riskwi$e project

Research Theme 1

“To fallow or not to fallow”: soil moisture management and cover crop risks and rewards.

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Commence date

March 2023

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Completion date 

March 2028

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Aim 

RiskWi$e is a five year national initiative that seeks to involve Australian grain growers in the identification of on-farm decisions that have unknown components of risk-reward. The aim of the ‘to fallow or not to fallow’ trial is to fill the knowledge gaps around crop sequencing and nitrogen management, in order to help growers make better risky decisions. The basic template for this experiment is a factorial crop sequence x nitrogen management strategy with full phasing of crop sequences (representing farmer practice).

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Funding Provider 

GRDC

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National Lead Project Organisation 

CSIRO

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WA Action Research Lead

GGA

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Project Background 

During fallow, growers forfeit production in one season in anticipation that there will be partial compensation by increased crop production the following season. Growing cover or break crops can also increase yields in subsequent years and improve soil nitrogen fixation. Some of the main benefits of fallow, cover, and break crops are; soil moisture conservation, disease, and weed break. Having stored soil moisture at seeding helps in growing seasons when rainfall is less than 280mm (Liebe Group region). The risk-benefits of fallow, cover, and break crop management is not often well understood.

The Liebe Group has designed and implemented a small plot trial to compare the cost-benefits, soil chemical and physiological characteristics between (i) continuous wheat, (ii) chemical fallow with stubble, (iii) legume crop and (iv) legume cover crop (worked into the soil as green manure).