Present Situation of Dictyophora Industry in China and Cultivation Technique of Dictyophora rubrovolvata

China is the earliest country to eat Dictyophora and to realize its artificial domestication. At present, 12 species of Dictyophora have been reported worldwide, 7 species of which are found in China. Dictyophora rubrovolvata, D. echinovolvata and D. indusiata have been cultivated on a large scale, and the main producing areas are Zhijin in Guizhou Province, Shunchang and Jangle in Fujian Province, and Qingchuan and Changning in Sichuan Province. The cultivation of D. rubrovolvata had experienced 4 stages: wild tending, casserole cultivation, outdoor simple greenhouse cultivation and rapid development of new cultivation techniques. The present integrated cultivation technique of bag removing and soil covering of D. rubrovolvata were introduced in detail from the aspects of production and selection of high-quality fungi bags, bag removing and soil covering, spawn running, as well as fruiting management and harvesting. As one of the “ten main promoting technologies” of Guizhou Province in 2022, it had realized rapid propagation of liquid strains and supporting cultivation of improved varieties and methods. The suitable strains were selected to support understory cultivation, layer cultivation, basket cultivation, factory cultivation and other modes, which had short cultivation period and can realize annual production and supply. With the development of the industry, it is expected that low-cost secondary fermentation or tertiary fermentation cultivation technology will be more widely used

Effects of Velocity and Permeability on Tracer Dispersion in Porous Media

During micro-scale tracer flow in porous media, the permeability and fluid velocity significantly affect the fluid dispersion properties of the media. However, the relationships between the dispersion coefficient, permeability, and fluid velocity in core samples are still not clearly understood. Two sets of experiments were designed to study the effects of tracer fluid flow velocity and porous medium permeability on the dispersion phenomenon in a core environment, using natural and sand-filled cores, respectively. From experimental data-fitting by a mathematical model, the relationship between the dispersion coefficient, flow velocity, and permeability was identified, allowing the analysis of the underlying mechanism behind this phenomenon. The results show that a higher volumetric flow rate and lower permeability cause a delay in the tracer breakthrough time and an increase in the dispersion coefficient. The core experimental results show that the dispersion coefficient is negatively correlated with the permeability and positively correlated with the superficial velocity. The corresponding regression equations indicate linear relations between the dispersion coefficient, core permeability, and fluid velocity, resulting from the micron scale of grain diameters in cores. The combination of high velocity and low permeability yields a large dispersion coefficient. The effects of latitudinal dispersion in porous media cannot be ignored in low-permeability cores or formations. These findings can help to improve the understanding of tracer flow in porous media, the design of injection parameters, and the interpretation of tracer concentration distribution in inter-well tracer tests