Decision‐making in agriculture is carried out in an uncertain environment with farmers often seeking information to reduce risk. As a result of the extreme variability of rainfall and stream‐flows in north‐eastern Australia, water supplies for irrigated agriculture are a limiting factor and a source of risk. The present study examined the use of seasonal climate forecasting (SCF) when calculating planting areas for irrigated cotton in the northern Murray Darling Basin. Results show that minimising risk by adjusting plant areas in response to SCF can lead to significant gains in gross margin returns. However, how farmers respond to SCF is dependent on several other factors including irrigators’ attitude towards risk.

This paper aims to compare the shift in frequency distribution and skill of seasonal climate forecasting of both streamflow and rainfall in eastern Australia based on the Southern Oscillation Index (SOI) Phase system. Recent advances in seasonal forecasting of climate variables have highlighted opportunities for improving decision making in natural resources management. Forecasting of rainfall probabilities for different regions in Australia is available, but the use of similar forecasts for water resource supply has not been developed. The use of streamflow forecasts may provide better information for decision-making in irrigation supply and flow management for improved ecological outcomes. To examine the relative efficacy of seasonal forecasting of streamflow and rainfall, the shift in probability distributions and the forecast skill were evaluated using the Wilcoxon rank-sum test and the linear error in probability space (LEPS) skill score, respectively, at three river gauging stations in the Border Rivers Catchment of the Murray-Darling Basin in eastern Australia. A comparison of rainfall and streamflow distributions confirms higher statistical significance in the shift of streamflow distribution than that in rainfall distribution. Moreover, streamflow distribution showed greater skill of forecasting with 0-3 month lead time, compared to rainfall distribution.

Understanding client needs, knowledge and practices offers a means of ensuring research outputs match intended audience requirements. This paper shows the initial impact of context evaluation on the development of a suite of decision support tools and information to help irrigators better manage their water resources under different climatic conditions. The context evaluation study involved a survey of ~170 irrigators in the northern Murray�Darling Basin in Australia. It sought to clarify how they make cropping area and water management decisions and their levels of understanding and use of climate information. We found irrigators consult widely on cropping decisions and those with large areas commonly apply the Southern Oscillation Index to property decisions. Respondents demonstrated a reasonably good understanding of climate phenomena in an Southern Oscillation Index knowledge test. Two-thirds use seasonal climate outlook information, but only 20% are very confident to apply climate information to decisions. More than half would find a decision support system (comprising tools and information) useful for cropping decisions. Almost 75% would change their crop area, and 43% their crop type, if given advance information about water availability up to 4 months ahead of irrigation season. About 70% have access to a computer and half to the internet, but two-thirds consider their personal computing skill is only nil or basic. Twenty-three percent of respondents expressed interest in working directly with the research team to interact regarding their requirements, indicating the potential for future participative research activities such as collaborative, on-farm research. The context evaluation facilitated formation of a focus group that cooperated to assess research findings and incorporate improvements to the project�s set of decision support tools. The evaluation was a new experience for the researchers and, albeit an arms-length consultation process, it has broadened our knowledge about our target audience and their preferred ways to access research findings.

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