早稻全生育期气温、水温、泥温特征及避灾应用

采用农田小气候与实景观测系统，辅以人工观测，以获取早稻各发育期气温、水温、泥温特点，探讨水分干预避灾措施的效果。试验表明：全生育期以水温积温最高，气温积温最低。营养生长期日平均气温落后于水温、泥温，生殖生长期气温、水温、泥温日均值均比营养生长期提高4℃左右并非常接近。叶面积指数较小或衰减时，受太阳辐射影响，午间水温常常超过气温值。水温维持较高的时间约9~ 10 h，是理想的调温目标介质。高温逼熟时采用活水灌溉3天，可拉低水稻冠层上方最高气温2.5℃、日均气温低1.0℃。且稻米粗脂肪含量、直链淀粉含量较高，垩白度较低；结实率提高，千粒重比高温逼熟对照要高6.65%。结果认为：叶面积指数与水温呈反相关特点，高温逼熟时、叶面积衰减时对应高水温、泥温。水分干预调温对产量和品质要素有确定改善，并以活水灌溉2~3天以上的控温效果较佳。

Characteristics of Air, Water and Soil Temperatures During Early Rice Growth Period and Water Regulation for Mitigating Disasters

In order to analyze the characteristics of air, water, and soil temperatures and assess the effectiveness of water regulation for mitigating disasters, environmental temperatures were recorded using a cropland microclimatic and real observation system supplemented with manual observation. The results indicated that the accumulated water temperature was the highest and the accumulated air temperature was the lowest. Daily mean air temperature was lower than daily mean water and soil temperatures during the vegetative growth stage. The differences among air, water, and soil temperatures were quite small during the reproductive growth stage, they were all about 4℃ higher than the corresponding values during the vegetative growth stage. When leaf area index (LAI) was low or declining, water was illuminated directly by solar radiation. Consequently, water temperature was normally higher than air temperature at noon. Water temperature was higher for 9-10 hours. Water had large heat capacity and could be used to adjust the temperature. When heat-forced maturity occurred, irrigation of flowing water lasting for 3 days might cause daily maximum and mean air temperatures over the canopy to decrease 2.5℃and 1.0℃, respectively. Such treatment might result in the increases of crude fat and amylocellulose content of rice. Chalk degree of rice decreased. The irrigation might also cause the setting percentage to increase and the thousand-grain weight to increase by 6.65%. LAI was negatively correlated with water temperature. During heat-forced maturity period, LAI declined while water and soil temperatures were high. Water regulation was able to improve yield and quality of rice. Irrigation with flowing water for 2-3 days might obtain optimal achievements.