| Determining the Toxicity Threshold Concentration of Herbicide on Radishes | |
Researched by Thomas H.
|
|
The purpose of this experiment was to determine the toxicity threshold concentration of herbicide on radishes.
I became interested in this idea when I read an article showing that if you use a low enough concentration of herbicide it can actually have a beneficial effect on the plant.
The information gained from this experiment would help farmers know
the largest possible amount of herbicide you could use in an area where
they are growing radishes and still not kill the radish with 2,4-D.
My first hypothesis was that if there were a small enough amount of herbicide it would not harm or kill the radishes.
My second hypothesis was that too much herbicide would harm or kill the plants.
I based my first hypothesis on the fact that a man named Edward Calabrese had seen a beneficial effect when he poisoned peppermint plants with the herbicide Phosfon. I based both of my hypotheses on the statement by a scientist of the 1600’s, Paracelsus, “All things are poison and nothing is without poison” and another statement by the same person, “It is the dose that makes it a poison”.
The constants in this study were:
- Type of plant
- Seed age and storage
- Soil moisture
- Temperature
- Amount of light
- Pot size and shape
- Amount of soil
- Soil type
- Testing procedure
- Planting depth
- The type of herbicide I used and how much I used for all plants of a specific test group
The responding variable was the amount of radishes left alive per group over a period of weeks.
To measure the responding variable I counted how many radishes were left alive per group out of 10.
QUANTITY ITEM DESCRIPTION
| 1 | plastic sheet |
| 240 | Radish seeds (radish champion) |
| Well water | |
| Herbicide (2,4-D Weedar) | |
| 16 quart bag | Natures Potting Soil |
| 120 | 6. 4 oz Styrofoam cups |
| 6 | cardboard trays lined with aluminum foil (which you line yourself) |
| 2 | Grow-lights 49cm long (must be able to screw into wood) |
| 1 | 179cm long by 99cm wide black cloth |
| 2 | A-frames |
| 8 | screws |
| 1 | screwdriver |
| 1 | graduated cylinder |
| 1 | graduated cylinder |
| 1 | pencil |
| 12 | 8. 5 ounce Styrofoam cups (called herbicide cups) |
| 1 | syringe |
| 1 | 500 ml flask |
1. Plant seeds:
a) Poke a pencil through the bottom side of 120 Styrofoam cups.
b) Fill each cup with the potting soil to within 2 cm of the rim.
c) Put the cups into 8 cardboard trays with 15 cups in each tray.
d) Fill each cup with 50 ml of water.
e) Place 2 radish seeds in each cup.
f) Next cover the seeds with a large pinch of potting soil.
2. Build the growing enclosure by:
a) Take one of the A-frames and 4 screws.
b) Then carefully hold one of the grow lights up onto the bottom of the A-frame and put the screws into their holes.
c) Repeat with the other A-frame.
d) Place the A-frames structures put them relatively close to each other.
3. Germinate seeds, grow seedlings:
a) Next put 4 trays under one A-frame and 4 under the other.
b) Drape the curtain over the two A-frames.
c) Maintain temperature between 16 degrees Celsius and 19 degrees Celsius.
d) Cover cups with plastic to assist germination.
e) Wait about 2 days for the radishes to germinate.
f) After the radishes have germinated turn on the grow lights.
g) After 4 more days add 16 ml of water to each cup.
h) Now add some topsoil to each cup so the plants don’t fall out.
i) 6 days later drench the soil with approximately 32 ml of water per cup.
j) Sort the 120 Styrofoam plant cups into 12 groups and label the groups 1-12.
4. Prepare herbicide concentrations:
a) Take the twelve 8. 5 ounce Styrofoam herbicide cups and label them #’s 1-12.
b) Fill herbicide cup #1 with 160 ml of water and add NO Weedar. This is the control.
c) Fill herbicide cup #2 with 160 ml of water and add 1 ml of Weedar using the syringe. ( Equals 6250 ppm)
d) Fill herbicide cup #3 with 160 ml of water and add 0. 1 ml of Weedar with the syringe. ( Equals 625 ppm)
e) Fill herbicide cup #4 with 160 ml of water and apply 0. 01 ml of Weedar using syringe. ( Equals 62. 5 ppm)
f) Fill a flask with 320 ml of H2O and apply 0. 01 ml of 2,4-D. Pour 160 ml into cup #5. ( Equals 31. 3 ppm)
g) Dilute 160 ml in flask with additional 160 ml of water. Pour 160 ml into cup #6. (Equals 15. 6 ppm)
h) Repeat last step, except pour into cup #7 (Equals 7. 8 ppm)
i) Repeat last step 5 more times, pouring dilutions into cups #8 - #12, having 3. 9 ppm, 2. 0 ppm, 1. 0 ppm, 0. 5 ppm, and 0. 2 ppm respectively)
5. Stir the mixture in herbicide cup #2 and apply 16 ml to each cup in group #2.
6. Repeat step 5 for all other herbicide groups, being sure to use each on the respective plant group (for example, herbicide #6 goes only on plant group 6. )
The original purpose of this experiment was to determine the toxicity threshold concentration of herbicide on radishes.
The results of the experiment were that the toxicity threshold was between groups 6 and 7 because this was the point where 40% of the plants died (in group 7) and 90% of the plants died (group 6). After group 7 then the number of deaths decreased to 10% in group 8 and then 9-12 were all 100% except for group 10 having 90%. Also groups 2-4 had 100% death and group 5 had 90% death. This claims the threshold to be between groups 6 and 7.
My first hypothesis was that if I gave the radishes a small enough dose of herbicide it would not kill it them.
