Effect of Different Watering Methods on the Growth of Peas

PURPOSE

The purpose of this experiment was to determine the effect of different watering methods on the growth of peas.  

I became interested in this idea while doing my science project last year. Plants grew relatively well while I watered them every five days. I wondered if other watering schedules would be better or worse.

 The information gained from this experiment could help gardeners and farmers figure out the best method of watering their crops.

HYPOTHESIS

My hypothesis was that the peas getting 40 milliliters of water every 8 days would grow the best. 

 I based my hypothesis on a statement by Dr. Dana Faubion, who is a WSU County Extension Educator and science Professor at Washington State University. He said, “Plants roots need water and oxygen and if the roots are in soil that is full of water they cannot  get oxygen.”

  EXPERIMENT DESIGN

The constants in this study were:

• Number of seeds put in each pot
• The temperature they grow in
• The type of seeds used
• How old the seeds are and how they are stored
• The amount of light the plants get
• Pot size and shape
• Type of soil
• The amount of soil
• Planting depth
• Testing procedures
• Overall amount of water each plant received

The manipulated variable was the watering schedule.  

 The responding variable was the mass of the peas after 32 days.  

To measure the responding variable I measured the biomass of the uprooted pea plants with a triple beam balance.

 MATERIALS

QUANTITY	ITEM DESCRIPTION
1	Pea Packets
54	Pots
12	Foil trays
1	Growing tent
1	Florescent light
1	Triple beam balance scale
1	40 milliliter watering cup
1	Bag of soil
4	21 1/2 inch 1/2 inch PVC pipes
10	12 inch 1/2 inch PVC pipes
3	Garbage bags
8	PVC elbows
5	PVC Tee's

PROCEDURES

1. Build growing “tent”

     A. Using 1/2 inch PVC pipe, elbows, and Tees, build an open framework that is 22 inches tall, 24 inches long, and 24 inches wide.   Reinforce this “box” to support a small fluorescent light.

     B. Suspend the fluorescent light from the top of the box, centered from the sides, attached with strong string, which can be adjusted for height.

     C. Drape black plastic over this framework to form a tent, which can be loosely sealed most of the time, yet easily opened for watering the plants.

2. Prepare growing trays

     A. Make five holes in the bottom of 6 foil trays one in each corner and one in the center. 

     B. Put 4 sticks in all foil trays that don’t have the holes. 

     C. Set each tray with holes onto sticks in tray without holes. 

     D. Label the trays with the correct amount of water to be given to that group.

3. Plant seeds

     A. Fill all 54 pots with soil leaving about 1 centimeter at the top empty. 

     B. Plant 3 pea seeds 2 cm deep in all 54 pots

     C. Put 9 pots in each tray.

     D. Water each group with the right amount of water for that group

4. Grow plants using different watering treatment

     A. Put all the pots in the growing tent and turn on the light for 12 hours. 

     B. Turn off the light for the remainder of the day. 

     C. Water plants based on their treatment group.

         i. Water first group every other day with 10 milliliters of water.

         ii. Water second group every a days with 20 milliliters of water.

         iii. Water third group every 8 days with 40 milliliters of water.

     D. Repeat this for the next 32 days.

     E. During this time record observations.

5. Measure growth

    A. After 32 days of watering the plants pull them out roots and all and label them in brown paper bags

     B. Weigh them with a triple beam balance. 

6. Record data.  

  

RESULTS

The original purpose of this experiment was to determine the effect of different watering methods on the growth of peas.

The results of the experiment were that the group getting 40 milliliters of water every 8 days clearly grew the least.  Their average biomass was 0.49 grams. Both of the other groups were around 0.87 grams, nearly twice as much.
 

  

CONCLUSION

My hypothesis was that the peas getting 40 milliliter of water every 8 days would grow the best. 

 The results indicate that this hypothesis should be rejected.

 Because of the results of this experiment, I wonder if using different water temperatures would change the results. Also different types of plants like corn or wheat. Would be interesting to use in similar experiments .

 If I were to conduct this project again I would grow my plants in a more controlled environment and have more plants for each group. I would do this during the summer in true sunlight. 

Researched by - Katie K