The Soil Wealth and Integrated Crop Protection (ICP) project works with growers nationally to put soil management and plant health research into practice.

The project team is currently working with New South Wales (NSW) vegetable grower Kim Ngov, who is using cover crops to not only build soil health and control weeds, but also eliminate singleuse plastic mulch.

Kim has sown another cover crop trial on his intensive vegetable farm near the southwest outskirts of Sydney (Wedderburn, NSW).

This time, Kim is focused on using cover crops to build soil health, control weeds and eliminate single-use plastic mulch.

Four cover crops were sown on February 14, 2021: ryecorn (cereal rye), millet (see Figure 2), sorghum and a mixture of sorghum and ryegrass.

At this stage, a broadleaf herbicide could be used to clean up roadways as well as bird-damaged cover crop areas and eliminate weeds like common mallow (Malva parviflora), wireweed (Polygonum aviculare) and common sow thistle (Sonchus oleraceus), which will compete against the cover crops all through the autumn and winter months.

We expect the millet and sorghum areas to self-terminate with the onset of winter.

Ryecorn and ryegrass areas will likely need to be mulched down several times, adding to the overall biomass on the soil surface.

Another option Kim has in mind is installing a weed mat later in the season, just before planting chillies in September–October 2021 on a flat surface.

The weed mat is a ground cover consisting of a woven polypropylene, needle-punched fabric with reinforced fibre for extra durability.

The cover crops will still recycle nutrients and increase infiltration rates. The five metre width rolls of weed mat — if needed — will lay over the cover crops between the roadways, allow fertiliser to flow into the soil, control weeds, warm the soil and be rolled back up at the end of the season to be re-used multiple times.

You can read more about Kim’s efforts in weed management in a case study that explains how an inter-row ryegrass cover crop was used to control weeds in his snow pea crops: soilwealth.com. au/resources/case-studies/interrowryegrass-cover-crop-a-winner-insnow-pea-production

He also explains more in this short podcast: soilwealth.com.au/resources/ podcasts/cover-crops-used-for-weed- suppression-in-snow-pea-production- 7-minutes

For more information, please contact project leaders Dr Gordon Rogers on (02) 8627 1040 or gordon@ahr.com.au and Dr Anne-Maree Boland on (03) 9882 2670 or anne-mareeb@rmcg.com.au

Soil Wealth ICP Phase 2 (VG16078) is a strategic levy investment under the Hort Innovation Vegetable Fund.

This project has been funded by Hort Innovation using the vegetable research and development levy and funds from the Australian Government. For more information on the fund and strategic levy investment visit horticulture.com.au

Project Number: VG16078