Large areas of South Australia, on the Eyre Peninsula and in the south east, are affected as well as parts of the Victorian mallee. Methods of assessing repellency are explained in Farmnote No. Symptoms of repellency problems in pastures Patchy emergence early in the autumn typifies pastures on water repellent soils. Light rains accumulate in hollows and hoof prints and wet the soil sufficiently for plants to survive for a few weeks. The pasture has patches of plants on wetted areas with dry, bare ground in between.
Subterranean clover is at a competitive disadvantage to aerial seeding plants.
Its runners do not preferentially place the seeds in the hollows, and seeds placed just below the soil surface may or may not be wet by light rains. When they do germinate, the roots may find only dry soil underneath the seed, so the seedling dies. This can lead to a decline in the productivity of clover pastures. The pasture contains younger and older plants, which results in difficulties with some herbicides, which are best applied at specific growth stages. Symptoms of repellency problems in crops Repellent soils require more rain at the break of the season before seeding than non-repellent soils.