| Water is the most important material base for human beings and all of the living things to live. In the north of our country, water resource is not enough, so establishing an efficient water-saving irrigation system is an inevitable choice in these places. This research is based on the real time observation of net radiation, air temperature, air relative humidity, wind speed and soil water content, etc; measure and calculate amplitude of air temperature of the lawn canopy in continuous time; studies the change rules of the lawn canopy’s amplitude of air temperature in a day and the characteristics of environmental influence, in different months, and under different weather conditions. Especially analyses the quantitative relationship between the amplitude of air temperature of the lawn canopy and environmental influence, in order to provide the accurate measure and calculation the amplitude of air temperature of the lawn canopy with theoretical basis and to support the water saving cultivation maintaining of the lawn. The conclusions are followed:(1) During the main growth period of the Zoysia Matrella lawn (from July to November in 2011), on sunny days, the temperature of the lawn canopy has a distinct change round the clock, which shows the variation of curve is unimodal. The average of the amplitude of air temperature of the lawn canopy is also different at the same time in different months. All of the digitals are below 0℃.(2) During the extra essential growth period of the Zoysia Matrella lawn (from December in 2011 to February in 2012), the amplitude of air temperature of the lawn canopy round the clock on sunny days is not as obvious as it in the main growth period. The variation tendency is not sharp, and the unimodal curve is not so obvious. The range of variation becomes small. Both of the maximum and minimum are less than they are in the growth period. All of the digitals are below 0℃.(3) On sunny days, the lawn shows obvious amplitude of air temperature from day to night. At night, the amplitude of air temperature of the lawn canopy is larger than it in the day, but the variation tendency is not so obvious; in the day, since sunrise, the amplitude become smaller; at about 3 o’clock pm, the digital reaches its minimum, and then the amplitude of air temperature of the lawn canopy begins to grow till 7 o’clock pm the variation tendency becomes mild. The variation tendency of the amplitude of air temperature of the lawn canopy is a unimodal curve. It is basically the same with the average of months of the rule of the amplitude of air temperature of the lawn canopy round the clock.(4) The amplitude of air temperature of the lawn canopy round the clock on cloudy days in months is a polymodal curve. the amplitude of air temperature of the lawn canopy is mild at night in months, the difference is no sharp; in the day, it becomes sharp; the time of the amplitude decreasing becomes less. It shows a big difference for the amplitude to decrease and reach to its minimum.(5) During the lawn’s growth period , the relativity between the amplitude of air temperature of the lawn canopy and air temperature, soil temperature, air relative humidity, total solar radiation, pure solar radiation, canopy temperature, wind speed, VPD from big to small is RH >VPD> Ta > Tc >W > Rn > R a> Ts . Zoysia Matrella lawn grass canopy-air temperature difference and partial correlation coefficients between the environmental factors in the non-growing season is relatively reduced. With the highest correlation coefficient of air relative humidity, remain significant for the whole year is relevant. This lawn provides an important reference for diagnosis of soil water status.(6) Using stepwise regression method to analysis the relationship of different periods of relative water content in different layers of soil and turf canopy-air temperature difference of Zoysia Matrella. It indicates the max correlation with Zoysia Matrella lawn grass canopy-air temperature difference is 20 cm Relative water content of soil in the deep soil layers. It also has some relevance with 10 cm and 40 cm depth of soil moisture content. |
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