1996—2016年松嫩平原传统大豆种植结构的时空演变

在转基因大豆冲击下,我国传统大豆种植面积大幅下降,研究大豆主产区传统大豆种植结构及其动态变化对我国大豆进出口贸易和保障国家粮食安全意义重大.本研究基于1996—2016年Landsat TM/OLI遥感影像,以遥感、地理信息系统技术为支撑,利用随机森林方法提取大豆空间分布信息,并结合景观格局指数分析松嫩平原大豆种植结构时空演变特征.结果表明: 1996—2016年,松嫩平原大豆种植面积呈波动变化;在与其他地物类型面积转换中,大豆与其他作物面积间的转换最明显;大豆斑块面积占作物总面积的比例呈先增后减特征,而斑块密度指数和分离度指数均呈先减后增趋势.松嫩平原传统大豆种植结构时空演变表现出种植面积波动变化、破碎度增加、空间分布趋于离散的特征;国内外市场及政策导向成为传统大豆种植结构变化的重要影响因素.

Spatio-temporal evolution of traditional soybean planting structure in Songnen Plain,China in 1996-2016

Under the impacts of genetically modified soybean, the planting area of traditional soybean in China has fallen sharply. Understanding the traditional soybean planting structure and dynamics in the main soybean producing areas is of great significance to China’s soybean import and export trade and safeguarding national food security. With the Landsat TM/OLI remote sensing images from 1996 to 2016, we extracted the spatial distribution information of soybean planting using random forest (RF) method based on remote sensing (RS) and geographic information system (GIS) techniques and analyzed the spatiotemporal evolution characteristics of soybean planting structure in the Songnen Plain using landscape pattern index. The results showed that the soybean planting area in the Songnen Plain was fluctuating during 1996-2016. Among the area conversion with other land-use types, the interchanges between soybean and other crop lands were the most obvious. The proportion of soybean patch area to the total crop area increased first and then decreased, while the patch density index and the resolution index decreased first and then increased. In conclusion, the spatiotemporal evolution of the traditional soybean planting structure in the Songnen Plain showed the characteristics of fluctuation in planting area, increase in fragmentation, and discrete spatial distribution. The domestic and foreign markets as well as policy guidance were the important factors afecting the traditional soybean planting structure.