Plasma nitrogen fixation system with dual-loop enhancement for improved energy efficiency and its efficacy for lettuce cultivation

Plasma nitrogen fixation(PNF)has been emerging as a promising technology for greenhouse gasfree and renewable energy-based agriculture.Yet,most PNF studies seldom address practical application-specific issues.In this work,we present the development of a compact and automatic PNF system for on-site agricultural applications.The system utilized a gliding-arc discharge as the plasma source and employed a dual-loop design to generate NO_(x)from air and water under atmospheric conditions.Experimental results showed that the system with a dualloop design performs well in terms of energy costs and production rates.Optimal operational parameters for the system were determined through experimentation,resulting in an energy cost of 13.9 MJ mol^(-1)and an energy efficiency of 16 g kWh^(-1)for NO_(3)^(-)production,respectively.Moreover,the concentration of exhausted NO_(x)was below the emission standards.Soilless lettuce cultivation experiments demonstrated that NO_(x)^(-)produced by the PNF system could serve as liquid nitrate nitrogen fertilizer.Overall,our work demonstrates the potential of the developed PNF system for on-site application in the production of green-leaf vegetables.

Design and experiment of a barrel-shaped aeroponic cultivation system

Theoretically,aeroponic cultivation is easy to make plant roots in a better growth environment.In order to give better play to the theoretical advantages of aeroponic cultivation,further optimize the structure of the aeroponic cultivation system,and make the aeroponic cultivation system more scientific and reasonable,a barrel-shaped aeroponic cultivation system is designed.The aeroponic cultivation system is composed of a monitoring and control system,power equipment,nutrient solution storage,and treatment facility,nutrient solution supply pipelines,aeroponic cultivation barrels,and nutrient solution return pipelines.The cultivation system working principle and its technical requirements were analyzed,and its structure for meeting the requirements of large-scale production was determined.A performance test of the barrel-shaped aeroponic cultivation system using cultivated narrow leaved Chinese chives was conducted.The Chinese chives were cultivated to 6 beds of the cultivation barrel.The system supplied nutrient solution every 30 min for 2 min each time.After 5 weeks growth,the length,leaf width,and single weight of Chinese chive ranged from 293-362 mm,4.1-6.7 mm,and 3.48-5.47 g,respectively,the average length,leaf width,and single weight of Chinese chive were 327 mm,5.1 mm,and 4.24 g,respectively,and there were no significant differences in the length,leaf width,and single weight of Chinese chive on 6 beds by One-way ANOVA.The test results showed that all the Chinese chive in each bed of the cultivation barrel grew well and uniform,which indicated that the circulation process of nutrient solution supply and return in the system was normal,the process of nutrient solution atomization in the system was uniform,and the aeroponic cultivation system operated normally and stable and could be applied in production.