AgriFutures Rice Program researcher spotlight: Brian Dunn

Why is this research project important?

Nitrogen is a very important nutrient for maximising rice grain yield and quality. Too little nitrogen results in low yield and quality while excess nitrogen can often lead to reduced yield due to increased cold induced sterility and lodging.

This research project is developing a protocol to deliver a red edge image and a nitrogen topdressing recommendation map of each rice crop at panicle initiation (PI). The maps will be delivered to growers and agronomists through the SunRice GIS (MapRice) with no or reduced physical sampling of the crop required.

The imagery allows growers to map crop nitrogen variability across the field. Variability that has been induced through grower practice is also easily identified, especially uneven applications of nitrogen and the impact of landforming cut and fill practices. Using this information growers can vary the rate of their nitrogen applications as required to maximise grain yield for all areas of the field. This is vitally important for increased profitability and water productivity.

Why did you get involved in the project?

I was involved in the delivery of the PI Nitrogen Tissue Test service to growers which involved physical sampling of the crop to determine PI nitrogen topdressing requirements and we could see a gradual decline in its use by growers and agronomists. It became obvious that a system utilising remotely sensed images which covered the variability in the field and which didn’t rely heavily on physical sampling of the crop, was required. The rice industry wanted to know more so we started investigating all sources of remotely sensed data to find a suitable commercial platform for the prediction of rice nitrogen at panicle initiation.

How will this research benefit the rice industry? Are there any learnings beyond this industry?

In the 2019-20 rice season, every rice field in southern NSW was planned to be imaged at panicle initiation for nitrogen management. The extreme levels of smoke from the bushfires made this impossible but the system was tested and worked well. The algorithm developed by our research team was planned to be used to produce a nitrogen uptake map and a recommended nitrogen topdressing map. The imagery would then be available to growers/agronomists through the SunRice GIS. The supply of these images to growers and agronomists will improve the mid-season nitrogen management of rice by allowing targeted nitrogen applications to address field variability. Improved nitrogen management will result in increased whole field grain yield which increases water productivity and profitability from rice.

Almost all research using remote sensing in crop growth is useful for identifying variability within the rice field at the specific time the imagery was collected. Our research which uses algorithms developed over multiple seasons to relate imagery with actual plant nitrogen uptake, is taking the process one step further. This type of research could be used to develop nitrogen management systems utilising remote sensing for many other crop types.

What’s the best piece of professional/career advice you’ve ever been given?

The quote by W. Edwards Deming “Without data, you’re just another person with an opinion” pretty much sums up the best advice I have been given.

Several mentors have instilled in me the importance of conducting high quality research experiments that you can have confidence in. Once you have good quality data you can confidently make recommendations that provide practical outcomes for growers with a high level of scientific rigour

Read more about the AgriFutures Rice Program agrifutures.com.au/rice