To improve nitrogen use efficiency on soils with high yield and moderate organic carbon levels
The Walkley-Black wet oxidation technique is the most widely used commercial assay to report soil organic carbon. For the sugar industry, the use of Walkley-Black organic carbon analysis is of significance. The industry endorsed BMP (Best Management Practice) utilises the ‘SIX EASY STEPS’ (6ES) nutrient management program. This program provides the industry with a set of soil and district-specific guidelines to manage N inputs based on a combination of district yield potential (DYP), organic carbon (%).
In the current 6ES framework, the contribution of N mineralized from soil organic matter available to the crop is based on the soil OC. Results from other sites have indicated a poor correlation between soil-organic carbon levels and potential soil mineralisation. Because of this reason many growers are apprehensive lowering their Nitrogen rates to 6 Easy Steps level.
This trail has chosen two sites that are consistently high yielding over several years. The trial will compare different rates of N application compared to the 6ES requirements for yields and NUE.