水层对稻田小气候影响及水稻高温防御

Effects of Water Layer on Microclimate in Paddy Field and Heat Damage Defense of Rice

高温热害是影响水稻产量与品质的主要气象灾害,科学防御高温对保障水稻安全生产具有重要意义。对稻田、湖泊水体小气候水温、气温进行试验观测,并与临近的气象台站观测数据同步对比分析。结果表明:三叶期、分蘖期稻田日最高水温较稻田气温高2~3℃,抽穗期则相反。稻田日最高气温与大气日最高气温之差、稻田日平均温度与大气日平均温度之差与日照时数均呈显著的负相关关系;纯水面日最高气温与大气日最高气温之差、日平均温度与大气日平均温度之差与日照时数呈显著的正相关;稻田和水面的日最低气温与大气的日最低气温差均与日照呈正相关;显示稻田通过叶片对太阳反射以及增加蒸散发有一定的自我缓解高温、调节小气候的能力。高温期间,稻田浅水灌溉即可,无需昼灌夜排。

Heat damage is one of the main meteorological disasters affecting rice yield and quality,scientific prevention of high temperature is of great significance to the safe production of rice.In this research,the temperature of paddy field and lake surface was observed and compared with the data from meteorological observation stations nearby.The results showed that the daily maximum water temperature in the three-leaf stage and tillering stage was 2-3℃higher than that of air temperature of paddy field,but in the heading stage,the result was the opposite.The D-value of Tmax in paddy field and meteorological observation station was negatively correlated with sunshine hours,so was the D-value of the mean temperature between the two underlying surfaces.The D-value of Tmax in water surface and meteorological observation station was positively correlated with sunshine hours,so was the D-value of the mean temperature between the two underlying surfaces.The D-value of Tmin in water surface and paddy field and meteorological observation station was positively correlated with sunshine hours too.Research showed that,when there was water in the paddy field,rice leaves could reflect solar radiation and increase evapotranspiration to reduce paddy field temperature,then the heat damage could be alleviated.In addition,heat damage alleviation could be achieved by shallow water in the paddy field,there is no need of flood irrigation.