Dingyang ZHOU, Kazuaki TSUCHIYA, Yuji HARA, Hirotaka MATSUDA, Tomoo OKAYASU and Kazuhiko TAKEUCHI （The University of Tokyo / Wakayama University）
Peri-urban agriculture has become an increasingly important policy concern, particularly in rapidly growing cities in emerging countries. An accurate understanding of changes in land use and their driving factors has important implications for assessing food security and policy making. We evaluated agricultural land use changes at the landscape scale in the Tianjin peri-urban area in China from 1993 to 2009 by using Landsat images. The main driving factors of the changes were investigated at the farm scale through a survey of local farmers. The image classification results showed an obvious loss of agricultural land since the early 1990s. Two other notable trends, which differ from results of previous studies of other peri-urban areas, were observed: (1) land had been converted from the production of traditional perishable foods to the production of staple foods, in this case, from vegetables and fruits to maize; and (2) there was a shift from staple production to fiber production, in this case, from rice and maize to cotton. The main driving factors of these changes were farmers adapting to insufficient amounts of labor and freshwater and to the use of treated wastewater for irrigation, rather than to market mechanisms or government policies, because growing perishable foods requires more labor and fiber production consumes less irrigation water. To improve food security and sustainably develop the region, agriculture must be integrated into a larger developmental plan.
agricultural land use change, driving force, peri-urban agriculture, Landsat image classification, Tianjin