Hydrogels can help save water because of the materials they are made of. If hydrogels are added to soil, the soil will retain more water and reduce the frequency of watering needed for plants to grow, because hydrogels can absorb and release water over time, improving water efficiency in agriculture.

Background Research

What are Hydrogels?

Hydrogels are a type of material that can absorb and retain large amounts of water. They are attracted to water and get a gel-like consistency when absorbing it. They act like a trap for the water. Hydrogels are great at trapping water, they are soft and flexible, and they are biodegradable. Lastly, they can retain high swelling points.

Types of Hydrogels

Synthetic

It is not a natural type of hydrogel and uses many unnatural chemicals. It is a water-absorbing material made to absorb water while maintaining its state.

Natural

It is a natural hydrogel made from plants and other natural materials.

It is biodegradable and mimics natural elements.

How can Hydrogels help save water?

Irrigating fields can take thousands of liters of water, with a portion evaporating from the unused water in the soil. Not only that, but plants transpire around 95-98% of the water that they suck up through their roots, meaning they only use around 2-5% of their water. This means that the hydrogels can slowly release the water, conserving the water and giving the plant what it needs. 

Hydrogels helping plants and the environment

Hydrogels are already used by some farmers, but a very small percentage of them. If hydrogels were widespread, it could save massive amounts of water and money. 

Examples of Hydrogels

• Agar
• Alginate
• Chitosan
• HEC powder 
• Carrageenan
• Hyaluronic Acid

• Sodium Polyacrylate 

• Cornstarch 

Hydrogels Effects

Hydrogels are already used for many things. For example, they are used in contact lenses, hygiene products, and even wound dressings. They can also be used for drug delivery and tissue engineering. It is also used in plant biology as it holds nutrients and vitamins for the plants. Agar also contains some of the nutrients that the new cells or tissues need to grow and become seedlings. It can be used in saving water for plants and big crops, but it is a lot of work. A lot of people mostly use a lot of water instead and a lot is wasted.

Agar hydrogels hold hormones to stimulate optimal development. Some of these hormones include:

• Cytokinins (helps the plant produce mitos, which splits a cell into 2 identical cells, leading to plant growth)
• Auxin (helps with new root growth and increases cell division) 

Citric Acid

Citric acid can be used in the making of the hydrogels to gain more density, more thickness, and better results. It also gives pH modification, it also increases the water solubility. Which dissolves into the water easily if stirred and spreads its own molecules.

Manipulated Variables
Type of Hydrogel
Different hydrogels such as (Agar hydrogel, Cornstarch hydrogel, and Chia seed hydrogel.)

Dependent Variables 

1. Water Absorption
   Measuring how much absorption there is, on graphs and tables.
2. Water Holding Time
   Recording how long the hydrogel will hold the water until it evaporates.

Controlled Variables

1. Container with Soil
   Same containers for every plant.
2. Soil Type
   Same type of soil will be used for every plant.
3. Water Amount
   Each hydrogel will get the same amount of water.
4. Temperature
   (Room Temperature)

Procedure

1. Gather the materials.
2. Label the Petri dish with the hydrogel type.
3. Combine and mix the products and make the 3 types of hydrogels.
4. Mix it thoroughly. 
5. Pour 40 ml into each of the Petri dishes.
6. Leave them to cool for 48 hours.
7. Add 10 ml water to the hydrogels and leave it for a few hours for maximum absorption.
8. Observe and record the results for 10 days.
9. Add it to graphs and tables.
10.  Print it out and glue it to the trifold.

 Procedure (For Agar Hydrogel)

1. Gather the Materials
2. Label the bottom of Petri dishes with which hydrogel will go in there
3. Start by making the Agar hydrogel
4. Combine 40 (grams) of the Agar powder and 10 (grams) of the Citric Acid In the heat-resistant measuring cup.
5. Boil 500 (ml) of water in the kettle
6. Put the boiled water into the hydrogel and stir it together
7. When all the citric acid and agar powder clumps are gone, pour 50 (grams) of the hydrogel into the Petri dish.
8. Leave it to dry for 24 hours, but not more than 48 hours, or it will turn into a brown crackly substance like ash.

        Procedure (For cornstarch Hydrogel)

1. Gather materials
2. Label the bottom of Petri dishes with which hydrogel will go in there
3. Start by making the Cornstarch hydrogel
4. Combine 40 (grams) of the Cornstarch powder and 10 (grams) of the Citric Acid In the heat-resistant measuring cup.
5. Boil 500 (ml) of water in the kettle
6. Put the boiled water into the hydrogel and stir it together
7. When all the citric acid and cornstarch powder clumps are gone, pour 50 (grams) of the hydrogel into the Petri dish.
8. Leave it to dry for 24 hours, but not more than 48 hours, or it will turn into a brown crackly substance like ash.

