plants and fertilizer

Introduction:

Without research and the use of fertilizers, today’s human population could not survive. Limited amounts of nutrients in the soil will be consumed by plants in just a few years. We need to feed the soil with nutrients to be able to use it again as a farm land. These nutrients for soil are called fertilizers. These are what plants need to grow.

For many years, humans knew that animal manure can be used as fertilizer. Possibly someone accidentally noticed that plants grow better around animal droppings. They also noticed that burying dead animals next to a tree will help the tree grow faster.
Why animal manure or animal flesh of animals are fertilizers was unknown for many years.

Finally chemical science developed and chemists were able to identify chemical elements and chemical compounds. They tested chemical ingredients of manure and also tested many different chemicals to see which one acts as a fertilizer. These studies and experiments lead to the fact that the main fertilizer elements are Nitrogen, Phosphates and Potassium. The reason that animal manure and dead animals are used as fertilizers is their nitrogen and phosphate contents. Even today meat byproducts and crushed bones are used as nitrogen based and phosphate based fertilizers. Commercial production and use of synthetic fertilizers started around 1850. Synthetic fertilizers are also called inorganic fertilizers.

Information Gathering:

Find out about what you want to investigate. Read books, magazines or ask professionals who might know in order to learn about the effect or area of study. Keep track of where you got your information from. This is a sample of the information that you may find about fertilizers.

Fertilizers are organic or inorganic material that contain a high level of nitrogen, phosphate, potassium or other nutrients needed for plants growth. Fertilizers must be water soluble in order for the plant to absorb them. Most inorganic fertilizers are 100% water soluble, but organic fertilizers have some water soluble contents.

Organic fertilizers such as animal droppings and animal flesh are not fully water soluble, but they will decompose and create more soluble material as time passes.

Inorganic fertilizer compounds differ greatly in their solubility in water. These differences are usually unimportant for application in the solid form. High solubility, however, is one of the major considerations for the grower who purchases solid fertilizer for dissolving in irrigation water, or for application in foliar sprays. Let’s compare the solubility of a few fertilizers.

Solubility of Some Fertilizers

Recently attention has been given to the production of fertilizers that have low initial solubility and release nutrients to the soil and plant gradually over an extended period of time.

Question/ Purpose:

What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.

Problem statement: High cost of fertilizers is a major problem for many farmers and producers of different plants. By identifying different materials that can be used as fertilizers we may be able to find some free or low cost fertilizers. For example we may discover certain household or industrial waste materials that are good fertilizers and are widely available at no or little cost.

Question: Any of the following questions can be used for this project.

• What material are fertilizers?
• What chemical elements play a major roll in fertilizers?
• What household waste can be used as fertilizer?
• Compare 5 materials (of your choice or assigned by teacher) to see which one is a better fertilizers.
• Compare different types of fertilizers for one specific plant to see which combination produces the best result?

If the question that you have selected is not listed above, consult with your project advisor.

Identify Variables:

When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.

Independent (manipulated) variables for testing fertilizers are usually the amount and the type of fertilizer. In some tests, instead of amount of fertilizer, you may consider only the amount of active elements of that fertilizer. For example amount of nitrogen may be considered as variable, not the amount of a nitrogen based fertilizer. The reason is that some fertilizers have more nitrogen than others.

This is a sample on how you may define your variables:

• Independent variable (also known as manipulated variable) is the type of fertilizer. Possible values are Miracle-Gro, Ground coffee beans, egg shell, meat, rice or any other substances that you may want to test their effects as a fertilizer.
• Dependent variable is the plant growth.
• Constants are the plant type, plant age, soil type, the amount of soil, and the amount of water.
• Controlled variables are light, temperature and other environmental conditions. We make sure that all our test plants grow under the same light and temperature conditions.

Hypothesis:

Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.

This is a sample hypothesis for comparing Miracle gro, Ground coffee beans, egg shell, meat and rice as fertilizers:

Miracle grow is a mixture of known inorganic fertilizers, so it must produce the best results.

Ground coffee contains some soluble material and is part of another plant with some organic contents, so it might contain some nutrition for plants.

Egg shell is not water soluble and does not easily decompose, so it must have no effect.

Meat is a protein with high level of nitrogen contents, but maybe it does not decompose fast enough to show any result for our 10 day experiment.

Rice is a carbohydrate (mostly starch) that does not contain any of fertilizer elements. Therefore it must be as bad as the egg shell.

Experiment Design:

Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”

Introduction: A general and simple method for testing fertilizers is using small pots and identical plants. All physical and environmental conditions for all sample plants must remain the same and the only variable will be the type or the amount of fertilizer that you add.

Procedure:

1. Obtain/ purchas six identical, same size, same type young plants for your experiment. Alternatively you may decide to start by planting seeds. If you plant your own seeds, your experiment takes about 4 to six more weeks to complete. In any case you need good weather and enough light for your plant experiments. If you start by planting seeds, use only top spoil in your flower pots. Do not use potting soil because it already contains a lot of organic mater and some fertilizers.

Fill up half of the pot with soil, place 3 seeds in each pot and then cover them with additional one inch soil. Give equal amount of water to all pots.

1. Each pot will be used for testing one fertilizer, so label each pot with the name of fertilizer you are planning to add to that pot. Label one of the pots as “Control”, this pot will not get any fertilizer.
2. Since you are comparing different fertilizers, you can add a certain weight of each fertilizer. For example you may add 5 grams of dry ground meat in one pot, 5 grams of ground coffee beans in second pot, 5 grams of egg shell in the third pot, five grams of rice in the fourth pot and five grams of Miracle-Gro in the last pot. Mix the fertilizer with the upper layer of the soil. When you water the plant, water will transfer nutrients down to other parts of the soil.
3. Water the plants daily and make daily observations.

At the end either visually or by other methods such as weight or height of plant you grade each fertilizer based on its effects.

How long does it take?

You may continue your experiment for a certain amount of time (2 months for example), or you may continue it until you see a clear difference between the growth rate of different plants.

Variations:

If you think there are other materials around you that may be a fertilizer for plants, feel free to test them. Just make sure that you grind everything and mix it with the upper layer of the soil. Also, try to use dry material or adjust their amount to compensate for their water content. For example you may think that a banana skin may be a good fertilizer, but more than 80% of banana skin is water, therefore you use 25 grams of fresh banana skin instead of 10 grams of dry banana skin. You may do the same for ground meat. Meat usually has about 75% water, so if you don’t have dry meat, use 20 grams of fresh ground meat for it’s 5 grams contents of dry meat.

Make your results more reliable:

You may want to use 3 identical plants for each fertilizer and 3 of the same plant for control in order to have a more reliable result.

Materials and Equipment:

Material and equipment needed for such experiments are:

• Ceramic pots
• Inexpensive and unfertilized potting soil for the test
• (Optional) Soil pH tester to make sure all soil samples have the same pH
• Identical young plants or some fast growing seeds

Results of Experiment (Observation):

During test period you make daily observations and record the results similar to the following:

After completion of the test period (for example 10 days), record the final results in a table similar to this:

Fruit amount is used only if you grow a plant that has fruit such as tomato.

Summary of Results:

Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during the experiments.

Conclusion:

Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.

Related Questions & Answers:

What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.

Possible Errors:

If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.

If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.

References:

List of References:

Fertilizer Zone