November 4, 2002
NS 1 Final Project
The hypothesis that we are testing is that the Jerusalem artichoke (Helianthus tuberosus) grows better in disturbed areas such as along roadsides rather than in non-disturbed areas such as in the middle of open fields or in the woods. We will test our hypothesis by measuring the width of the stems of the plant, the number of branches, the number of leaves, the width of the largest leaf and the number of flowers on each plant. At first our plan was to research the intriguing “living fossil” Equisetum. However, we were not able to find a big enough abundance of samples to satisfy our project.
We then decided to do our research on the Jerusalem artichoke after the lecture on weeds in the fourth week of class, given by professor Nicholson. The biggest problem we have encountered thus far was devising a specific hypothesis to test; we found it hard to narrow down variables to measure in order to come up with a research project.
The Jerusalem artichoke is native to North America and Oxford, Ohio. This alone shows that its ideal climate and growing conditions are supplied in Oxford. Helianthus may already be adapted to the environment that is consistently affected by human disturbance.
Generally, human disturbance is anywhere that there is some sort of clearing including: farming fields, roadsides, buildings, and pastures. Our background research described how the Jerusalem artichoke needs a large amount of sunshine, so the edges of the many clearings described above are excellent growing environments for the Helianthus. The majority of the other experiments about the Jerusalem artichoke that we found while doing background research were about the edible parts of the plant. The main root is a bulb-like tuber (hence the generic name artichoke), and is edible. These other studies mainly involved the study of the nutritional value of these bulbs.
By the end of the semester we aim to produce a student generated lab that studies the growth of the Jerusalem artichoke in both human disturbed and non-disturbed natural areas. By measuring the productiveness in both conditions, hopefully we will be able to determine whether or not the plant grows and produces a better crop in its natural environment with no disturbance. The plant is considered in most caes as a weed (Nicholson, Sept. 12), however it produces a tuber that is edible and often cultivated for its product. This, and the origin of the plant being Butler County Ohio, interests our group. Samples must be taken before winter arrives, because after the first frost, the plants become damaged.
The Jerusalem artichoke is not a completely unknown plant as one
would assume, by reading the peer critiques that are posted on the WCP 121
website. Most people do not know the name of it, however, have probably seen it and overlooked it as they drive down highway 27, or walk down the street or around campus. In one study (Seiler, 1993) the growth rate of four wild Jerusalem artichokes was compared to the growth of six cultivated plants. This study found that the cultivated plants had a higher forage (plant matter) yield and a higher tuber (bulb of the root) yield than the wild plants. It is also stated that, “the significant negative correlation between forage yield and IVDDM (in vitro digestible dry matter) concentration indicates that these characteristics cannot be simultaneously improved in a breeding program.” this gives us a good reason to believe the plant strives better in wildly disturbed areas.
A separate study by a German scientist (Schittenhelm, 1999) compared the crop production of root chicory, Jerusalem artichoke, and sugar beets in stressed and nonstressed environments (Schittenhelm, 1999). It was found that, “the Jerusalem artichoke yield was only affected under conditions of high weed and N stress.” in the event of absence of water, the amount of the yield Jerusalem artichoke was consistent with the average yield of those of sugar beets (Schittenhelm, 1999). This aspect leads us to suspect that the plants grow better along road sides were less weeds are, compared to in the woods or in a field where more weeds thrive.
Since the Jerusalem artichoke is not exactly a common topic for experiments, our research, being posted on the Internet, may help other students from other schools looking for information, or experiment ideas. Also, with our experiment centered on the affects of human disturbance, any information concerning human affects on the environment may be beneficial. It may be key to foreseeing environmental degradation, or even the effects of this.
To look at the big picture, if we perform an experiment on the effects of human disturbance on the Jerusalem artichoke in Oxford, Ohio; then this sets the stage for a sister experiment somewhere else, and a comparison of results. This would be beneficial because if the health of these distant plants of the same species is different, then an assumption may be made about the effects of human disturbance and/or environmental degradation.
Materials and Methods:
We will be taking random samples of the Jerusalem artichoke in places in and surrounding the Oxford City limits. To insure an unbiased, statistically sound experiment and produce precise samples we will go to the clusters of plants we have encountered, randomly throw the cardboard ring into the cluster of plants. Once plants have been chosen, we examine the base of the plant to determine if two branches or two completely formed plants are indeed part of the same root structure. If the roots are not shared they can be considered as separate plants.
For further investigation, we plan to dig up one or two plants to observe the root structure. These will be plants that are not within our sampling areas, therefore not affecting our samples. We are curious to determine if the plant branches from the tuber. We anticipate on collecting two to four samples from each cluster. We will take a sample from the taking our measurements form the random plants that our cardboard ring lands on. To insure the sampling process is entirely random, we will throw the ring while wearing a blindfolded; picking out particular plants to test would not be a random sampling process. For the most part we believe our experiment is statistically sound because our method is as close to perfectly random as possible.
