中国北部冬小麦安全种植的农业气候因子及其阈值

Agricultural Climatic Factors and Their Thresholds for Winter Wheat Cultivation in Northern China

【背景】基于农业气候指标判定冬小麦安全种植界线,是科学合理利用资源、避免冷冻灾害、保障冬小麦稳产高产等重要参考依据。然而,地处冬小麦种植敏感地带的中国北部,由于全球气候变化导致的极端气候事件增多,加剧了冬小麦安全种植的波动性,亟需在大区域尺度明晰影响冬小麦安全种植的农业气候因子,并确定其阈值范围。【目的】开展冬小麦安全种植的农业气候因子及其阈值研究,为冬小麦适应气候变化的可持续生产及布局提供科学依据。【方法】以冬小麦安全种植敏感性较强的中国北部为研究区,基于中高空间分辨率冬小麦空间分布和地面气象观测数据,运用核密度估计、地理探测器等方法模型,揭示实际冬小麦种植北界空间格局特征,定量分析农业气候因子对实际冬小麦种植北界形成的影响,并探测关键气候因子的影响阈值。【结果】(1)全长约2 200 km的实际冬小麦种植北界,由西南向东北波动变化,而农业气候因子在正宁—旬邑—铜川—白水—合阳—韩城—稷山一线的波动变化较为剧烈;(2)越冬期负积温、最冷月平均气温、年极端最低气温和越冬前积温是影响实际冬小麦种植北界形成的关键因子(q>0.45),农业降水因子对冬小麦种植的影响较小(q<0.19),但与气温因子之间的交互影响力较强(q>0.57);(3)明确越冬期负积温≥-620℃·d、最冷月平均气温≥-8℃、年极端最低气温≥-22℃和越冬前积温≥529℃·d,作为中国北部冬小麦安全种植北界气象参数;(4)潜在冬小麦种植北界相较于实际冬小麦种植北界向北移动了约107 km,两者存在约23.39×10~3 km^(2)的冬小麦扩种空间。【结论】确定影响中国北部冬小麦安全种植的关键农业气候指标和阈值,可较好判定冬小麦潜在安全种植区。研究成果可为冬小麦种植如何韧性应对气候变化,合理调整农业种植布局提供理论参考和技术支撑。

【Background】To determine the safe planting limit of winter wheat based on agricultural climate indicators is crucial for the scientific and rational utilization of resources,avoiding freezing disasters,and ensuring stable and high yields of winter wheat.However,in the north of China,which is located in the sensitive area of winter wheat planting,the fluctuation of safe winter wheat planting has been intensified due to the increase of extreme weather events caused by global climate change.It is urgent to clarify the agroclimatic factors affecting the safe planting of winter wheat on a large regional scale and to determine their threshold ranges.【Objective】The research on the agricultural climatic factors and their thresholds for the safe planting of winter wheat was conducted to provide a scientific basis for the sustainable production and planning of winter wheat in response to climate change.【Method】The northern China was selected as the research area,which was highly sensitive to the safe planting of winter wheat.Based on the spatial distribution of winter wheat with medium and high spatial resolution and ground meteorological observation data,this research utilized methods such as kernel density estimation,geographic detector to reveal the spatial pattern characteristics of the actual northern limit of winter wheat planting,to quantitatively analyze the influence of agricultural climate factors on the formation of the actual northern limit of winter wheat planting,and to explore the threshold of key climate factors.【Result】(1) The actual northern limit of winter wheat planting,with a total length of about 2 200 km,fluctuated from southwest to northeast.However,agricultural climate factors exhibited more significant fluctuations along the line of Pingning-Xunyi-Tongchuan-BaishuiHeyang-Hancheng-Jishan.(2) The negative accumulative temperature during winter,average temperature of the coldest month,extreme minimum temperature of the year,and accumulative temperature before winter were crucial factors(q >0.45) in shaping the actual northern limit of winter wheat planting.Agricultural precipitation factors had a minor effect(q <0.19) on winter wheat planting,but interacted strongly with temperature factors(q >0.57).(3) Specific meteorological parameters for the northern limit of winter wheat safe planting in northern China were established:negative accumulated temperature in overwintering period≥-620℃·d,coldest monthly mean temperature≥-8 ℃,annual extreme minimum temperature≥-22 ℃,and accumulated temperature before overwintering≥529 ℃·d.(4) The potential northern limit for winter wheat planting has moved about 107 km northward compared to the actual limit,with approximately 23.39×10~3 km~2 of expansion area.【Conclusion】This study identified the key agricultural climate indicators and thresholds influencing safe winter wheat planting in northern China,which provided a basis for determining potential safe planting areas for winter wheat.The research results could provide the theoretical reference and technical support for how winter wheat planting could adapt to climate change and adjust agricultural planting layout reasonably.