The mid-row banding project has been running in the local area since 2015 on researcher Leigh Vial's property, North Dale. This property is situated 40km from Moulamein NSW and 33km from Swan Hill VIC. Leigh saw the need for better nitrogen management within his rice stubbles. In his experience, the moderately sodic clay soils on his property were able to retain moisture post flooding in a rice crop, minimising the need for irrigation the following season. However, crops grown in rice stubble are always nutrient poor and suffer waterlogging during the growing season. As a result copious amounts of nitrogen are applied to these crops, with much of it being lost from the system. Leigh decided to trial mid-row banding his nitrogen to slow the conversion of Urea into plant-available nitrate. In theory, the high concentration of nitrogen should inhibit microbial activity on the fertiliser until later in the season. The longer that fertiliser is in an ammonium state, the less likely it is to be lost via leaching or waterlogging. If successful, this should result in lower crop nitrogen requirements, labour and increased yield potential.
In 2015 Leigh enlisted the help of our Project Officer, Laura Kaylock to create a trial protocol and take in-crop samples to measure crop uptake of banded nitrogen. The first year produced promising results, with strongly visual differences in crop growth between different banding concentrations. Apparent nitrogen use efficiency was around 19-30% and high grain protein suggested that potential yield was not obtained due to a dry finish. Using a SPAD chlorophyll meter (N Tester), a nitrogen uptake graph was created. This showed that plants did not begin to access the bands until 10 weeks after sowing and were accessing banded nitrogen after flowering. Last year the trial experienced prolonged periods of waterlogging, which slowed the uptake of banded nitrogen until 13 weeks after sowing. Again, nitrogen was still being accessed until after flowering but not to the extent of 2015. Nitrogen use efficiency reached 10-17%.
In 2017 the mid-row banding trial received funding from the Murray Local Land Services through the Australian Government's National Landcare Programme, the Grains Research and Development Corporation and Murray Irrigation Limited. It is being administered through WMLIG and we hope to spread the word about the potential for this methodology. The trial design now includes 2 topdressing plots and a 150kg N/ha mid-row band plot to compare to the control. This will allow for the comparison of nitrogen efficiency between banding and topdressing in our local soils. Moisture sensors have also been installed by staff of the Centre for Regional and Rural Futures, Deakin to accurately measure periods and intensity of waterlogging.