1- Agronomy Department, College of Agriculture, Tehran University, Islamic Republic of Iran
2- Department of Agronomy and Farming Systems, College of Agriculture, The University of Adelaide,
Adelaide, Australia.
Abstract: (5725 Views)
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 (3 kg/ha), Medium (15 kg/ha) and High (75 kg/ha) (based on pure germinating seed
which gave 75, 375 and 1875 seedlings/m2 respectively); four defoliation intensities: Control
(undefoliated), Low (6 cm from ground level), Medium (4 cm) and High (2 cm) to
simulate different grazing pressures and two defoliation systems of continuous (defoliation
from June 1) and deferred (defoliation from June 29). The total combination for
experimental blocks was:Main plots, defoliation systems (2) x Sub plots. sowing densities
(3) x Sub-sub plots defoliation intensities (4) x Blocks (4) = 96 micro plots.The continuous
defoliation system produced significantly higher (P<0.05) available forage as well as total
pasture production (P<0.05) than the deferred. High sowing rate increased (P<0.01) forage
availability and total pasture production. Medium and high defoliation intensities
significantly (P<0.01) reduced available forage and total pasture production in the deferred
defoliation system. Seed production was adversely affected by defoliation intensity.
Subject:
Range Science Received: 2010/05/15 | Accepted: 2010/05/15 | Published: 2010/05/15