The results indicate that this hypothesis should be accepted, because the plants with the recommended dose of herbicide or higher all died.
My second hypothesis was that too much herbicide would harm or kill the radishes.
My hypothesis should be accepted because the plants with lower than
the recommended dose mostly lived except for the two groups right after
the recommended dose, which had 90% and 40% die.
My second hypothesis should also be accepted, because the plants with less than the given dose had 60% or more of the plants surviving.
Because of the results of this experiment I wonder if I used a different plant or a different herbicide would I get the same effect that I did with radishes and 2, 4-D. I also wonder if there is a certain amount of herbicide that would actually have a beneficial effect.
If I were to conduct this project again I would check my plants more, make a better curtain to make sure the light is somewhat contained, water the plants more accurately, have the project run for at least an additional week, and I would use at least 20 plants in each group.
|
Introduction: Humans and animals need plants. Plants also need animals. Animals help spread the seeds from plants. Animals and humans need plants for food and shelter. They all have a beneficial relationship to each other. One of them could not exist without the other. Plants: Plants are important to our society. They provide food,
lumber, clothing, paper, shelter, and many other products we use. Without
them we wouldn’t be alive because we are omnivores eating both animals
and plants, Animals that eat plants would not exist and carnivores would
have no food source.
Plants live through photosynthesis where they make their own food using
sunlight and an important plant chemical called chlorophyll. The equation
for photosynthesis is:
Agriculture: Agriculture is the most important industry in the world and is also the largest. When our ancestors began to grow food society was changed. Villages, cities, and towns began to grow rapidly due to agriculture. Communities no matter how advanced could not ignore agriculture’s importance. Now because of the new technologies we have obtained people often don’t look at its importance. About half of all the world’s workers are working in agriculture. It provides us food, clothing, and jobs. Farming is the common use of agriculture to grow natural resources like food, wood, and materials to make clothing. Farming provides us meat and plants. A few of the many plants farmers harvests are beans, potatoes, fruits, nuts, tobacco, radishes, wheat, rice, vegetables, and many other plants. Radishes: A radish is a fast maturing plant known for spiciness
and its fleshy root. The scientific name for radish is Raphanus sativus.
Radishes are found all over the world. There are two main types of radishes,
spring radishes and winter radishes. Radishes maturing times range from
20 to 60 days after planting. Radishes that mature in 30 days or less are
called spring radishes, which can be grown in fall gardens. Winter radishes
are radishes that take 50 or more days to mature. Skin colors of radishes
vary. There are red radishes, white ones, lavender radishes, scarlet radishes,
and many other colors.
Herbicides: Herbicides are used for the eradication of unwanted
plants (usually weeds). However herbicide can harm animals and people.
That is why people must be extremely careful with herbicide.
2, 4-D: 2,4-D was the first successful selective herbicide made. It was made in 1946 and is currently the herbicide used most in the world. It is also the most researched herbicide in the world. Its major use in agriculture is with wheat, grains, corn, soybeans, and other major crops. Also it is used to kill weeds, aquatic weeds, and other unwanted plants. The herbicide is a growth inhibitor getting sucked into the plant and causing abnormal growth blockage throughout the system, which stops the plant from taking in liquids and nutrients. This starves the plant causing it to die. However herbicides are extremely dangerous because this specific weed killer 2, 4-D is corrosive, its effects are it causes irreversible damage to the human eye, can be fatal if absorbed through skin, and is also extremely dangerous if swallowed or inhaled. Summary: Although herbicides are useful in the destruction of unwanted plants they continue to be a threat to humans, plants (including radishes), and wildlife through pollution. Unfortunately the escape of herbicides and other pollutants continues to contaminate our water and hurt plants and animals alike. |
|
“A little poison can be good for you,” November 12, 2003. http://www. fortune. com/fortune/brainstorm/0,15704,454888,00.html Calabrese, Edward J. edwardc@schoolph. umass. edu”6th Grade Hormesis Science Project Interview. ” December 9, 2003 Personal e-mail Cathy, Henry. “Plants,” World Book Encyclopedia, 1999. Cobbe, Harold. “Herbicide,” World Book Encyclopedia, 1999. “Easy Gardening…. Radishes,” November 19, 2003 http://aggie-horticulture. tamu. edu/ “Farm and Garden. ” November 5, 2003. http://www. farm-garden. com/growing-vegetables/growing-radishes. php Freeborn, Joel. “Agriculture,” December 10, 2003. http://www.Selah.k12.wa.us/Soar/SciProj2003/Joel F.html Freeborn, Joel. Personal Interview. November 12, 2003. “Herbicides,” November 19, 2003 http://www. pestproducts. com/herbicides/herbicidestypes.htm Hughes, George R. “Radishes,” World Book Encyclopedia, 1999. Mortazavi, Javad. “An Introduction to Radiation Hormesis. ” December 3, 2003 “Radish. “Microsoft Encyclopedia Deluxe. 2001 “Radish. ” November 12, 2003. http://www. urbanext. uiuc. edc/ Shconeweis, Susan D. ” Growing Radishes and Table Beets. ” November 5, 2003. http://www. ianr. unl. edu/pubs/horticulture/g1004.htm “The Importance of Agriculture,” December 17, 2003 http://www. onecountry. org/oc82/oc8202as.html Welsh, Frank. "Kinds of Poisons,” World Book Encyclopedia, 1999.
|
I would like to thank the following people for helping make my project possible:
- My parents for helping me conduct my science experiment, helping me e-mail an expert, also for helping record my results, and giving me an idea for my science experiment.
- I would also like to thank Mr. Newkirk and Mrs. Helms for helping me get resources for my experiment and project board.
Top of page
Menu of 2003-2004 Science Projects