I will be doing an experiment where I create 3 different types of hydrogel with each material and test 3 things from each, how well can each dissolve water, how well can each provide moisture to the soil and finally how biodegradable each is.  I will also be running a comparison by using plain water in soil 

My question for this experiment will be: How does hydrogel perform compared to traditional watering methods, and which hydrogel would perform best?

I hypothesise that hydrogels would give similar moisture as water due to its high levels of water retention but I think it would be slower to give moisture as when you water the moisture is immediately given but with hydrogels, it takes time to release. Adding on to that, I believe the recombination of hec and agar would give us the best hydrogel as both have been tested as biodegradable and if their individual properties are good, then combining them would create a hydrogel that would retain the moisture best. 

As our future populations continue to skyrocket, finding a sustainable method to grow crops to fuel this many people becomes more and more difficult. 

Growing large amounts of crops requires large amounts of water,  some of which is lost to evaporation. Now we all know that water is an essential component in our lives, need it be in drinking, showering, washing etc, and if such a precious substance is used such vaguely in these practices, how shall we preserve it?

This pressing topic has pushed scientists to come up with more efficient ways to allow our crops to get the water they require. One of these ways is called hydrogels. 

Hydrogels are materials that easily absorb water and holds on to it. It is composed of a net of polymers or repeating molecules placed into a lattice pattern. Together these polymers cage the water molecularly. 
In an agricultural sense, these gels are gradually added to soil to help retain moisture. When irrigated, the gel collects water over time, reducing the frequency of irrigation as it gradually releases this water over time. THis can be particularly useful in drought experiencing climate such as ethiopia, sudan, eritrea, afghanistan, and china.
Personally, this experiment means a lot to me as in Alberta, agriculture plays a huge role in our economy and our jobs. Especially here in Calgary where there has been a warning of water use in the past couple of days, I truly understand the significance of such a precious liquid. This has made me research for ways to help water our plants efficiently, eventually stumbling upon hydrogels.

Traditional hydrogels have struggled to break into the agricultural field over the years due to their poor chemical composition and environmental impact.  They contains traces of  polyacrylamide or polyacrylonitrile which are neither biodegradable or safe for human consumption as they contain a neurotoxin known as acrylamide which, at high enough doses, can cause cancer.  A study from Harvard found, .people consume food and beverages containing high levels of acrylamide, a naturally occurring chemical found in grains, potato chips, pretzels and other common baked and snack foods. 

Now to combat this I have set out to test 3 different hydrogel prototypes and their efficiency. I will be testing a gel composed of seaweed, cellulose and a combination of both to see which gel can grow my plants successfully while harmlessly breaking down.

1. Seaweed

A hydrogel made from agar, derived from seaweed, is a sustainable agricultural solution due to its ability to retain and gradually release water, reducing the need for frequent irrigation. 

This is due to an ingredient known as argrose, which gives agar its water-retaining and gelling properties that make it useful as  a hydrogel in agriculture.  

Agar is also quite biodegrade able and can break down in the natural environment without leaving a trace.  Since agar comes from seaweed, a rapidly renewable resource, it also has a low environmental impact during production.

2. Hec

A hydrogel made from hydroxyethyl cellulose (HEC) is beneficial for agriculture due to its ability to absorb and retain water, gradually releasing it to plants, which helps maintain consistent soil moisture and supports plant growth, especially in arid conditions. 

HEC is derived from cellulose, a natural polymer found in plant cell walls, making it a renewable and biodegradable material. 

This biodegradability ensures that the hydrogel breaks down naturally without harming the environment, while the use of cellulose, sourced from sustainable plant resources, further enhances its sustainability.
 

3. Combined 

A combination of agar and hydroxyethyl cellulose (HEC) in a hydrogel would be beneficial because it merges the strengths of both materials. 
Agar would help give excellent water retention and structure while the HEC would make it flexible. Together, they would make a great, sustainable hydrogel that would water our plants and completely change they face of future agriculture. 

Though this idea sounds so fascinating, we shall consider the drawbacks such as costs and the risk of over retaining water, which would lead to clogged roots. 

Controlled: 

• Potting soil
• Petri dishes
• Amount of citric acid and water per gel

Manipulated 
 Type of hydrogel material

Dependent
 Which hydrogel holds more moisture 

As per the instructions, I will split this experiment into 3 sections, 1. The making, 2. Testing the creation’s absorption of water and finally, testing the creations effectiveness.
Step 1.
Start by making the agar hydrogel. Label the outside bottom of petri dishes with the word "Agar". 
Recipe: weigh out 40 grams (g) of agar and 10 g of citric acid. Mix those dry ingredients in a heat-resistant measuring cup that can hold at least four cups (one liter) of liquid. Heat more than 500 mL of water in a kettle to boiling. Place the measuring cup with the agar and citric acid on the scale and tare it
 slowly and carefully pour the heated water into the measuring cup with the agar and citric acid until the tared scale reads 500 grams. Use caution with the boiling water; it is hot enough to burn. Since measuring cups are not very accurate at the milliliter level we will use weight instead; 1 milliliter of water weighs 1 gram. 
A measuring cup containing agar powder sitting on a scale while boiling water is poured into it to make a hydrogel. Hydrogels are made by mixing biodegradable polymers with boiling water. Take the measuring cup off of the scale and mix the solution for several minutes until all lumps are gone. The hydrogel mixture will be very thick and it will take a lot of mixing. When the hydrogel has been thoroughly mixed, place a petri dish on the scale and tare the scale. 
Repeat the same procedure for the HEC and Agar + HEC hydrogel recipes.
 

