中国东北春玉米区干旱时空分布特征及其对产量的影响

Spatial distribution characteristics and impact on spring maize yield of drought in Northeast China

  • 摘要: 为了研究东北地区春玉米不同生育阶段干旱时空分布规律及其对产量的影响, 基于研究区域1961— 2012年69个气象站点逐日气象资料和春玉米生育时期及产量资料, 采用Penman-Monteit法计算潜在蒸散量, 在此基础上利用农业干旱指标标准化降水蒸散指数(SPEIPM)划分干旱等级, 最后利用干旱等级权重及发生概率评分等级计算每个站点的干旱危险指数(DHI); 利用Mann-Kendall检验法计算5个生育阶段的SPEI变化趋势, 利用回归分析进行SPEI与玉米气候产量的关系分析。结果表明, 吉林省西部和辽宁省西部在玉米生长季内始终为干旱高风险区, 吉林省东部和辽宁省东部则为干旱低风险区, 黑龙江省东部干旱风险随生育进程增大; 近52 a玉米苗期干旱强度和范围有减小趋势, 而生育后期在增加; 1991—2012年辽宁省西部玉米气候产量与SPEIPM3-7(5—7月份的SPEIPM)以及吉林省西部、吉林省东部和松嫩平原气候产量与SPEIPM3-8(6—8月份的SPEIPM)的关系达极显著(P<0.01), 吉林省中部气候产量与SPEIPM3-8(6—8月份的SPEIPM)关系达显著水平(P<0.05)。春旱严重地区如松嫩平原、吉林省西部、辽宁省西部和南部的干旱强度和范围正在减小, 而东北干旱程度在玉米生育后期整体呈增强趋势, 其中东部最明显。在降水充沛的吉林省东部, 气候产量与干旱指数的回归方程对称轴在0附近, 表明正常降水情况下即能保证高产和稳产。降水较少的地区如辽宁省西部和吉林省西部等地, 回归方程对称轴在1附近, 提高玉米产量需增加灌溉和提高水分利用效率。

     

    Abstract: Global warming has caused strong increase in temperature in China and this especially evident in Northeast China. As a consequence, drought stress has been more frequent, severe and over larger areas in this region. The severe drought stress has increased the risk of spring maize production in this major maize cultivation area of China. Thus understanding the spatial distribution of drought in relation to spring maize growth and yield formation was critical for in depth understanding of policy and decision making to deter yield reduction in Northeast China. Daily meteorological data for the period 19612012 were collected at 69 meteorological stations to analyze the effects of global warming on drought stress and yield of maize in Northeast China. Also spring maize growth and yield data were collected for the same period in the study area. The Penman-Monteit method was used to calculate potential evapotranspiration (PET). Based on the PET, the Standardized Precipitation Evapotranspiration Index (SPEI) was calculated (SPEIPM), which was used to classify drought grade of the study area. The drought hazard index in each meteorological station was calculated then with weight and occurrence rating score of every drought grade. The trend in SPEI was calculated for five growth stages using the Mann-Kendall test and the relationship between SPEIPM and climate-driven maize yield determined using regression analysis. The results showed West Jilin Province and West Liaoning Province were high drought risk areas during maize growing season, while East Jilin Province and East Liaoning Province were low drought risk areas. Drought risk also increased with maize growth in East Heilongjiang Province. Moreover, drought intensity and drought-affected area decreased at maize seedling stage but increased at later growth stages of maize for the 52-year study period. High correlations were observed between SPEIPM3-7 (SPEIPM from May to July) and climate-driven maize yield in West Liaoning Province for 1991–2012 and also between SPEIPM3-8 (SPEIPM from June to August) for West Jilin Province, East Jilin Province as well as Songnen Plain (P < 0.01). In addition, climate-driven yield in Central Jilin Province and SPEIPM3-8 were significantly correlated (P < 0.05). Generally, drought intensity and drought- affected area in spring drought areas such as Songnen Plain, West Jilin Province, West Liaoning Province and South Liaoning Province decreased gradually. However, drought intensity in study area increased in frequency and severity at late growth stages in Northeast China, especially in the east. In areas with abundant rainfall (e.g., East Jilin Province), the axis of symmetry of the regression equation between climate-driven yield and drought index was closed to 0, suggesting that normal rainfall was sufficient to ensure high yield in the area. In areas with scarce rainfall (e.g., West Liaoning Province and West Jilin Province), the axis of symmetry of the regression equation between climate-driven yield and drought index was closed to 1, suggesting that irrigation was necessary to improve both yield and water use efficiency.

     

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