东北地区春玉米需水量与缺水量时空分布特征
Spatial and temporal distribution of water requirements and irrigation requirements of spring maize in Northeast China
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摘要:为分析东北地区春玉米需水量与缺水量时空分布特征, 本研究以东北地区为区域界限, 以水资源三级分区结果为基础, 要求每个水资源三级分区至少有一个代表点, 依据东北地区1951—2020年(70 a)分布于东北地区26个站点历年的试验统计资料, 从不同水文年型春玉米的需水量、有效降雨量和缺水量计算入手, 确定东北地区春玉米在不同水文年型下的需水量和缺水量数据, 以建立东北地区春玉米节水灌溉发展所需的基础数据库; 利用GIS技术对作物需水要素进行空间化处理并加以分析。结果表明: 1)各年型间春玉米需水量相差超过22 mm, 各年型的春玉米平均灌溉需求指数分别为0.37 (丰水年)、0.44 (平水年)、0.50 (枯水年)和0.55 (特枯水年); 2)春玉米缺水量由东北向西南呈先增大再减小的趋势, 同一水文年型对应的缺水量西高东低; 春玉米需水量由东北向西南逐渐增大, 同一水文年型对应的需水量西南部较大、东北部较小; 同一地域春玉米需水量和缺水量均随干旱程度的升高(即经验频率增加)而增大。研究区域西部地区(内蒙古东部、黑龙江西南部、辽宁西北部)对灌溉的依赖程度最高, 需要超过300 mm的灌溉水来保障春玉米的生产, 必要时应适当调整种植结构、采用非充分灌溉制度, 优先保证春玉米需水关键期的用水; 辽东地区春玉米的需水量较高, 但降雨充足, 故缺水量和灌溉需求指数均低于平均水平, 可以适度扩大春玉米种植面积, 以最大化利用降雨并实现增产增收。Abstract:Spring maize is one of the main grain crops grown in Northeast China. Drought and flood disasters frequently occur with irrational irrigation in this region; therefore, it is important to develop a rational irrigation system for spring maize production. In this study, the spatiotemporal distribution of water demand and shortage of spring maize in Northeast China was analyzed based on 70 years of experimental statistics from 26 stations in Northeast China, and crop water requirements were spatialized and analyzed using GIS technology. The results revealed the following: 1) the difference in water demand of spring maize was over 22 mm among wet, normal, dry, and extremely dry years, and the irrigation demand indices were 0.37, 0.44, 0.50, and 0.55, respectively. 2) Water shortages for spring maize first increased and then decreased from the northeast to the southwest, and the water shortage in the same hydrological year was higher in the west and lower in the east. The water requirements of spring maize increased gradually from the northeast to the southwest, and water requirements in the same hydrological year were higher in the southwest and lower in the northeast. Water requirements and shortages increased with increasing drought degree in the same region. The western region of the study area had the highest degree of dependence on irrigation, requiring long-term irrigation to ensure spring maize production. The planting structure should be adjusted appropriately and an inadequate irrigation system should be adopted to ensure water supply to spring maize during the critical period of water demand. Water requirements for spring maize were higher in eastern Liaoning, whereas water shortage and irrigation demand indices were lower than average because of abundant rainfall. Spring maize planting areas can be moderately expanded to maximize the use of rainfall and increase crop production and income.