Institute for Agro-Environmental Sciences, NARO

Carbon and Nutrient Nexus Unit

Accurate estimation of emissions of greenhouse gases (GHG) is indispensable for promoting countermeasures against global warming and climate change. In this regard, accuracy improvement of the agricultural sector in the national GHG inventory is needed. Our unit is devoted to research of material (here, carbon and nutrients) flows in food production and consumption as data of human activities related to the national GHG inventory. Human-induced nitrogen loads are the root of various environmental problems including climate change. Development of indices of nitrogen loads due to food production and consumption is of a particular interest, which are helpful for other stakeholders such as public and decision-makers to understand and communicate the environmental nitrogen issue. Furthermore, unraveling unknown processes in carbon and nitrogen cycles and their responses to environmental changes such as elevated atmospheric CO2 levels and climate change is also an important aim to enhance the predictability of their behaviors in the future. Our three major research topics are as follows:

Accuracy improvement of food-related material flows in the anthroposphere

Accuracy improvement of material flows in food production and consumption is conducted by data survey and analysis. In addition to their flows in the anthroposphere, loads to each of environmental media (air, soil and water) and ecosystems due to the material flow are also evaluated.

Development of indices on environmental nitrogen issues

Environmental nitrogen loads due to food production and consumption is of concern in terms of climate change via emissions of nitrous oxide as a potent greenhouse gas. Adequate indices of the environmental nitrogen loads are useful for nitrogen management to maximize the benefit of nitrogen as macronutrient and minimize its environmental threats. Thus, development of environmental indices of nitrogen is a research target.

Unraveling unknowns of carbon and nitrogen cycles and their responses to environmental changes

We focus on biogeochemical processes of carbon and nitrogen, about their unknown remains and their responses to environmental changes. Agro-ecosystems are included as part of subsystems in the earth system. Any changes in the agro-ecosystems spread to other subsystems and vice versa. New findings from various types of ecosystems are precious also to agro-environmental sciences.


Unit Leader

Research Topic : Nitrogen biogeochemistry

Unit Members

Research Topic
Shin-ichiro MISHIMA Principal Researcher Flows and stock of phosphorus and potassium
Takeshi TOKIDA Researcher Free-Air CO2 Enrichment (FACE), Stable isotope biogeochemistry, Plant-soil-microbe interactions, Rice, Methane