All soils can be no-tilled! However, some compactable sandy soils (eg. Wongan Hills loamy sands) may require occasional deep ripping, even in a no-till system. In sandy soils, no-till with stubble retention minimises wind erosion and where it leaves furrows, makes water harvesting easier in water repellent soils.
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No-till reduces erosion by wind and water.
In clayey and loam soils, no-till minimises run-off and erosion by water and improves soil structure. In dispersive loamy or clayey soils, no-till with stubble retention reduces splash erosion as rain drop impact is minimised.
No-till is excellent for soils that slake and/or disperse and form surface seals or crusts or set hard on drying, as well as for cracking clay soils. These 'Sunday soils' have a narrow-moisture-cultivation range and no-till allows early sowing and better trafficability when soil moisture is optimal.
Some soils with clay contents greater than a loamy sand are prone to slaking and/or dispersion. For a description of, and tests for slaking and dispersion and the management of these soils, refer to the Crop Monitoring Guide, page 1 - 9 (please contact Carol Llewellyn on (08) 9690 2126 for this issue). Ideally, heavy soils should be no-tilled and grazing should be eliminated when the soil is wet. Biological soil improvements are still not well understood, yet their impact is often obvious after three or more years.
Retention of stubble has major benefits in increasing microbial activity, some of which suppresses rhizoctonia and take-all when a new microbial species equilibrium is reached after a few years of no-tilling. Heavy stubble can also suppress crop growth particularly in the initial years of no-tilling. |
