广西LUCC过程与气候波动对农田生产潜力的影响

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

【目的】分析近20年广西土地利用／土地覆盖变化（Land Use and Land Cover Change，LUCC）过程与气候波动对农田生产潜力的影响。【方法】基于20世纪80年代末至2010年的5期土地利用遥感监测数据，分析近20年广西耕地资源的变化过程；结合1990～2010年的逐日气象资料，采用环境因子逐步订正方法估算农田生产潜力。【结果】根据遥感监测结果，近20年广西耕地面积净减少了20843．81ha。在1990～2010年平均气候条件下，广西林地变耕地动态对农田生产潜力总值增加贡献最大，占新开垦耕地农田生产潜力总值的80．73％；耕地变建设用地动态使农田生产潜力总值减少最多，占流失耕地农田生产潜力总值的74．39％。当耕地保持20世纪80年代末状态不变时，气候波动使1990-2010年广西水田生产潜力均值变化总体上呈上升趋势，但旱地生产潜力均值变化总体上呈下降趋势。【建议】广西新开垦耕地的农田生产潜力不及流失耕地的农田生产潜力，优质耕地面积减少。因此要求在强调耕地占补平衡的同时，注重耕地质量的平衡，一方面要防止优质耕地面积的减少，另一方面要通过改土改水、节水灌溉等措施提高粮食综合生产能力，弥补由优质耕地减少和气候变化给粮食产量带来的损失。

[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.