Science Fair Project Effects of Salt Water on Plant Growth Jimmy Ester .Mr. Williams; 7/8 Science A.N.L.C.
The Question: What affect will a 20% saline solution have on the growth of a bean plant?
Project Overview Irrigated agricultural regions of the Southwest United States are accumulating high concentrations of dissolved mineral salts in soil due to overuse and recycling of water resources . When salt concentrations reach high levels, the soil becomes “sodic.” Sodic soils are characterized by a poor soil structure: they have a low infiltration rate, they are poorly aerated and difficult to cultivate. Thus, sodic soils adversely affect the plants' growth. This experiment will illustrate the effect of water containing a high concentration of salt on the growth of plants.
Research Soils that contain a harmful amount of salt are often referred to as salty or saline soils. Soil, or water, that has a high content of salt is said to have a high salinity. A soil may be rich in salts because the parent rock from which it was formed contains salts. Sea water is another source of salts in low-lying areas along the coast. A very common source of salts in irrigated soils is the irrigation water itself. Most irrigation waters contain some salts. There are two types of salt problems which are very different, those associated with the total salinity and those associated with sodium. Soils may be effected only by salinity or by a combination of both salinity and sodium.
Variables • Control: The control for this experiment will be half of the bean plant population receiving water from the City of Phoenix supply. • Independent variable: The plants in the group receiving the treatment of being watered with the salt solution are being tested for ability to thrive with saline solution. • Dependent variable: The dependent variables to be measured will be actual plant height and leaf color.
Hypothesis Bean plants receiving the 20% saline solution will die or fail to thrive as compared to the control bean plant group.
Materials • Two 1000 ml beakers • Digital Balance • Table Salt- 20 g/L • 20 pinto beans • 20 ¼ cup peat pots • Outdoor area receiving appox. 6 hrs. of sunlight per day • 30 cm ruler • Kellogg potting mix- 150 g/pot • 60 liters of tap water • 60 liters of 20% salt water • Excel growth log template • Digital camera
Procedure 1.Establish an outside area that receives approximately 6 hours of sunlight per day that will accommodate 20 pots- 2. Fill 20 ¼ cup peat pots with 150 grams of Kellogg potting mix per pot- 3. Place one pinto bean in each pot at a depth of 3 centimeters. 4. Divide plants into two groups of ten. 5. Label one group “Control” and the other group, “Treatment.” 6. Place both groups in the outside sunlit area determined in step #1. 7. Label beakers #1 and #2- 8. Fill beaker #1 with 1000 ml of tap water. 9. Weigh 20g of salt, add to beaker #2. Fill the beaker up to the 1000ml line. (This will result in the 20% solution). 10. Water the control group of plants with 100ml of water, from beaker #1, twice per day- 7:00AM and 5:00 PM. Refill the beaker as needed from the City water supply- • Water the treatment group with 100ml of water from beaker #2. Twice per day, 7:00AM and 5:00PM- Prepare more solution as needed describer in step 9- • Measure plant growth and observe leaf color every 3 days for 4 months. 13. Enter data in Excel program, analyze data, report results, list conclusions.
Data/Observations Bean Plant Growth: Treatment/Control Color: The treatment plants started to yellow at observation four where the control maintained a healthy deep green color. The color change corresponded to the slowing of growth relative to the control plants.
Conclusion The salt solution eventually killed 100% of the treatment plants. The treatment group failed to thrive in growth and remained pale or yellow throughout the growth cycle , which impeded photosynthesis. The control group continues the thrive and have actually produced been pods. The hypothesis: “Bean plants receiving the 20% saline solution will die or fail to thrive as compared to the control bean plant group.” has been proven correct.
Works Cited “Evaluating Recycled Waters for Golf Course Irrigation” http://turf.lib.msu.edu/2000s/2004/041125.pdf “Irrigation Water Quality” http://www.fao.org/docrep/R4082E/r4082e08.htm#7.6.1 “IRRIGATION WATER QUALITY STANDARDS AND SALINITY MANAGEMENT” http://agnewsarchive.tamu.edu/drought/DRGHTPAK/SALINITY.HTM