The Effect of Deferred Harvesting, Sowing Density and Harvest Intensity on Forage Yield and some Vegetative Characteristics of Annual Medic (Medicago scutelatta Var Robinson)

To evaluate the effects of sowing density, deferred harvesting, and harvest intensity on forage yield and an some vegetative characteristics of annual medic (Medicago scutelatta Var Robinson) an experiment was conducted on the Research Farm of College of Agriculture, University of Tehran, Karaj, during 2005 growing season. The expremental treatments were arranged in split-split plots based on a complete randomized block design of four replications. Where the commencement of harvesting (continues and deferred) were allocated to main plot, the sowing density of 25, 75 and 225 plant/ m2 to split plots and the harvest intensities (different heights of forage cutting from ground level) of 2, 4 and 8 cm to the split-split plots. The results indicated that the total forage (accumulated forage) production in continuous harvesting system (3624 kg/ha) was significantly higher than in the deferred system. As the sowing density increased, forage production followed an increasing trend. The best harvest height was determined as 4cm from ground surface. As sowing density and harvest intensity increased, branch number per plant, number of nodes/plant and branch length followed a decreasing trend. Time of defoliation commencement was significant (P<0.01) on mean availability of forage, Medic forage yields and growth rates across all harvests.