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Over the last 10 years, there has been a rapid expansion of rainfed cotton production in Australia. The majority of this area has used “skip row” configurations in which certain rows in the crop are not sown with the aim of providing a slowly available supply of soil moisture during periods of low rainfall. In the past, the OZCOT cotton crop simulation model has been used with long-term climate records to assess the impact of different management strategies for irrigated cotton production and to study the prospects for rainfed cotton production in the major cotton growing regions. In this paper, we present modifications made to OZCOT to better accommodate skip row. First, a simple procedure previously used to approximate light interception of row crops was assessed for its ability to enhance the capability of OZCOT to simulate skip row configurations and second, a modification to allow for the possibility that water in the skip is not as freely available as the water in the plant row was also explored. Including modifications to allow for differences in soil water extraction significantly improved predictions of crop yield for cotton in skip row configurations across a number of locations in the Eastern Australian cotton producing regions, but modifications to account for light interception in row configurations reduced the ability of the model to simulate skip row cotton yields. The modified model gave reasonable predictions of yield for solid planted and skip row crops. The performance was within the range of results published for solid planted crops over a range of nitrogen and irrigation treatments and planting dates. The model’s simulation of skip row yields when compared to solid planted crops grown under the same conditions, reflected the relationships seen in the measured data and those published in the industry literature. [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]

This paper draws on a decadal dataset of 250 farms in south-western Australia. These farms, when categorised according to their type of farming system and business strategy, faced different trends in their terms of trade. Profitability measures of these farms for the period 2002/3 to 2011/12 were compared. Most farms, other than some highly crop dominant ones, applied a strategy of maintaining or increasing their cropping intensity and farm size over the decade. The strategy of a greater commitment to cropping was supported by cropping technologies and beneficial change in agronomic practices. Increased cropping was universally profitable among all types of farming systems, providing a statistically significant increase in operating surpluses. By contrast, irrespective of their underpinning farming system, farms which did not strategically increase their intensity of cropping generated statistically significant less returns to their business equity. By maintaining rather than increasing their cropping intensity these businesses failed to capture the operating surplus upside available from increased cropping. Overall, the results show that management of farming systems is not solely about tactics and flexibility. Strategic management can additionally influence the nature and profitability of farming systems. • Business strategies applied to different Australian farming systems are assessed. • The strategy of increased cropping is consistently significantly profitable. • Managing farming systems is not solely about tactics and flexibility. • A beneficial strategy can greatly add to farm business wealth and profit. [ABSTRACT FROM AUTHOR]