Radical Plan to Plant Radish as a Water Saver

August 28, 2017

Dwindling water levels at Tinaroo Dam have driven lime growers Debbie and Jose Caamano to look for different ways to save water. They are hoping that growing daikon radish as a deep- rooted cover crop could be a part of the solution.

The Caamanos have spent 30 years transforming degraded tobacco land near Mareeba into a thriving commercial lime, pomelo and custard apple farm. During that time they have implemented a number of strategies to increase their water efficiency including setting up Enviroscans across all their blocks. These probes continuously measure soil moisture so the Caamanos can control their irrigation schedule from their phones and tablets.

They have also taken an active interest in biological and regenerative farming practices, which has resulted in them implementing a number of new farming practices including mulching their trees with a heavy layer of grass mulch annually. After a trip to Central America to learn more, they also began making their own bio-fertilisers. As a result of these changes, their fruit quality has risen and is in very high demand.

The idea to use daikon radish as a cover crop first came to the Caamanos at the National Biological Farming Conference in Cairns in 2016. They recognised the potential and wanted to conduct a trial on their farm to see if deep-rooted cover crops in tropical, sandy soils can improve water use efficiency by improving the water infiltration rate.

Due to the added potential to improve water holding capacity and reduce nutrient and sediment runoff into the Barron catchment, they applied for a reef water quality grant to help them fund their innovation trial. They were successful in receiving funding from the Queensland Government’s Department of Environment and Heritage Protection and will begin sowing 50kg of radish seeds in early September.

Why Daikon?

Daikon radish has been bred and developed to produce a large taproot that penetrates compacted soil. This increases soil aeration and water infiltration, decreases compaction and increases rooting depth opportunities for successive crops.

It is better known in the USA but it hasn’t been trialled in the northern tropical areas of Australia. Otherwise known as tillage radishes, they can also be of great value in nutrient retention. The large taproot can absorb and retain a significant amount of macro and micronutrients that might otherwise be prone to leaching.