Impact of land use change and climate fluctuations on potential productivity for farmland of Guangxi

【Objective】This paper aimed to analyze the impact of land use change and climate fluctuation on the potential productivity for farmland of Guangxi in recent 20 years. 【Method】Based on the remote sensed land use data from the late 1980s to 2010, the paper analyzed the farmland dynamic changes of Guangxi. Using the method of step-by-step revision of environmental factors combined with the daily meteorological data from 1990 to 2010, the paper estimated the potential productivity of farmland. 【Result】In recent 20 years, Guangxi's farmland decreased 20843.81 ha. Under the multi year average climate conditions in 1990-2010, the land use change type of ‘forest land becomes arable land' contributed the most increment of the gross potential productivity for the newly reclaimed farmland, and the percentage was 80.73%.The land use change type of ‘arable land becomes construction land' induced the most loss of the gross potential productivity for farmland with the percentage of 74.39%. The impact of climate fluctuation on paddy field's potential productivity was optimistic given that the land use maintained the conditions of the late 1980s, while the situation was not conductive for the non-irrigated farmland. 【Suggestion】The newly reclaimed farmland's potential productivity was less than that of the lost farmland, meaning higher quality farmland was decreasing. Accordingly, when emphasizing the balance of cultivated land area, attention should also be paid to the balance of cultivated land quality. On the one hand, the reduction of high quality arable land should be prevented. On the other hand, water-saving irrigation and other measures should be taken to improve the grain production capacity, so as to make up for food production losses caused by reduction of quality arable land and climate changes.