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Abstract: The worldwide need to improve water use efficiency within irrigated agriculture has been recognised in response to environmental concerns and conflicts in resource use. Within the Australian cotton industry, the imperative to reduce water use and optimise irrigation management through the understanding of risk, using information generated by computerised decision aids was identified and subsequently developed into the HydroLOGIC irrigation management software. This paper summarises the attributes of the HydroLOGIC irrigation management software, with particular emphasis on functionality and its application to irrigation decisions within the Australian cotton industry. The software development process is documented to provide direction for future software application initiatives, with particular emphasis on a process of user feedback, evaluation and support requirements providing direction to software development. On-farm experiments throughout the development period allowed the validation of internal software logic, irrigator decision processes, and the OZCOT cotton growth model. The software demonstrated the ability to improve yield and water use efficiency by optimising strategic and tactical irrigation decisions in the Australian furrow irrigation cotton production system. In 7 of the 11 on-farm experiments conducted, the use of HydroLOGIC helped improve overall field water use efficiency by optimising the timing of irrigation events or by indicating further irrigations would not provide yield or maturity benefits. The paper also presents useful insights into the development of software targeted for irrigation utilising in-field measurements of soil water, crop growth and a crop growth simulation model. [Copyright &y& Elsevier]

The question addressed in this paper is whether the agronomic efficiency of cropping sequences can be improved in the northern grain zone of Australia. Analysis of whole systems over multiple seasons is particularly important in cropping regions such as Australia's northern grain zone, where farmers have the option of growing a variety of winter and summer crops and where fallowing is required to store water to safeguard yields of following crops. The study is based on a detailed longitudinal survey of the inputs and yields of 94 farmers' fields over 7 seasons. The Agricultural Production Systems Simulator (APSIM) was used to benchmark the 94 cropping sequences and to determine if the productivity of these cropping sequences can be improved through changed management, particularly of nitrogen nutrition and timely sowing of individual crops. Comparison of surveyed and simulated yields were then used to determine the yield gap that can be explained by factors unaccounted for in APSIM, i.e. biotic stresses such as weeds, pests and diseases or inadequate operational management. Using a generalised N response curve, data from the simulation analysis were plotted relative to a normalised input-output relationship to determine their position relative to an efficiency frontier representing the simulated production function. This analysis was conducted separately for both individual crops and for whole sequences in individual fields. The analysis of 193 individual crops showed that the average yield of 1.90t/ha was 65% of the simulated water and nitrogen-limited yield potential of 2.92t/ha. Investigation of nitrogen unlimited and early sowing management options revealed that there was relatively little yield advantage (0.15t/ha) to be gained from these management improvements. The remaining gap between observed yields and what the simulations suggest may be attributed to factors such as weeds, pests and diseases, sub-optimal operations or extreme weather events. Three production criteria were used to compare cropping sequences: (1) dollar income, (2) metabolisable energy yield, and (3) crude protein yields. While the income from 36% of the individual crops in the study was found to be more than 80% of their production frontier values, only 29% of whole cropping sequences achieved this benchmark. Similar results were achieved when crops and crop sequences were evaluated in terms of their metabolisable energy and crude protein yields. It is concluded that in order to increase the agronomic efficiency of cropping in Australia's northern grain zone, attention should be focussed on the intensity and configuration of cropping sequences and on the management of fallows in addition to the management of individual crops. [ABSTRACT FROM AUTHOR]

