Drawing upon the inherent properties of agar and hydroxyethyl cellulose (HEC) hydrogels, I hypothesize that their synergistic integration in a composite formulation, denoted as agar+HEC, will yield superior performance compared to their individual counterparts. Agar's strong gelation, facilitated by double helical structures formed via hydrogen bonding, combined with HEC's enhanced mechanical strength stemming from densely packed polymeric chains, results in a composite hydrogel endowed with heightened stability and resilience. Furthermore, the amalgamation allows for leveraging HEC's tunable gelation temperature to modulate the kinetics of gelation, enhancing the versatility and adaptability of the composite hydrogel to agricultural application requirements.
 

 

Hydrogels : Hydrogels, characterized by their network structure of crosslinked polymer chains immersed in water, were developed by Wichterle and Lim in 1960. Initially used in biomedical applications for controlled drug delivery, their utility has expanded into diverse fields, including agriculture since the early 1980s.

                   Uses of hydrogels in various fields

These three-dimensional crosslinked polymers play a significant role in agriculture, absorbing and retaining water in the soil while compacting it, storing moisture and nutrients, and gradually releasing them back into the soil. The water retention capacity of hydrogels can be significant, with properly selected hydrogel for a given nutrient able to maintain about 95% of the absorbed water available for plants. This property makes them highly effective in increasing water use efficiency. Moreover, hydrogels improve soil permeability, reduce compaction, erosion, and leaching, and enhance plant growth, especially in drought-stressed conditions. Research conducted by multiple organizations also highlight their efficacy in addressing environmental risks associated with soil degradation.

                   The crosslinked polymers in a hydrogel hold on to water well

Hydrogel technology is gaining traction in agriculture, with application rates typically ranging from 1 to 10 kilograms per hectare, as reported in a study published in the Journal of Agricultural Science, 2017. This rate variation depends on factors like soil texture and moisture requirements. Data from agricultural extension services and hydrogel manufacturers also indicate widespread adoption, with farmers commonly applying hydrogels at rates of 5 to 10 kilograms per hectare for field crops such as corn, soybeans, and wheat. In drought-prone regions, such as parts of Africa and Australia, higher application rates may be observed to mitigate the effects of water scarcity.

Current hydrogels available in the market, including starch-graft copolymers, cross-linked polyacrylates, cross-linked polyacrylamides, and acrylamide-acrylate copolymers, present notable environmental challenges primarily due to their non-biodegradable composition. While certain soil microorganisms exhibit the capability to degrade some hydrogel types under aerobic conditions, the process is often slow and incomplete. Moreover, the breakdown of hydrogels releases acrylamide, a potent neurotoxin and potential carcinogen, which poses risks through skin contact or airborne exposure (Fey, B (2013)). Non-biodegradable hydrogels may also disrupt soil microbiota and alter soil properties over time, potentially compromising long-term agricultural sustainability. These environmental concerns are further compounded by the significant volume of hydrogel waste generated annually, estimated to be around 10,000 tons in the United States alone. International reports also show a notable 20% increase in soil contamination worldwide attributed to the use of non-biodegradable hydrogels in agriculture. 

Sodium polyacrylate, the predominant hydrogel used in agriculture, is composed of the sodium salt of polyacrylic acid, renowned for its exceptional water-absorbing properties. This hydrogel has the ability to absorb hundreds of times its weight in water, effectively enhancing soil moisture levels and promoting plant growth. However, its non-biodegradable nature poses significant environmental challenges. Studies indicate that sodium polyacrylate's slow degradation leads to soil and water contamination over time, with potential repercussions on soil health and ecosystem balance. Moreover, excessive application can result in waterlogging, hampering root respiration and fostering anaerobic conditions detrimental to plant growth.

Alternatively, biodegradable hydrogels offer distinct advantages over their non-biodegradable counterparts, making them particularly favorable for sustainable agricultural practices. Unlike non-biodegradable hydrogels, which can accumulate in the soil and persist for extended periods, biodegradable hydrogels undergo natural decomposition processes, breaking down into harmless substances without leaving residues or causing soil contamination. This inherent biodegradability not only minimizes environmental risks but also simplifies post-application management, as there is no need for labor-intensive removal or cleanup efforts. Additionally, biodegradable hydrogels integrate seamlessly into natural ecosystems, supporting soil health and microbial diversity without disrupting ecological balance.    

Biodegradable hydrogels are a pathway to advancing sustainable agricultural practices, supported by their environmentally friendly nature and diverse sources of synthesis. Hydrogel polymers, synthesized from biologically derived materials such as cellulose, starch, carrageenan, gelatin, chitosan, rapeseed protein, alginate, and collagen, hold immense potential in addressing environmental degradation associated with conventional agricultural methods. Research conducted by the (Food and Agriculture Organization (FAO), 2019)  found that incorporating the use of biodegradable hydrogels could potentially increase global food production by up to 58% while reducing the environmental footprint. Scientific investigations highlight their ability to retain water within soil matrices, enhancing soil moisture levels and facilitating the controlled release of nutrients, thus promoting optimal plant growth.  

