The Effects of Varying Soil Composition on Growth in Bush Beans Over a 42 Day Period

How changing different amounts of sand, soil and clay affects bean plant growth.
Madison Roy
Grade 6

Hypothesis

If I add different combinations of clay, sand and potting mix into 12 plastic cups, labelled A through L, to which I plant two beans, then I think that soil F will grow the tallest. This is because soil F has more sand than clay, which bean plants prefer. Bean plants cannot grow in highly compacted soil, therefore soil I, containing the highest percentage of clay, will perform the worst of all the soil samples. Clay is great at water retention, but bean plants prefer soils with high drainage properties and soils that are less compacted, therefore soil I will do the worst.

Research

 

Aluminium is made up of aluminum oxide, silica and iron oxide. Aluminium is not the best for plants because it is not an essential element to plants, but can help plant growth.

Iron is made up of iron stone, limestone, coke (the fuel) and air.  

Clay is made up of silica, alummine, magnesia and water. Clay is great for bean plants because clay is a great foundation for plants to securely anchor their roots. Clay also has a lot of nutrients which are calcium, potassium and iron and is great for retaining water.

Potting Soil Mix is composed of:

  1. Humus: formed by decaying plant material such as leaves by soil microorganisms. Clay has the highest humus levels.
  2. Peat moss: Great for bean plants that prefer acidic soils. Has an acidic pH ranging from 3 to 4. The more peat moss present in the potting soil, the more acidic the soil will be.
  3. Sand: beans like well drained soil, so sand helps with this.

Perlite: expanded volcanic rock that provides great drainage and allows moisture and oxygen to flow to roots better.

Sand is made up of tiny quartz crystals (silica), eroded rocks and feldspar. Sand promotes airflow in soil and is ideal for soil microbes to survive, but has no ability to hold onto nutrients.

Silica is made up of silicon, oxygen and silicon dioxide. Silica is great for plants because it regulates the plants uptake of iron, nitrogen, phosphorus, potassium, zinc and aluminium, thus reducing their toxic effects.

Feldspar is made up of sodium, potassium, barium, calcium and aluminium minerals. Feldspar is great for plants because it encourages water and nutrient uptake.  

Photosynthesis is the process of a plant making its own food with the input of water, sunlight and oxygen.  Nutrient levels can affect photosynthesis.  Less nutrients for a plant slows down photosynthesis. Too much nutrients can kill the plant, because some nutrients become toxic in high amounts to plants.  Bean plants absorb carbon dioxide through their leaves, and combine that with water from the ground ( in the water there are minerals and nutrients) and sunlight to make sugar (food for the plant).

Acidity is how acidic an object is, for example The ph of a soil can range from 0 ( highly acidic) to 14 ( highly basic), with a ph of 7 being neutral. A bean’s acidity ranges from 6 to 7 on the ph level. Acidity can affect photosynthesis because too much or too little acidity decrease photosynthesis for a bean plant.

 

 

 

 

 

Variables

Controlled Variable:  Water (one tablespoon per day), 12 hours of light per day, regulated room temperature (22 degrees Celsius), same type of plastic cups, and two bean seeds planted in each cup.

Manipulated VariableDifferent measured amounts of sand, clay and potting soil mix in each cup.

Responding Variable: Bean plants measured growth. 

Procedure

  1. First plase on gloves gently on your hands  
  2. Next lay out 12 plastic cups in a line
  3. Fill the 12 individual cups with the differing amounts of clay, sand and potting soil mix, as per the instructions below.
  4. Label the 12 cups from A-L with tape, place on the cups
  5. Next plant 2 bean seeds 1 cm deep in each of the 12 soil mixtures
  6. Then add one tablespoon of water to each of the 12 cups ( room temperature water)
  7. Place all of the 12 cups under two grow lights ( make sure the two grow lights are on)
  8. Add 1 tablespoon of water to each cup everyday ( room temperature water)
  9. Observe and measure each bean plant growth, using a standardized metric tape measure.

