基于种植制度利用MODIS数据提取冬小麦种植面积

    Extracting winter wheat planting area based on cropping system with MODIS data

    • 摘要: 为了及早获取冬小麦种植面积,为国家制定相关政策提供科学依据,该文基于山东省种植制度,将山东省冬小麦划分为“机播冬小麦—玉米”和“人工撒播冬小麦—水稻”两种类型,利用MODIS影像数据,分析冬小麦播种后、越冬期前冬小麦、大蒜、温室蔬菜的归一化差值植被指数(NDVI)值特征,结合9月中旬前茬作物NDVI特征建立当年机播冬小麦提取条件;鉴于稻茬麦播种后、越冬前的光谱特征与温室蔬菜光谱特征极为相似,则在水稻种植区利用拔节期冬小麦生物量迅速增长的特点提取上一年稻茬麦种植面积,由于“人工撒播冬小麦—水稻”这种耕作模式在山东特定地区较为固定,因此将上一年稻茬麦面积作为当年稻茬麦种植面积;合并两种类型冬小麦面积,用284组定位点数据对提取结果进行检验,精度达到了94.01%,结果表明:于越冬期前提取冬小麦种植面积是可行的,提取时间较利用拔节期NDVI值方法提前4个月。

       

      Abstract: Winter wheat is one kind of important crop in China. Its planting area is one key element to explain yield change. To obtain winter wheat planting area as soon as possible can provide scientific reference for our country to make related policy. Based on the cropping system in Shandong Province, winter wheat is divided into two kinds “winter wheat sowed by machine-maize” and “labour broadcast winter wheat-rice”. Using MODIS data, NDVI characters of winter wheat, garlic, greenhouse vegetable, from sowing till overwintering stage were analyzed. Together with NDVI characters of former stubble crops in middle September, extracting requirements were set up for winter wheat planting area which was sown by machine this year. In view of the spectrum similarity between rice wheat and greenhouse vegetable from sowing stage till overwintering stage, rice wheat planting area of former year was extracted relying on the character of biomass rapid growth at jointing stage. Because of the “labour broadcast winter wheat-rice” cropping system is very fixed in Shandong Province, then the rice wheat planting area of former year can take the place of the rice wheat planting area this year. Two kinds of winter wheat area were merged, and tested by 284 groups of located spots data, with the accuracy reached 94.01%. It is feasible to extract winter wheat area before overwintering stage, and the time is 4 months earlier than using jointing stage NDVI.

       

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