Ms Alice Butler1, Bindi Isbister1, Dr Stephen Davies1
1Department Of Primary Industries and Regional Development, Perth, Australia
Biography:
Alice Butler is a research scientist at the Department of Primary Industries and Regional Development, working within the Soil Science and Crop Nutrition portfolio. Alice studied Environmental Science at UWA and has a strong interest in spatial science and GIS.
Abstract:
Soil water repellence is a multi-faceted issue, affecting crop germination and weed management, and is a key soil constraint in the Great Southern region of Western Australia.
Spatial data layers and in season measurements were used to benchmark soil type responsiveness to mechanical soil mixing for management of soil water repellence.
Grower case study paddocks were followed between 2020-2023 within the Great Southern region. Case study paddocks contained a range of soil types including deep sandy gravel, duplex sandy gravel, loamy gravel, and shallow gravel.
The molarity of ethanol droplet (MED) rating was used to test soil water repellence within the untreated control and ameliorated areas. Five paddocks studied had ratings for water repellence ranging from severe (2.3-3.5) to very severe (>3.5) in the untreated area, with the adjacent ameliorated area rated lower, although some ameliorated sites were still rated severe or very severe.
Yield results also showed positive responses, with mechanical soil mixing increasing grain yields in the ameliorated area compared to the adjacent control for more than 70% of yield observations. However, there were large variations in yield response within soil types over different seasons, and it is important to be mindful of seasonal interactions and other soil constraints present when implementing soil mixing. Ensuring the tillage implement is working effectively at full working depth was important for amelioration of water repellence and crop yield.
Parts of this landscape are highly water repellent, and it is likely water repellence will still impact on crop establishment post amelioration.