基于多时相遥感信息的中国农业种植制度空间格局研究

Characterizing spatial patterns of multiple cropping system in China from multi-temporal remote sensing images

多熟种植是中国重要的种植制度,对保持和增加粮食产量和促进农村经济发展有重要意义。复种指数受自然条件和农村社会状况的影响处于不断变化之中,及时获取其变化信息对估计粮食产量变化及其原因和农业发展科学决策有非常重要的意义。中国地域辽阔,作物种植制度复杂多样,传统的统计方法不能及时满足政府获取种植制度变化的要求。卫星遥感是探测大尺度土地覆被格局及变化最有效手段,因此可以作为获取区域和全国尺度作物复种指数的一个重要途径。该研究探讨了应用多时相遥感数据定量表达全国种植制度信息提取的方法及可行性,采用峰值特征点检测法结合作物生长季相特征及农田管理特点(播种和收获)提取了中国农田的多熟种植信息,并与统计数据的复种指数进行比较验证,为进一步进行农业种植制度变化研究奠定了基础。

Multiple cropping system (double- and triple-crop in one year) is an important agricultural system in China, which is significant to increase grain yield and promote agricultural economic development. Multiple Cropping Index (ratio of sown area and cropland area) is fluctuating year by year due to the changing natural conditions and rural social status, so, getting the change information timely is undoubtedly very important to assess grain yield change and its reasons, as well as to make scientific decision for agricultural development. China is a vast country with complex cropping system, however, the traditional statistic method cannot meet the government demands on cropping system variation. Satellite remote sensing is the most effective means to identify land cover pattern and change on a regional scale, so it should be an important way to discriminate multiple cropping characteristics on a large scale. In this study, the authors attempt to extract multiple cropping information from 8 km 10-day composite AVHRR/NDVI time series images according to the phenological metrics and farmland practices (such as sowing and harvest) temporal features, so as to research the cropping system change in the past twenty years. Official agriculture statistics contain the information about sown areas and cropland areas of each county, which provide a useful data source for the validation of remotely sensing based crop rotation retrieval. Multiple cropping system spatial pattern was mapped using this method, then its availability and precision were discussed.