What is a superabsorbent polymer (SAP)?
Potassium polyacrylate is a kind of superabsorbent polymer. So, what is a superabsorbent polymer (SAP)?
As an advanced physical absorbent material, SAP can quickly absorb a large amount of water and lock it firmly. When the water absorption reaches saturation, it changes from a powder or granular state to a hydrogel state.
Generally, the water absorption capacity of SAP can reach hundreds of times of its own. For special purposes, it can reach thousands of times.
As an eco-friendly material, it is totally non-toxic, harmless, and nonpolluting.
What is potassium polyacrylate?
Potassium polyacrylate is a type of SAPs for plants as a water-retaining agent.
Compared with ordinary SAP, agriculture grade SAP (potassium polyacrylate) has undergone post-processing in the production process (such as grafting), which makes it have the unique advantages of being specially used in agriculture:
- Change the cation of the polymer from sodium ion to potassium ion. This not only eliminates the risk of soil salinization caused by sodium ions, but also fertilizes the soil with potassium ions after decomposition.
- Extends the decomposition time in nature. Generally, ordinary SAP will melt and decompose after absorbing water to form a gel in about a month, while SAP for agricultural use can repeatedly absorb and release water in the soil for dozens of months.
- Improved water absorption capacity in the soil: increased pressure absorption and ionized water absorption.
These advantages make it like a “mini reservoir”: it absorbs enough water and stores it during the rainy season or during irrigation, and then continuously provides water to the plants when the soil is dry.
As a result, it brings many intuitive benefits to agriculture such as:
- improve seed germination & emergence, give plants an early, healthy start;
- contains Potassium 18.3% and releases the fertilizer efficiency slowly;
- save the irrigation and improve the soil water holding capacity by 85% (for sand);
- increase crops and fruit yield by 70% (for melon planting in California).
How does it work?
Agriculture grade SAP consists of a set of polymeric chains that are parallel to each other and regularly linked to each other by cross-linking agents, thus forming a network.
When water comes into contact with one of these chains, it is drawn into the molecule by osmosis. Water rapidly migrates into the interior of the polymer network where it is stored. That’s how SAP powder turns to water gel.
As this water gel’s absorption ability is bigger than soil but less than roots of plants, the absorbed water by SAP will be released to plants when it is dry.
Tips: the specific retention of agriculture SAP is 1.3-1.4 MPa and the specific retention of roots is about 1.6-1.7 MPa.
Test the Potassium Polyacrylate
Water Holding Capacity Test
Performance Study in varying soil classifications (test the water retention capacity of SAP in different soils)
Sample volumes Used
Soil: 500ml; Water: 750ml; SAP: 5 gram;
Test 01 – Soil Type: 100% Sand
|Test item||Control Group (without SAP) – 762g||Test Group (with SAP) – 768g|
|Water passing (ml)||425||150|
|Water retaining (ml)||325||600|
Test 02 – Soil Type: 37% Sand + 40% Silt + 25% Clay
|Test item||Control Group (without SAP) – 615g||Test Group (with SAP) – 626g|
|Water passing (ml)||275||100|
|Water retaining (ml)||475||650|
Test 03 – Soil Type: 30% Sand + 48% Silt + 22% Clay
|Test item||Control Group (without SAP) – 407g||Test Group (with SAP) – 400g|
|Water passing (ml)||352||200|
|Water retaining (ml)||398||550|
Laboratory Test ( wilting point )
Common plants and crops
15 to 30 kg per Hectare dosage, along with seeds hole application or ditch application to the soil around the seed, the seed germination rate can effectively improve and promote seedling growth. Gets success planting corn in the U.S, mature in the arid area of Inner Mongolia, potatoes are grown in Cape Verde Africa, and melon yield increased by more than 70%.
Seed coating use SAP should be fine particle size of 0.3 mm or less, after SAP coating the seed emergence quickly, strong and good disease resistance, this is the easily available way to use SAP to plants in a drought area, which also with small quantity, low cost and good performance.
Gardening, Horticulture, and landscape
SAP is ideal for mixing soil matrix, for indoor and outdoor pots, planters, window boxes, balconies, terraces, roofs, hanging, gardens, and city landscape. Planting shrubs, flowers, grass, and vegetables are available. Using SAP can bring water-saving, labor-saving, and time-saving benefits and reduce the drought or wilting risk caused by a long time no watering the plants, longer the green time, and the blossom period.
Lawn and Golf course
Application in golf and lawn can save about 50%-70% water, Reduce the cost of maintenance, and Save about 30%-50% fertilizer. Lawn grows faster, and healthier, and the green lasts longer, with less pollution caused by the loss of fertilizer.
Using 10-20g SAP can double the survival rate of young trees when planting tree seedlings (bare root).
For adult deciduous fruit trees, put SAP with organic fertilizer, taken with a ring groove or furrow in the root area. The dosage is on the soil condition, tree size, and the ditching situation should generally be 0.3% of the backfill soil and fertilizer.