Problem statement
When plants are grown collectively grown in a place, they are often seen to have an abnormal growth pattern. The realization of this happening is the core propeller to the establishment of this experiment. Plant growth is affected by several natural factors. However, some of them are caused by the farmer himself. Among this is the crowding effect. The core aim of the experiment is to identify how exactly crowding affects growth.
Relevance of the testable question
Congestion affects all other facets of the society. In most cases, congestion causes a form of competition for the available resources. This question is relevant in that it seeks to answer how the congestion affects the growth of plants. The main aim of the experiment is to explain how crowding affects the growth of the all plants.
Literature review
There are several other experiments that investigate the various factors that affect the plant growth rate. These include an experiment to investigate the manner in which fertilizers affect the rate of growth of plants and the experiment to show how weeds and other pests affect the growth rate of plants. These experiments are related to this experiment.
1. Experiment to show how different types of fertilizers affect the plant growth rate. (Burgess, 1985). This experiment has used a design that has incorporated several exhibits. The first is a plant grown with no fertilizer, the rest have all used different fertilizers. The aim of this experiment is to establish how different fertilizers affect the rate of growth of plants. The outcome of the result shows that different fertilizers have a different effect on the plants. Nitrates for instance boost the growth of the plants more that phosphorus fertilizers though each of them has its own role. These fertilizers would be compared to minerals which are essential for plant growth. It is similar to this experiment since it shows the role of mineral salt in growth. My design shows how competition for these minerals affects growth.
2. Experiment to demonstrate how weeds affect plants and their growth pattern (Watson, Zinyowera &Moss 1998). The aim of this experiment is to establish the how weeds affect growth. This experiment resembles this experiment design in that it is shows how competition affects the growth rate. The outcome is a stunted growth in the exhibit with most weeds.
3. Experiment to illustrate how carbon concentration affects plant growth (Luqman 2007) this experiment shows uses a design that uses 1 plant in the first exhibit and several in another exhibit as well as one of the plants that does not have any carbon dioxide in its exhibit. One of the exhibits shows the competition for carbon content. This exhibit is similar to my experiment design since it is all about competition.
The experiment design
Materials required
(a) Six medium sized pots
(b) Water
(c) Ruler
(d) Measuring cup
(e) Soil
(f) Lamp
(g) Pencil
(h) 10 bean seeds
Procedure
1. Fill all the six pots with an equal amount of water to ensure that the pots are damp.
2. In one of the pots, plant 5 seeds that are spaced at equal intervals.
3. In the rest of the pots plant one bean seed in each of the pots at a depth of 2 cm below the ground.
4. Place the pots under a desk and ensure that each of them receives an adequate amount of light from the desk lamp.
5. After seven days, measure the consecutive lengths of the seedlings. Record your findings.
6. Make another measurement of the plants’ heights seven days from the previous recording, i.e. on the fourteenth day.
7. Record all the measurements obtained in a table.
Reasoning for choosing this experiment design
Experts say that the accurate experiments require much attention and monitoring over the time they are under observation (Gupta 2006). For this reason it was essential to observe the plants on a daily basis to ensure that all of the plants have all the necessary requirements such as water and light. It is also essential to record any observations noted in the experiment that may have an effect on the final outcome. This design is satisfactory in that it meets all these standards. The experiment design also ensures that all the exhibits are kept at a constant. The experiment also uses other experiments as points of reference. Two of them in the end results show evidence of a similar growth pattern. These two experiments have been used as control experiments.
Tools used in the collection of data and Measurement units:
Height will be measured using the metric ruler. The units used in the measurement of the height plant are in centimeters. The measurements should be taken after a period of one week each. After the experiments have been
Constant variables: Light. All the exhibits, i.e. the plants in each pot, are exposed to an equal amount of light, which originates from the desk lamp.
Dependent variables: Height of the plants. The plants heights depend on the number of plants in the pot. This is because the more the plants in a pot the higher the competition for the available resources.
Independent variables: Mineral content of the soil and the amount of water. The mineral intake by each plant will be varied depending on the number of plants in the pot. The amount of water added in each pot is the same but the intake by each plant depends on the number of plants in each pot.
