VRT Program

IK Calwell & Variable Rate Fertiliser Application in Rice

 Variability has a huge impact on our rice crops in terms of yield, manageability and profitability. Variability can be very difficult to see at ground level and only in recent years have we had the tools to effectively tackle this issue.

For three years now IK Caldwell have been offering a variable rate program for the application of top dressing fertiliser in rice. Using GPS technology, satellite imagery and in field paddock work coupled with NIR testing, IK Caldwell can now recognise and effectively manage variability in rice crops.

Satellite Infrared photography is usually taken in December/ January (see figure 1) and shows crop vigour. This image is a very useful visual aid and coupled with the growers' knowledge of cut & fill areas it is a great tool to determine were NIR sampling should be done in the paddock. 

Based on this infrared image and the NIR test results, zones are added to the image and marked with applicable nitrogen rates and form the basis for the variable prescription for that paddock (figure 2). A prescription is then written and sent to the nominated aerial operator.


The equipment in the plane will then apply fertiliser to the paddock as it is written in the prescription (Note - not all aerial operators will have the required equipment).

Using variable rate technology enables growers to more effectively and efficiently allocate top dressing inputs and in some cases has saved growers thousands of dollars in fertiliser costs.

In short, the program allows you to put the right amount of fertiliser where it is really needed in your rice crop.

Satellite imagery as seen in figure 1 also gives growers and agronomists the ability to further investigate the reasons for variability and the chance to implement other crop management tools or programs if required.


Charles DuBourg - IKC Cobram
Email: charlesd@ikc.com.au

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