Shifting planting date of Boro rice as a climate change adaptation strategy to reduce water use
Shifting planting date of Boro rice as a climate change adaptation strategy to reduce water use
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DOI：
10.1016/j.agsy.2018.11.006
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发表时间：
2019-01-01
影响因子：
6.6
通讯作者：
Supit, Iwan
中科院分区：
文献类型：
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作者：
Acharjee, Tapos Kumar;van Halsema, Gerardo;Supit, Iwan
未来气候变化情景下适合旱季水稻种植的适应策略对孟加拉国未来的粮食安全至关重要。本研究以未来气候情景下的水分需求为重点，评估了旱季水稻改期/播期作为适应策略的影响。利用CropWat 8.0估算了2050年代和2080年代水稻早、正常和晚播期作物潜在需水量、有效降雨量和满足作物蒸散的灌溉需水量。利用5个全球环流模式（GCM）输出的RCP 4.5和8.5，通过统计降尺度和偏倚校正构建了未来气候情景。在水稻的关键时期，计算超过阈值温度（最高35℃，最低25℃）的天数，以了解改变种植日期的相容性。结果表明，晚播可以通过增加Boro生长期间的降雨量来大幅减少灌溉需求，但由于白天和夜间的热胁迫，这种选择非常有限。另一方面，早播既需要大量的水分，又能保证作物生长关键期的适宜温度。正常的种植日期显示白天热胁迫的可能性。因此，根据当地的水分状况，建议晚播耐温品种或早播高产品种。然而，由于研究区域没有耐高温品种，目前种植日期的调整受到限制。
Suitable adaptation strategies for dry season Boro rice cultivation under future climate change scenarios are important for future food security in Bangladesh. This study assessed the effect of shifting trans- /planting date of dry season Boro rice as an adaptation strategy, with focus on water requirements under future climate scenarios. Potential crop water requirement, effective rainfall and irrigation requirement to satisfy crop evapo-transpiration of Boro rice were estimated using CropWat 8.0 for early, normal and late planting dates for 2050s and 2080s. Future climate scenarios were constructed using five global circulation model (GCM) outputs for RCP 4.5 and 8.5 by statistical downscaling and bias correction. Number of days exceeding the threshold temperatures (maximum of 35 degrees C and minimum of 25 degrees C) was counted for critical period of Boro rice to understand compatibility of the changed planting dates. Results indicate that late planting can substantially reduce irrigation demand by increasing rainfall availability during Boro growth duration, but the option is very limited due to both day- and night-time heat stress. An early planting, on the other hand, accounts for high water demand but ensures suitable temperature during the critical growth stages of the crop. The normal planting dates show the possibility of day-time heat stress. So, late planting of temperature-tolerant cultivars or early planting of high-yielding varieties would be recommended based on local water availability. However, adjustment of the planting date is currently limited because high temperature-tolerant cultivars are not available in the study region.