考虑未来降水的南方水稻灌溉风险决策节水效果分析

Assessment of Water-savings Through Risk-based Irrigation Decision-making for Rice in South China with Consideration of Future Rainfall

提高降雨利用率是节约灌溉用水的一种有效途径。提出了一种考虑未来降水的灌溉风险决策方法,以广西青狮潭灌区为例验证这一方法的节水效果。收集了桂林站2013-2014两年早稻和晚稻生育期逐日对未来7d的气象预报数据和相应时段的气象观测数据,推求了两年淹灌和间歇灌溉两种灌溉模式下采用常规灌溉决策和风险灌溉决策的灌溉制度,并分析了风险决策的节水效果。结果表明,早稻和晚稻平均降低灌水量23.5和21.9mm,节水分别为38.3%和6.7%。采用风险决策可以避免因灌后遇雨造成的灌水浪费,从而减少灌溉用水量、排水量以及灌水次数。

Increasing effective rainfall is an effectual way for saving irrigation water use. We proposed a risk-based irrigation decision -making method with with consideration of future rainfall and tested its performance with a case study of Qinshitan Irrigation District, Guangxi. Daily 7-day lead time weather forecast data and observed meteorological data for 2013--2014 rice seasons were collected from Guilin Station. Irrigation was scheduled for two irrigation schemes, flooded irrigation and intermittent irrigation, and traditional and risk-based irrigation decision-making strategies, and performance in saving water was evaluated. Results showed that average irrigation water use was reduced by 23.5 and 21.9 mm for early and late rice, accounted for 38. 3% and 6.7% of total irrigation water use. The proposed risk-based irrigation decision-making method could help to avoid irrigation water losses through rainfall immediately after an irrigation event, thus reduce irrigation use, drainage and irrigation times.