The materials we intend on using consist of:
-1 tape measure
-1 cardboard ring
-1 hand shovel
-1 piece of string
-1 blind fold
-1 data sheet
For the class part of our project, on Tuesday October 22, we will take the class to a population of the Jerusalem artichoke on Western campus to take measurements. We will insist the class wear a blindfold or turn completely around while throwing the ring to chose the samples to insure complete randomness and consistence. We would prefer the person throwing the ring to wear the blindfold, to ensure that we are as close to completely random as possible. Given the necessary tools, the class will help us take measurements from the plants with our specific instructions. Their participation will consist only on collecting data from this particular population of Jerusalem artichoke.
The process they will need to go through to collect thorough samples must be explained clearly. Our explanation of their effort is explained thusly: First, the group members toss a cardboard ring, blindfolded to be completely random, into the large group to Helianthus that we specify. The class will need to examine the roots to see if there are branches from separate plants or branches that are joined at the root to form one plant. If they are joined the plants will be considered as branches. To separate this fact and allow for clarification in our experiment: if there are two branches or plants stemming from one root, we will label one branch as branch #1 and the second as branch #2. We will need measurement of how tall the plants are, also taking note of our definition of the branches/stems being one plant with two or more branches or entirely separate plants. The circumference of the plants stem will be recorded by using a piece of string. The string will be wrapped around the plant one inch from where the plant enters the ground. Then the length of the string will be measured on the ruler and recorded.
Next, the number of leaves, number of buds/flowers, and the measurement of the largest leaf of each plant in each sample will be needed. For this population we will be taking enough samples that each group will have one sample to measure. All information and data collected will be recorded on the data sheets we will provide for the class. This part of our research will inform the class on how we are doing our sampling, give them participation in our sampling part of our research study and also save us time on the little we have left on taking samples. Because there are factors working against us, possible frost this weekend and human construction in the area, it is essential for us to obtain the sampling data as soon as possible. Also the class participation will be greatly appreciated because we only have two group members to complete this entire project.
Sept. 26-First day of sample taking-Across the street from Speedway between Locus and Spring streets.
Sept. 27-Proposals due, posted.
Sept. 28-Take samples-Private residence off of Stephenson Road.
Oct. 5-Took samples-Huston Woods State Park.
Oct. 8-Took samples-Private residence on Route 73, way off from main road.
Oct. 14-Take samples-U.S. Bank on Contreras Road, across from Arbys.
Oct. 22-Class participation/Take samples-Western Bridge.
Nov. 4-Finalize data.
Nov. 11-Entered data into StatView.
Dec. 2-Finished final report.
See attached sheets
Our results came from the translation of the p-values and the data sheets that we acquired. After entering the information into the StatView program on the school computer, we found some very interesting results. Of our five variables: height of the plant, width of the plant stem, number of flowers or buds per plant, number of leaves, and the width of the largest leaf; only two showed that they made a significant difference between disturbed and non-disturbed habitats.
First off, our variable on the height of the tallest plant had a
P-value of .0290. This means that there was a difference in height of plants in a non-disturbed area as opposed to a disturbed area. There may be a few reasons for this. We found in the areas that were not disturbed, the populations were out in the open, not shaded by anything. An integral part of a Jerusalem artichoke's growth is sunshine, and unhindered sunlight may make the plants grow taller to compete with other Artichoke's for sun.
Maybe more important than sunlight in Helianthus growth, is soil. It can be assumed that the soil in less disturbed areas is not as polluted by car exhaust, human waste and any trampling or cutting by humans. This could keep the soil more nutritious for the plant. The higher quality the soil is, could directly lead to taller plants.
Likewise, these two variables can be related to number of buds or flowers on each plant. The condition of flowers on a plant is always good element to measure a plant's health. When the flowers droop, you know the plant is unhealthy. The flower of any plant is always directly related to the sun; simply because of the fact the flower opens and closes with the sunlight. The soil is also related to the condition of the flowers.
The question remains that how do these factors affect these two aspects only and not the rest of the plant? If everything is a part of the whole plant, then everything is affected by the sunlight and soil. To answer that question, you have to think about our original hypothesis. It was about the effect of human disturbance. The variables: width of stem, number of leaves and width of largest leaf seem to be more related to the plant spacing. When the plants grow farther apart, the leaves can more easily spread out and multiply, while the stems and leaves have room to expand. A big factor is also the sun and soil, but all the many factors tend to somehow blend together so that we found there was no significant difference between disturbed and non-disturbed.
