Urban-rural sustainability in Chinese mega cities focusing on the functions of farmland to food production and environmental protection: a case study in Tianjin City

Research Project , Research Report 2006

Kazuhiko TAKEUCHI Professor, Graduate School of Agricultural and Life Sciences, Univ. of Tokyo
Shigenori MORITA Professor, Graduate School of Agricultural and Life Sciences, Univ. of Tokyo
Shinya YOKOYAMA Professor, Graduate School of Agricultural and Life Sciences, Univ. of Tokyo
Akira KIMINAMI Professor, Graduate School of Agricultural and Life Sciences, Univ. of Tokyo
Kensuke FUKUSHI Associate Professor, Integrated Research System for Sustainability Science (IR3S),Univ. of Tokyo
Tetsuo TAKANO Associate Professor, Asian Natural Environmental Science Center (ANESC), Univ. of Tokyo
Yuji SAKAI Research Associate, Graduate School of Engineering, Univ. of Tokyo
Yuji HARA Project Research Associate, Integrated Research System for Sustainability Science (IR3S), Univ. of Tokyo

Abstract

This project has been carried out under the memorandum on promoting exchanges of scientific knowledge and people between The University of Tokyo and Tianjin City Government, and aims to create technologies and visions for urban-rural sustainability through biomass recycling oriented society in Tianjin City, China. On the basis of this project’s previous results, in fiscal 2006, we have field practiced the following four subprojects: (1) Understanding of the current urban-rural land-use mixture and spatial planning system, (2) Reinforcing agricultural vitality through improving quality of rice and its relish, (3) Developing techniques to reclaim sodium-affected farmland, (4) Developing techniques to remove heavy metals from farmland. We then gained the following results. (1) We quantified a spatial expansion of urban land uses as well as suburban agricultural fields such as vegetable greenhouse. Considerable vegetable production was exported outside Tianjin City, which didn’t contribute to biomass recycling within city scale. (2) We confirmed that the people’s needs of delicious rice are increasing nowadays due to the income growth, and a level of research activities on improving rice taste and quality is also considerably developing. (3) We proposed the sodium-affected soil reclamation method that performs not only the use of desulfurization gypsum but also desalinization due to phytoremediation in Tianjin. The soil reclamation tests with desulfurization gypsum or construction waste gypsum caused the increase of the agricultural production. Moreover, new data and concept necessary for the improvement of integrated evaluation model that can evaluate the economic impact, environmental impact, health effect, and soil reclamation effect could be obtained. (4) Mercury and cadmium concentrations markedly reached to comparable level with those around Japan’s large point source. Polluted irrigation water was considered as wide-area and common contribution in Tianjin together with copper, zinc and lead.

Keywords:

Tianjin City, Land use, Urban-rural sustainability, Biomass