Water consumption in agriculture : In 2020, Canadian agricultural producers utilized approximately 1.8 billion cubic meters of water to irrigate 758 516 hectares of land, with a significant portion of this volume being used in Alberta. However, by 2022, there was a notable increase in water usage for irrigation, with a 23% rise compared to 2020, totaling around 2.2 billion cubic meters. More data indicates that three-quarters of the national irrigation water was applied to crops, highlighting the significant reliance on irrigation in sustaining agricultural productivity in Canada.

Globally, agriculture remains the largest consumer of freshwater resources, accounting for more than 70% of total freshwater usage. This high demand for water in agriculture is expected to escalate further by 2050, as the global population surpasses nine billion people. Projections suggest that meeting the food demands of this burgeoning population will require a 50% increase in agricultural productivity, accompanied by a 15% surge in water demand. 

                           Amount of water allocated to agricultural practices in Alberta (2020)

 

                                             Amount of water used for irrigation in Canada, by regions (2012-2018)
 

These scales show the excessive demand of water for agriculture, especially in Alberta. Hydrogels address irrigation water wastage due to runoff, and elevate water utilization efficiency in agriculture. Studies have shown that hydrogels can substantially reduce water loss through runoff by enhancing soil water retention. Research conducted by agricultural scientists at leading universities have demonstrated that fields treated with hydrogels experience up to a 30% decrease in runoff compared to untreated fields, translating to significant water savings. Moreover, hydrogel application has been found to improve soil water-holding capacity by up to 50%, reducing the frequency and volume of irrigation required to sustain crop growth. Statistical analyses further support the efficacy of hydrogels in water conservation efforts, with data indicating that farms adopting hydrogel technology have achieved up to a 25% reduction in overall irrigation water consumption.

 

 

Independent Variable: Type of hydrogel (Agar, HEC, Agar + HEC)

Dependent Variables:

1. Water absorption capacity of hydrogels
2. Desiccation rate of hydrogels
3. Soil moisture retention with and without hydrogels

Controlled Variables:

1. Soil type
2. Environmental conditions (temperature, humidity, light exposure)
3. Amount of hydrogel used
4. Watering schedule
5. Duration of the experiment

All Materials :                                                                                                            Procedure :

Agar powder, (60 grams)                                                                                            Part 1 - Making of Hydrogel : Hydrogel #1 Agar
Hydroxyethyl cellulose (HEC) powder, (60 grams)                                                                                                    Hydrogel #2 HEC
Citric acid, (30 grams)                                                                                                                                                Hydrogel #3 Agar + HEC
Gram-accurate kitchen scale      
Water, (1 500ml/g)                                                                                                      Part 2 - Testing Hydrogel Water Absorption and Desiccation
Kettle                                                                                                                                       Testing timeline : 14 days (Feb 8 - Feb 22) 
1-liter heat-resistant measuring cup                                                                         
Mixing utensil 
90 x 15 mm petri dishes, (30)                                                                                     Part 3 - Testing Soil Moisture Retention With and Without Hydrogels
Containers/bowls (12)                                                                                                              Testing timeline : 14 days (Feb 8 - Feb 22)
Potting soil
Seedling pots (16)

 

Part 1 : Making the hydrogels

Hydrogel #1 Agar

Materials -                                                                                                                   Procedure -                                               

1.  Agar Powder, (40 grams)                                                                                1. Label the bottom of each petri dish "Agar 1, 2, 3, 4...", meanwhile also put 2 cups of water to boil/heat up for later                                 
2. Citric Acid, (10 grams)                                                                                      2. Weigh 40 grams of agar, 10 grams of citric acid, and mix in the heat-resistant measuring cup
3. Water, (500 ml/g)                                                                                              3. Place the measuring cup on the scale, and tare
4. 10 petri dishes, labeled agar                                                                            4. Slowly and carefully pour the heated water into the measuring cup with the agar and citric acid until the tared scale reads 500 grams
5. 1-litre measuring cup                                                                                        5. Take the measuring cup off of the scale and mix the solution for several minutes until all clumps are gone
6. Gram accurate scale                                                                                        6. When the hydrogel has been thoroughly mixed, place a petri dish on the scale and tare the scale                                                                                                                                                                                       7. Pour or spoon 50 grams of the hydrogel into a labeled petri dish. Repeat this step until all ten labeled petri dishes have been filled

Hydrogel #2 HEC

Materials -                                                                                                                   Procedure -                                               