Discussion & Conclusions
We asked ourselves some questions before we started sampling; the following are the answers to the questions that we were able to respond to.
How many samples does it take to make enough samples?
Generally about twenty samples are enough to have to test a hypothesis.
Is there any other outside influences on the Jerusalem artichokes growth that we did not take into account?
As with any environmental experiment, there are many, many other factors at work. When working in a natural environment, it is nearly impossible to have a “control.” The factors that we did recognize and take into account are all highlighted within the discussions section of this lab.
Do our measurements of diameter and height really give an accurate measurement into how well the artichoke is growing?
As far as measuring goes, we believe that all measurements are true, exact and statistically sound.
Due to our background research the Jerusalem artichoke is native to North America, showing Oxford provides and ideal climate for the plant. In our study, we measured the growth and productiveness of Helianthus to determine, while in an ideal climate, if human disturbance had an impact on its growth. Generally, human disturbance is anywhere that there is some sort of clearing including farming fields, roadsides, buildings, and pastures. Some general observations were clear such as the plants observed in full sun, and in traffic congested areas, seemed to be the healthiest and growing the best of all the groups we sampled. The plants that seemed to be the healthiest had large numbers of leaves, many buds and flowers and grew tall; however, we found no significant difference between disturbed and non-disturbed, besides the number of flowers and the height of the plants. We conclude our research with, according to our Statview results; the plants in disturbed areas had the most number of flowers and consisted of the tallest plants.
However, each population had characteristics that were unique to that sample. These outside factors also may have had an effect on our results. We will never know whether these factors had a greater effect on the Jerusalem artichoke’s growth than human disturbance. The population located across from speedway was right next to a busy intersection. There were busy roads on three sides of the population, and electric lines base on the fourth side. Also, it was growing on the side of a culvert that ran underneath the roads. This culvert may have had an effect on their growth.
The population located on the Western Bridge, where the class assisted the sample taking, was almost completely in the forest. It was on the very edge of the tree line, which meant it probably got the most shade out of all our populations. Also, there was some sort of construction going on very near to the sample. When the class arrived at the location, a downed tree had fallen, nearly in the middle of this population. It is easy to say, that at least for the duration of the construction, that this population was very human disturbed. And along with this constant shade, these could be important factors in the condition of the plants.
Near the US Bank, we found our hugest and healthiest sample. It was on the side of a relatively steep incline, with a guardrail at the top, and a road very close to it. Since it was no close to the road, and the bank building there were no trees near it. It seemed to us that this population had sun 10 to 12 hours a day. Without any cover, the sun most likely helped these plants to flourish the most.
The non-disturbed samples all seemed to be mostly in the open. However, they all bordered something or other; not completely in the open like the US Bank population. These similar conditions between he different sample sizes made us more confident of accurate results. Although we know that at each population, there could be many, many other factors at work affecting the conditions of the plants.
In the bigger scheme of things, the way we see it, our research and work can play a big role in discovering what plant species are endangered to extinction due to the various types of human disturbance. Our simple methods can contribute to saving plant species that we are destroying do to pollution and construction. Just think… how can we save the world without destroying it first?
Grieve, M. (2002) Artichoke, Jerusalem. [Online]. Availible: http://www.botanical.com/botanical/mgmh/a/artic065.html
Michigan State University (1996) Jerusalem Artichoke. [Online]. Available: http://www.msue.edu/msue/imp/mod03/01701437.html.
Nancy Nelson. Lecture on September 12, 2002.
Schittenhelm, S. (Nov/Dec 1999) Agronomic Performance of Root Chicory, Jerusalem Artichoke, and Sugar beet in Stress and Nonstress Environments. Crop Science. 39 no. 6: 1815-1823.
Seiler, G. J. (Jan/Feb. 1993) Forage and Tuber Yields and Digestibility of Selected Wild and Cultivated Genotypes of Jerusalem artichoke. Agronomy Journal. 85 no.1: (Madison, Wis. American Society of Agronomy): 29-33.
Seiler, G. J. (1990) Protein and Mineral Concentrations in Tuber of Selected Genotypes of Wild and Cultivated Jerusalem Artichoke. Economic Biology. 44: 322-335.
Swanton, C. J. and Cavers, P. B. (1989). Biomass and Nutrient Allocation patters in Jerusalem Artichoke (Helianthus tuberosus). Canadian Journal of Botany. 67: 2880-2887.
University of Arkansas (2002). Jerusalem Artichoke-Helianthus-tuberosus. [Online]. Available: http://www.arhomeandgarden.org/vegetables/varieties/jerusalem_artichoke.asp.
www.hort.purdue.edu/newcrop/duke energy/helianthus tuberoses.
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