Mrs Amanda Pearce1,2, Dr Nigel Wilhelm1,2,3
1Sardi, 2University of Adelaide, 3Cooperative Research Centre for High Performance Soils
Biography:
Dr Nigel Wilhelm is a senior research scientist with the South Australian Research and Development Institute, and has been involved in applied field research in southern Australia for more than 30 years. His speciality is crop nutrition with a particular interest in management of trace element deficiencies. Soil amelioration and improved soil management practices for better crop production is another area in which Dr Wilhelm has been active over the last two decades.
Abstract:
The purpose of this presentation is to summarise several years of investigations into the cause and correction of severe yellowing and stunting in broad bean crops grown on highly calcareous clay soils in the south-east of South Australia. Highly calcareous soils are common in some areas of south-eastern Australia and can challenge crop production due to a range of constraints. The cause of yellowing in broad beans was believed by local growers and advisers to be a combination of iron (Fe) and manganese (Mn) deficiencies brought on by cold wet conditions during winter. Current corrective practices have little impact on the disorder.
Two seasons of field trials and follow up pot experiments under controlled conditions showed that the primary cause of the disorder in beans was Fe deficiency, that Fe ethylenediamine-N,N′-bis(2-hydroxyphenylacetic acid) (Fe-EDDHA) was an effective source for correcting the disorder but that multiple applications gave the best outcomes in terms of grain yield. Grain yield increases of up to 5 t/ha in the field were recorded with effective strategies. However, the rates of Fe-EDDHA required to correct the disorder are very expensive and the best timing for applications is not yet clear. Further work is required to fine tune rates and timings of applications for the most cost-effective outcomes for bean growers. Other crops grown in the area also suffer this disorder so Fe-EDDHA based strategies may also have a role in other crops.