Procedure (For cornstarch + Agar Hydrogel)

1. Gather materials
2. Label the bottom of Petri dishes with which hydrogel will go in there
3. Start by making the Cornstarch + Agar hydrogel
4. Combine 20 (grams) of the Cornstarch powder, 20 (grams) of the agar powder, and lastly 10 (grams) of the Citric Acid In the heat-resistant measuring cup.
5. Boil 500 (ml) of water in the kettle
6. Put the boiled water into the hydrogel and stir it together
7. When all the citric acid, cornstarch powder, and agar powder clumps are gone, pour 50 (grams) of the hydrogel into the Petri dish.
8. Leave it to dry for 24 hours, but not more than 48 hours, or it will turn into a brown crackly substance like ash.

Observations

Day 1-3

You can still see tiny white bubbles. 

Agar: Hydrogel hardened but was still moist. It was also transparent.

Cornstarch: Hydrogel was opaque and tiny grains were still visible inside. 

Agar + Cornstarch: It was opaque and was expanding outward. 

Day 3-6

Hydrogels were cold and turning sticky

Agar: It was very hard and was still sticky, but was a little moist. 

Cornstarch: The hydrogel was losing water on the top and was a little dry and hard. 

Agar + Cornstarch: It was very big and almost reached the lid. 

Day 6-9

Some of the hydrogels have cracks in them.

They have become dry and are becoming shriveled up. 

Day 10

All hydrogels are slowly shrinking and there is very little water inside. 

Hydrogels have reached maximum absorption. 

       Purpose

The purpose of this project is to find out how hydrogels can absorb and retain water during our experiment. Our experiment is to test the hydrogels and see if they can help save water in agriculture. We will make the hydrogels, put the water in them, and see how they absorb the water and release it. 

 It is important to save water during agriculture, as water waste is a serious problem in many countries. Some countries don’t have a lot of water, so we need to preserve it during farming. Farming can use a lot of water at a time, so this experiment will help save water. If all farmers in Canada started using hydrogels to save water, they could all save a lot of water together. 

If we save that amount of water, we can save a lot of money. Tens of millions of dollars are spent on water usage annually (around 25.5 million dollars). Hydrogels, if widely adopted by farmers in Alberta, could save millions of dollars (around 5 to 13 million dollars).

Conclusion

To conclude our experiment, the hydrogels absorbed their maximum efficiency of water. The cornstarch hydrogel absorbed most of the water that was put into it. The agar hydrogel reached the maximum absorption. The cornstarch + agar wasn’t an amazing match, as it absorbed the minimum amount of water. 

This shows how our hypothesis was correct, as we stated that hydrogels can absorb water efficiently and save water. When the hydrogel is placed into the soil, it saves water by slowly releasing the water. Once they start to dry, they become lighter showing how they release the water into the soil. The hydrogels used are biodegradable, eco-friendly, and they help to reduce the carbon footprint. This shows how hydrogels help save water and have no bad effects on the environment. 

One of our sources, Science Buddies, explains the meaning of environmental science and agricultural biochemicals. Britannica explains how hydrogels can be very helpful for the environment and how it is biodegradable. 

   Application

We can add this to our daily life by using this in agricultural 

 fields. Instead of water, they can use hydrogels as when the water is put into the hydrogels they release the water slowly over time, giving the plant the moisture and hydration it needs. The hydrogel is also full of hormones that help the plants grow, such as cytokinins and auxins.

Sources of Error

A very important mistake we made was that when we made our hydrogels and put them in our Petri dishes it made an air pocket under the hydrogel, which made our measurement slightly wrong.

Another error we had made was the stirring efficiency we gave to each hydrogel, some got less stirred than others.

The last error we made was that the kitchen scale was getting the number a little off track and was putting the wrong calculations.

   Sources

• ScienceBuddies- https://www.sciencebuddies.org/science-fair-projects/project_ideas/AgTech_p013/agricultural-technology/water-conservation-hydrogels

• Sciencedirect- https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/hydroxyethyl-cellulose

• Britannica.com- https://www.britannica.com/science/polyHEMA

We want to acknowledge our parents as they bought the materials that we needed, they also helped us glue and print our papers.

We would also like to thank our science teacher, Rimi Deb, who gave us advice and helped us improve our project.