The Effect of Overcrowding on Plant GrowthBotanyExperimental Investigation___________________________________________Signature of Sponsoring Teacher___________________________________________Signature of School Science Fair Coordinator Teacher                                                   Emily White640 W. Scott St. Chicago, IL 60610Grade 7Table of ContentsAcknowledgments Page 3Purpose and Hypothesis Page 4Background Research         Page 5-7Materials and Procedure Page 8-9Results Page 10-11 Conclusion, Reflection, Application Page 12-13Reference List Page 14-16Acknowledgments I would like to acknowledge my mom.  She has supported me throughout my project and she supplied my materials.  Also, she let me use the windowsill to grow my plants on which was helpful for my science experiment.  Also,  my brother had ideas that sparked ideas of my own, which then improved my project.  I would also like to acknowledge my science teacher, Ms. Machado, because she set up check-ins for us.  Without that, I would have procrastinated.  I am very thankful to everyone who helped me with my project.Purpose and Hypothesis This experiment is to find out if cherry radishes that have more seeds planted in a cylinder with the diameter of 9 centimeters, grow shorter than the less crowded plants.  The  information found in this experiment can be useful to many people, ranging from professional scientists to home gardeners.  This experiment will help determine if plants that live in a crowded environment grow better or worse than plants that have more space.  My hypothesis is, the cups with 1 seed will grow the tallest and the plants with 20 seeds will grow the shortest, because my research shows that overcrowded plants compete for food and water, so they don’t grow as tall.  Review of Literature Research has shown that overcrowded plants do not grow as well as plants that are not.   The article ‘Effects that plants growing in overcrowded conditions’ has an example of an experiment.  The author (2015) states, “The overcrowded plants grew at a faster rate than that of the ideal conditions plants yet the overcrowded plants became weak very quickly and as a result weaker plants remained small or died and taller plants grew flimsy.” (p. 1)  There are many reasons and examples that support this theory.  One, overcrowded plants can develop diseases, according to many sources.  Also, there is far more competition when many plants are living in a small space.  Many experiments show results that agree with the claim overcrowded plants do not grow as well as plants that have more space. First, overcrowded plants can develop diseases, which does not help their growth.  Beal (2017) writes, “Overcrowding will affect plant growth in many ways, including encouraging the development of diseases, hampering fruit and flower production, stimulating insect and pest problems and influencing the overall growth and development of a plant.” (p. 1)  This shows that when there are too many plants in one space, diseases can develop and have detrimental effects on the plant’s health.  A common disease that many plants could get is Fire Blight or Alternaria Blight.  These diseases cause plants to blacken, and die.  To prove this point, the article ‘Poor Garden Spacing, Overcrowding, Failure to Thin’ says, “Overcrowding always leads to an unnecessary crash course in pest control and disease management.” (p. 1).  This piece of evidence shows it is hard to manage diseases when there are so many plants in a small space.  This is because they can spread, harming the plants.Overcrowded plants don’t grow as tall as other plants because there is more competition for different resources.  Peterson ( writes, “If the root systems overlap, the plants will compete for water and nutrients.  If the leaves overlap, they will shade each other, causing competition for sunlight.” (p. 1).  This shows that when there are too many plants in one area, they will compete for food and water, which could cause shorter plants.  Weiner, Mallory, and Kennedy (1989) wrote, “When plants are competing, this growth is altered through mechanisms of interference.” (p. 513).  This also supports the claim that overcrowded plants compete with one another.  It also explains how their growth is affected.  The competition interferes with the typical growth of the plant, which is one of the reasons why overcrowded plants don’t grow as well as ideally spaced plants.  Also, Nagashima and Hikosaka (2011) wrote, “Previous theoretical studies have suggested that plants should not overtop neighbours because greater allocation to supporting tissues is necessary in taller plants, which in turn lowers leaf mass fraction and thus carbon gain.” (p. 1).  