|Around Darnum, Loy Yang, Giffard and Leongatha South are plains of very low relief, although there are a few incised streams. They are comprised of Neogene and Early Quaternary alluvial and fluvial sediments derived from the Eastern Uplands immediately following the Kosciuszko Uplift but, with the possible exception of the Munro Plains, prior to the uplift of the Southern Uplands. Almost all of the soils developed on these sediments have a bleached subsurface soil (A2 horizon). Sodic texture contrast soils (Sodosols) are common around Loy Yang, Woodside and Darriman and the A2 horizons of all of these soils are conspicuously bleached. Around Leongatha South, where the rainfall is higher, the soils are also texture contrast but are acidic (Kurosols) with some of the more sandier surface soils developing “coffee rock” layer at the base of the A2 horizon (Podosols). The soils of the plains east of Darnum are acidic and lack texture contrast (Dermosols).|
The original vegetation varied according to annual rainfall with lowland forest and grassy woodland/swamp scrub mosaic in the humid areas and plains grassy woodland in areas receiving an annual rainfall of less than 700 mm. Very little of the original vegetation remains on the plains and almost all is used for grazing, predominantly cattle in the higher rainfall areas and sheep elsewhere. Minor gully erosion may occur in drainage lines around Loy Yang and Darriman.