抚河流域农业干旱的影响机制研究

    Impact mechanism of agricultural drought in Fuhe River Basin

    • 摘要: 农业干旱是制约农业生产的主要自然因素,研究其影响机制是科学应对农业干旱的前提。以长江流域的抚河流域作为研究对象,基于二元水循环模型评估了农业干旱的演变规律,并采用多因素归因分析方法研究了气候变化和人类活动对农业干旱演变的贡献。结果表明:抚河流域农业干旱呈现减少趋势,在1980年出现突变现象。相对于1956~1980年,1981~2019年抚河流域农业干旱的月平均干旱历时和月平均干旱强度均减少,其中气候变化和人类活动均起到减缓的作用。具体地,气候变化和人类活动对灌区单元农业干旱历时变化的贡献率分别为-31.0%和-69.0%,对干旱强度变化的贡献率分别为-33.5%和-66.5%;气候变化和人类活动对其他单元农业干旱历时变化的贡献率分别为-74.3%和-25.7%,对干旱强度变化的贡献率分别为-60.1%和-39.9%。降水作为导致干旱发生的关键因素,其变化期年均值高于基准期年均值,因此使得气候变化在农业干旱演变过程中起到减缓的作用。相应地,在表征人类活动的各项指标中,水库库容增加能一定程度保证干旱发生时的农业用水量,同时社会经济取用水量和灌溉面积的增加能弥补作物关键生育期土壤水分的不足,保证作物的正常发育,这在一定程度上能达到缓解农业干旱的目的。

       

      Abstract: Agricultural drought is the main natural factor restricting agricultural production.Studying its influence mechanism is the premise of scientific response to agricultural drought.Taking the Fuhe River Basin, a tributary of Changjiang River, as the research object, we evaluated the evolution law of agricultural drought based on a dualistic water-cycle model, and analyzed the contribution of climate change and human activities to the evolution of agricultural drought by a multi-factor attribution method.The results showed that the agricultural drought in Fuhe River basin showed a decreasing trend and a sudden change in 1980.Compared with 1956 to 1980,the average monthly drought duration and intensity of agricultural drought in the Fuhe River Basin decreased during 1981 to 2019,the climate change and human activities both played a role in slowing down the drought.Specifically, for irrigate area the contribution rates of climate change and human activities to drought duration were-31.0% and-69.0% respectively, and the contribution rates to drought intensity were-33.5% and-66.5% respectively.For other area, the contribution rates of drought duration change were-74.3% and-25.7%,respectively, and the contribution rates of drought intensity change were-60.1% and-39.9%,respectively.Precipitation, as the key factor leading to the occurrence of drought, had a higher annual mean in variation period than that in the base period, so climate change played a role in slowing down the evolution of agricultural drought.Accordingly, among the indicators of human activities, the increase of reservoir capacity can guarantee the water consumption in the drought period to a certain extent, while the increase of social and economic water intake and irrigated area can make up for the shortage of soil water in the key growth period of crops and ensure the normal development of crops, which can alleviate agricultural drought to a certain extent.

       

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