This explains how studies have shown that  overcrowding plants is harmful to them. To further prove this point, Creed (2016) explained, “Just like animals in an environment, plants compete for the resources they need in the given space. In your garden, if there is not enough space between plants then resources like nutrients, water and light are squeezed out or over consumed and the plants can suffer.” (p. 1).  And, Ssali (2016) wrote, “Overcrowding of crops may reduce yields and it may also lower quality of the fruits produced because of competition for light and soil nutrients.” (p. 2).  All in all, what these sources are saying is that overcrowded plants have other organisms that need the same nutrients, making it harder for them to get what they need.Furthermore, there have been previous experiments that have shown overcrowded plants growing shorter than ideally spaced plants.  For example,  Papadopoulos and Ormrod (1991) said, “A consistent increase in plant height and internode length with closer plant spacing and an apparent trend for taller plants and longer internodes in the inside of four-row canopies compared to outside were found in both spring and fall seasons” (p. 297).  Also, Jiang, Wang, Wu, Dong, Liu, and Zhang (2013) wrote, “Grain yield and aboveground biomass were 5.0% and 8.4% lower in the narrow plant spacing than with normal plant spacing” (p. 77).  These experiments show   that overcrowded plants don’t grow as well as the plants that are ideally spaced.  Furthermore, there are other experiments that show this.  For example, Bitew, Asargew, and Beshir (2014) wrote in their paper, “Main effects of variety and intra row spacing had significant effect…on plant height” (p. 368).  Essentially, there are many reasons why overcrowded plants don’t grow well, and these previous experiments validate those reasons and show that overcrowded plants will not grow as well as ideally spaced plants would grow.All in all, overcrowded plants will not grow as well as ideally spaced plants.  This is because they can develop diseases more easily, they have far more competition for nutrients and water, and many previous experiments have shown similar results-where the overcrowded plants don’t grow as well as other spacings of plants.  This leads to the conclusion that overcrowded plants struggle, which leads to them growing shorter than other plants.Materials and ProcedureMaterials:2 blue plastic cups with diameters of 9 cm2 yellow plastic cups with diameters of 9 cm2 purple plastic cups with diameters of 9 cm2 pink plastic cups with diameters of 9 cm68 cherry radish seeds1 centimeter ruler1 windowsill0.96 liters of waterSunlight6 ‘wonder soil’ wafers1 fork1 spray bottleProcedure:Add 1 wafer of ‘wonder soil’ to each cup.Gradually add 0.12 liters of water to each cup.Mix the soil wafer and the water with a fork for 30 seconds.Place the correct number of seeds into each cup-blue: 1 seed, yellow: 3 seeds, purple: 10 seeds, pink: 20 seeds.Place all of the cups on the same windowsill.Give the plants 4.93 milliliters (0.00493 liters) of water.Measure the plants’ height. (for cups with multiple plants, take the measurement of the tallest plant)Record the data in a table.Rotate the plants on the windowsill.Repeat steps 6-9 for 8 days.ResultsPlant #Day 1Day 2Day 3Day 4Day 5Day 7Day 810cm0cm0cm3cm3cm7cm7.5cm20cm0cm0cm1cm2cm4cm5cm30cm0cm1cm3cm4cm6cm6cm40cm0cm0.5cm3cm5cm8.5cm9cm50cm0cm0.75cm4cm5cm8.5cm9cm60cm0cm1cm4cm5.5cm9cm9.5cm70cm0cm1cm3cm5cm8.5cm8.5cm80cm0cm2cm4cm4cm7.5cm7.5cmKey:Blue=1 seedYellow=3 seedsPurple=10 seedsPink=20 seedsMy results were somewhat showing what I hypothesized.  While the pink cups didn’t have the tallest plants, they weren’t the shortest.  I hadn’t expected the purple cups, with 10 seeds, to have the tallest growing plants.Conclusion, Reflection, and ApplicationConclusion: My project was about the overcrowding of plants, and how that may affect their height.  I wanted to know if plants that had more space to grow grew taller than the others.  My hypothesis was that the plants that were less crowded would grow taller and the plants that were more crowded wouldn’t grow as tall as the other plants.  I tested my hypothesis by planting different seed numbers in the same sized cups to see if some plants grew taller than others.  I noticed that the cups with 10 seeds had the tallest growing plants and the cups with 1 seed had the shortest plants.  My hypothesis is incorrect.  I know this because the heights of all the other plants were greater than the heights of the plants in the blue cup.  But, I think my hypothesis was onto the right idea.  