Abstract: The prospect that decision support systems (DSS) can help farmers adjust their management to suit seasonal conditions by putting scientific knowledge and rational risk management algorithms at farmers’ fingertips continues to challenge the science and extension community. A number of reviews of agricultural DSS have called for a re-appraisal of the field and for the need to reflect on past mistakes and to learn from social and management theory. The objective of this paper was to investigate whether there is an emerging consensus, among stakeholders in DSS for Australian agriculture, about the lessons learned from past experience with DSS tools. This investigation was conducted in three parts. The first part was a distillation of suggestions for best practice from the relevant literature. The second part was a reflection on what the champions of five current DSS development and delivery efforts in Australia learned from their recent efforts. The third part tested the level of support for the combined findings from the first and second approaches by surveying 23 stakeholders in the research, development, delivery and funding of DSS. The key propositions relating to best practice that were supported by the survey, listed according to the strength of support, were: 1. It is essential to have a plan for delivery of the DSS beyond the initial funding period. 2. DSS need to be embedded in a support network consisting of farmers, consultants and researchers. 3. DSS development requires the commitment of a critical mass of appropriately skilled people. 4. A DSS should aim to educate farmers’ intuition rather than replace it with optimised recommendations. 5. A DSS should enable users to experiment with options that satisfy their needs rather than attempt to present ‘optimised’ solutions. 6. DSS tools stand on the quality and authority of their underlying science and require ongoing improvement, testing and validation. 7. DSS development should not commence unless it is backed by marketing information and a plan for delivery of the DSS beyond the initial funding period. While the DSS stakeholders supported the proposition that it is essential to have a plan for delivery of a DSS beyond the funding period, the majority resisted the notion of DSS development being market-driven and especially commercial delivery of DSS. We argue that since public funding of the delivery of DSS for farmers’ management of climate risk is highly unlikely, reaping the benefits of lessons learned from past efforts will require that DSS stakeholders change their perception of the commercial delivery model or find an alternative way to fund the delivery of DSS beyond the R&D phase. [Copyright &y& Elsevier]

The seasonal break is a rainfall event that has traditionally initiated sowing and enabled plant establishment in Mediterranean-type environments. Despite its importance to crop production, neither the pattern of the seasonal break, nor the impact of recent autumn rainfall decline in eastern Australia on the pattern has been quantified at a national scale. Adaptive strategies to remove reliance on the seasonal break for crop establishment can include combinations of novel genotypes and innovative crop management. This paper (i) shows how seasonal changes may be altering the pattern of sowing opportunities across southern Australia, and (ii) evaluates the potential for adaptive management to deal with these changes using a case-study in southern Australia involving early, deep-sown wheat cultivars with long coleoptiles to reduce the dependence on the seasonal break for successful crop establishment. In the first part of the study, the timing of the seasonal break across the southern Australian cropping regions was determined using the sum of a 7-day rolling mean rainfall to evaporation ratio > 1 to trigger a sowing opportunity between 1 March and 30 July using long-term (1971–2018) gridded (0.05° × 0.05°) historical climate data. The relationship between early-season climatic conditions and adaptive management options was then evaluated using a growth chamber experiment and a field experiment in a Mediterranean-type environment to evaluate the factors leading to successful establishment of earlier deeply sown wheat cultivars with long coleoptiles. The analysis revealed spatial and seasonal variability with the earliest median seasonal break (27-March) in New South Wales (NSW) and Victoria, and the latest (3-June) in Western Australia (WA). The largest shift in seasonal break was a 17-day advance in the Mallee and Sandplain of WA, and an 11-day delay in Central NSW during the period 1990–2018. Evaluation of the factors controlling establishment of a long coleoptile wheat cultivar suggested that soil temperatures in the early sowing windows were unlikely to reduce coleoptile length, but seeding depth, soil type and water availability will play an important role on emergence. In summary, the shifts in the climatic conditions at the break of the growing season have not been the same across the southern cropping region. Adaptations for this climatic shift such as long-coleoptile, deep-sowing strategies for wheat show significant promise but careful consideration of soil factors is required to ensure success and to improve on-farm decision making regarding its use. [Display omitted] • Understanding recent climate shifts that influence the seasonal break underpins better decisions on GxM responses on-farm. • The seasonal break varied spatially in southern Australia, but it has seen shifts of −11 to 17 days in recent decades. • Long coleoptile wheat cultivars are a promising option for adaptation to this shift. • Soil temperatures during early sowing periods will not inhibit long coleoptiles, but soil moisture and texture were critical. • Combining knowledge of climatic shifts with successful crop emergence factors is critical to develop adaptive GxM strategies. [ABSTRACT FROM AUTHOR]