INVESTIGATORY PROJECT

Submitted By:Ma. Phoebe T. Subo

Mary Camille SamsonMary Agnes Jardeleza

EFFECT OF THE NUMBER OF EARTHWORMS ON THE

GROWTH OF BUSH SITAW (Vigna unguiculata ssp. sesquipedalis)

I. PROBLEM

How does the number of earthworms affect a plant’s

growth?

II. HYPOTHESIS

I think that if there are more earthworms, then the plant will

grow faster.

III. EXPERIMENTAL DESIGN

a. CONTROLLED VARIABLES

• Type of plant• Type of soil• Size of worms• Size of pots• Amount of sunlight• Time for recording the growth• Time for watering• Amount of water• Amount of soil

b. MANIPULATED VARIABLE

• Number of worms in each pot

c. RESPONDING VARIABLE

• Bush Sitaw’s growth

IV. MATERIALS

• 12 identical plastic pots• 60 Sitaw seeds• 15 kg of soil• 36 earthworms• Water• Ruler• Measuring cup• Weighing scale• Garden soil• Sunny area

V. PROCEDURES1. Measure 1.25 kg of garden soil using the

weighing scale and pour into plastic pot. Repeat for each pot.

2. Place the earthworms in pots according to treatment:

Control – noneTreatment A – 2 earthwormsTreatment B – 4Treatment C – 6

3. Each treatment should be replicated three times.

4. Label the pots accordingly.

5. Place 5 Sitaw seeds in each pot.6. Pour one (1) cup of water into each pot.7. Place the pots in a sunny area so that

they receive the same amount of sunlight.8. As soon as the seeds germinate and has

fully developed its two (2) leaves, select three (3) healthy plants and pull the two (2) remaining. Three (3) Sitaw plants should be used as samples for each pot.

9. Start recording the number of leaves developed and plant height one day after thinning.

10. Recording of the number of leaves and plant’s height should be done thrice a week.

11. Watering of plants should be done in the morning at 11:30 and in the afternoon at 2:30.

VI. RESULTS

BACKGROUND INFORMATION

Earthworm, name given to more than 1000 species if worms in the Oligochaeta class pf the phylum Annelida. It has a cylindrically shaped, segmented body that tapers off at both ends. Earthworms live in deep, dark, long, and narrow tunnels or burrows under the ground.

By its burrowing actions, the earthworm is of great value in keeping the soil structure open, creating a multitude of channels which allow the process of both aeration and drainage to occur.

Earthworms also increase the productivity of many soils. They do this by improving the structure of the soil, by bringing up nutrients to the surface layers of the soil from deeper down and assissting in the breakdown of organic matter in, or on the surface of the soil.

After digestion, earthworms produce excrement about the size of a pin head. This excrement is called ‘casting’ or ‘vermicompost’ and is an excellent soil conditioning material.

Investigations in the US show that fresh earthworm casts are 5 times richer in available nitrogen, seven times richer in available phosphates and 11 times richer in available potassium than the surrounding upper six inches of soil. In conditions where there is plenty of available humus, the weight of casts produced is greater than 4.5 kg per worm per year.

When Earthworms die, usually in the dry summer, the organic material making up their bodies is gradually released, providing additional nutrients for plants. These minerals are essential to healthy plant growth.

SEPT. 17

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 4.5 2

TREATMENT A 4.5 2

TREATMENT B 4.6 2

TREATMENT C 4.8 2

SEPT. 19

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 11.13 2

TREATMENT A 9.2 2

TREATMENT B 9.8 2

TREATMENT C 9.4 2

SEPT. 21

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 12.01 2

TREATMENT A 10.6 2

TREATMENT B 13.03 2

TREATMENT C 14.11 2

SEPT. 23

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 14.73 3

TREATMENT A 13.52 3

TREATMENT B 14.42 3

TREATMENT C 16.2 3

SEPT. 25

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 16.44 4

TREATMENT A 15.41 4

TREATMENT B 16.67 4

TREATMENT C 18.04 5

SEPT. 27

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 16.5 5

TREATMENT A 15.77 4

TREATMENT B 16.77 5

TREATMENT C 18.53 5

SEPT. 29

PLANT HEIGHT (cm)

# OF LEAVES

CONTROL 23.4 5

TREATMENT A 23.4 5

TREATMENT B 25.5 5

TREATMENT C 27 5

The results show that the plant’s growth has no difference in the Control and treatment A pots.

However, there is a difference in the plant’s growth between

Treatment A, B, and C.

VII. CONCLUSION

• The results show that my hypothesis should be accepted for even though there is no difference in the plant’s growth between Control and Treatment A, there is a difference between Treatment A, B, and C. The plant with the fastest growth is the Treatment C while the plants of Control and Treatment A have the slowest growth.