Reducing the threats to internal validity
To reduce the threats of internal validity, all the factors necessary for the growth of the plants had to be put at a constant in all exhibits. This can be done through ensuring that each of the plant is well watered and that the soil is always moist in all pots. This prevented the possibility of the experiment being jeopardized by an inequality in the amount of water or any other necessities of plant growth in any of the exhibits. The use of a control experiment was to ensure that there was a reference point for the experiment in which other measurements would be compared. Keeping one of the core factors at a constant by constant checking (Ray 2008)
Hypothesis
Crowding deprives off the plant ample nutrients due to competition thus slows down the growth rate. The amount of nutrients and the quantity of water in a given piece of land remains constant. An increased number of plants will mean that each of the plants will require a share of the minerals and the water to sustain its life. This will result in a form of competition for the available nutrients and water and thus resulting in reduced growth.
Observations
Following all of the above specifications, I observed the plant on a daily basis and wrote down my recordings on a note book. After every week, I took the height readings for the plants and compared them. The plants had different heights. Notably, the plants in the pot which was crowded were way shorter than those in the other pots.
The process of data collection
The data is collected on a weekly basis and the heights should be recorded in a table. The heights are measured using a metric ruler. The average heights for the plants in pot one was attained through the adding the total heights of the five plants then dividing the sum by the total number of plants. The heights of the plants were as follows:
Pot height after 14 days height after 7 days
I. Average height of 20mm Average height of 12mm
II. 28mm 13mm
III. 29 mm 14mm
IV. 27mm 13mm
V. 28mm 14mm
VI. 25mm 13mm
As seen, one of the single-bean-planted-pots was far of the height level. This can be attributed to unavoidable digressions in the experiment. Incidences such as these are the reason as to why the experiment uses five experiments to establish the average height of the plants. The five single plant pots are control experiments (Burton & Kaguni 1997). These findings were further represented in a graph for a detailed comparison of the different growth rates.
Explanation of the experiment
The crowding effect of plant promotes unhealthy competition between the plants for the available nutrients (Goodman 1991). This thus deters the growth rate and thus stunts the plants. This explains why the plants in the first pot are stunted as compared to those in the other pots. When plants compete for nutrients and other some are better fit for the competition as compared to others thus some of the plants will be much taller than others in the first pot.
The uneven growing pattern in the sixth pot could be explained on a totally different ground. Since all the conditions are similar, the only probable cause for the difference in height of the plant in pot five as compared to the other pots is genetics (Jordan 1906). The short nature of the seed may have resulted from the parents being short or having genes of a short height in their DNA.
Conclusion
The outcome of this experiment proves the hypothesis set in the experiment design was absolutely correct. Just as predicted, the growth rate of the plants was slowed. The crowding of the plants resulted in a stunted growth or a slower growth rate. This was as a result of competition for the available resources which slows the rate of growth. The experiment success can be attributed to a number of factors. First of all was the use of several pots with one plant each, which was very essential since they were used as control experiments (Burton & Kaguni 1997). Each of the pots with one seed planted in them would be used as a point of reference. This ensured that the results were accurate.
This experiment can also be used by other parties exactly as it is. The results obtained by the other person would be compared with the results obtained in this experiment to prove the validity of this experiment. Other people could also use the experiment in other ways modifying the procedure and by using a different number of experiment but they can be rest assured that the outcome will be similar to the outcomes of this design.
Graph showing the recorded growth rates of the plants in the different pots
Y axis- represents the height of the plants in millimeters (mm).
X axis- represents the pots
Reference
Gutpa P.K., (2006) Genetics Classical to modern New Delhi: Rastogi Publications
Jordan S.T., (June, 1906). Popular Science. CA: Stanford University Press.
Burgess G. R. (1985). Issues in educational research: qualitative methods. Great Britain: Taylor & Francis
Watson R. T., Zinyowera M. C. & Moss 1998 H. R. The regional impacts of climate change:
an assessment of vulnerability. UK: Cambridge University Press
Goodman H. D., (1991) Biology Today. California: Holt, Rinehart and Winston
Burton Z. F. & Kaguni M. S. (1997) Experiments in molecular biology: biochemical applications California: Academic Press
Ray J. W. (2008) Methods toward a Science of Behavior and Experience California: Cengage Learning
Luqman H., (2007) Experiment on plants Indonesia: Anggun Publications