Testing Hydrogel Water Absorption and Desiccation

Label 3 containers for each hydrogel recipe for a total of 9 containers. Record the weight of each empty container in a data table in your lab notebook. Table below shows an example data table.
Carefully, using a butter knife or similar utensil, remove one agar hydrogel from its petri dish and place it in the container labeled Agar Weigh each hydrogel with its container. Record the weight in your data table.
After an hour, drain each container. Carefully, without touching the hydrogel, use a dish towel or paper towel to blot any excess water from the containers.
Weigh the soaked hydrogels and containers one at a time. Record the weight for each one in your data table in the "day 0" column.
Weigh every hydrogel in its container once a day for ten to fourteen days. Record the weights in your data table. Also record your observations and take pictures to document the changes.

Testing Soil Moisture Retention With and Without Hydrogels

Label 3 pots for each hydrogel recipe. You should have 9 labeled pots in total.
Using the scale, add 75 g of potting soil to each pot. Remember to tare the scale after placing each empty pot on the scale!
Add 25 g of hydrogel to the twelve pots labeled for them.
Add 50 mL of water to each of the sixteen pots
Get an initial weight for each prepared pot.
Weight each prepared pot daily for ten to 12 days. Record the weights in your data table. Also, write down any observations you have.

Step 1:  For the first step where I created the hydrogels, i notes that the agar one was very slimy and looked like apple sauce. It also released a weird odor.  It was quite durable. The hec on the other hand, was smooth almost silicone-like but quite tearable. When i mixed the, It was just like agar but a bit more liquidy.

Step 2: WHen we put them into containers, I notice that there was a lot of moisture release every day which is a good sign that the gel is slowly releasing water, especially in the both mixture. After the days, the gel was still quite sizeable which proves to me how it's gonna last a while.

Step 3:  When I measure the water in the soil, I can see that it's getting less and less everyday, showing improving signs of water absorption. In fact, since there is no hole at the bottom of each pot, I infer that the water is being absorbed by the hydrogel a lot everyday. Now yes the controller looks as if its absorbing the same, but keep in mind that the pot was a bigger size and there's only one controller so that's why I believe it's not as efficient than hydrogels.
 

Hydrogels were quite noticeably more efficient than soil and absorbing and retaining water 

Hec+Agar was the best material of hydrogel as we saw in all 3 methods of testing 

Quiet strange that hec + agar #2 yielded quite bit less results than the other two 
 
 

To finalise this experiment, as we have seen, all 3 type of gels were way more efficient at absorbing water that just pure soil and again, this is perceivably due to their amazing polymer capabilities that allow them to store water in tiny holes like books on a bookshelf.  Now also taking in form my observations, it was noted that each day the gels released a bit of moisture that I would see and in the actual fields, if there are thousands of these gel particles, this moisture would be more than enough to hydrate our plants. Additionally, they would still have more that they could release as supposed to needing to water it again.

Additionally, as we can see from the graph, the highest performing gels were the combination of agar and hec, which is what I predicted and it makes sense as the combined powers of both would make the strongest absorbing gel.

Biodegradable hydrogels have so much power and potential and I am extremely excited to see what the future holds.  Not only can hydrogels rescue dependency on frequent irrigation for crops, it also allows for the use of water elsewhere such as bathing, and in very rural drought-prone regions, such as Ethiopia this is vital.  And even in more developed regions, water could be used to help build green roofs or other practices that benefit the earth.

Additionally, since hydrogels are biodegradable and renewable, they don't raise concern over an environmental impact during use. This ensure the technology can help grow safe crops and aid in preservation of nature such as refrotestion. If all goes well, this technology has the power to drive sustainable agriculture, urban greening, and environmental restoration worldwide.
 

Occasional over or underuse of ingredients

Environmental Factors
 

Measuring Times
 

Biodegradation of Hydrogels
 

https://www.sciencedirect.com/science/article/abs/pii/S0014305724006372

https://aehinnovativehydrogel.com/news/a-guide-to-integrating-hydrogels-into-your-farming-practice/

https://www.mewburn.com/news-insights/hydrogels-in-sustainable-agriculture

https://www.ijfmr.com/papers/2023/6/8786.pdf

https://pmc.ncbi.nlm.nih.gov/articles/PMC9781869/

https://wotaichem.com/everything-about-cellulose-hec/

Credits
Mr Rip and Mr Klaassen-For being my coordinator and helping me plan out every part of my project
 My Parents-For effortlessly helping me structure and compose this project and giving me the idea 
My friends and Judges: for viewing my project and giving their feedback to improve it