The Effects of Acids
and Bases on Plants
By
Matt Goasdone, Jamie Dufault, and Andrew
Charlton
Contents
1) Problem
2) Background
a. Matt’s
b. Charlton’s
c. Jamie’s
3) Hypothesis
4) Materials
5) Procedures
6) Plant Data
7) Conclusion
Problem: The reason we are investing this topic is to discover if
tomato plants can
grow in soil with different pH levels. Can pH be too basic
or too acidic for
plants to grow? That was the problem our group was
faced with. In order
to investigate this problem we had to grow tomato plants
in soil with
different levels of acidity. We then observed over a period
of three weeks
the results of our experiment.
Background Papers:
Matt’s:
Acid rain can have a devastating effect on the
environment, especially in soils and plants. In order to
understand the effects of acid rain, we must first examine
what it really is. Acid rain is formed when
chemicals enter the water cycle, either thorough the
burning of fossil fuels or chemical dumping. Despite its
name, acid rain is not always in the form of rain. Acid may
enter the atmosphere in a dry or wet state. Dry
deposition is when the acid is in the form of gas. Wet
deposition is when the acid is in rain, fog, or snow.
Therefore, a better way ofdescribing the acid that enters
the atmosphere is by referring to it as acid
deposition (What is Acid Rain).
If acid rain contaminates soil, there are numerous
effects that it can have, none of which are positive. Large
farms are less affected by acid rain than forests are
because they have the ability to neutralize the acid. This
ability is called buffer. A soils’ ability to buffer, or
neutralize, acids varies between different types of soils.
Limestone acts as a good buffer, so often farmers will use
crushed limestone to fertilize their fields in order to
protect them against the negative effects of acid rain.
However not all soils have the ability to buffer acid rain
(What is Acid Rain). If these types of soils are affected,
the plants that grow in that area are in trouble. If the soil
is contaminated, the acid dissolves and releases toxic
substances, such as mercury and aluminum, allowing them
to pollute other plants. When plants are polluted, the acid
dissolves and washes away nutrients needed by plants in
order to grow. So ultimately, the plants ability to grow is
disabled. Acid deposition also affects large trees, much in
the same way that it affects smaller plants. If the tree is
poisoned, its ability to photosynthesize is often
compromised. Its leaves begin to deteriorate and its
“immune system” is shut down, leaving it vulnerable to
disease (Acid Rain).
I acid rain is not controlled, it will continue to infect
and destroy countless numbers of plants. The only
way to get rid of acid rain completely is to stop chemical
dumping and the burning of fossil fuels (Acid Rain).
In today’s modern society, it is virtually impossible to stop
these things from happening. However, it is not
impossible to decrease the amounts of chemicals being
dumped or fossil fuels that are being burned. This
process can be slowed, but in order for that to happen,
everyone must do their part. Together, we can lessen
the amounts of acid rain that pollute our environment as
long as we work together.
Charlton’s:
Knowing about the acidity and alkalinity of soil
is of great importance to all gardeners. It can
determine what plants can and can’t grow in the
particular area of soil. It is fairly easy to find out the
soil’s pH level and to change it.
There are three ways to determine the pH level
of your soil. The most accurate way is to take a
soil sample and send it to a lab to be analyzed.
This is the most expensive way to determine the
pH level. Another way is to buy a home test kit
that will give you a reliable result. The test kit
procedures are as follows; 1) put a bit of soil in a
test tube. 2) Add a few drops of test solution. 3)
Shake it up and leave it to settle for about one
hour. 4) Once the solution has cleared, compare
the color of the test tube to the chart that
comes in the kit to determine the pH of your soil.
The final and least effective way to determine the
pH of your soil is to identify what kinds of weeds
and plants grow in the soil and see what pH the
weeds and plants need in the soil to grow. This is a
highly unreliable method. (Finding out about your
pH 1)
It is quite easy to create a movement of 0.5 on
the pH scale but because the scale is logarithmic,
a movement of 2.0 is difficult because there is a
factor of ten between each pH point. To raise the
pH level of your soil it is better to use lime then
any other material. However, depending on the
soil you may be required to use different amounts
of lime. Sandy soils require the least then comes
loam then comes clay and finally peat, moss or fen
soils require the most amount of lime to raise its
pH level. (Raising the pH to make the soil more
alkaline 1)
In order to lower your pH level you can add
peat, compost or manure. Adding 2.5 lbs/square
yard of peat to your soil can lower the pH by 1.0.
Adding 14 lbs/square yard of compost or 5
lbs/square yard of manure can also lower the pH
by 1.0. Another way to lower the pH of your soil is
to add Flowers of Sulfur or Ground Rock Sulfur.
To reduce pH by a level of 1.0, add 1.2 oz per
square yard on sandy soils, or 3.6 oz per square
yard on all other soils. Finally, an emergency
measure is the annual application of Sequestrine
of Iron, although this is not a permanent solution.
(Lowering the pH to make the soil more Acidic 1)
These aspects of soil pH are all important in
how plants grow in a certain soil. It seems to be
that it is usually quite easier to raise the pH of
the soil then it is to lower it. The pH of a soil is
also a great factor in determining how well plants
grow in the particular area of soil.
Jamie’s:
Tomatoes are one of the most common plants grown by
people in America.
They are also one of the easiest vegetables to grow. In
order to grow a successful crop of tomatoes you need
to know what type of tomato you need for planting,
what type of soil it needs, how and where to plant them,
and how they need to be cared for. When choosing a
tomato you want one that is resistant to diseases that
you might find in your garden. Examples of these are
Verticillium wilt, Fusarium wilt, Nematodes, or Tobacco
mosaic virus. If your not sure about whether or not the
areas you are planting in have these diseases you can call
the Federal Department of Agriculture (FDA) or in the
Rhode Island area you could get in touch with URI's
vast department of agriculture. To find a tomato
resistant to these diseases look at the tag on the bag of
seeds you are purchasing and it should be labeled with
the letters V. F. N. or T. to indicate that this type of
tomato is resistant to any of those diseases (Growing
Terrific Tomatoes). There are two main types of
tomatoes. They are either determinate or indeterminate.
