Mr BRIAN DZOMA1
1SARDI, Adelaide, Australia
Biography:
Brian is a Senior Research Officer with the South Australian Research and Development Institute (SARDI). His work involves research and extension on soil-based constraints affecting crop productivity and farm profitability on the Eyre Peninsula and mallee farming systems in South Australia
Abstract:
Highly calcareous soils are common in some areas of south-eastern Australia and can challenge crop production due to a range of constraints. Replicated field trials were conducted on the upper Eyre Peninsula of South Australia from 2021 to 2023 with the aim of identifying major soil constraints limiting crop production and investigating the impacts of subsoil (deep ripping with or without inclusion plates and amendments) and topsoil amelioration strategies (granular and fluid phosphorus, microbial seed coating, sweep cultivation, trace elements, carbon coated mineral) on overall crop growth. We found that improving the fertility of subsoils in highly calcareous profiles can improve grain yields, but the responses can take several years to appear and were quite modest in size compared to their cost. Deep ripping as a physical intervention to manage subsoil compaction did not result in any significant productivity gains in all three years of trials. Topsoil strategies showed stronger productivity gains in the first 2 years compared to the control; however, these responses did not carry through into the third year, possibly due to less rainfall during spring in 2023. A novel product called carbon coated mineral applied under the seed rows consistently resulted in greater early crop vigour, shoot biomass and grain yield in the first two years compared to the control. The outcomes of this work focussed on improving understanding of high carbonate on crop performance and the development of management strategies to improve soil condition, improve nutrient and water use efficiency of crops and increase farm profitability.