THE EFFECTS OF MINIMUM CULTIVATION AFTER 3 YEARS ON SOME PHYSICAL AND CHEMICAL-PROPERTIES OF A RED-BROWN EARTH AT FORBES, NSW

Reducing cultivation may improve many soil physical and chemical properties of a red-brown earth. A trial was set up in 1986 on a red-brown earth near Forbes, N.S.W., comparing direct-drilling and conventional-cultivation crop establishment techniques. The surface soil (0-100 mm) was sampled at the end of the third year and assessed for macropore structure, infiltration characteristics, bulk density, pH, electrolytic conductivity, organic carbon and total nitrogen content. Cultivation degraded some desirable soil physical properties as indicated by data obtained from image analysis and infiltration. Bulk density did not mirror differences in macroporosity. Organic carbon, total nitrogen and electrolytic conductivity levels were higher in direct-drilled soil in comparison to conventionally tilled soil. It is concluded that the improvement of soil chemical and physical properties afforded by a reduction in tillage would lead to an increase in soil water infiltration rate and storage.