Currently, the "five transformations" of straw utilization mainly refer to the following five processes.
First, there is the process of fertilizerization. This includes direct application of crop residues (such as plowing, rotary tillage mixed burial, covering, etc.) and the production and application of organic fertilizers from crop residues. Second, there is the process of feed conversion. Through biological, physical, and chemical methods, crop residues are transformed into animal roughage, including briquetting processing, green and yellow storage, extrusion, twisting and filamentization, bagged micro-storage, etc. Third, there is the process of energy conversion. This includes direct combustion and new energy utilization. Direct combustion is one of the most direct and traditional utilization methods for crop residues. New energy utilization mainly includes solidification and shaping, baling and direct combustion, pyrolysis and carbon gas co-production, production of biogas or bio-gasoline, production of liquid fuels, etc. Fourth, there is the process of base materialization. Processing or preparing them into organic solid materials to provide favorable conditions and certain nutrition for the growth of animals, plants, and microorganisms, including edible fungus cultivation substrates, crop seedling cultivation substrates, and livestock and poultry breeding bedding materials, etc. Fifth, there is the process of raw materialization. Processing or preparing them into pulp for papermaking, artificial boards, straw weaving materials, industrial packaging, disposable tableware, lactic acid, hydroxybutyric acid and other bio-based chemicals, as well as nano-cellulose, carbon-based energy storage materials, and other new bio-based materials. In 2024, the total amount of crop residues in China was 870 million tons, and the total collectable amount was 730 million tons. The comprehensive utilization rate of collectable crop residues remained above 88%, with the utilization rates of fertilizerization, feed conversion, energy conversion, base materialization, and raw materialization being 54.6%, 24.4%, 8.0%, 0.7%, and 0.7% respectively. The utilization pattern of "mainly for agriculture, with five forms of utilization in parallel" has basically taken shape.
