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The Effects of Soil Type on Bean

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					The Effects of Soil Type on Bean Germination

                    Mr. Spotts
                18 December, 2007
                       6A
                    C.O.R.E.
ABSTRACT
     This experiment was designed to test the idea that bean seeds might sprout better

depending on the type of soil in which they were planted. I hypothesized that the beans

would sprout faster in Soil A, which is browner and contains more organic matter. The

independent variable in the experiment was soil type, and the dependent variable was the

growth of the beans. Variables that were controlled include the amount of light and water

the beans received, the type of seeds and the method in which they were planted.

         Each student in class prepared their planting cup by punching five holes in the

bottom and placing a 2 inch by 2 inch piece of paper towel in the inside. One of two

types of soil was filled to the blue line, and five pinto bean seeds were place on that.

Seeds were covered by 0.25 additional inches of soil and then placed water-filled trays

contained in the classroom growth chamber. Results of how many seeds sprouted in each

cup and for each treatment as a whole were recorded in the data table at the beginning of

class for four class periods.

         Classroom data was compiled and graphed using Microsoft Excel. The data

showed that while a greater number of seeds planted in Soil A sprouted, the percentage of

seeds that sprouted in each soil type were very similar. Problems that were encountered

included 1) mold growing on the top of the cups that might have prevented additional

seeds from sprouting; and 2) some students not planting seeds according to directions.

Analysis of the limited data we had led me to the conclusion that the bean seeds did not

sprout faster in Soil A compared to Soil B, meaning that my hypothesis was proven

wrong.
QUESTION

       The question we attempted to answer by conducting this experiment was “Does

the soil type in which bean seeds are planted determine how fast the beans will sprout?”



HYPOTHESIS

       Based on what I knew about soils from the science unit “Solving the Garden

Problem”, I thought that the bean seeds would sprout first in Soil A.



VARIABLES

       The independent variable in this experiment was the type of soil used to plant the

seeds. The dependent variable was the sprouting of the bean seeds. Variables that were

controlled include the amount of light and water the beans received, the type of seeds and

the method in which they were planted.


INTRODUCTION

       The first unit covered in 6th grade science class dealt with properties of soil. We

examined different soils and learned about soil composition, texture, organic matter and

nutrients. Our textbook was set up so we could examine a school garden and identify

potential problems as to why the garden wouldn’t grow plants. One possible explanation

was that the soil was the wrong type to grown the plants.

       In the lessons, we learned that there are different types of soil in different areas of

the country, and I know that certain crops can only be grown well in certain areas of the

country. For example, corn and soybeans are grown in Illinois, while cotton is better

grown in Mississippi. This got me to thinking about how soil type might affect whether
or not plants would germinate or not. I decided to do this experiment in order to test if

one type of soil would be better for growing pinto beans.


MATERIALS

The materials we included in our experiment included the following:

Cup                               Soil A                            Water

Paper Towel                       Soil B                            Growth chamber

Pencil or pen                     Pinto bean seeds                  Data sheet




METHODS

       Students followed a precise order of steps in order to test their hypotheses. First,

each student in class prepared his/her planting cup by punching five holes in the bottom

of the cup with a pencil or pen. Next, a 2 inch by 2 inch piece of paper towel was placed

inside the cup to act as a wick to get water up into the soil. Then, students put one of two

types of soil in their cup up to the pre-marked blue line and lightly packed the soil with

their fingers. Five pinto bean seeds were place on the lightly packed soil, and the seeds

were then covered by 0.25 additional inches of the same type of soil. After writing their

names and soil types on the outside of their cups, students placed their seed cups in

water-filled trays contained in the classroom growth chamber. Results of how many

seeds sprouted in each cup and for each treatment as a whole (Soil A and Soil B) were

recorded in the data table at the beginning of class for four class periods.
RESULTS
       Data on the bean germination was collected four times after the initial planting.
Results are shown in both table and graph form below.


                             Class Bean Seed Germination Data Table


                         Sampling                 Total Sprouts             Total Sprouts

                             Date                 in Soil A Cups            in Soil B Cups

                   19 Nov 07                            0                            0

                   22 Nov 07                            1                            0

                   23 Nov 07                            2                            1

                   27 Nov 07                            5                            3

                   29 Nov 07                            5                            3




                               Soil Type Vs. Bean Seed Germination

                         6
Number of Bean Sprouts




                         5

                         4
                                                                                         Soil A
                         3
                                                                                         Soil B
                         2

                         1

                         0
                                19 Nov



                                         22 Nov



                                                       23 Nov



                                                                   27 Nov



                                                                            29 Nov




                                         Observation Dates
CONCLUSIONS

       The hypothesis in this experiment is that bean seeds will sprout more quickly in

Soil Type A. After four series of classroom observations, the data showed that in fact a

greater number of seeds planted in Soil A sprouted. On the surface, this would lend

support to the hypothesis. However, the percentage of seeds that sprouted in Soil A and

Soil B were both very low and ended up being similar. In Soil A, 5 out of 75 seeds

germinated, which was only 6.7%. In Soil B, 3 out of 55 seeds germinated, which was

only 5.4%. At such low levels of germination, it is impossible to state with confidence

that the soil type had any affect on bean seed germination.

       Possible explanations for the low germination rate are centered on two problems.

First, many students noticed a white filamentous mold growing both on bean seeds and

on the top of both types of soil in the cups. This could be due to non-sterile conditions in

the growth chamber or too much moisture in the general area of the growth chamber.

Posters hung to shield the experiment from the other science classes may have acted like

a barrier, preventing moisture from spreading out into the science room. Either the mold

itself or the humid conditions that led to the mold growth may might have kept other

seeds from sprouting.     Secondly, some students did not plant their seeds exactly

according to directions. This could have introduced other variables into the experiment

that kept bean seeds from germinating.

       Final analysis of the limited data we had led me to the conclusion that the bean

seeds did not sprout faster in Soil A compared to Soil B, meaning that my hypothesis was

proven wrong. Based on these results, one possible extension of this research would be

to conduct the experiment in a less humid environment. Less water could be kept in the
trays, and a small fan could be used to blow humid air out of the growth chamber.

Additionally, a student could conduct further research on the effects of mold and/or

humidity on the germination of bean seed.


ACKNOWLEDGEMENTS

       I would like to extend my appreciation to the sixth grade students at NKO

Middles School, without whom this experiment could not have occurred. Secondly, I

would like to thank Mr. Hudson who fixed the electrical outlet in the science lab, and Mr.

Bly, who provided insight and feedback on the experimental design. Finally, I would like

to thank Michael Anthony Booker, my former student at Greenville-Weston High School

in Greenville, MS, who convinced me that in order for students to learn about science,

they must be involved in doing science.



BIBLIOGRAPHY

   1. Science Buddies Topic Selection Wizard, Kenneth Lafferty Hess Family

       Charitable Foundation, http://www.sciencebuddies.org/mentoring/tsw_start.shtml

   2. University of California at Berkely, Issues and Earth Science. Berkely: Lab Aids

       Inc., 2006.

				
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