Fertilizer additives have broad development space and great prospects

Eco-friendly and high-efficiency chemical substances

Regarding fertilizer additives, the definition reviewed and published by the National Committee for Terms in Sciences and Technologies is: chemical substances used to improve fertilizer performance, promote fertilizer efficacy, decompose residual pesticides and nitrates, and improve the soil environment. They improve fertilizer performance and promote fertilizer efficacy; they can decompose residual pesticides, nitrates and agrochemicals to improve the soil environment, purify and remediate soil, and improve the soil ecological environment; they decompose organic matter to increase soil organic matter content, and extracellular polysaccharides can promote the formation and stability of soil aggregate structure, break up compaction, improve physical and chemical properties, build soil fertility, turn lean fields into fertile soil, and raise the sustainable production capacity of soil; they can continuously release nutrient elements fixed by the soil to supply the needs of plant growth.

⟦NL> At present, fertilizer additives can be divided into 9 types by category: fertilizer property improvers; fertilizer slow- and controlled-release types; fertilizer synergists; nutrient or beneficial element types; plant growth regulator types, including auxins, gibberellins, etc.; soil conditioner types, including humic acid, organic matter, etc.; pesticide additive types, including insecticides, fungicides, herbicides, etc.; plant-derived extract types, including alginic acid, bamboo vinegar, etc.; and microbial inoculant types, including rhizobia, nitrogen-fixing bacteria, etc. Among them, fertilizer synergists have the functions of retaining nitrogen, phosphorus and potassium to prevent loss; regulating transformation and release; promoting absorption and transport; and releasing nutrients in the soil.

In agriculture, γ-polyglutamic acid (γ-PGA), as a fertilizer synergist, can promote crops' absorption of nutrients, save fertilizer and increase efficiency, increase yield and improve quality, enhance crop disease resistance, and has a very good slow-release effect on fertilizers, which can reduce environmental pollution caused by excessive or improper application of chemical fertilizers. It also has multiple anionic properties, enabling crops to absorb nutrient elements in the soil more effectively, promoting crop root development, and enhancing disease resistance. For heavy metal ions such as Pb2+ and Cu2+, γ-PGA has a good chelating effect and can be used as a heavy metal absorbent; in addition, it has a good buffering capacity against acids and bases, can effectively balance the pH value of the soil, and avoid soil acidification and soil compaction caused by long-term use of chemical fertilizers. γ-PGA is a purely natural biological preparation that can decompose naturally to produce amino acids and will not cause secondary pollution to the environment. Therefore, as a green biological macromolecule, γ-PGA is a bio-eco-friendly fertilizer synergist with great application potential.

Apply growth regulators skillfully to avoid pitfalls

Plant growth regulators among additives are a class of pesticides used to regulate plant growth and development, including artificially synthesized compounds and natural plant hormones extracted from organisms. Plant growth regulators can control sprouting and dormancy; promote rooting; promote cell elongation and division; control lateral buds or tillering; control plant type to be short and sturdy to prevent lodging; control flowering or male and female sex, and induce seedless fruit; thin flowers and fruit, and control fruit drop; control fruit shape or ripening period; enhance stress resistance; enhance the ability to absorb fertilizers; increase sugar content or change acidity; improve aroma and color; promote latex or resin secretion; defoliate or ripen (to facilitate mechanical harvesting); and preserve freshness, etc. However, each plant growth regulator has a specific use, and the application technical requirements are quite strict. Only under specific application conditions can it produce a specific effect on the target plant. Often, changing the concentration will produce the opposite result. Therefore, when using plant growth regulators, several pitfalls are likely to occur: first, arbitrarily increasing the dosage; second, arbitrarily mixing with other substances; third, not considering the timing and spraying at any time; fourth, using "regulators" instead of "fertilizers."

Microbial inoculants can prevent diseases and pests

In addition, regarding microbial inoculants, Zhang Shuqing also introduced their functions to reporters. Microbial inoculants do not directly provide nutrient substances to plants like ordinary fertilizers. Among them, disease-preventing and nematode-killing microbial preparations can prevent and control soil-borne diseases of vegetables, with a recommended dosage of 250-500 grams/mu; Bacillus wettable powder can be used for sclerotinia, gray mold, phytophthora blight, sheath blight, fusarium wilt, root rot, damping-off and other various fungal and bacterial leaf spots of all kinds of vegetables, fruit trees, cucurbits, field crops and cash crops, with a recommended dosage of 50-100 grams/mu; Clonostachys rosea spore wettable powder is a new type of biological fungicide product, with strong inhibitory effects on many plant pathogenic fungi, and can be used for the control of sclerotinia, gray mold, phytophthora blight, sheath blight, fusarium wilt, root rot, damping-off and other various fungal leaf spots of all kinds of grain crops and cash crops; a special microbial inoculant for vegetable seedling raising has functions of disease prevention, nematode killing, phosphate solubilization, potassium solubilization and chemical pesticide degradation, and especially has obvious preventive and inhibitory effects on soil-borne diseases such as damping-off, sudden wilt, root rot, fusarium wilt and root-knot nematode disease caused by continuous cropping in soil.

Seaweed fertilizer has good fertilizer efficiency and high returns

According to Zhang Shuqing, in recent years, the Chinese Academy of Agricultural Sciences has built a platform specifically for seaweed fertilizer through technology transfer and achievement transformation. Seaweed is one of the most abundant resource marine plants in the world, containing dozens of active ingredients, including kelp polysaccharides, ammonium alginate, mannitol, amino acids, etc., as well as mineral trace elements such as boron, iodine, copper, magnesium and zinc, vitamins, phenolic polymer compounds, betaine, and plant growth regulating substances.

At present, seaweed fertilizer has already been promoted to some extent on strawberries. After one year of soil improvement with seaweed liquid fertilizer, strawberry growers not only overcame the occurrence of strawberry root rot, but also successfully grew the Japanese variety Benihoppe, which has a high price and good returns. The price of strawberries rose from 16 yuan/kg in the past to the current 50 yuan/kg, and in 2013 the net income per mu reached 120,000 yuan. In addition, the rate of premium strawberries increased by 11.2%, the sugar content increased by 1-1.5 degrees, aromatic components increased, fruit firmness was significantly improved, and the shelf life was extended by 5 days.

Zhang Shuqing concluded that the application of fertilizer additives in agriculture has many benefits, and the multi-faceted, multi-functional application effects are obvious. At present, the Chinese Academy of Agricultural Sciences is making great efforts to build a platform for organic green agricultural products, conducting more research on issues such as building new agricultural economic entities and creating industrial chains.