Publication Date

1985

Location

Kyoto Japan

Description

Stands of alfalfa (Medicago sativa) become sparser as cutting frequency is increased (Takasaki, 1980), while stands of orchardgrass (Dactylis glomerata) or tall fescue (Festuca arundinacea) become denser as cutting frequency is increased (Jung et al., 1974; Ishida et al., 1971). It is assumed that defoliation of swards increases the difference in growth between individual plants and causes some of them to die in the case of alfalfa, whereas in those of orchardgrass or tall fescue defoliation decreases the difference in growth and relieves stand reduction. In order to prove this assumption two experiments were carried out. Alfalfa and tall fescue were used in experiment 1 and alfalfa and orchardgrass were used in experiment 2. Model swards of each of these species were set up, where large and small plants coexisted. The performance of large and small plants in the cut and uncut swards was examined. The results of experiment 1 contradicted the assumption. In experiment 2, the fact that the defoliation worked on large and small plants in almost the same manner for both alfalfa and orchardgrass did not support the assumption. However, it was considered that the disparity between alfalfa and orchardgrass in the change of the rate of increase in the difference in plant length top dry weight between large and small plants supported some part of the assumption.

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Effects of Defoliation on the Difference in Growth Between Large and Small Plants in Swards

Kyoto Japan

Stands of alfalfa (Medicago sativa) become sparser as cutting frequency is increased (Takasaki, 1980), while stands of orchardgrass (Dactylis glomerata) or tall fescue (Festuca arundinacea) become denser as cutting frequency is increased (Jung et al., 1974; Ishida et al., 1971). It is assumed that defoliation of swards increases the difference in growth between individual plants and causes some of them to die in the case of alfalfa, whereas in those of orchardgrass or tall fescue defoliation decreases the difference in growth and relieves stand reduction. In order to prove this assumption two experiments were carried out. Alfalfa and tall fescue were used in experiment 1 and alfalfa and orchardgrass were used in experiment 2. Model swards of each of these species were set up, where large and small plants coexisted. The performance of large and small plants in the cut and uncut swards was examined. The results of experiment 1 contradicted the assumption. In experiment 2, the fact that the defoliation worked on large and small plants in almost the same manner for both alfalfa and orchardgrass did not support the assumption. However, it was considered that the disparity between alfalfa and orchardgrass in the change of the rate of increase in the difference in plant length top dry weight between large and small plants supported some part of the assumption.