基于APSIM模型的春玉米生育期旱灾损失敏感性定量分析

作物不同生育期旱灾损失敏感性研究对于提高农业干旱监测准确率、采取合理的农业抗旱减灾措施等有重要意义。干旱发生时,农业用水被压缩,充分利用当前可用灌溉水量以取得较好的作物产量效益是农业抗旱减灾中的重点。目前已有研究大多从水分胁迫试验出发,分析不同干旱胁迫对作物产量的影响,定性分析作物各生育期旱灾损失敏感性。由于农田试验样本有限,无法从统计手段定量研究作物旱灾损失敏感性。该文利用作物模型模拟的方法,基于历史数据设置干旱情景,模拟春玉米生长,研究不同生育期干旱胁迫与产量关系。选取典型年,通过历史气象数据替换典型年不同作物生育期同期气象数据的方法,构造典型年不同生育期干旱情景,驱动作物模型,模拟春玉米生长过程及产量。选用标准化降水指数(SPI)识别干旱程度,建立不同生育期SPI与产量之间定量统计关系,利用SPI变化所引起的产量变化率构建旱灾损失敏感性指标,定量评估春玉米不同生育期旱灾损失敏感性。结果表明:(1)不同生育期阶段发生不同程度干旱对产量的影响差异较大。其中拔节-抽雄、开花-吐丝旱灾损失敏感性较大,播种-七叶以及乳熟-成熟阶段敏感性较小。在典型正常年景下,春玉米播种-七叶、拔节-抽雄、开花-吐丝以及乳熟-成熟阶段的旱灾损失敏感性指数分别为90.5、804.7、772.5和401.9。(2)不同典型年水平下,春玉米旱灾损失敏感性差异明显,其中典型干旱年各生育期阶段旱灾损失敏感性最大,典型丰水年各生育期阶段旱灾损失敏感性最小;典型干旱年、正常年和丰水年春玉米生育期平均旱灾损失敏感性指数分别为862.7、518.9和35.2。(3)典型丰水年景下,即使是抽雄、开花-吐丝期春玉米产量形成关键阶段发生严重干旱,春玉米产量影响较小,表明春玉米单个生育期受旱,相邻生育期水分充足时,产量受到明显的水分补偿作用。

Quantitative Analysis of the Sensitivity of Spring Maize to Drought in the Growth Period Based on APSIM Model

It is critical to explore the sensitivity of crop to drought in different growth periods to improve the accuracy of agricultural drought monitoring and to take reasonable agricultural drought resistance and mitigation measures.How to use the available irrigation water to get better crop yields is the key to agricultural drought resistance when drought occurs.At present,most of the existing researches use the experiment method to analyze the effects of drought on crop yields.It qualitatively analyze the sensitivity of crops to drought in each growth period.Due to the limit of period for field trials,it fail to quantitatively analyze the sensitivity of crop to drought using statistical methods.Crop model is employed in this research to simulate the growth of maize and to explore the sensitivity based on drought scenarios.The relationship between drought indictor in different growth periods and yield is established.The meteorological data after the current day is replaced by the data in typical year at same periods.Drought scenarios in different growth periods are set up to drive crop model to simulate the growth process and yield of spring maize.The Standardized Precipitation Index(SPI)is selected to identify the severity of drought.The linkage between yield and SPI in different growth periods are established.The yield change due to the SPI is used to measure the sensitivity to drought of spring maize in different growth periods quantitatively.The results showed that:1)The impact of drought in different growth stages on yield have a big difference.The jointing-tasseling,flowering-silking period are more sensitive than the sowing-seven leaves and milk maturity-maturity stages.In typical normal year,the sensitivity index to drought of spring maize in the sowing-seven leaves,jointing-tasseling,flowering-silking,and milk maturing-maturity stages are 90.5,804.7,772.5 and 401.9 respectively.2)The sensitivity to drought of spring maize is significantly different with varies typical years.The sensitivity to drought in each growth period in typical drought year is the largest while the sensitivity to drought in each growth period in typical wet year is the smallest;The average sensitivity to drought in typical drought year,normal years and wet year are 862.7,518.9,and 35.2.3)In typical wet years,severe drought occurs in the key stage of spring maize,the tasseling,flowering-spinning period,has little impact on spring maize yield.It indicate the spring maize is exposed to drought in a single growth period when the water in the adjacent growth period is sufficient,the yield will be benefit by water compensation.