气候变化对甘肃农牧交错带春小麦种植区划的影响

    Impacts of climate change on the regionalization of spring wheat planting in agro-pastoral ecotone of Gansu Province, China

    • 摘要: 为探索气候变化对甘肃农牧交错带春小麦种植区划的影响,科学合理地调整春小麦种植格局。该研究以甘肃农牧交错带30个气象站点1971—2020年的气温和降水时序数据为基础,用BP神经网络对异常和缺失数据进行了插补,依据春小麦生长关键期和整个生育期对光、热和水的需求选取了年均温(温度因子)、年均降水量(水分因子)和≥0 ℃积温(热量因子)作为春小麦种植适宜性区划指标。采用线性倾向率法、累计距平法及Mann-Kendall突变检验法对3个区划指标进行了时间变化特征分析及突变检验,运用ArcGIS技术对区划指标进行了空间分析。结果表明:研究区多年年均温为6.84 ℃,年均温以0.56 ℃/10 a的速率增加,增温趋势明显,于1998年发生突变;年降水量以6.10 mm/10 a的速率呈略微增加趋势,1980年发生突变;≥0 ℃积温以155.41 ℃/10 a的速率呈显著升温趋势,≥0 ℃积温没有发生突变现象。从空间分布来看,年均温和≥0 ℃积温呈现出西部地区气温低,其他地区气温高的空间格局,而年均温倾向率和≥0 ℃积温倾向率则呈现出由西向东、由北向南逐步递增的变化趋势;年降水量表现为由南向北逐步递减的空间分布格局,而年降水量倾向率则呈现出自南向北逐步递增的趋势。气候变化导致甘肃农牧交错带春小麦可种植区海拔提升了565 m,使适宜春小麦种植的范围显著扩大,空间上向南、西扩展,总面积增加到1.66×106 hm2,比1998年前增加了8.10×104 hm2,占总耕地面积的5.06%,其中最适宜区范围扩大最为显著,增加了24.44个百分点。同时,春小麦种植适宜程度区划的区域分配呈现出明显的差异性,1998年后甘肃农牧交错带春小麦种植最适宜区耕地面积较1998年前增加了4.18×105 hm2,适宜区缩小了2.20×105 hm2,次适宜区缩小了1.17×105 hm2,不适宜区缩小了6.80×104 hm2。研究结果可为气候变化背景下甘肃农牧交错带春小麦种植结构的优化调整提供科学依据,有助于区域决策,制定合理利用气候资源的策略,以促进甘肃农牧交错带农业可持续发展和春小麦高产优质。

       

      Abstract: Climatic factors have posed a great challenge to grain growth in agricultural production, particularly in the arid areas. This study aims to investigate the impacts of climate change on the spring-wheat planning in the ecotone region of northern China. Air precipitation and temperature time series datasets were obtained from 30 meteorological stations in the study area over the past 50 years. The BP neural network was employed to interpolate the irregular and missing data in the time series data. Annual average temperature, annual average precipitation, and the accumulated temperature above 0℃ were selected as the agricultural zoning indicators for the regionalization of spring-wheat planting. The linear propensity rate method, cumulative anomaly method, and Mann-Kendall mutation test were employed to examine the temporal variation and mutation test of the three zoning indicators. Additionally, ArcGIS technology was utilized to perform the spatial analysis of the zoning indicators. The experimental results demonstrated that the annual average temperature was registered at 6.84 ℃, indicating a distinct warming trend characterized by an annual increase rate of approximately 0.56 ℃/10 a. Furthermore, a significant abrupt change was observed in 1998. The annual precipitation displayed a subtle upward trend of 6.10 mm/10 a, marked by a sudden shift in 1980. Lastly, the accumulated temperature above 0℃ manifested a significant warming trend at a rate of 155.41℃/10 a, without any abrupt changes. In spatial distribution, the accumulated temperature above 0 ℃ and the annual mean temperature showed a spatial pattern of low temperature in western regions and high temperature in the rest, while their tendency rate showed a gradually increasing trend from west to east and from north to south. The annual precipitation showed a decreasing spatial distribution pattern from south to north, while their tendency rate was an increasing trend from south to north. The cultivated area of spring wheat in the agropastoral ecotone increased by 565 m, as the climate changed. There was a notable expansion of the suitable planting area in the south and west. There was an increase in a total area of 1.66×106 hm2, and an increase of 8.10×104 hm2 since 1998, accounting for 5.06% of the total cultivated land. Notably, there was the most significant growth of the spring wheat in the most suitable area for planting, expanding by 24.44 percentage pints. Meanwhile, there were significant disparities in the regional distribution of spring wheat planting. The cultivated land area in the most suitable region for the spring wheat planting within the Gansu agropastoral ecotone expanded by 4.18×105 hm2 post-1998, while the suitable area contracted by 2.20×105 hm2, and the sub-suitable area diminished by 1.17×105 hm2. However, the unsuitable area has experienced a reduction of 6.80×104 hm2. The findings of this study can provide a scientific foundation for optimizing and adjusting the spring wheat planting structure in the agro-pastoral ecotone of Gansu province, considering the backdrop of climate change. Moreover, they contribute to regional decision-making and formulation of strategies for rational utilization of climatic resources, thereby promoting sustainable agricultural development as well as enhancing both yield and quality of spring wheat in the agro-pastoral ecotone of Gansu Province.

       

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