Seaweed extract refers to using large algae growing in the ocean as raw materials, through chemical, physical or biological methods, to extract the natural nutrients needed for crop growth and development in the seaweed, including a variety of natural plant growth regulators ( Auxins, cytokinins, gibberellins, alginic acid, seaweed polyphenols, protein amino acids, nucleotides, plant anti-stress substances, etc.) are made into fertilizers and used on crops to promote crop growth and increase yields. Improve the quality of agricultural products.
There are three main categories of production methods: physical methods, chemical methods, and biological enzymatic hydrolysis methods. The extraction method has a great impact on the active substance and nutrient content of the product. Even if the nutrient content is the same, the active substance content may be very different.
1.The physical method, also known as the mechanical crushing method, uses physical means such as high-pressure grinding and crushing. In order to reduce the loss of active ingredients, the entire process tries to avoid high temperatures and chemicals. However, the physical method is less effective and once the algae are broken, the algae are not completely broken. , resulting in the nutrients not being fully extracted.
2.Chemical methods mainly include organic solvent and alkaline extraction. In the organic solvent method, factors such as the crushing of raw materials, solvent dosage, temperature, time, etc. will affect the extraction efficiency during the entire process. The alkaline hydrolysis extraction method is simple and easy to operate, but it causes high damage to nutrients and incomplete retention of nutrients.
3.Biological enzymatic hydrolysis mainly involves microbial fermentation and enzymatic hydrolysis. The process conditions are mild and will not affect the biological activity of natural substances. Its original activity is retained to the greatest extent.
Different processes of Green Seaweed Extract and Black Seaweed Extract:
- Black seaweed extract is extracted using chemical methods. Potassium fulvate was used as the adsorption carrier. So the resulting product color is black.
- Green seaweed extract is extracted by biological enzymatic hydrolysis without the need for adsorption carriers, so that seaweed extract with a pure green content of more than 40% can be extracted.
The difference between green Seaweed Extract and black Seaweed Extract lies in their core components and internal constituents.
This constitutes the fundamental reason for the disparity in their effects.
| Component Category | Green Seaweed Extract | Black/Brown Seaweed Extract |
| Pigments | Rich in Chlorophyll a/b, as well as Lutein. | Rich in Fucoxanthin (a carotenoid) and Chlorophyll a/c. |
| Energy Storage Substances | Primarily stored as starch. | Primarily stored as Laminarin (a soluble carbohydrate) and Mannitol (a stress-resistance factor). |
| Cell Wall Components | Primarily cellulose. | Primarily Alginic Acid (Alginate) and Fucoidan. |
| Bioactive Substances | Rich in amino acids and vitamins (especially B-complex and Vitamin C); high protein content. | Rich in natural plant growth regulators (precursors to auxins, cytokinins, and gibberellins), betaine, and phenolic compounds (polyphenols). |
| Mineral Elements | High content of core chlorophyll elements, such as magnesium and iron. | Extremely high content of iodine, potassium, calcium, and magnesium, as well as trace elements abundant in seawater. |
Comparison of Agricultural Efficacy
Based on the aforementioned differences in composition, these substances exhibit distinct performance characteristics in the field:
Characteristics of Green Seaweed Extract :
Focus on Nutrition and Photosynthesis: Since green algae naturally possess high levels of protein and chlorophyll, their extracts can rapidly replenish organic nitrogen and magnesium. Following foliar application, crop leaves typically become greener and thicker within a short period.
Growth Promotion: Rich in amino acids and small-molecule peptides, the extract can be directly absorbed by crops to participate in protein synthesis, thereby exerting a significant stimulatory effect on seedling growth.
Microbial Activation: The starches and sugars present in green Seaweed Extract are readily decomposed and utilized by soil microorganisms, thereby enhancing soil microbial activity.
Characteristics of Brown Seaweed Extract :
Focus on Stress Resistance and Regulation: Having evolved over long periods in harsh environments—characterized by tidal fluctuations, low temperatures, and high salinity—brown algae have developed exceptionally robust mechanisms for stress resistance. The betaine and mannitol found in their extracts can significantly bolster a crop’s resilience against drought, salinity, and low-temperature stress.
Rooting and Fruit Enlargement: The abundant alginic acid acts as a chelating agent for soil metal ions, thereby improving soil structure; meanwhile, the naturally occurring auxins and cytokinins promote root system development and fruit enlargement, while helping to prevent premature senescence.
Soil Improvement: Alginic acid serves as a natural flocculant, effectively improving compacted soils.
Practical Application Recommendations
1.Scenarios for Using Green Seaweed Extract :
- When crops exhibit yellowing due to magnesium deficiency.
- When there is a need to rapidly boost leaf photosynthetic efficiency and restore a vibrant green color to the foliage.
- When serving as a supplementary source of organic nitrogen to promote the vegetative growth of the plants.
2.Scenarios for Using Brown/Black Seaweed Extract :
- When crops are exposed to late-spring cold snaps, drought, or are being cultivated in saline-alkaline soils (to enhance stress resistance).
- To promote root development and shorten the recovery period following transplanting.
- When aiming to alleviate soil compaction and improve soil aeration.
- During the fruit expansion stage, when the goal is to enhance fruit quality and sweetness.
In summary, green seaweed extract and black seaweed extract are both high-quality natural plant growth regulators, but there are certain differences in efficacy and use objects. Choosing suitable seaweed extract products according to needs can improve the stress resistance of plants, promote growth and increase yields, and contribute to the development of green agriculture.
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