湖北省小麦潜在产量时空异质性特征及驱动因子分析

Analysis of spatiotemporal heterogeneity of wheat potential yield and the driving factors in Hubei Province

  • 摘要: 气候变化致使气象要素的时空分布格局发生了不同程度的变化, 加剧了作物产量空间异质性的形成。因此, 评估气候因子对潜在产量的贡献程度, 有利于解析区域间潜在产量差异的形成机制, 这对于区域内作物的合理规划和缩小区域间产量差具有重要意义。本研究基于1985—2021年湖北省小麦生长期间的气候数据, 应用验证后的APSIM-Wheat模型模拟小麦的潜在产量, 利用多元回归等方法评估各气候因子对潜在产量变化的贡献程度, 解析潜在产量空间异质性的形成机制。结果表明: 湖北省小麦潜在产量变化范围为5068.9~7895.3 kg∙hm−2, 平均潜在产量为7187.6 kg∙hm−2。近35年来, 小麦生育期内的平均温度和总降水量分别以0.1 ℃∙(10a)−1 和13.2 mm∙(10a)−1的速率增加, 但总太阳辐射以123.3 MJ∙m−2∙(10a)−1的速率下降。这些气候因素变化加剧了生育期内易涝、弱光环境的形成, 导致小麦生产潜力降低, 潜在产量平均每10年下降422.0 kg∙hm−2, 降水量的增加对潜在产量下降的贡献最大, 相关系数高达−0.73。湖北省小麦潜在产量的空间分布特征为北高南低, 南北小麦平均潜在产量和光热熵差距分别为218 kg∙hm−2和0.06 MJ∙m−2∙d−1∙℃−1。光热熵的高度空间异质性是造成潜在产量差异的主要因素, 二者相关性高达0.82。受光热熵时空分布不均的影响, 荆州小麦拔节至成熟期的平均每日生长速率较襄阳地区低28.5 kg∙hm−2∙d−1, 最终导致荆州小麦的潜在产量较襄阳地区低。综上, 气候变化使得湖北省小麦潜在产量整体呈下降趋势, 针对以江汉平原地区为代表的易涝、弱光的小麦生长环境, 选育具有高光效和耐涝性的小麦品种对于缩小区域间的产量差距和实现区域粮食总产的全面提高具有重要意义。

     

    Abstract: Climate change has induced diverse spatiotemporal alterations in climatic factors, intensifying the spatial disparities in crop yields. Assessing the impact of climatic factors on potential yield is pivotal for comprehending the mechanisms influencing spatial variations in potential yield. This understanding is crucial for strategic crop planning within regions and for mitigating interregional yield disparities. This study used climate data spanning the wheat-growing season in Hubei Province from 1985 to 2021. The validated APSIM-Wheat was employed to simulate the potential wheat yield. Various methods, such as multiple regressions, were employed to assess the impact of different climatic factors on variations in potential yield. These approaches were utilized to analyze the mechanisms underlying the spatial heterogeneity of potential yield. Our results showed that wheat potential yields were ranged from 5068.9 to 7895.3 kg∙hm−2 with a mean of 7187.6 kg∙hm−2 in Hubei Province. Over the past 35 years, the mean temperature and total precipitation during the wheat growth period escalated at rates of 0.1 ℃∙(10a)−1 and 13.2 mm∙(10a)−1, respectively, whereas total solar radiation declined at a rate of 123.3 MJ∙m−2∙(10a)−1. These shifts in climatic factors exacerbated waterlogging and suboptimal light conditions during the growth period, culminating in diminished wheat production potential. The potential yield declined by an average rate of 422.0 kg∙hm−2∙(10a)−1, with heightened precipitation primarily contributing to this reduction, as evidenced by a substantial correlation coefficient of −0.73. Spatially, the potential wheat yields exhibited a pattern of higher yields in the north and lower yields in the south of Hubei Province. The potential yield difference and photothermal quotient disparity between northern and southern wheat were 218 kg∙hm−2 and 0.06 MJ∙m−2∙d−1∙℃−1, respectively. The significant spatial heterogeneity in photothermal quotient emerged as the primary determinant of variations in potential yield, supported by a notable correlation coefficient of 0.82. Due to the uneven spatiotemporal dispersion of photothermal quotient, the average daily growth rate of wheat from jointing to maturity was 28.5 kg∙hm−2∙d−1 lower in Jingzhou compared with Xiangyang. This discrepancy consequently led to a lower potential yield in Jingzhou. In summary, climate change has precipitated an overarching decline in the potential wheat yield across Hubei Province. In the context of the prevalent waterlogging and insufficient light conditions in the wheat growth environment of the Jianghan Plain region, the development of wheat varieties with high light utilization efficiency and soil waterlogging resilience is of significance in bridging interregional yield disparities and fostering a comprehensive upswing in regional food production.

     

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