Rainfall Simulator Extension Tour: ‘Twin-Butts’ Wandoan

Level 1 General description


A rainfall simulator was used to examine the influence of different management options on infiltration of rainfall and runoff.

Methods (brief)

The soil present on site is a ‘soft’ grey clay brigalow soil. The surface was moist with some cracks present where the soil had not been cultivated. Very light standing wheat stubble present, the result of a failed zero-till wheat crop.

The rainfall simulator was applied to the following four plots:

A) No-till. Soil was not disturbed and was similar to that after harvest, but with rain having closed some of the soil cracks (cover 20%).

B) Cultivated. Similar to D but with extra stubble added (cover 90%).

C) Dimpled. Was ‘cultivated’ then 6 pits (4 per square metre) were created on the soil surface with a shovel to duplicate the effect of a pitting implement such as the Conservation King (cover 5%).

D) Scarified. Was ‘cultivated’ with a shovel to create conditions similar to those left behind a scarifier. The soil surface was furrowed (cover 10%)

Key findings (brief)

  • Cultivating soil which had cracks increased runoff compared to uncultivated soil (Figure 1);
  • Stubble cover increased infiltration of intense rainfall;
  • A heavy storm can result in considerable runoff (and erosion) even though the soil is dry below the surface; and
  • Soils pits reduced runoff compared to bare soil but were not as effective as cover or cracks in improving infiltration.


‘Twin-Butts’ Wandoan

Related studies

‘Orion Downs’ Orion; ‘Enderley’ - Gindie; ‘Kurrajong’ Capella; ‘Marylands’ Retro; ‘Innisfree’ Wolfgang; ‘Tarvellon’ Kilcummin; ‘Bundella’ Wallumbilla; ‘The Limes’ Chinchilla; ‘Moruya’ Goondiwindi; ‘Forest Park’ Warwick

Key references and sources of this data synthesis

These data summaries have been extracted from:

  1. Cawley ST, Hamilton NA, Freebairn DM, Markey LJ. Viable Farming Systems Group Project: Evaluating fallow management options by using rainfall simulation. Queensland Department of Primary Industries October 1992.