The research we are carrying out is a fundamental research into understanding and resolving of environmental issues that may arise in connection with biogeochemical material cycling in soil–plant system. In some regions nutrients including nitrogen and others are expected to be prone to flowing out from a part of agricultural ecosystems and human life systems, so this mechanism is being examined. In order to understand the impact of acid rain on the natural ecosystems, basic data on material cycling in forest ecosystems that have not become a pollutant source are collected. Dynamics of substances, such as carbon dioxide, methane, and nitrous oxide, of concern to the global environment like global warming are assessed in various ecosystems as well. In addition, in order to carry out those activities, examinations of measurements and estimation methods are necessary. From the perspective of material cycling, quantitative measurements are necessary. And from the perspective of environmental quality, data on concentration is exceedingly important. In order to specify the pollutant source, data must be collected from numerous spatial points. Furthermore, to identify the timing of pollution, data must be collected with temporal variation. And those must be expressed in a simplest possible model.
The objectives of our research are to understand below points.

• Nutrient dynamics in agricultural ecosystems
• Dynamics of greenhouse gas (nitrous oxide, methane, carbon dioxide) in agricultural ecosystems
• Nitrate leaching in agricultural ecosystems
• Nitrogen cycling in regional scale
• Development of an integrated model