Chelated fertilizers are carefully formulated using chelating agents to combine essential plant trace elements such as zinc, iron, manganese, and copper. Compared to traditional inorganic trace element salts, chelated metal elements exhibit superior biochemical stability, significantly reducing antagonism between nutrients, and their utilization rate is two to three times higher than that of inorganic ions.
Furthermore, the application rate of chelated metal fertilizers can be flexibly adjusted according to the fertilizer requirements of different crops. These advantages make chelated fertilizers an ideal choice for agricultural development.
The preparation of chelated fertilizers primarily relies on ligands such as ethylenediaminetetraacetic acid (EDTA), N-β-hydroxyethylethylenediaminetriacetic acid (HEDTA), citric acid, amino acids, humic acid, and sugar alcohols. These ligands bind tightly to essential plant metal elements such as zinc, iron, manganese, and copper through coordination bonds, forming chelates with a pincer-shaped ring structure. Sugar alcohols, as primary products of plant photosynthesis, exhibit significant advantages as chelating agents. Unlike traditional calcium fertilizers, which are absorbed only through the fruit surface, sugar alcohol chelated calcium fertilizers are absorbed simultaneously through the leaves and fruit surface, ensuring efficient calcium delivery to the fruit interior.
Furthermore, chelated trace element fertilizers significantly promote the absorption of nutrients by crops and ensure their optimal distribution throughout the crop’s organs. This not only helps increase crop yields but also significantly improves the quality of agricultural products. For example, chelating agents such as small organic molecules like sorbitol and mannitol can directly transport trace elements into leaves, significantly enhancing their transport capacity within the plant.
Chelated calcium fertilizers developed using sugar alcohols as adjuvants have demonstrated excellent performance in promoting nutrient absorption, increasing crop yields, and improving agricultural product quality. Furthermore, chelating agents such as humic acid, due to their active groups such as carboxyl, phenolic, and quinone groups, not only promote plant growth and development but also significantly enhance crop resistance to drought, salinity, low/high temperatures, and disease.
Numerous studies have further confirmed that the application of chelated trace elements significantly improves crop yield and quality. For example, adding amino acid chelated magnesium to compound fertilizers can effectively increase the chlorophyll, soluble sugar, soluble protein, and vitamin C content of Chinese cabbage.
In drought conditions, applying chelated trace elements not only increases chlorophyll, soluble sugar, and soluble protein content in crops but also reduces malondialdehyde (MDA) levels, thereby promoting root growth, increasing the surface area of root hairs, and further broadening the root system’s nutrient absorption range, ultimately increasing crop biomass and yield.
Improving Crop Quality and Stress Resistance: The use of chelated fertilizers enhances the quality of agricultural products and strengthens their resistance to drought, salinity, and other stresses. For example, the use of chelated trace element fertilizers can effectively improve crop adaptability and yield performance under adverse conditions, thereby providing strong support for sustainable agricultural development.
Chelated fertilizers efficiently transport trace elements into crops through chelating agents such as sugar alcohols and humic acid. Their utilization rate is 2-3 times higher than that of traditional fertilizers. They can not only increase yields by 20%-30%, but also enhance drought and disease resistance, increasing the VC content of cabbage by 15%.
