基于冠气温差的冬小麦水分亏缺诊断试验研究

为提高灌溉预测的精度和及时性，基于两个生长季的冬小麦田间试验资料，揭示了冠气温差与多因素的响应关系，阐明了冠气温差对叶片光合速率、蒸腾速率的差异区间，获得了以相对冠气温差为基础的冬小麦水分亏缺调控阈值。结果表明：冬小麦冠气温差响应土壤水分调控，数值呈增大变化趋势。0~60cm的土壤平均水分、饱和水汽压差与冠气温差显著负相关，叶片光合速率、蒸腾速率与冠气温差呈显著的二次抛物线关系，冠气温差、相对冠气温差对叶片光合速率、蒸腾速率的差异区间可作为反映冬小麦叶片水分高效利用的调控阈值。不同水文年相对冠气温差差异区间较为一致，不同生育阶段（抽穗开花期、灌浆期、成熟期）范围分别是0.40~0.60,0.40~0.55和0.40~0.65。

Diagnosis and experimental study on water deficit of winter wheat based on the variation of canopy air temperature difference

Based on the field trial data of winter wheat of two growing seasons for improving the forecasts accuracy and timeliness of irrigation, this study revealed the response relationship between the canopy-air temperature difference and multi-factors, expounded the different interval of canopy-air temperature difference to leaf photosynthetic rate and transpiration rate, obtained the winter wheat water deficit control threshold based on the relative canopy-air temperature difference. The results showed that the winter wheat canopy-air temperature responds to the soil moisture regulation and the value presented an increasing variation tendency. The average soil water at the depth of 0~60cm, saturated vapor pressure difference and canopy-air temperature difference were significantly negatively correlated. The photosynthetic rate, transpiration rate and canopy-air temperature difference were presented significantly quadratic parabolic relation. The regulatory threshold of winter wheat leaf water use efficiency and water deficit diagnosis could be reflected by the different interval of canopy-air temperature difference and the relative canopy-air temperature difference to leaf photosynthetic rate and transpiration rate. In different hydrological years, at different growth stage (heading to flowering, filling stage and mature stage), the relative canopy-air temperature difference interval were 0.40~0.60, 0.40~0.55 and 0.40~0.65.