This should also be indicated on the tag with a D. or an
I. Determinate tomatoes stop growing after they reach a
certain height. The advantage of using this type is that
most of the fruit ripens at the same time and in a short
period of time. This is the type of tomato you would
want to use in this area because we have a relatively
short growing season. Indeterminate tomatoes continue
to grow throughout the season until they die. An
advantage to using determinate tomatoes is they take up
less space than indeterminate tomatoes and they do not
require support or staking (Groves 426).
Another aspect of growing tomatoes is the type of
soil you're planting them in. One of the reasons
tomatoes are so easy to grow is because they yield very
well in almost any soil and need very little care.
Tomatoes respond best rich, composted soil. Also make
sure the fertilizer is low in nitrogen, because if there is
to much you will end up with more vines and leaves than
tomatoes. Our group will find out later whether or not
the pH level of the soil effects how well the plants
grow, which may be important in growing a well yielding
crop (Groves 426). The most important aspect of growing
tomatoes is where to plant them and the actual process
of planting. Tomatoes are a very generous crop so they
will grow in almost any location, but in order to grow the
best crop they should be planted in an area with six
hours of direct sunlight. When planting the tomatoes in
the garden you should set the plants about two feet
apart in rows that are about three feet apart (Groves
426). The actual process of growing the plants is fairly
simple. Since tomatoes are a long season crop, the seeds
should be started indoors eight to ten weeks before
transplanting, or putting the plants into the ground.
Then dig holes about 18 inches deep for each plant and
set them apart as stated. You can stake the plants or
put them in small cages to support them and help them
grow better, but it is not necessary. Water the plants
immediately after planting. You should always keep the
plants well watered (Growing Terrific Tomatoes). This is
the process of growing tomatoes. The tomatoes are
ready to be eaten when they are a lush red color and
pull off easily from the plant. Hopefully this information
will help you grow a successful crop and realize why
tomatoes are America's favorite vegetable to grow.
Hypothesis: Plants growing in soil with a ph level between 6 and
9 will survive
and plants growing in soil with a ph level below 6 or
above 9 will not.
Procedures:
1. Line up ten planting pots in two rows. Do this in two separate
baskets.
2. Line the bottom of the pots with rocks.
3. Mix soil with water to make moist (topsoil) and put soil in the
pots
4. Equally distribute the acid and base in the following order: 20 ml.
in two pots, 15 ml. in two pots, 10 ml. in two pots, 5 ml. in two
pots, and two pots with no acid or base in it.
5. Plant the tomatoes in each pot.
6. Water the plants with 20 ml. of water immediately after planting.
7. Frequently take pH readings of each of the pots with an acid or
base.
8. Make sure to keep plants well watered.
Plant Data:
Plant #
Amount Of
Sulfur/Lime
Plant 1
Plant 2
Plant 3
Plant 4
Plant 5
Plant 6
Plant 7
Plant 8
Plant 9
Plant 10
Plant 11
Plant 12
Plant 13
Plant 14
Plant 15
Plant 16
Plant 17
Plant 18
Plant 19
Plant 20
18 grams of Lime
18 grams of Lime
13.5 grams of Lime
13.5 grams of Lime
10.5 grams of Lime
10.5 grams of Lime
6.2 grams of Lime
6.2 grams of Lime
0 grams of Lime
0 grams of Lime
21.5 grams of Sulfur
21.5 grams of Sulfur
16.5 grams of Sulfur
16.5 grams of Sulfur
12 grams of Sulfur
12 grams of Sulfur
7 grams of Sulfur
7 grams of Sulfur
0 grams of Sulfur
0 grams of sulfur
Date/Status of
pH level Plant
11/1/2001 11/5/2001 11/9/2001 11/13/3001 11/17/2001 11/21/2
13 Alive
Dead
Dead
Dead
Dead
Dead
13 Alive
Dead
Dead
Dead
Dead
Dead
11 Alive
Dead
Dead
Dead
Dead
Dead
11 Alive
Dead
Dead
Dead
Dead
Dead
9 Alive
Alive
Alive
Alive
Dead
Dead
9 Alive
Dead
Dead
Dead
Dead
Dead
8 Alive
Alive
Alive
Alive
Alive
Alive
8 Alive
Alive
Alive
Alive
Alive
Alive
7 Alive
Alive
Alive
Alive
Alive
Alive
7 Alive
Alive
Alive
Alive
Alive
Alive
2 Alive
Dead
Dead
Dead
Dead
Dead
2 Alive
Dead
Dead
Dead
Dead
Dead
3 Alive
Dead
Dead
Dead
Dead
Dead
3 Alive
Dead
Dead
Dead
Dead
Dead
5 Alive
Dead
Dead
Dead
Dead
Dead
5 Alive
Dead
Dead
Dead
Dead
Dead
6 Alive
Alive
Alive
Alive
Alive
Alive
6 Alive
Alive
Alive
Alive
Alive
Alive
7 Alive
Alive
Alive
Alive
Alive
Alive
7 Alive
Alive
Alive
Alive
Alive
Alive
Conclusion: After observing the growth of the plants for 2
months we
concluded that the plants in a pot with a pH of less than 6
or
more than 8 was not effective for growing tomato plants.
Are conclusions concurred with our hypothesis, which was
that tomato plants grow better in soil with a neutral pH
level?
We were surprised at how quickly the plants died in soil with
a pH of less than 6 or more than 9 as well.