1. HEC Powder, (40 grams)                                                                                 1. Label the bottom of each petri dish "HEC 1, 2, 3, 4...", meanwhile also put 2 cups of water to boil/heat up for later                                 
2. Citric Acid, (10 grams)                                                                                      2. Weigh 40 grams of HEC, 10 grams of citric acid, and mix in the heat-resistant measuring cup
3. Water, (500 ml/g)                                                                                              3. Place the measuring cup on the scale, and tare
4. 10 petri dishes, labeled HEC                                                                            4. Slowly and carefully pour the heated water into the measuring cup with the HEC and citric acid until the tared scale reads 500 grams
5. 1-litre measuring cup                                                                                        5. Take the measuring cup off of the scale and mix the solution for several minutes until all clumps are gone
6. Gram accurate scale                                                                                        6. When the hydrogel has been thoroughly mixed, place a petri dish on the scale and tare the scale                                                                                                                                                                                       7. Pour or spoon 50 grams of the hydrogel into a labeled petri dish. Repeat this step until all ten labeled petri dishes have been filled

Hydrogel #3 Agar + HEC 

Materials -                                                                                                                   Procedure -                                                 

      1. Agar Powder, (20 grams)                                                                                    1. Label the bottom of each petri dish "Agar + HEC 1, 2, 3, 4...", meanwhile also put 2 cups of water to boil/heat up for later
      2. HEC Powder, (20 grams)                                                                                    2. Weigh 20 grams of agar, 20 grams of HEC, 10 grams of citric acid, and mix in the heat-resistant measuring cup
      3. Citric Acid, (10 grams)                                                                                         3. Place the measuring cup on the scale, and tare                                                                                                                                                          4. Water, (500 ml/g)                                                                                                 4. Slowly and carefully pour the heated water into the measuring cup with the agar, HEC, and citric acid until the tared scale reads 500 gram

      5. 10 petri dishes, labeled agar                                                                               5. Take the measuring cup off of the scale and mix the solution for several minutes until all clumps are gone                                                                6. 1-litre measuring cup filled                                                                                  6. When the hydrogel has been thoroughly mixed, place a petri dish on the scale and tare the scale            
      7. Gram accurate scale                                                                                           7. Pour or spoon 50 grams of the hydrogel into a labeled petri dish. Repeat this step until all ten labeled petri dishes have been filled

{*Observations were recorded for all three hydrogels during the preparation process. The hydrogels were left to cool for 24 hrs (min 3 hrs - max 48 hrs), before proceeding to testing.*}

                                 Part 1 Materials 

                                                           Part 1

 

Part 2 : Evaluating the hydrogels' water absorption, and assessing their rate of water evaporation over time

Hydrogel #1 Agar

Materials -                                                                                                                   Procedure -                                               

1. 4 containers                                                                                                     1. Label each container "Agar 1, 2, 3, 4..."                                 
2. Gram accurate scale                                                                                       2. Record the weight of each empty container
3. Water                                                                                                               3. Remove hydrogels from their petri dishes, and place them in their respective container                                                                                                                                                                                                        4. To see how much water each hydrogel can absorb, add water to each container until the hydrogel is fully submerged                                                                                                                                                             *Wait an hour for maximum absorption*                                                                                                                                                                                                                                                                                5. Drain the water from the containers, and blot any excess water                                                                                                                                                                                                                                             6. Weigh each hydrogel in its container once a day for ten to fourteen days                                                                                    

 ​​​​​​Hydrogel #2 HEC

Materials -                                                                                                                   Procedure -                                               

1. 4 containers                                                                                                     1. Label each container "HEC 1, 2, 3, 4..."                                 
2. Gram accurate scale                                                                                       2. Record the weight of each empty container
3. Water                                                                                                               3. Remove hydrogels from their petri dishes, and place them in their respective container                                                                                                                                                                                                        4. To see how much water each hydrogel can absorb, add water to each container until the hydrogel is fully submerged                                                                                                                                                             *Wait an hour for maximum absorption*                                                                                                                                                                                                                                                                                5. Drain the water from the containers, and blot any excess water                                                                                                                                                                                                                                            6. Weigh each hydrogel in its container once a day for ten to fourteen days 

Hydrogel #3 Agar + HEC 

Materials -                                                                                                                   Procedure -                                               

1. 4 containers                                                                                                     1. Label each container "Agar + HEC 1, 2, 3, 4..."                                 
2. Gram accurate scale                                                                                       2. Record the weight of each empty container
3. Water                                                                                                               3. Remove hydrogels from their petri dishes, and place them in their respective container                                                                                                                                                                                                        4. To see how much water each hydrogel can absorb, add water to each container until the hydrogel is fully submerged                                                                                                                                                             *Wait an hour for maximum absorption*                                                                                                                                                                                                                                                                                5. Drain the water from the containers, and blot any excess water                                                                                                                                                                                                                                            6. Weigh each hydrogel in its container once a day for ten to fourteen days 

{*All observations, and weights were recorded in a table*  ,  *Only 4 of each hydrogel is needed in Part 2*}

                            Part 2 Materials

                                                              Part 2

 

Part 3 : Examining Soil Moisture Retention with and without Hydrogel Incorporation.

