The role of seed coatings in enhancing rhizobium colonisation and yield increases in pulse crops in the northern Mallee of South Australia

Shane Phillips1, Richard Saunders2

1 Landmark, PO Box 1310, Berri, SA, 5343, [email protected]

2 Dodgshun Medlin, 60 East Terrace, Loxton, SA, 5333

Abstract

The colonisation of pulse crops by rhizobia in the northern mallee of South Australia is at times highly variable and in many cases inadequate for optimum plant growth. The aim of this work was to collate recent research publications to develop a seed coating that would enhance colonisation of seed coated rhizobium onto roots in low rainfall cropping regions such as the northern Mallee of South Australia. The coating of chickpeas, peas and lentils in this trial based out of Loxton with a product based on kelp, zinc, manganese, molybdenum and bacterial suspensions (Foundation TN) at 5L per ton of seed had significant benefits in plant growth and development. There was also a visual reduction in the incidence of root disease in treated plants. Statistically significant yield results were seen with Lentils (614kg/ha control to 677kg/ha coated), Field peas (729kg/ha control to 911kg/ha coated). Increases in Chickpeas were not significant (602 to 640kg/ha) but this may have been as a result of the lower seeding rate and severe frosts at flowering. Plants that had coated seeds in conjunction with rhizobia had greater numbers of efficient colonies and reduced root pathogens suggesting that good colonisation by rhizobium suppresses pathogenic infection points.  Trial results over recent years have suggested that appropriate seed coats that enhance root colonisation by rhizobium are highly cost effective and in maximising the symbiotic relationship between rhizobium and the host species.