A keen interest in tropical cropping systems compelled Frederik van der Bom to explore research opportunities in Kenya and Tanzania. But he says Australia is where the ultimate challenge is, since it is where production constraints abound.

With GRDC investment, he is working with Professor Mike Bell and Dr Alwyn Williams at the University of Queensland, examining root architecture to develop more resource-efficient crops for dryland northern Australian environments.

Root frontier

The root-soil interface is the new frontier in which science is seeking production gains.

“Narrow, deep-root systems are expected to improve water and nitrate capture in dryland environments such as Australia,” Dr van der Bom says.

However, there is still a dearth of information demonstrating how these plant attributes contribute to resource uptake, and whether they will actually confer benefits in northern region growing conditions, in particular.

“It is these gaps in knowledge that my research is addressing with rhizoboxes, large soil columns and field experiments.”

Insights

Dr van der Bom says wheat and sorghum lines bred for specific traits such as a wide or narrow root angle are being assessed in conditions of spatially separate water and phosphorus distributions, which commonly occur in the northern region. Particular attention is being paid to how these lines react to these complex conditions.

“Some root architectural patterns relating to soil profile exploration and the plants’ ability to find soil resources are becoming evident. But we also see that without adequate phosphorus nutrition, root growth is limited, and these predefined root patterns essentially do not express anymore.”

Applying starter phosphorus early could alleviate this and boost early root growth, soil exploration, resource uptake and, subsequently, crop performance. However, interactions and trade-offs are also evident.

“Take, for example, plants with a wide root system that might be better at scavenging a phosphorus-rich topsoil. This advantage quickly disappears as topsoil dries,” Dr van der Bom says.

“Similarly, under some conditions, narrow root systems reach a deep phosphorus band somewhat quicker, which could be beneficial to get some phosphorus in the crop early. However, we also see more variation, with some plants seemingly ‘missing’ the band, going right past it.

Ultimately, though, I think we are seeing root traits can deliver productivity benefits under specific conditions. The challenge is to assess which cropping systems are most likely to benefit from which traits.

Skill set

Dr van der Bom brings a unique skill set to the task, with bachelor’s and master’s degrees from Wageningen University and Research, Netherlands, specialising in international land management and crop science.

“During this study, I ran field experiments across the Rift Valley Province of Kenya and completed a research internship in Tanzania. In both cases, I aimed to identify farming constraints and to test the potential for increasing reliance on nitrogen fixation in smallholder systems.”

“Subsequently moving to Denmark to do my PhD at the University of Copenhagen, I focused on how current and long-term nutrient management affects crop resilience under nutrient and environmental stress and developed an interest in phosphorus nutrition.”

It was this interest that led to his move to Australia, after he established contact with Australian nutrition researchers during his PhD.

While focused long term on an international academic career, Dr van der Bom says his immediate goal is the development of a robust research portfolio that delivers for Australian grain growers.

More information: Frederik van der Bom, 0490 056 184, f.vanderbom@uq.edu.au