What is a microbial fertilizer? What are the functions of microbial fertilizers?

　　With the advancement of the times, China’s agricultural sector has undergone fundamental progress. Organic fertilizers, once the primary choice, have gradually been phased out, and in recent decades, chemical fertilizers have come to dominate. However, the extensive use of these synthetic inputs has led to substantial consumption of resources and energy, as well as severe environmental pollution. In recent years, with the rise and development of “green agriculture,” there has been growing attention to quality of life and personal health, along with increased emphasis on the quality of agricultural products. Consequently, the production and development of microbial fertilizers have garnered increasing recognition and support.

　　I. What is a microbial fertilizer?

　　Microbial fertilizers are products that harness the life activities of microorganisms to produce specific fertilizer effects, thereby promoting robust crop growth or increasing yields. Like chemical and organic fertilizers, they constitute an integral part of the fertilizer products used in agricultural production. Also known as microbial inoculants, these fertilizers contain live microorganisms whose metabolic activities supply crops with essential nutrients, stimulate growth, mitigate plant diseases, enhance the efficiency of chemical fertilizers, and ultimately boost yields while reducing the environmental pollution caused by chemical fertilizers and pesticides to both agricultural products and soil.

　　II. What are the functions of microbial fertilizers?

　　1. It promotes nutrient uptake by crops and enhances their resistance to diseases. The beneficial microbial communities in bio‑fertilizers secrete plant growth‑promoting substances and antibiotics, bolstering plant disease resistance and strengthening biological control of soilborne pathogens. This improves tolerance to continuous cropping disorders as well as to diseases such as wilt, yellow wilt, root rot, and root‑knot nematode infestation. Nitrogen‑fixing bacteria convert atmospheric nitrogen into ammonia, while phosphate‑ and potassium‑solubilizing microbes transform fixed phosphorus and potassium into readily available soluble forms. When used in combination with common chemical fertilizers and organic manures, it boosts fertilizer efficiency and delivers significant yield and income gains.

　　2. Enhance soil fertility. A diverse microbial community can activate the soil, increase its fertility, promote the development of a well‑structured soil aggregate, improve soil permeability, and encourage robust root growth, sturdy stems, thick leaves with a deep green color, while also enhancing the soil’s ability to retain nutrients and moisture.

　　3. Promotes root initiation, strengthens roots, and nourishes them. It has a reparative and regenerative effect on the root system, fostering robust, vigorous plant growth and laying a solid foundation for increased yield and income.

　　4. Enhance the quality of agricultural products and promote earlier maturity and earlier market entry. Bio‑fertilizers can reduce pests and diseases, degrade residual pesticides and chemical fertilizers in the soil, and minimize nitrate accumulation. They also increase the levels of protein, sugars, vitamins, and other beneficial compounds in crops, significantly improving product quality—resulting in vegetables and fruits that are vividly colored, delicious, and of superior quality, thus turning agricultural products into safe, green, and high‑quality offerings. A premium bio‑fertilizer should possess multiple functions: it must both activate the soil and suppress disease incidence while nurturing root systems; it should provide or activate nutrients, produce bioactive substances that stimulate crop growth, accelerate the decomposition of organic matter, enhance the quality of agricultural products, and improve the stress resistance of crops. Most importantly, it should ameliorate and restore soil health. At present, products such as Bacillus subtilis, humic acid, and fulvic acid—widely recognized both domestically and internationally—have demonstrated outstanding efficacy in soil remediation.