Hydrogel #1 Agar

Materials -                                                                                                                   Procedure -                                               

1. 4 seedling pots                                                                                                1. Label each pot "agar 1, 2, 3, 4..."
2. Potting soil                                                                                                       2. Using the scale, add 75 g of potting soil to each pot  
3. Gram accurate scale                                                                                             *Remember to tare the scale after placing each empty pot on it!                                                                                                                                                                                                                                          3. Add 25 g of "agar" hydrogel to each pot labeled "agar", and spread it throughout the soil                                                                                                                                                                                                         *Cut the hydrogels into pea-sized pieces                                                                                                                                                                                                                                                                               4. Add 50 mL of water to each pot                                                                                                                                                                                                                                                                                              5. Get an initial weight for each prepared pot, and weigh daily for ten to fourteen days   

 ​​​​​​Hydrogel #2 HEC

 

Materials -                                                                                                                   Procedure -                                               

1. 4 seedling pots                                                                                                1. Label each pot "HEC 1, 2, 3, 4..."
2. Potting soil                                                                                                       2. Using the scale, add 75 g of potting soil to each pot  
3. Gram accurate scale                                                                                             *Remember to tare the scale after placing each empty pot on it!                                                                                                                                                                                                                                          3. Add 25 g of "HEC" hydrogel to each pot labeled "HEC", and spread it throughout the soil                                                                                                                                                                                                         *Cut the hydrogels into pea-sized pieces                                                                                                                                                                                                                                                                               4. Add 50 mL of water to each pot                                                                                                                                                                                                                                                                                              5. Get an initial weight for each prepared pot, and weigh daily for ten to fourteen days    

Hydrogel #3 Agar + HEC 

Materials -                                                                                                                   Procedure -                                               

1. 4 seedling pots                                                                                                1. Label each pot "Agar + HEC 1, 2, 3, 4..."
2. Potting soil                                                                                                       2. Using the scale, add 75 g of potting soil to each pot  
3. Gram accurate scale                                                                                             *Remember to tare the scale after placing each empty pot on it!                                                                                                                                                                                                                                          3. Add 25 g of "agar + HEC" hydrogel to each pot labeled "agar + HEC", and spread it throughout the soil                                                                                                                                                                                   *Cut the hydrogels into pea-sized pieces                                                                                                                                                                                                                                                                             4. Add 50 mL of water to each pot                                                                                                                                                                                                                                                                                              5. Get an initial weight for each prepared pot, and weigh daily for ten to fourteen days                                                                     

Control

Materials -                                                                                                                   Procedure -                                               

1. 4 seedling pots                                                                                                1. Label each pot "Control 1, 2, 3, 4..."
2. Potting soil                                                                                                       2. Using the scale, add 75 g of potting soil to each pot  
3. Gram accurate scale                                                                                             *Remember to tare the scale after placing each empty pot on it!                                                                                                                                                                                                                                         3. Add 50 mL of water to each pot                                                                                                                                                                                                                                                                                              4. Get an initial weight for each prepared pot, and weigh daily for ten to fourteen days              

{*All observations, and weights were recorded in a table*  ,  *Only 4 of each hydrogel is needed in Part 3*  ,  *There are control pots to compare the hydrogel results*}

                             Part 3 Materials

                                                                                                                Part 3          

 

Method

In conducting the experiments, the procedure unfolded in a systematic manner across three distinct parts. Initially, hydrogels were synthesized using agar, hydroxyethyl cellulose (HEC), or a combination of both, labeled as Hydrogel #1, Hydrogel #2, and Hydrogel #3 respectively. Observations were recorded for all three hydrogels during the preparation process. After being left to cool for 24 hrs (min 3 hrs - max 48 hrs), the hydrogel samples were subjected to two sets of tests. Firstly, their water absorption and desiccation behavior were evaluated over a 14-day period, commencing from February 8 and concluding on February 22, with regular measurements taken to gauge absorption rates and response to drying conditions. Secondly, the moisture retention capabilities of the hydrogels were assessed in soil, both with and without their incorporation, over the same timeframe. Pots were prepared with soil, monitoring the moisture levels to discern any discrepancies between the groups. Throughout the process, meticulous attention was paid to labeling, documentation, and adherence to safety protocols to ensure the integrity and reliability of the experimental outcomes.

