Abstract: To evaluate the water requirement of perennial ornamental grasses in Beijing,the evapotranspiration of one2 year2old Arundinella hirta, Stipa tenuissima, Calamagrostis brachytricha and Festuca glauca was measured in mini2lysime2 ters fromJune to October in 2006,based on evapotranspiration feedback irrigation. The evapotranspiration between different ornamental grasses differed significantly in every month except October. The evapotranspiration of the same ornamental grass in different months differed significantly except Festuca glauca. The total evapotranspiration of Arundinella tenuissima, Sti2 pa bungeana, Calamagrostis brachytricha and Festuca glauca was respectively 812184,642126,524102 and 333149 mm. The highest evapatranspiration of warm2season Arundinella hirta and Calamagrostis brachytricha showed in Semptember,and which of cold2season Stipa tenuissima and Festuca glauca was in July. Combined with the fact rain fall in 2006,irrigation was necessary fromJuly to October for Arundinella hirta and Stipa tenuissima,and from September to October for Calama2 grostis brachytricha and Festuca glauca. The reasonable irrigation amount was respectively 440180,268145,267109 and 108102 mm.By means of Penman2Monteith equation,crop coefficients of Arundinella hirta, Stipa tenuissima, Calamagrostis brachytricha and Festuca glauca fromJune to October were respectively 0163 — 2115,0164 — 1184,0138 — 1146 and 0156 — 0177.Based on the evaporation of evaporation pan,the water requirement coefficientsof Arundinella hirta, Stipa tenuissima, Calamagrostis brachytricha and Festuca glauca from June to October were respectively 1102 — 3140,0194 — 2147,0161 — 2131 and 0189 — 0198. The factors influencing irrigation amount evaluation were discussed.

Key words: Ornamental grass, Evapotranspiration, Crop coefficients, Water requirement coefficients, Irrigation

CLC Number: 

• S688.4

• S161.