Abstract:

The evapotranspiration characteristics of the common lawn species of Poa pratensis and Festuca arundinacea in Beijing was investigated by the weighing method of Microlysimeter. The result revealed that the daily evapotranspiration of the lawn was high at noon and low in morning and evening, and the change pattern had appropriate ecology synchronism with solar radiation and other environmental factors. Daily mean evapotranspiration of P. pratensis , under full sunlight and half shade was 5.78 kg·m^-2 and 3.86 kg·m^-2 respectively. While the daily average of F. arundinacea , under full sunlight, half shade and all shade, was 4.41 kg·m^-2, 3.03 kg·m^-2 and 2.63 kg·m^-2 respectively. According to physical and physiological characteristics of the grass after withdrawing water, soil moisture content of the lawn could be divided into three grades, sufficient water supply(water potential -0.18~-0.06 MPa), slight water deficit(water potential -0.44~-0.18 MPa) and medium water deficit(water potential -1.06~-0.44 MPa). Reduction of sunlight and soil moisture content could reduce evapotranspiration consumption of the lawn. Compared with full sunlight and sufficient water supply, and slight water deficit could reduce evapotranspiration of P.pratensis and F.arundinacea by 62.0% and 47.0% respectively. Evapotranspiration of F.arundinacea in half shade and medium water deficit could reduce 76.0%. Control of water supply and sunlight for the lawn could reduce consumption of water and save irrigation water.

Key words: urban landscaping, lawn, evapotranspiration, saving water management