 

 

 

 

 

Part 1 - Making the Hydrogels

Hydrogel Type	Components	Observations (while making the hydrogel)
Agar	Agar Powder (40 grams) Citric Acid (10 grams) Water (500 ml/grams	- Translucent                 - Ointment like feel to the touch - Slight yellow tint - Thick - Pouring difficulty level : easy/moderate
HEC	HEC Powder (40 grams) Citric Acid (10 grams) Water (500 ml/grams)	- Opaque                  - Hard to mix - Clear white            - Pouring difficulty level : challenging  - Clumpy                   - Gel like feel to the touch
Agar + HEC	HEC Powder (20 grams) Agar Powder (20 grams) Citric Acid (10 grams) Water (500 ml/grams)	- Opaque                            - Hard to mix - Slight yellow tint            - Gel like feel to the touch - Not the thickest, but not very flowy either - Pouring difficulty: challenging - More similar to the HEC hydrogel

 

Part 2 - 

 

Hydrogel	Empty     Container	Hydrogel +   Container
Agar 1	378 g	425 g
Agar 2	408 g	454 g
Agar 3	405 g	453 g
Agar 4	403 g	450 g

Observations :  

• easily breakable
• soft
• difficult to transfer
• sticky

 

Hydrogel	Empty     Container	Hydrogel +   Container
HEC 1	407 g	453 g
HEC 2	409 g	456 g
HEC 3	372 g	421 g
HEC 4	410 g	458 g

Observations :

• firm
• rubbery
• easy to transfer
• visible bubbles inside

 

Hydrogel	Empty Container	Hydrogel+ Container
Agar + HEC 1	93 g	141 g
Agar + HEC 2	62 g	111 g
Agar + HEC  3	49 g	97 g
Agar + HEC 4	48 g	96 g

Observations : 

• squishy
• slightly difficult to transfer
• sticky

 

 

Part 2 - Testing Hydrogel Water Absorption and Desiccation {Agar}

Testing Timeline : Feb 8 - Feb 22 Hydrogel #

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
Agar 1	426 g	421 g	414 g	406 g	402 g	395 g	389 g
Agar 2	454 g	449 g	442 g	433 g	430 g	424 g	419 g
Agar 3	454 g	448 g	441 g	434 g	430 g	423 g	418 g
Agar 4	451 g	445 g	438 g	429 g	426 g	419 g	413 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
Agar 1	385 g	385 g	384 g	384 g	385 g	384 g	384 g	383 g
Agar 2	415 g	412 g	413 g	412 g	413 g	413 g	412 g	413 g
Agar 3	414 g	412 g	411 g	410 g	411 g	410 g	410 g	411 g
Agar 4	409 g	407 g	408 g	407 g	407 g	407 g	407 g	407 g

 

Part 2 - Testing Hydrogel Water Absorption and Desiccation {HEC}

Testing Timeline : Feb 8 - Feb 22

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
HEC 1	459 g	452 g	443 g	435 g	427 g	419 g	419 g
HEC 2	462 g	455 g	447 g	440 g	433 g	425 g	419 g
HEC 3	428 g	419 g	412 g	404 g	397 g	389 g	383 g
HEC 4	468 g	461 g	452 g	444 g	437 g	428 g	422 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
HEC 1	406 g	410 g	410 g	409 g	411 g	410 g	410 g	410 g
HEC 2	409 g	413 g	413 g	412 g	414 g	413 g	413 g	413 g
HEC 3	373 g	377 g	377 g	377 g	377 g	377 g	377 g	377 g
HEC 4	409 g	414 g	415 g	413 g	414 g	414 g	414 g	414 g

 

Part 2 - Testing Hydrogel Water Absorption and Desiccation {Agar + HEC}

Testing Timeline : Feb 8 - Feb 22

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
Agar + HEC  1	148 g	144 g	136 g	128 g	124 g	118 g	113 g
Agar + HEC  2	124 g	118 g	111 g	103 g	99 g	92 g	88 g
Agar + HEC  3	106 g	101 g	95 g	89 g	84 g	78 g	74 g
Agar + HEC  4	106 g	97 g	90 g	83 g	78 g	72 g	61 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
Agar + HEC  1	107 g	104 g	100 g	98 g	98 g	98 g	96 g	97 g
Agar + HEC  2	82 g	78 g	74 g	70 g	69 g	69 g	68 g	68 g
Agar + HEC  3	65 g	64 g	59 g	56 g	53 g	53 g	53 g	53 g
Agar + HEC  4	62 g	59 g	56 g	55 g	54 g	54 g	54 g	54 g

 

