Straw really contains fulvic acid, and turning waste into treasure offers high value

A crudely made fertilizer advertisement made the words "golden granules" an overnight staple of the comedy world, but in the field of biomass utilization, "golden granules" really do exist. This is fulvic acid.

????Straw is always simply burned

Before discussing fulvic acid, we must first talk about one of its carriers - straw.

China is a major agricultural country, producing 800 million tons of straw each year, but rural straw resources in China remain in a state of high consumption, high pollution and low output. Abandoning and burning straw has long been an urgent problem for China to solve.

"Burning straw causes ground temperature to rise sharply, can directly burn and scorch beneficial microorganisms in the soil, affects crops' full absorption of soil nutrients, destroys soil structure, and directly affects crop yield and quality, while also causing air pollution and forming smog. At the same time, unordered piling and arbitrary abandonment of straw allow it to enter water bodies, causing eutrophication and polluting water sources," said Hu Shuwen, professor in the Department of Environmental Science and Engineering, College of Resources and Environmental Sciences, China Agricultural University.

There are many reasons why straw burning has been repeatedly banned but not stopped. For example, rising living standards have reduced farmers' demand for firewood and grass, the cost of straw disposal is too high, and the economic value of straw is difficult to realize. There is also a lack of proper guidance.

But the most critical reason is still the lack of disposal technology. Farmers cannot find a way to turn straw from waste into treasure.

A treasure dug out of dry grass

Countries around the world have carried out unremitting research on straw utilization, including the extraction of fulvic acid.

Fulvic acid is a gray-black powdery substance soluble in water. It is a plant growth regulator that can promote plant growth, plays an important role in drought resistance, can improve plant stress resistance, increase yield and improve quality.

Potassium fulvic acid fertilizer can also activate compacted soil, improve soil aggregate structure, loosen soil, improve the soil's water- and fertilizer-holding capacity, regulate pH, reduce the content of heavy metals in soil, and reduce the harm of salt ions to seeds and seedlings.

At present, Europe uses fulvic acid as a biostimulant, with the world's largest usage; in Asia, Japan's fertilizer legislation in the 1960s stipulated that fertilizers must contain fulvic acid; some Southeast Asian countries use fulvic acid as a fertilizer and feed additive.

The Notice of the Ministry of Science and Technology, the Ministry of Agriculture and the Ministry of Finance on Issuing the "Catalogue of China's High-Tech Products 2006" (Guokefajizi [2006] No. 370) defines fulvic acid as: "A plant growth activator, belonging to a class of humic acid with relatively small molecular weight. Fulvic acid content >=8%, pH <=5.5, arsenic <=0.002%, cadmium <=0.002%, lead <=0.01%, used as a growth promoter, fertilizer efficiency enhancer, pesticide synergist and detoxifier, and soil improver."

An old comrade gains a new world

As an "old comrade" used across centuries in China's agricultural production, fulvic acid has long shown five major effects: "enhancing fertilizer efficiency, improving soil, strengthening stress resistance, improving quality, and stimulating growth." Constrained by a large population and limited land, excessive fertilization, non-point source pollution and soil fertility degradation in recent years have become shortcomings in China's modern agricultural development. With the advocacy of "storing grain in the land and storing grain in technology," as well as the successive introduction of policies such as zero growth in chemical fertilizers and pesticides and the "Soil Ten Measures," practical actions to prevent and control agricultural non-point source pollution and improve soil fertility have provided a broad stage for developing new functions of fulvic acid.

The new straw comprehensive utilization model of Shandong Quanlin Group has "drawn a circle" of a green and efficient circular chain for scientific fertilization and straw disposal, the one input and one output in farmland.

"The key innovation of Quanlin's 'clean straw pulping and resource utilization of waste liquid fertilizer technology' is new-style material preparation, vertical continuous cooking, mechanical defibration + oxygen delignification, and technology for producing fulvic acid fertilizer from straw lignin. The most critical part is extracting fulvic acid," said Song Yujie.

At present, Quanlin Group is the only enterprise in the world that extracts fulvic acid from straw. According to infrared spectrum analysis by the Taiyuan Humic Acid Quality Testing Center of the China Humic Acid Industry Association, the fulvic acid produced by "Quanlin" technology belongs to the same class of substances as coal humic acid and fulvic acid, and quality testing reports show that the fulvic acid content of Quanlin fulvic acid stock solution is as high as more than 20%, with other indicators also superior to the quality standard requirements for fulvic acid in the above "Catalogue of China's High-Tech Products." Because the industrialization of technological achievements has shown obvious results, especially because fulvic acid plays a significant role in boosting agricultural development, Quanlin Group received the "National Technology Invention Second Prize" in 2012.

According to statistics, if refined straw fulvic acid fertilizer is applied continuously for 3-5 years, it can reduce chemical fertilizer use by 20%-50%; reduce pesticide use by more than 30%; and raise the soil fertility grade by more than 0.5 grade.

The new model lets farmers earn more money

From the establishment of a technical research team by the enterprise in 1998 to the initial establishment of a straw comprehensive utilization industry in 2002, Quanlin's straw processing and utilization technology has been operating in factories for 14 years, basically forming a completely new model for the circular economy development of China's papermaking industry.

This model is jointly supported and formed by multiple circular economy utilization sub-chains, including the pulp and paper production chain, the waste resource utilization circular chain, the wastewater treatment and reuse circular chain, and the waste ammonia recycling chain: cellulose and part of the hemicellulose in straw are used for pulping and papermaking, realizing resource utilization of agricultural residues; lignin, xylitol, nitrogen, phosphorus, potassium and other organic matter in the pulping process are converted into fulvic acid fertilizers through evaporation concentration and spray granulation processes, while waste residues such as leaves and ears are fermented to make organic substrate, realizing comprehensive utilization of waste and "returning straw to the field"; industrial waste ammonia liquid can be used for boiler flue gas desulfurization, and the generated ammonium sulfite is returned to the pulping section as a chemical raw material for pulping; white water from the paper machine is fully reused in production after recovery and treatment; most middle-stage water is reused in production after advanced treatment, and the rest is discharged up to standard.

Song Yujie calculated an account for the reporter. Taking a single project that annually uses 3 million tons of straw to produce fulvic acid fertilizer and cellulose products such as pulp and paper and ethanol as an example, after the project is put into operation, it can achieve an annual output value of 12.5 billion yuan, create nearly 6,000 direct jobs, and at the same time, through straw collection and storage business, the enterprise directly increases local income by 1.5 billion yuan, driving ten thousand farming households to start businesses and become prosperous. (Reporter Ma Aiping)