Information

Rainfall Simulator Extension Tour: ‘Innisfree’ Wolfgang

Level 1 General description

Purpose:

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

Methods (brief)

The soil at 'Innisfree' is described as an open downs brown cracking clay. The demonstration was carried out on an uncultivated sorghum fallow. The soil was dry with some cracks present in the no-till area; no cracks were present where cultivation took place.

The rainfall simulator was applied to the following four plots:

A) Cultivated bare and left with little sorghum stubble cover Cult/bare (cover 5%).

B) Was not cultivated, some sorghum straw cover was added to simulate a previous heavy sorghum crop, some standing stubble, referred to as Zero-till (cover 80%)

C) 'Cultivated' then 6 pits (4 per square meter) were created on the soil surface with a shovel to duplicate the effect of a pitting implement. This treatment is referred to as Dimpled (cover 2%).

D) Was 'offset disc cultivated' with a shovel and mattock to create conditions similar to those left behind a disc plough, referred to as Rough/disc (cover 5%).

Key findings (brief)

  • Nearly 50% of rainfall was lost as runoff when the soil surface was finely cultivated and had no stubble cover.
  • This simulation convincingly showed that delayed tillage when the soil is cracked  or  stubble cover reduces runoff from intense rainfall.
  • Reducing tillage maximises stubble cover and maintains access to soil cracks.  If soil is cultivated, stubble cover is reduced, and cracks are closed.

Various Clippings

Location

‘Innisfree’ Wolfgang

Related studies

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

Key references and sources of this data synthesis

These data summaries have been extracted from:

  1. Freebairn D, Wockner G, Huff S, Agnew J, Carroll C, Halpin M, Douglas N, Wade J. 1992. Rainfall simulator extension tour: central Queensland 27-29th October 1992.