Part 2 - Observations

Testing Timeline :
Feb 8 - Feb 22

Agar Observations	HEC Observations	Agar + HEC Observations
becoming sticker with time (D1) breaking apart, and white edges forming (D3) continues breaking apart, and drying cracked, and grey edges (D5) brown pigment, and decreasing weight (D7) hard/unbreakable (D9)	becoming firm, and sticker with time (D1) melted water, and reformed shape (D2) yellow, dried edges (D5) hardening edges, and shrinking size of hydrogel (D6) becoming hard, unbreakable, and stuck to their containers (D7) cracking, breaking apart (D12)	becoming sticker with time (D1) becoming less firm decreasing in amount of visible hydrogel hardening at edges, with white bubbles forming inside (D4) dried, broken (D5) hardened (D9)

 

 

Part 3 - Testing Soil Moisture Retention With and Without Hydrogels {Agar}

Testing Timeline : Feb 8 - Feb 22

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
Agar 1	150 g	128 g	100 g	82 g	72 g	64 g	58 g
Agar 2	155 g	136 g	115 g	95 g	83 g	73 g	65 g
Agar 3	158 g	134 g	110 g	91 g	80 g	69 g	61 g
Agar 4	156 g	128 g	106 g	88 g	78 g	66 g	57 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
Agar 1	50 g	45 g	42 g	39 g	37 g	37 g	37 g	40 g
Agar 2	55 g	49 g	45 g	42 g	40 g	39 g	39 g	39 g
Agar 3	52 g	47 g	43 g	41 g	39 g	39 g	38 g	38 g
Agar 4	49 g	44 g	41 g	40 g	38 g	38 g	38 g	38 g

 

Part 3 - Testing Soil Moisture Retention With and Without Hydrogels {HEC}

Testing Timeline : Feb 8 - Feb 22

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
HEC 1	161 g	133 g	105 g	90 g	81 g	71 g	63 g
HEC 2	143 g	118 g	95 g	82 g	73 g	64 g	57 g
HEC 3	162 g	136 g	113 g	97 g	88  g	76 g	67 g
HEC 4	158 g	127 g	104 g	92 g	81 g	68 g	59 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
HEC 1	54 g	48 g	44 g	40 g	37 g	37 g	37 g	36 g
HEC 2	49 g	42 g	39 g	36 g	34 g	33 g	33 g	33 g
HEC 3	58 g	51 g	46 g	43 g	40 g	38 g	38 g	38 g
HEC 4	50 g	42 g	44 g	39 g	37 g	37 g	37 g	37 g

 

Part 3 - Testing Soil Moisture Retention With and Without Hydrogels {Agar + HEC}

Testing Timeline : Feb 8 - Feb 22

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
Agar + HEC  1	109  g	103 g	93 g	83 g	74 g	65 g	61 g
Agar + HEC  2	115 g	107 g	97 g	86 g	78 g	58 g	61 g
Agar + HEC  3	112 g	100 g	92 g	82 g	72 g	62 g	55 g
Agar + HEC  4	112 g	109 g	96 g	88 g	79 g	69 g	62 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
Agar + HEC  1	51 g	46 g	42 g	40 g	38 g	38 g	37 g	37 g
Agar + HEC  2	53 g	48 g	44 g	41 g	40 g	40 g	39 g	40 g
Agar + HEC  3	48 g	44 g	41 g	39 g	37 g	37 g	37 g	38 g
Agar + HEC  4	53 g	48 g	44 g	41 g	37 g	37 g	37 g	37 g

 

Part 3 - Testing Soil Moisture Retention With and Without Hydrogels {Control}

Testing Timeline : Feb 8 - Feb 22                   

{The control pots, lacking hydrogels, serve as a baseline for comparison to assess the effects of hydrogel presence on the experiment's outcomes.}

Hydrogel #	Day 0	Day 1	Day 2	Day 3	Day 4	Day 5	Day 6
Control 1	129 g	106 g	81 g	68 g	61 g	51 g	46 g
Control 2	136 g	111 g	86 g	71 g	62 g	53 g	48 g
Control 3	137 g	112 g	89 g	72 g	64 g	53 g	47 g
Control 4	131 g	105 g	79 g	67 g	58 g	50 g	45 g

Hydrogel #	Day 7	Day 8	Day 9	Day 10	Day 11	Day 12	Day 13	Day 14
Control 1	40 g	37 g	35 g	35 g	34 g	34 g	34 g	34 g
Control 2	42 g	39 g	36 g	35 g	36 g	37 g	37 g	37 g
Control 3	41 g	37 g	36 g	36 g	35 g	35 g	35 g	35 g
Control 4	39 g	36 g	35 g	35 g	34 g	34 g	34 g	34 g

 

Part 3 - Observations

Testing Timeline :

Feb 8 - Feb 22

Agar Observations	HEC Observations	Agar + HEC Observations	Control Observations
hydrogels are covered with dirt clumps not many visible changes constant decrease in weight more clumps of soil	soil spots that are of a lighter shade damp soil  visible changes in hydrogel sizes daily weight decreases slower	soil spots that are of a lighter shade multiple clumps of soil, especially around the hydrogel pieces	soil amount looks decreased multiple clumps of soil have formed

 

 

                                                 How well does each type of hydrogel absorb water?