 

 

Different amouts of clay, sand and potting soil mix for the 12 cups (A-L):

  1. Soil A is 120 milliliters of potting soil mix.
  2. Soil B is a mixture of 14 milliliters of clay and 176 milliliters of potting soil mix.
  3. Soil C is a mixture of 120 ml of sand, and 179 ml of potting soil mix.
  4. Soil D is 14 mL of clay and sand, and 176 mL of potting soil mix. 
  5. Soil E is a mixture of  21 mL of clay, 14 mL of sand, and 176 mL potting soil mix.
  6. Soil F is a mixture of 14 mL of clay, 28 mL of sand, and 162 mL of potting soil mix. 
  7. Soil G is a mixture of 14 mL of clay and sand, 134 mL of soil.
  8. Soil H is a mixture of 120 mL of sand and 120 mL of soil.
  9. Soil I is a mixture of 120 mL of clay and 120 mL of potting soil mix.
  10. Soil J is a mixture of 120 mL of potting soil mix, and 21 mL of clay and sand.
  11. Soil K is a mixture of 14 mL of sand and 120 mL of potting soil mix.
  12. Soil L is a mixture of 14 mL of clay and 235 mL of potting soil mix.

 

Observations

Day 5 

Beans Start To Sprout

In the afternoon of day 5, plant C sprouted, followed by plant L. Later that night plants K, F and E sprouted. On day 6, plants A, J, H, B and D sprouted around the same time, and plants C and G had 2 leaves.

       Soil L

       Soil C

 

 

 

 

 

Day 9

 

Day 10

 

Day 11

Day 15

 

 

 

Day 42

                 

 

Results 

First to Sprout:

  1. C (day 5) 
  2. L (day 5)   
  3. E (day 6)
  4. K (day 6)
  5. F (day 6)
  6. A (day 6)
  7. J (day 6)
  8. H (day 6)
  9. B (day 6)
  10. D (day 6)
  11. I (day 7)
  12. G (day 7)    

First to Grow Leaves: 

  1. C (day 5)
  2. K (day 6)
  3. L (day 6)
  4. F ( day 6)
  5. E ( day 6)
  6. A ( day 7)
  7. H ( day 7)
  8. B ( day 7)
  9. J ( day 8)
  10. D ( day 8)
  11. I ( day 8)
  12. G ( day 9)

First to grow leaves:

  1. A (day 40)
  2. C (day 40)
  3. B (day 40)
  4. L (day 41)
  5. ( the rest did not grow beans in 42 days)

Plants that died:

  1. G (day 40)
  2. I  (day 38)

 

 

 

Analysis

Bean plants A and H surprisingly were 42cm after two days. Plants A and H were more directly under the LED lights which might have affected the results.

Plants G and I died, most likely because they weren't directly under the LED lights, or because the two seeds in each cup were bad seeds, therefore not growing as big as the others in 42 days. Also not enough water, or too much.

 For plant D being 21cm, might have been from bad seeds or not enough water or too much. Plant D was directly under the LED light, so maybe too much light. 

Plant E did very well, being 40 cm in 42 days, plant E was not directly under the light, but surprisingly did very well in 42 days, this might have happened, because plant E maybe had good seeds, therefore taller in 42 days.

Plants J and k only measured at 31 cm (J) and 28 cm (k) in 42 days. Plant J and K were not exposed to as much light as other plants such as A, H and E, which might have messed up their growth. 

Plant C and L did very well, with plant C being only 1 cm taller than plant L, because they were right next to each other, therefore the same amount of light, resulting in an almost identical result of growth.

Lastly Bean plant B surprisingly grew the tallest throughout a 42 day period. Apart from this, uneven amounts of LED light distributed among the bean plants, may have affected their growth., resulting in misleading or inaccurate results. On the other hand, outliers G and I were the furthest away from the LED lights, which drastically affected their growth, eventually dying during the last few days of the experiment. The controlled variables stayed consistent throughout the experiment, resulting in controlled and accurate test results.

