Dr Md Shahinur Rahman1, Dr Gaus Azam1
1Department of Primary Industries and Regional Development
Biography:
Dr Shahin Rahman is a Research Scientist at the Department of Primary Industries and Regional Development, WA. He has expertise in Soil Chemistry and Plant Nutrition including a PhD from the University of Melbourne and a Master of Science. Before joining DPIRD, he worked for the University of Melbourne as a Research Associate and Assistant Professor at Bangladesh Agricultural University. His previous research focused on acidic soil to increase the availability of phosphorus for plant acquisition. Currently, he is working on the Soils Re-engineering research project for removing multiple soil constraints to increase crop yield and water use efficiency.
Abstract:
Non-sodic heavy soil in the low rainfall regions of Western Australia can be dense and poorly structured with alkaline clay in the subsoil, which prevents root exploration and potentially restricts grain yield. A 4-year long (2020-2023) field experiment was established near Bencubbin in 2020 to investigate whether the loosening of dense soil layers with a strategic deep ripping followed by a summer crop, super sweet sudan (SSS) forage sorghum and crop species of varying root architecture (barley, canola, chickpea, and vetch+oat), or fallow in 2021 can increase barley root exploration in the subsurface soil layers and yield in subsequent years (2022 and 2023). The results showed that deep ripping and SSS had no significant impact on barley grain yield in 2021, 2022 and 2023 compared to no ripping and without SSS. Barley grain yield in 2022 was significantly increased following fallow, chickpea and canola compared to following vetch+oat and continuous barley. In 2023, barley grain yield showed no significant difference due to extremely dry conditions. We concluded that, in this dense, non-sodic, heavy soil, deep ripping might have limited benefit for increasing crop root exploration or yield. Summer crops such as SSS could be grown to fill the feed gap for grazing without significantly affecting the yield of the crops in the following years. Keeping the land fallow or growing break crops (e.g. canola/chickpea) might be beneficial for increasing cereal crop yield compared to continuous barley.