. Which mixture is the second most effective is unclear, as our results differed across plants.  For the radish plants, 4 10% biochar radishes sprouted, 0 unactivated biochar radishes sprouted, and 5 no biochar radishes sprouted. For the beans, 2 10% biochar radishes sprouted, 1 unactivated biochar bean plant sprouted and 0 no biochar bean plants sprouted. We had expected that 10% biochar mixture would be most effective, as that was the recommendation from the producer. Our results, however, indicate that 40% biochar soil was the most effective on plant growth, under the growing conditions tested in our experiment. In conclusion, biochar can accelerate plant growth.

Experiment #2

Consistent with our hypothesis, the controlled oxygen stove was more efficient at maintaining heat, and conserved more water, which is better for cooking. This stove also yielded usable biochar, which can then be used for fertilizer. In contrast, the uncontrolled oxygen stove yielded only a small amount of ash (< 1 g), which suggests that the majority of the fuel was converted to ash and released into the environment. In conclusion, these findings suggest that the controlled oxygen stove is more environmentally friendly and yields a renewable product, namely, biochar. 

 

Application

Application

In developing world countries many people use mud stoves and mud ovens that produce lots of black carbon (soot). Black carbon is responsible for 18% of the Earth’s warming. Specifically, black carbon is very heavy and can’t travel very far into the atmosphere. Black carbon is carried by wind and lands on the ice in the arctic or in Antarctica. The black carbon sticks to the ice and attracts sunlight. The ice on our planet is responsible for reflecting the sunlight and helping keep our planet cool. Not only does black carbon affect the environment, but black carbon causes lots of health issues, including negative effects on the cardiovascular system and respiratory system as well as cancer and certain birth defects.

 

To help prevent the production of black carbon, we propose that replacing the mud ovens and stoves with biochar stoves could greatly reduce the warming of our planet. Based on our stove experiment, the controlled oxygen stove could boil water and therefore, cook food. Using a biochar stove, you also produce biochar which is great for agriculture and gardens, as we showed that it affects plant growth in a positive way. Biochar is very useful when it comes to sequestering carbon from the air as well which will help reduce our carbon footprint and will take carbon out of the atmosphere and hold it in the ground. This can reverse the effects of climate change and air pollution. 

 

Sources Of Error

Experiment #1

One of our source of error was that our container where we planted our plants was too small and prevented the radishes from growing. The radishes stayed as sprouts and were getting too crowded near the end of the experiment. We didn’t was optimal growing conditions due to the time of year and environment. Due to the temperature of the house for the bean plants, many of the seeds weren’t able to germinate.

Experiment #2

A source of error for this experiment was that we weren’t able to get to a very high temperature with our stoves due to the wind and temperature outside. It was cold and windy, which created a lot of difficulty when lighting the stove and keeping the stove burning. 

Citations

Citations

https://regenerationinternational.org/2018/05/16/what-is-biochar/

https://www.airterra.ca/

http://www.soilquality.org.au/factsheets/cation-exchange-capacity

https://brainly.in/question/8359761

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/biochar

https://www.sciencedaily.com/releases/2010/08/100810122030.htm

https://permaculturenews.org/2010/11/18/beware-the-biochar-initiative/

https://www.nytimes.com/2009/04/16/science/earth/16degrees.html

https://www.economist.com/international/2018/04/05/household-smoke-may-be-the-worlds-deadliest-environmental-hazard

https://www.epa.gov/air-research/black-carbon-research

https://insideclimatenews.org/news/19032018/global-warming-arctic-air-pollution-short-lived-climate-pollutants-methane-black-carbon-hfcs-slcp

https://e360.yale.edu/features/carl_zimmer_black_carbon_and_global_warming_worse_than_thought

https://www.teriin.org/environment

https://www.sciencedirect.com/science/article/abs/pii/S0360544210005104

http://www.canadianagrichar.ca/faq#what_is_biochar

https://en.wikipedia.org/wiki/Biochar

https://regenerationinternational.org/2018/05/16/what-is-biochar/

https://e360.yale.edu/features

https://www.epa.gov/sites/production/files/2014-05/documents/health-effects.pdf

https://www.epa.gov/sites/production/files/2013-12/documents/black-carbon-fact-sheet_0.pdf

 

Photo

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=22132

https://www.allotment-garden.org/composts-fertilisers/biochar-terra-preta/how-to-make-biochar-at-home/

https://ensia.com/features/black-carbon/

https://physiotherapypedia.com/lungs-and-respiratory-system/

https://traxghana.com/2014/10/08/improved-mudstoves-save-more-than-just-energy/

https://www.ccacoalition.org/en/slcps/black-carbon

 

 

 

Acknowledgement

I would like to acknowledge...

  • Jasmine Sun for being an amazing partner who was unfortunately unable to participate in Science Fair
  • M. Abbott for helping and supporting our project
  • M. Savoie for helping and supporting our project
  • John Gerlach for helping with experiments, gathering material, giving ideas, providing resources and supporting us through our project
  • Susan Graham for supporting us and helping us with our project
  • Rob Lavoie for providing information and supplying us with biochar