Publication Date

1993

Description

Swards of barrel medic (Medicago truncatula cv. Parnggio), sown at 20 kg/ha (1990), or 20 kg/ha or 200 kg/ha ( 1991 ), were mown to 3 or 6 cm height at intervals up to flowering, or 10 or 20 days after the start of flowering. In 1990, the swards were heavily grazed in July before imposing the defoliation treatments; in 1991 the swards were mown to 3 cm once in July. The responses to defoliation differed between the 2 years, because of the vigour of the sward at the time of imposing the cutting treatments. In 1990 severe defoliation at flowering or during flowering reduced yields because of reduced pods/m1 and mean seed weight. In 199 I, severe defoliations before flowering generally increased yields because of increased pod set and/or seed size and number of seeds per pod. The results of the 2 experiments show the importance of canopy growth during flowering and the necessity to manage it to maximise light penetration and water use for pod set and seed development.

Share

COinS
 

Effects of Defoliation Intensity, Frequency and Time of Final Defoliation of Seed Yield of Barrel Medic

Swards of barrel medic (Medicago truncatula cv. Parnggio), sown at 20 kg/ha (1990), or 20 kg/ha or 200 kg/ha ( 1991 ), were mown to 3 or 6 cm height at intervals up to flowering, or 10 or 20 days after the start of flowering. In 1990, the swards were heavily grazed in July before imposing the defoliation treatments; in 1991 the swards were mown to 3 cm once in July. The responses to defoliation differed between the 2 years, because of the vigour of the sward at the time of imposing the cutting treatments. In 1990 severe defoliation at flowering or during flowering reduced yields because of reduced pods/m1 and mean seed weight. In 199 I, severe defoliations before flowering generally increased yields because of increased pod set and/or seed size and number of seeds per pod. The results of the 2 experiments show the importance of canopy growth during flowering and the necessity to manage it to maximise light penetration and water use for pod set and seed development.