|Home > Trial recommendations for the amelioration of a degraded chromosol landscape: Duri District, Northern NSW.|
The chromosol soils of the Duri district range from highly to moderately degraded. The poorer condition results in high overland flow, reduced plant available water, and can lead to greater recharging of lower lying vertosol soils, which have a greater salt store and as a consequence of recharge may result in salt mobilization. Application of fertilizer and sub-clovers on chromosols has been analyzed to determine economic benefits on two properties in the Duri area. Using a low ($80) and high ($130) pasture establishment cost for improving the grass- Danthonia spp dominated chromosol soils. Total Farm Gross Margins (TFGM) were modeled (Hassall & Associates Pty Ltd.) on a dominate (68%) degraded chromosol site (Site 1) and a vertosol dominated (25% chromosol) site (Site 2). Results for Site 1 indicated that there was an increase in TFGM in subsequent years with a low establishment cost. Increasing the establishment cost resulted in an initial decrease in TFGM, with subsequent years leading to TFGM improvement. However, the degraded nature of this soil makes the short term improvements highly unlikely. Site 2 has less potential for pasture improvement due to the limited chromosol area within this property. However, result of the modeling indicate that under both low and high establishment costs, depending upon seasonal conditions, it may take years before greater returns are observed. In fact to warrant the investment a minimum carrying capacity of 3.5 DSE/ha at Site 1 and 3.5 to 4.5 DSE/ha at Site 2 is required. Overall further investigation into remediation options are needed, with farmer negotiation an important aspect of any recommendation.