The most crowded cup, didn’t grow the tallest.  Based on my measurements, I can conclude that the cups with 1 and 3 seeds were undercrowded.   I learned that when there is 1 seed in a cup with the diameter of 9 cm, it is under crowded, and 20 seeds somewhat overcrowded, because 10 seeds was the sweet spot.Reflection: I think my test was fair.  There was one day when I forgot to water and measure the plants, which could have thrown off my results.  If I were to redo this experiment, I would have been more accurate when measuring the height of the plants.  My controlled variables were the same for each plant.  I could have been a little more accurate with my soil measurements since the amount in each cup looked slightly off.  Now that I have finished my experiment, I’m wondering if other plants would have the same results, or if it varies depending on the plant.Application: My experiment can apply to anyone who is growing plants.  For example, people who want to grow plants in their own gardens can benefit from my experiment because they can appropriately space their plants so they can grow as tall as possible.  Scientists can use this too for the same reason.  This can benefit anyone who wants to grow tall plants.  This experiment connects to our lives because many people have their own gardens. To add on, most of our food is or uses plants some way and many people need more food than they currently get.  If we can get our plants to grow to their fullest height, we could improve the situation.Reference ListA. (2017, August 10). Common Types of Blight in Plants. Retrieved from https://www.airoclean420.com/blight-in-plants/ Beal, S. K. (2017, April 19). Does Overcrowding Plants Affect Their Growth? | Hunker. Retrieved November 20, 2017, from https://www.hunker.com/12564751/does-overcrowding-plants-affect-their-growth Bitew, Y., Asargew, F., & Beshir, O. (2014, October 10). Effect of plant spacing on the yield and yield component of field pea (pisum sativum L.) at Adet, North Western Ethiopia [Scholarly project]. In Http://article.sciencepublishinggroup.com/. Retrieved November 20, 2017, from http://article.sciencepublishinggroup.com/pdf/10.11648.j.aff.20140305.16.pdf Creech, D., & About Dave CreechI am a Husband, Foodie and Entrepreneur striving to live healthier and happier through better food and outdoor living. I started my Urban Garden in early 2013 in an effort to grow as much of my own food as possible. I am continually learning to live more simply, waste less, be more efficient and generally build a better skill set. (2016, June 21). The Importance of Plant Spacing. Retrieved November 20, 2017, from https://modernsteader.com/importance-plant-spacing/ Effects that plants growing in overcrowded conditions. (2015, March 23). Retrieved November 19, 2017, from https://www.ukessays.com/essays/biology/effects-that-plants-growing-in-overcrowded-conditions-biology-essay.php Jiang, W., Wang, K., Wu, Q., Dong, S., Liu, P., & Zhang, J. (2013, July 26). Effects of narrow plant spacing on root distribution and physiological nitrogen use efficiency in summer maize. Retrieved November 19, 2017, from http://www.sciencedirect.com/science/article/pii/S2214514113000123 Nagashima, H., & Hikosaka, K., (2011, July). Plants in a crowded stand regulate their height growth so as to maintain similar heights to neighbours even when they have potential advantages in height growth. Retrieved November 19, 2017, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3119620/ Papadopoulos, A. P., & Ormrod, D. P. (n.d.). Plant spacing effects on growth and development of the greenhouse tomato. Retrieved November 19, 2017, from http://www.nrcresearchpress.com/doi/abs/10.4141/cjps91-040#.WhI1HbT810v Peterson, S. (n.d.). How the Closeness of Plants Affect Growth. Retrieved November 20, 2017, from http://homeguides.sfgate.com/closeness-plants-affect-growth-25342.html ROL staff. (2015, July 21). Top Ten Gardening Mistakes: Mistake 5, Poor Garden Spacing. Retrieved November 20, 2017, from http://www.grow-it-organically.com/mistake5-poor-garden-spacing.html Ssali, M. J. (2016, May 11). Why crop spacing is important. Retrieved November 20, 2017, from http://www.monitor.co.ug/Magazines/Farming/What-is-crop-spacing-/689860-3197968-2jswg9z/index.html  Weiner, J., Mallory, E. B., & Kennedy, C. (1989, October 15). Growth and Variability in Crowded and Uncrowded Populations of Dwarf Marigolds {Tagetes patula) [Scholarly project]. In Http://www.jacobweiner.dk. Retrieved November 20, 2017, from http://www.jacobweiner.dk/site/Publications_files/Weiner_et_al_1990a.pdf

Leave a Reply

Your email address will not be published. Required fields are marked *