气候变化对石羊河流域棉花生产和耗水的影响

    Impact of climate change on cotton production and water consumption in Shiyang River Basin

    • 摘要: 为了预测未来气候变化对石羊河流域棉花生产和耗水的影响,该文采用英国Hadley中心的区域气候模式PRECIS并结合COSIM棉花模型,对SRES A2(强调经济发展)和B2(强调可持续发展)2种排放情景下民勤地区的棉花生产和耗水情况进行模拟,并对石羊河流域扩大棉花种植范围的可能性进行了探讨,最后通过调整播期、引进新品种和改变灌溉量等适应措施的提出分析了石羊河流域棉花生产对未来气候变化的响应。结果表明,在PRECIS预测的未来气候变化情景下,到2080s(2071-2100年)民勤地区棉花的生长期明显延长,产量升高,且A2情景下产量高于B2情景,但B2情景下产量的增长速度更快。棉花产量的变异系数减小,种植棉花的风险降低;到2080s民勤棉花的参考作物蒸散量、耗水量和水分利用效率明显提高,棉花生长的用水需求提高,单位水分生产力上升。参考作物蒸散量和耗水量的变异系数增大,棉花受干旱影响的风险加大,水分利用效率变异系数减小,棉花生长的用水效率更稳定;在A2和B2的未来气候情景下,到2080s武威能满足棉花的正常生长,且在A2情景下获得了较高产量,仅从气候变化方面来考虑,未来石羊河流域棉花适宜种植区将扩大, 棉花生产存在一定潜力;当假设其他条件不变时,到2080s,A2情景下适当推迟播期,B2情景下适当提前播期有利于棉花增产。选择早中熟品种替换早熟品种, A2情景下产量明显增加,而B2情景下产量下降,品种的替换存在一定风险。到2080s随着灌溉量的减少棉花产量明显下降,未来如果灌溉量不足、生产用水让位于生态用水将增加石羊河流域棉花生产的风险。

       

      Abstract: Based on the COSIM cotton model associated with the climate change scenario produced by the UK Hadley Centre regional climate model-PRECIS (Providing Regional Climates for Impacts Studies), the cotton production and water consumption were simulated in Shiyang River Basin under A2 (concentration on the economic development) and B2 (concentration on the sustainable development) emission scenarios, and the potential of enlarging cotton cultivation scope in SRB was discussed. Finally, the impact of future climate change on cotton production in SRB was analyzed based on the proposed adaptation measures such as adjusting sowing date, breeding the new cotton variety and adopting different irrigation amount. The results showed that the cotton growth stages would prolong and the yield would obvious increase by 2080s(2071-2100)in Minqin under future emission climate change scenarios, and the yield under A2 scenario would be higher than that under B2 scenario, but the increase rate under B2 scenario would be faster than that under A2 scenario. The risk of cultivating cotton would reduce with the decrease of variation coefficient of cotton yield. The reference crop evapotranspiration, water consumption and water use efficiency would obvious increase by 2080 in Minqin, which demonstrated water requirement of cotton tended to rise and water productivity per unit would increase. The risk of cotton drought would rise with the increase of variation coefficient of reference crop evapotranspiration and water consumption.WUE of cotton tended to more stable with the decrease of variation coefficient of WUE. The cotton could natural grow in Wuwei under future A2 and B2 emission scenarios, and cotton would obtain high yield under A2 scenario, which demonstrated the cotton cultivation scope would be expanded and there was a certain potential for cotton production in future SRB when only climate change was considered. If keeping other managements unchanged, the sowing date was delayed under A2 scenario or advanced under B2 scenario, the cotton yield would increase. Breeding the early-mid maturing cotton variety into SBR, the cotton yield would obvious increase under A2 scenario but decrease under B2 scenario, which indicated that there could be some risks on breeding the new variety in the future climate scenarios. If irrigation amount decreased under A2 and B2 emission scenarios, the cotton yield would obvious decrease, which demonstrated the risk of cotton production would rise if irrigation amount was insufficient and production water use gave place to ecological water use in future SRB.

       

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