针对西藏牧区海拔高、日温差大、太阳辐射强、空气干湿变化大的特点，在田间试验基础上，分析了燕麦叶水势（ψL）的日变化规律及其与西藏典型气象因子—大气温度（T）、太阳辐射(RS)、空气相对湿度(RH)的关系，并建立了回归模型。结果表明，燕麦不同生育期ψL的日变化差异显著，其中幼苗期和抽穗期呈“V型”变化趋势，分蘖期和拔节期呈“W型”变化趋势，最高日变幅可达6MPa。经回归分析判定气象因子对燕麦各生理指标影响显著性的先后关系为ψL：T>RH>RS。研究结果对探求灌溉草地水文循环规律，制定科学灌溉制度，提高高寒牧区人工草地的水分利用效率具有重要意义。

The alpine pastoral area of Tibet has high elevation, large daily temperature range, strong solar radiation, and high variation of air humidity. In this study, the field experiment was conducted to analyze the diurnal variation of leaf water potential of oat (ψL) and its relationship with the typical meteorological factors such as atmospheric temperature (T), solar radiation (Rs), and relative air humidity (RH) to establish the corresponding regression models. The experiment results showed that the daily variation of oat’s ψL is significantly different during different growth stages. The oat’s ψL showed ‘V-type’ during the seeding stage and heading stage; while it showed ‘W-type’ during the jointing stage and tillering stage, and the maximum variation range of ψL can reach 6 MPa in a day. Based on the regression analysis, the order of significant effects of meteorological factors on oat's ψL was T>RH>Rs. These results are of vital significance for seeking the hydrologic cycle rules of the irrigated grass, formulating the scientific irrigation schedule, and increasing the water use efficiency of grass growing in the alpine area.

中国水科院科研专项基金项目“西藏高寒牧区灌溉人工草地节水高产综合技术研究”