The Effects of Sowing Rate, Defoliation Intensity and Time of Defoliation Commencement on Vegetative and Reproductive Growth of Medic Swards

To obtain detailed information of sowing density and defoliation intensity under more controlled conditions on herbage production and seed yield, Paraggio medic was grown on raised-beds located outdoors at the Waite Agricultural Research Institute. A split split randomised block design was used. Treatments comprised three sowing rates (densities): Low (۳ kg/ha), Medium (۱۵ kg/ha) and High (۷۵ kg/ha) (based on pure germinating seed which gave ۷۵, ۳۷۵ and ۱۸۷۵ seedlings/m۲ respectively); four defoliation intensities: Control (undefoliated), Low (۶ cm from ground level), Medium (۴ cm) and High (۲ cm) to simulate different grazing pressures and two defoliation systems of continuous (defoliation from June ۱) and deferred (defoliation from June ۲۹). The total combination for experimental blocks was:Main plots, defoliation systems (۲) x Sub plots. sowing densities (۳) x Sub-sub plots defoliation intensities (۴) x Blocks (۴) = ۹۶ micro plots.The continuous defoliation system produced significantly higher (P<۰.۰۵) available forage as well as total pasture production (P<۰.۰۵) than the deferred. High sowing rate increased (P<۰.۰۱) forage availability and total pasture production. Medium and high defoliation intensities significantly (P<۰.۰۱) reduced available forage and total pasture production in the deferred defoliation system. Seed production was adversely affected by defoliation intensity.

کلیدواژه ها:

Forage production ، Medic ، Sowing rate ، Defoliation ، Seed production