Progress and trend of world agricultural engineering discipline

Here is an accurate track of the evolution process of the agricultural engineering discipline in the world in recent years. This article aims to understand the development trend of the discipline, and to provide a strong reference for China's agricultural engineering discipline, particularly for the discipline that supports agricultural power construction and Chinese modernization. Among them, 30 journals of the world's most representative ones were selected in the agricultural engineering field. The worldwide research on agricultural engineering was then mapped in the six periods from 1965-2021 using bibliometric methods and visual mapping software. The six periods were as follows: 1965-1970, 1971-1980, 1981-1990, 1991-2000, 2001-2010, and 2011-2021, respectively. The data were also collected in the scientific literature from the above 30 journals covered by the Web of Science (WoS) core collection. The results showed that the research objects were developed steadily from the conventional to the interdisciplinary fields in the world agricultural engineering discipline. The conventional research fields included water and soil resources, porous media, solute transport, the drying of agricultural products, the interaction between tillage tools and soil, the performance of tractors, livestock manure treatment, and environmental pollution control. The interdisciplinary research fields were associated with the development and utilization of biomass resources (lignocellulosic, biochar bioadsorption, heavy metal, dye removal, biofuel production, anaerobic digestion, and bioenergy system life cycle assessment), algae-related research (screening and cultivation of microalgae and macroalgae, lipid increase and carbon dioxide fixation in photobioreactors, conditions, technologies and methods related to harvesting, processing and production of biofuels, microalgae biorefining, life cycle analysis of microalgae biodiesel production), hydrology and water quality research (impacts of climate change on watershed hydrology, and SWAT (soil and water assessment tool) model), application of Internet of Things, information network technology, big data, artificial intelligence, and Global Position System (GPS), Geographic Information System (GIS), Remote Sensing (RS) advanced technologies in modern agriculture (unmanned aerial vehicle system, precision agriculture, smart agriculture, vertical farm), and membrane pollution. Six periods were then named after the initial, growing, transition, sublimation, flourishing, and blending period, according to the development of world agricultural engineering disciplines. In terms of research output, the USA was the world leader in the first four periods, then Canada and England. In the last two periods, China, India, and Brazil were among the top three, China jumped to the top in the final period. There was an ever-increasingly prominent interdisciplinary in the six periods. The output and influence of the related interdisciplinary research journals were strengthened gradually, such as Bioresource Technology, Industrial Crops and Products, Water Resources Research, Biomass and Bioenergy, and Computers and Electronics in Agriculture. Several suggestions were also proposed for the development of China's agricultural engineering discipline: 1) To systematically make the overall development plan of the discipline according to the needs of Chinese modernization development and agricultural power construction; 2) To continuously strengthen the cooperation with Europe, America, and the emerging developing countries in the fields of agriculture, biological systems engineering, environmental engineering, water and soil resources, computer and electronic information technology. 3) To develop a discipline that is guided by the goals and requirements of agricultural power construction. The findings can provide an important reference for the innovation and development of the agricultural engineering disciplines in China, particularly for the powerful science & technology and talent support for Chinese agricultural modernization.