The Effect of Water pH Levels on the Growth Rate of Rice

Researched by Dan O.
2003-04

PURPOSE

The purpose of this experiment was to determine how water pH would affect the growth rate of rice.

I became interested in this idea when reading that much of the world depends on rice and many people are dying because of not having enough food. I decided on testing pH because I read that pH might affect the growth of plants.

The information gained from this experiment should help rice producing areas produce better crops by controlling the pH of the water.  

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HYPOTHESIS

My hypothesis was that the plants grown at of six-pH would grow fastest.  

I based my hypothesis on the Canadian Journal of Forest Research, which said that aspen seeds grew best with the pH at six.

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EXPERIMENT DESIGN

The constants in this study were:

  •  Species of rice.
  •  How many seeds are planted in each container.
  •  The growing facility.
  •  The temperature of the growing facility.
  •  The soil moisture.
  •  The amount of light.
  •  The amount of soil.
  •  The planting depth.
  •  The amount of water.


The manipulated variable was the level of pH of the water.

The responding variable was the growth of the rice over a certain period of time.  

To measure the responding variable I used a centimeter ruler to measure the height.

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MATERIALS


QUANTITY		 ITEM DESCRIPTION
150  Rice Seeds
5 Plastic Planters
Potting Soil
1 Light Bulbs and Holder
Plenty Wood Ash
See Above Distilled Vinegar
See Above  pH tabs
10  Plastic ware 1. 8ml
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PROCEDURES

1. Build the growing facility.
a) Duct tape all the holes in the planters
b) Set up the Grow-Light 30. 5 cm from the planters
2. Make the plastic containers ready
a) Poke holes in the containers (9 holes, 3rows of three)
b) Fill the containers with 7. 5 cm of potting soil
c) Put fifteen seeds in each plastic container. Use a handful of potting soil to bury the seeds.
3. Flood the containers.
a) Fill five containers with 10 liters of water
b) Use wood ash to raise the water of one containers pH to ten, (use pH strips to check the pH)
c) Dilute the remainder of Solution D (pH 10) to get to the pH of 8 in one container
d) Use a light dusting of baking soda to get to the pH of 7
e) Use vinegar to get to the pH of 6
f) Use vinegar to get to the pH of 4 
4. Get the seeds ready to grow.
a) Turn on the light for twelve hours
b) Turn the light on at 8 a. m. and turn it off at 8 p. m.
5. Check the pH 
a) Add enough water to fill the containers just past the lip if the water has leaked 
b) Check the pH every two days
c) If the pH is below what it is supposed to be, use wood ash to raise it
d) If the pH is above what it is supposed to be use vinegar to lower it
6. Measure the rice
a) Measure the rice seeds every two days after you check the pH
b) Record how many rice seeds have germinated

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RESULTS

The original purpose of this experiment was to determine how water pH would affect the growth rate of rice.

The results of the experiment were that in test one the pH of ten grew highest and fastest. In test two the pH level of six grew both highest and fastest. On average the pH six had the most growth.

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See my Data table and graph.
 
 

CONCLUSION

My hypothesis was that the plants grown at of pH six would grow fastest.  

The results indicate that this hypothesis should be accepted because on average my pH six grew higher than any of the other plants at the end of twenty-one days.

Because of the results of this experiment, I wonder if the pH level of the soil would affect the rice production at harvest. I also wonder if the pH of the water affects the nutrition value of the rice.

If I were to conduct this project again I would grow the plants longer. I would do the experiment during the summer and let the plants get real sunlight. I would use real soil instead of potting soil. I would use a more natural substance to lower the pH. I would also use more rice plants.

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RESEARCH REPORT

Introduction
Rice is a very important plant, it provides half the world with a valuable food. If the pH positively affected the growth rate of rice, then we could grow more rice at a faster rate. I wanted to see if the pH really did affect the growth.

Rice
Rice is not only a very important food source for animals; humans in half the world depend on rice to live. Rice is very nutritious plant and provides ninety percent of its calories as carbohydrates. It also provides you with thirteen percent of all protein calories. There are twenty known species of rice, but only two are cultivated today. Asian rice is grown more than African rice. Though Asian rice grows faster, African rice is hardier. Asian rice is grown with modern techniques, pesticides, irrigation, fertilizers, and chemicals. Asian rice is preferred in growing because it has more seed to a plant. African rice is more productive with traditional farming methods. There are approximately fifty-thousand different varieties in these two species.  
 Rice is two to six feet tall. It has thin and pointed leaves. It has lots of flower stalks. It has twig like branches. Depending on the type most rice provides about two handfuls of grain per panicle (a loose group of stems). When most of the grain has developed, the panicle sags under the weight.  
 A grain of rice has a covering that is fairly hard called a hull.

pH
pH is the measure of acidity or alkalinity of liquids. On a pH scale, seven is neutral. If the pH is below seven, it is acidic. If the pH is above seven it is alkaline. Baking soda naturally rings the pH of any liquid back towards seven. Wood ash naturally brings pH up past seven. Vinegar brings pH down below seven. Wood Ash can be helpful to plants when the pH level is acidic. pH levels can be dangerous to plant growth if they are to high or to low. It is not unusual for soil to become acidic. Soil often becomes acidic because of rainwater getting rid of basic ions. (potassium, calcium, magnesium, and sodium. Another reason for soil becoming acidic is buildup up acids such as sulfuric acid. “carbon dioxide from decomposing matter and root respiration dissolving into soil water to form a weak organic acid. ”http://www. esf. edu/pubprob/brochure/soilph/soilph.htm 

Agriculture
Without agriculture, most humans could not survive. Without agriculture societies have a very large risk of malnutrition or starvation. The countries that have war have more malnutrition than most other countries. “Civilization began with agriculture. ” http://www. onecountry. org/oc8202as.html Human communities cannot, and never have been able to ignore agriculture and its importance. Agriculture has over half the world’s employees, and is the largest industry in the world.  
 

Summary
Extreme pH can be dangerous to plants, health and many other things. The farther from seven he pH level is the more damaging and dangerous the liquid. Plants grow best when the pH of their environment is at an ideal range.

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BIBLIOGRAPHY

Flynes, Erin “Rice,” ENCARTA Encyclopedia Deluxe, 2001.

Freeborn, Joel. Personal Interview. November 12, 2003

Hershey, Dave R. Plant Biology selah schools, science project, SIS science, S.I.S.. New York: John Wiley and Sons

Keating, Richard C. "Germination," World Book Encyclopedia,  1999.

“The Importance of Agriculture,” January 21, 2004 http://www. onecountry. org/oc8202as.html.
 

ACKNOWLEDGEMENTS

 I would like to thank the following people for helping make my project possible:

  • My parents for helping me set up my light and flooding.
  • Marty Coleman for sending me rice seeds at short notice.
  • Mr. Ken Newkirk for showing me how to set up the board and correcting my papers.
  • Mrs. Carol Helms for helping me with my board.

 
 

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