基于冠层温度的典型沙生植物土壤水分状况诊断

Application of typical psammophytes canopy temperature in the diagnosis of soil moisture status

冠层温度是植物体能量平衡结果的体现,是衡量植物水分多寡和有效性的重要指标,在农业中已经被广泛的应用于植物干旱程度的评价。本研究以柠条(Caragana korshinskii)、沙柳(Salix psammophila)、油蒿(Artemisia ordosica)3种典型沙生植物为研究对象,以土壤田间持水量的A(5%~20%)、B(20%~40%)、C(40%~60%)、D(60%~100%)设置4个水分梯度,监测并分析不同土壤水分条件下植物冠层温度日变化特征及差异性,探究沙生植物冠层温度对气象因子及土壤水分的响应规律。结果表明:1)在同一监测时间,即气象条件背景相同情况下,植物所处的土壤含水率越低,其正午的植物冠层温度越高。2)在日尺度范围内,植物冠层温度的高低受到气象因子、土壤水分的共同影响;通过相关性分析结果表明,气象因子对冠层温度的影响比土壤水分较为显著。3)基于日尺度上多时间点的冠层温度数据建立的冠层温度数据对气象因子响应的敏感度系数,可以判定植物所处的土壤水分状况。土壤含水率越低其植物冠层温度对气象因子的敏感度越小。利用植物冠层温度可以实现对于植物所处的土壤水分状况的判定,为大田植被的水分管理提供1种新的、便捷有效的途径。

[Background] Water is an important limiting factor for crop growth and development,water shortage is one of the most frequently encountered adversity with plant growth in arid regions,under the stress of adversity,a series of physiological changes usually occur in plants,the change of canopy temperature is the most direct manifestation of many physiological and biochemical processes of crops and is determined by the heat balance and the water vapour movement in the soil-crop-atmosphere cycle.Canopy temperature has been widely used in agriculture to evaluate the degree of drought as an importantindicator of the amount and effectiveness of plant water. [Methods] Three typical psammophytes of Caragana korshinskii,Salix psammophila,and Artemisia ordosicaas were choosen to be planted under 4 soil moisture treatments,each plant dug up 40 seedlings that were about 30 cm tall and had basically the same growth. The soil moisture treatments were defined account for A（ 5%-20%）,B（ 20%-40%）,C（ 40%-60%）,D（ 60%-100%） of the field water holding capacity. Determination of plant canopy temperature,soil moisture content,air temperature,air humidity,poor water saturation pressure index,analysis of the plant canopy temperature under different soil moisture conditions,characteristics and differences,and to explore the psammophyte canopy temperature of meteorological factors and the response regularity of soil moisture. [Results] Main results were as follows： 1） in the same monitoring time,under the same background of meteorological conditions,the lower the soil moisture content of the plant,the higher the canopy temperature at the noon; 2） in the daily scale,the temperature of the canopy is influenced by meteorological factors and soil moisture as the daily cycle of meteorological factors changes,the correlation analysis shows that the influence of meteorological factors on canopy temperature is more significant than that of soil; 3） by calculating the sensitivity of plant canopy temperature and meteorological factor response under different soil moisture conditions,it was found that with the decrease of soil moisture content,the sensitivity of the temperature of C. korshinskii,S. psammophila,A.ordosicaas canopy to the response of meteorological factors increased. That is,the sensitivity coefficient of the temperature data of canopy temperature based on the temperature data of the canopy temperature based on the multiple time points on the daily scale can determine the soil moisture status of the plant.The lower the soil moisture content, the smaller the sensitivity of plant canopy temperature to meteorological factors. [Conculsions] This study proved that using plant canopy temperature can be achieved for the determination of soil moisture condition of plants,and the field of vegetation water management provides a new convenient and effective way.