东北地区水稻扩张的海拔优势区间分析

及时掌握水稻的时空分布信息,对调整和优化农业生产结构至关重要。论文利用综合考虑植被物候和地表水变化的水稻自动制图方法,结合海拔、地表水体因素开展2001—2017年东北地区水稻分布的时空演变研究。通过889个地面调研点位对水稻分类结果验证,总体精度达90.66%,Kappa系数为0.8128。研究表明:① 21世纪初,东北地区水稻种植面积呈先略减后持续增加的趋势,2017年水稻种植面积达2001年的2.13倍。其中,水稻扩张面积的60%分布在三江平原,30%分布在松嫩平原,下辽河平原仅占不足5%。水稻扩张的海拔优势区间在200 m范围内,随着海拔的上升水稻扩张与地表水关系越来越密切。② 三江平原内,水稻扩张幅度在海拔30~70 m范围内逐渐增加,使优势区间从相对高度70 m缩减至40 m内,也使得分布优势逐渐趋向于距地表水体较远的区域。而松嫩平原和下辽河平原水稻种植分布的海拔优势区间始终分别保持在相对高度100 m、40 m内。③ 三江平原水稻的集中分布和急剧扩张,使水稻分布优势逐渐趋向于距地表水体远的区域,这将对地下水带来更大的压力;而松嫩平原水稻分布受地表水体影响较大,分布优势随着距地表水体距离的增加而减小。研究可为农业部门评估水资源承载力、保障农业可持续发展提供数据支撑及理论参考。

Optimal elevation interval of rice expansion in Northeast China

Timely acquisition for the spatiotemporal distribution information of rice planting is very important for adjusting and optimizing the structure of agricultural production. Based on the elevation and surface water data, we used a rice field mapping method that takes into consideration of vegetation phenology and surface water variations to carry out the research of spatiotemporal dynamics of paddy rice in Northeast China from 2001 to 2017. Through the verification at 899 survey sites, the overall accuracy of data reached 90.66% and the Kappa coefficient was 0.8128. The results indicate that: 1) At the beginning of the 21st century, the rice planting area in Northeast China decreased slightly at first and then increased continuously. In 2017, the rice planting area reached 2.13 times of that in 2001. About 60% of the rice planting expansion area was distributed in the Sanjiang Plain, 30% in the Songnen Plain, and less than 5% in the Lower Liaohe Plain. The dominant altitude range of rice planting expansion was within 200 m. With the increase of altitude, the relationship between rice planting expansion and surface water was getting closer. 2) Because the rice planting expansion in the Sanjiang Plain was increasingly more extensive at an altitude of 30-70 m, the dominant range was reduced from a relative altitude of 70 m to 40 m. In addition, the optimal rice planting area was gradually moving away from surface water bodies. However, the dominant altitude range of rice distribution in the Songnen Plain and the Lower Liaohe Plain was relatively stable. They were always at a relative altitude of 100 m and 40 m. 3) The concentrated distribution and rapid expansion of rice planting in the Sanjiang Plain led to the gradual shift of the optimal distribution area of rice planting away from surface water bodies, which will bring more pressure on groundwater. The distribution of rice planting in the Songnen Plain was greatly affected by surface water, and its distribution advantage decreased with increasing distance from surface water bodies. This study provides data support and a theoretical reference for the agricultural sector to assess water resources carrying capacity and ensure the sustainable development of agriculture.