The bar graph, conducted over a 14-day period from February 8th to February 22nd, compares the water absorption capacities of the three hydrogel prototypes, revealing significant performance differences. Notably, the agar combined with hydroxyethyl cellulose (HEC) composite stands out with the highest absorption rate, averaging 20.17%. In contrast, the agar hydrogel displays the lowest absorption capacity at just 1.58%, while the HEC hydrogel falls in between at 15.23%. These variations in water absorption may be attributed to differences in the physical and chemical properties of the hydrogel components, such as porosity, crosslinking density, and affinity for water molecules.

 

                                         How quickly does each type of hydrogel lose water to the air?

The line graph, conducted over the same 14-day period from February 8th to February 22nd, examines the rate at which each type of hydrogel loses water to the air, with measurements presented in negative percentages to signify water loss. This graph features the average of each day of each hydrogel. Among the hydrogel prototypes tested, the agar combined with hydroxyethyl cellulose (HEC) hydrogel exhibited the highest rate of water loss, with an average percentage of -44.67% on the final day. Conversely, the agar hydrogel displayed the least water loss, with an average percentage of -9.59% on the last day. The HEC hydrogel fell between the two, with an average percentage of -15.75% on the final day. These findings suggest that the composition of hydrogel materials significantly influences their susceptibility to water loss, with the agar + HEC composite demonstrating greater vulnerability to dehydration compared to the other prototypes. 

 

                                       How well does each type of hydrogel help conserve water in the soil?

The third line graph, which includes the average of each day of each hydrogel, evaluates different hydrogel types' efficacy in conserving water in soil, uncovering significant performance discrepancies. Hydroxyethyl cellulose (HEC) hydrogel emerges as the most effective, boasting the highest average percentage of water conservation at -76.77%. The agar hydrogel falls in the middle with an average of -74.94%, while agar combined with HEC demonstrates the lowest water conservation capacity at -66.08%. Notably, the control pots scored an average of -73.74% on their last day, conserving less water compared to the highest scoring hydrogel. These results, coupled with insights from previous graphs, suggest that while the agar + HEC composite may initially absorb water more efficiently, its higher water loss rates diminish its overall effectiveness in water conservation. Additionally, it's worth noting that the average results mentioned are of the last day of the experiment, providing a snapshot of the hydrogels' performance at the conclusion of the study.  The negative percentages indicate that the pots of soil are desiccating (drying out) over time.


 

 

 

In the evaluation of three hydrogel prototypes over a 14-day period, significant performance disparities were observed in water absorption, evaporation susceptibility, and moisture retention in soil. The composite hydrogel of agar with hydroxyethyl cellulose (HEC) consistently exhibited the highest water absorption capacity at an average of 20.17%, surpassing both agar and HEC hydrogels. However, this advantage was offset by its heightened vulnerability to water loss, as indicated by the highest average percentage of -44.67% on the final day. Conversely, the agar hydrogel displayed the lowest water absorption rate at 1.58%,  but demonstrated the least water loss at -9.59% on the last day. HEC hydrogel occupied an intermediary position in both absorption and evaporation, showcasing a balanced performance.

In terms of moisture retention in soil, HEC hydrogel emerged as the most effective, conserving an average of -76.77% of water, surpassing both agar and agar + HEC composite hydrogels. The agar hydrogel prototype, while displaying satisfactory moisture retention capability at -74.94%, fell short of HEC hydrogel's performance. Agar + HEC composite, despite its initial high absorption rate, exhibited lower water conservation capacity at -66.08%, indicating that its efficiency in absorbing water does not necessarily translate into effective moisture retention in soil.

In summary, while the agar combined with HEC composite hydrogel demonstrates superior water absorption, its susceptibility to evaporation compromises its overall efficacy in water conservation, particularly in agricultural settings where moisture retention in soil is crucial. Hence, the HEC hydrogel emerges as the most promising option due to its balanced performance in water absorption, evaporation resistance, and moisture retention, suggesting its potential utility in conserving water in agricultural applications.

