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Legacy created for Australian mungbeans

Dr Heather Pasley is applying systems thinking to mungbeans to improve the widely used APSIM computer model for the Australian grains industry.
Photo: Brett Cocks

A flair for creativity has proven to be a valuable attribute for Heather Pasley to pursue a career in crop modelling.

Dr Pasley moved to Australia from the US in October 2020 to work on building an improved mungbean simulation model in Agricultural Production Systems sIMulator (APSIM) Next Gen.

This work, supported by GRDC and involving collaborations between La Trobe University and CSIRO, aims to improve mungbean agronomic recommendations to reduce climate risks and yield variability.

“My passion lies in crop model building, especially as it pertains to low-yielding crops in stressed conditions. Here in Australia, I have the privilege to work with and learn from an amazing group of growers, scientists and modellers,” Dr Pasley says.

I enjoy thinking about the whole cropping system – how every part is interwoven with the others.

“With modelling, I get to map out the complex interactions of the soil, climate and crop without losing sight of the big picture. Modelling lets me utilise my creative side, but at the same time build practical tools that can help growers and policymakers to make agriculture more productive, efficient and sustainable.”

Dr Pasley brings experience working as a postdoctoral scientist on improving the earlier version of APSIM for soybeans and applies this to her task for Australian mungbeans.

Mungbean model

She explains that the mungbean model will be part of the larger cropping systems model – APSIM Next Gen – with which researchers can execute complex farming system experiments virtually to answer growers’ practical questions about management strategies and cultivar selection as well as broader scientific questions about sustainability and climate change.

While there is a mungbean model in the older version of APSIM (APSIM Classic), this model reflected the limited knowledge researchers had about mungbeans at the time and was also based on outdated cultivars.

“This new model will incorporate a deeper understanding of mungbean growth and physiology (gained from recent GRDC-supported University of Queensland field studies) and take advantage of improvements made to the overall APSIM model.”

Dr Pasley hopes the outcome for Australian growers will be greater confidence in what they can expect from a mungbean crop under different management schemes and climatic conditions. She says outputs from the model have the potential to provide insight into what sowing dates, water or irrigation regimes, and cultivar combinations are optimal for growers in different regions.

This work will generate legacy information for the grains industry that can be used in different projects into the future.

“Such information can be put into the GRDC GrowNotes™ and act as guidelines for farmers throughout Australia,” she says. “The model can also provide a tool for mungbean breeders to test new varieties in more environments without having to spend more money on field trials.”

Creative networks

Dr Pasley holds an undergraduate degree in geology and anthropology and a doctor of philosophy in agronomy on nutrient cycling and cropping systems in Kenya and Zimbabwe.

With a keen interest in connecting to people and communicating her work, particularly to her non-agricultural family in the US, Dr Pasley has harnessed her creative skills to develop a regular comic strip to explain her research.

Dr Pasley’s current work in the form of a comic. She is starting with the soybean model (panel 1) as a baseline and then rebuilding it to be a mungbean model (panel 3). In the third panel, RMSE (Root Mean Squared Error) is a statistical metric for how well the model fits the data (the lower, the better). Credit: Dr Heather Pasley

In the future, Dr Pasley has her sights set on developing crop models to help growers and researchers in sub-Saharan Africa improve their agricultural systems. But in the meantime, she will continue to expand her professional network and broaden her understanding of dryland farming systems in Australia.

More information: Dr Heather Pasley, 0448 500 597,

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