 

Conclusion

In conclusion, my hypothesis was partially correct because plant I ( DAY 38 died) did the worst, along with plant G (day 40 died) . The poor outcome of plant I is most likely due to the high amount of clay (120mL). Plant B grew the tallest at 45cm, in 42 days, followed by plant F at 41cm, in 42 days. The plants with a higher amount of potting soil mix seemed to have benefitted from the extra acidity the peat moss provided, as bean plants prefer slightly acidic soils. Also the extra pockets of air from the perlite and sand, and added nutrients from the humus. 

So now you know if you are going to grow a bean plant, you should be using mostly a good potting soil mix (176 mL), to which you can add 14 mL of clay.

 

Application

This project would be useful for farming, indoor farming and agriculture, because if farmers know which soil is best for a bean plant ( which is  mostly a good potting soil mix (176 mL), to which you can add 14 milliliters of clay or more depending on the amout of land. )  then farmers will make better prophet and a lot of money. If the beans sprout faster farmers can produce and harvest faster, therefor better for the farmers.

Sources Of Error

Sources of error may have come from the artificial LED light sources, as some bean plants were positioned more directly underneath the lights than others. These plants would have, therefore, received more direct light to speed up growth. Also some bush bean seeds might of been bad seeds, therefore not growing that large.

Citations

https://education.nationalgeographic.org/resource/photosynthesis/

https://www.britannica.com/video/185632/formation-sand-quartz-role-processes-weathering-grains#:~:text=Well%2C%20much%20of%20the%20wo

https://www.britannica.com/science/clay-mineral

https://www.enigmatic-consulting.com/semiconductor_processing/CVD_Fundamentals/films/SiO2_properties.html

https://www.shinetsusilicone-global.com/info/begin1.shtml#:~:text=The%20main%20sources%20of%20silicone,chemical%20reactions%2C%20silicon

https://pubchem.ncbi.nlm.nih.gov/element/Iron#section=Estimated-Oceanic-Abundance

https://www.britannica.com/science/feldspar

https://natural-resources.canada.ca/our-natural-resources/minerals-mining/mining-data-statistics-and-analysis/minerals-metals-facts/alum

s://www.xometry.com/resources/materials/what-is-aluminum/https://www.garciamunte.com/en/combustibles-solidos/https://www.peacefulmind.com/crystals/metaphysical-properties/limestone-properties/https://www.stockwell.com/blog/silicon-metal-a-critical-need-to-support-the-silicone-rubber-induhttps://www.belmontmetals.com/silicon-and-its-most-popular-uses-metals/https://www.realsimple.com/home-organizing/gardening/indoor/popular-house-plantshttps://www.monash.edu/student-academic-success/excel-at-writing/annotated-assessment-samples/science/science-lab-reporthttps://www.georgina.ca/sites/default/files/page_assets/planting_growing_harvesting_green_beans.pdf

https://www.webmd.com/diet/foods-high-in-phytic-acid https://www.onlymyhealth.com/why-people-with-persistent-acidity-should-avoid-beans-1691225988 https://www.pickyourown.org/ph_of_fruits_and_vegetables_list.htm https://extension.umn.edu/vegetables/growing-beans#:~:text=Beans%20grow%20best%20in%20slightly,to%20increase%20soil%20organic%20matter. https://cdnsciencepub.com/doi/abs/10.1139/b87-156?download=true&journalCode=cjb1#:~:text=Addition%20of%20acidic%20sulfate%20solution,lesions%20or%20any%20visible%20symptoms. https://byjus.com/question-answer/what-are-the-factors-that-affect-photosynthesis/

Acknowledgement

I would like to thank my mom and dad for buying the materials used for this project, I would also like to thank  Ms. Davis, for helping me.

Attachments

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