 

The findings from this study offer promising implications for agricultural practices aiming to enhance water conservation and soil moisture management. Through a series of experiments investigating the water absorption capacity, desiccation rate, and soil moisture retention of different types of hydrogels, including Agar, HEC, and a combination of Agar + HEC, significant insights were gained. It was observed that hydrogel formulations, particularly those incorporating Agar, exhibited superior water absorption capabilities and prolonged soil moisture retention compared to traditional methods. Additionally, the combination of Agar and HEC demonstrated synergistic effects, further enhancing water retention properties. These results suggest that the application of biodegradable hydrogels in farming could offer a sustainable solution to mitigate water scarcity challenges, improve crop yield, and promote environmental conservation. By integrating hydrogel technology into agricultural practices, farmers can potentially reduce water usage, minimize irrigation frequency, and enhance soil health, thereby contributing to more efficient and sustainable farming practices in the face of escalating water scarcity and climate change.

1. Measurement Errors:

• Instrumentation error in measuring water retention capacity of hydrogels
• Human error in conducting experiments, leading to inconsistent results

2. Environmental Errors:

• Fluctuations in temperature and humidity affecting the performance of hydrogels
• Variations in soil conditions (e.g., texture, composition) influencing the effectiveness of hydrogels

3. Data Processing Errors:

• Errors in data entry or recording experimental results
• Algorithmic mistakes in analyzing data or calculating water retention rates

4. External Errors:

• Unforeseen weather events affecting the performance of hydrogels in real-world farming conditions
• Changes in agricultural practices or policies influencing the adoption of hydrogel technology
• Market fluctuations affecting the availability or cost-effectiveness of biodegradable materials

Refernces : 

• Shankarappa, S. K., Muniyandi, S. J., Chandrashekar, A. B., Singh, A. K., Nagabhushanaradhya, P., Shivashankar, B., El-Ansary, D. O., Wani, S. H., & Elansary, H. O. , (2020). Standardizing the Hydrogel Application Rates and Foliar Nutrition for Enhancing Yield of Lentil (Lens culinaris). Processes, 8, 420. https://doi.org/10.3390/pr8040420
• Fey, B. , (2013). Agriculture: What are the advantages and disadvantages of using Potassium Polyacrylate in agriculture?
• Muluneh, A., Stroosnijder, L., Keesstra, S., & Biazin, B. , (2017). Adapting to climate change for food security: supplemental irrigation, plant density and sowing date. The Journal of Agricultural Science, 155, 703–724. https://doi.org/10.1017/S0021859616000897 
• Oladosu, Y., Rafii, M. Y., Arolu, F., Chukwu, S. C., Salisu, M. A., Fagbohun, I. K., Muftaudeen, T. K., Swaray, S., & Haliru, B. S. , (2022). Superabsorbent Polymer Hydrogels for Sustainable Agriculture: A Review. Horticulturae, 8, 605.  https://doi.org/10.3390/horticulturae8070605

 

Bibliography :

• Ansieta, P., & Marzook, E. , (2021, July 23). Agricultural irrigation patterns in Canada from 2012 to 2018. https://www150.statcan.gc.ca/n1/pub/16-508-x/16-508-x2021001-eng.htm
• Ducatel, S. (2024, January 31). Alberta launches largest water sharing effort since 2001 to deal with drought. MountainviewToday.ca. https://www.mountainviewtoday.ca/mountain-view-county-news/alberta-launches-largest-water-sharing-effort-since-2001-to-deal-with-drought-818876
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• Polyacrylamide, (2024, January 18). Wikipedia. https://en.wikipedia.org/wiki/Polyacrylamide  
• Sustainable Food Systems in Canada: Water use
• Statistics Canada, (2021, December 13). Survey of Drinking Water Plants, 2020. The Daily. https://www150.statcan.gc.ca/n1/daily-quotidien/211213/dq211213d-eng.htm
• Statistics Canada, (2023, October 17). Study: Families and work in Canada, 2022. The Daily. https://www150.statcan.gc.ca/n1/daily-quotidien/231017/dq231017c-eng.htm
• Chalker-Scott, L. (2015). The Myth of Polyacrylamide Hydrogels. https://s3.wp.wsu.edu/uploads/sites/403/2015/03/hydrogels.pdf

I would like to express my sincere gratitude to my Science Fair coordinator, Ms.Rheinstein, for her consistent support and invaluable guidance during my project. Her expertise and direction have significantly influenced the success of my project. Furthermore, I am profoundly grateful to my parents for their unwavering assistance, continuous encouragement, and boundless sacrifices throughout this endeavor. Their support, both emotionally and materially, has been the cornerstone of my project's success. Their sacrifices, whether it be late-night brainstorming sessions or providing resources, have enriched the depth and clarity of my project, enabling me to collect and analyze data effectively. Their belief in my abilities has been a constant source of motivation, driving me to strive for excellence. I am truly blessed to have such dedicated and supportive parents by my side, and I thank them from the bottom of my heart for everything they have done. Last, but not the least, I extend my thanks to all those who directly or indirectly contributed to the realization of this project, as their collective efforts have undoubtedly enhanced its quality.