Frequencies of annual species of Medicago on subgroups of the grey and brown soils of heavy texture of the Macquarie Region of New South Wales

Abstract

Four broad subgroups were recognized in the grey and brown soils of heavy texture in the Macquarie region of central New South Wales, and five annual species of Medicago (medics) were found occurring naturally on these soils, but with different frequencies on various subgroups.

Some medic material was found in all quadrats on three subgroups and in nearly all fields and the majority of quadrats on the soils of the other.

Medicago denticulata Willd. dominated one subgroup, occurring in all quadrats of all fields sampled. This species also occurred in approximately three quarters of the fields and half the quadrats sampled on two other subgroups, and was found in half the fields and a quarter of the quadrats of the fourth subgroup.

Medicago minima (L.) Bart. showed a contrary preference, occurring with only slight frequency on the first, and with greatest frequency on the fourth subgroup.

Medicago laciniata (L.) Mill. and Medicago tribuloides Desr. were of an intermediate nature and occurred principally on soils of the second and third subgroups.

Medicago praecox DC. was found only on soils of the fourth subgroup and at low frequency.

The nature of associations between medics showed that differences existed between subgroups of soils with respect to the preference of one species or another for them.