Effects of irrigation frequency and transient waterlogging on the production of a perennial ryegrass–white clover pasture

摘要: Summary. Perennial ryegrass–white clover swards were irrigated for 3 years every 50, 80 and 120 mm of crop evapotranspiration minus rainfall (ETc–R) water ponded on the soil surface either 4, 12 or 24 h at each irrigation. Pasture production content highly seasonal, peaking in spring autumn. Frequent irrigation increased dry matter by an average 56%. When irrigating 50 ETc–R, was decreased ponding plots, 17% 14% if h. However, when interval ETc–R 7% 25% ponding. Ponding also but only 2.4% While these increases are large relative terms absolute increase is small. More infiltrated per longer intervals, times. Frequently irrigated, rapidly drained used most efficiently. The small gain achieved prolonging intervals inefficient use likely to recharge regional groundwater systems. Oxygen diffusion rate measurements suggested that as short 4 cause waterlogging stresses higher frequently. stress extending period from