This special feature is edited in accordance with JVSS symposium held on July 9th, 2025 of the agricultural technology utilizing vacuum and plasma technology. Through four technical reviews, we aim to deepen the knowledge of users and manufacturers involved in vacuum technology regarding advanced agricultural technologies utilizing vacuum and plasma technology.

Atmospheric-pressure plasma (APP) technology has attracted significant attention for its ability to generate reactive species from air using electrical energy. We have developed an air-based APP device that produces high-density dinitrogen pentoxide (N₂O₅) with exceptional selectivity. This achievement broadens the potential applications of plasma-generated, short-lived reactive nitrogen species in agriculture and related fields. As a representative application, plasma-generated N₂O₅ gas was shown to enhance plant immunity in Arabidopsis thaliana. Notably, cytosolic calcium signaling observed within seconds after N₂O₅ exposure indicates a rapid activation mechanism associated with subsequent gene expression changes. Furthermore, N₂O₅ treatment increased several valuable secondary metabolites in sweet basil leaves through the activation of plant defense responses. Based on these findings, we aim to develop sustainable farming systems that reduce dependence on chemical pesticides and fertilizers, contributing to a more sustainable future society.

Nitrogen fixation is essential for modern food production, yet the conventional Haber–Bosch process requires high temperature and pressure and involves significant energy consumption and CO₂ emissions. This article reviews nitrogen oxide (NOx) formation in air thermal plasmas generated by a direct-current arc, focusing on reaction field design and energy efficiency. Air thermal plasmas create high-temperature conditions that activate nitrogen and oxygen, leading to reactive nitrogen species. Key factors affecting NOx generation, including energy input, gas flow conditions, and energy consumption per unit nitrogen production, are outlined together with representative experimental trends relating arc current, NOx concentration, and energy consumption.

The feasibility of plasma-driven nitrogen fixation as a decentralized, electricity-based process is discussed. Its operational flexibility and compatibility with renewable energy sources suggest potential for distributed fertilizer production, while further improvements in energy efficiency remain necessary.

Atmospheric-pressure plasma applications in agriculture have attracted attention as an environmentally friendly technology for enhancing agricultural productivity. Here we introduce research findings on the effects of plasma irradiation on seeds, particularly its role in promoting germination and growth. Notably, plasma treatment of seeds with restricted physiological activity has been shown to induce epigenetic modifications. This discovery has catalyzed the integration of plasma science with agronomy and molecular biology, fostering the emergence of a new interdisciplinary field : Plasma Seed Science.

The lunar surface is a unique environment characterized by a vacuum (zero atmospheric pressure), low gravity (1/6 G), and cosmic radiation. In lunar development plans, it is considered to construct living quarters and food production facilities underground to block cosmic radiation, and to use artificial light-based plant factories for edible crops production. To achieve the production of edible crops on the Moon under 1/6 G conditions, it is necessary to resolve the challenges associated with this low-gravity environment. Previous studies have shown that even in low-pressure environments, such as high-altitude regions (70–90 kPa), plants can exhibit growth patterns similar to those at sea level if the partial pressures of O₂, CO₂, and water vapor, as well as the air temperature, are maintained at levels comparable to those at sea level. This paper discusses plant production under low-pressure conditions, focusing primarily on the research findings of the authors.

In order to discuss chemical vapor deposition (CVD) and atomic layer deposition (ALD), it is necessary to understand chemical reactions. Part 3 of this course will explain actual reaction analysis and process control technologies for CVD and ALD. In this, Part 2, the basics of chemical reactions were explained for application to CVD and ALD.

First, the reasons for the need for chemical reaction analysis were explained. The shape and quality of the films are important factors in determining the rate-limiting process of a chemical reaction. Next, the definition of the reaction rate of CVD reactions was confirmed, and the existence of incubation time was explained. Selective CVD is explained as an application example that utilizes the existence of incubation time.

Furthermore, Arrhenius Plots, which are essential for analyzing chemical reactions, and how to calculate activation enthalpy (activation energy) were explained. Regarding Arrhenius Plots, practical plotting techniques that make reaction analysis easier were explained. The techniques explained here will be carried over to Part 3.