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This paper presents a comprehensive substance flow analysis (SFA) of phosphorus (P) for a six-year period (2008–13) in Gippsland, a key agricultural region of Australia with high economic and environmental significance. The analysis has revealed that around 71% (10,904 t) of the mean annual total inflow of P was stored in this region. This finding is different from other published regional scale SFAs, where more than 50% of the P in annual total inflow eventually left the region. Per capita P inflow in Gippsland is also found substantially higher compared to available SFAs. In Gippsland, the annual inflow of P primarily occurred as commercial fertilizer (66% or 10,263 t) and livestock feed (29% or 4443 t), and the outflow mainly occurred as livestock products (94% or 4181 t); while the majority (66% or 7218 t) of the P storage occurred in soils of the livestock farming area. A comparative analysis of the magnitude of P flow in different subsystems indicates that more than 80% of the annual total inflow, outflow, and storage of P in this region is associated with the livestock (mainly dairy and meat cattle) farming subsystem. For the Gippsland region as a whole and almost all subsystems, significant annual variations in the magnitudes of P inflow, outflow, storage and internal flow have been observed. Between 2008 and 2013, both the annual total inflow (mainly as commercial fertilizer) and the annual total storage (mainly in soils) of P in this region showed a substantial decrease (41% and 54% of the 2008 level, respectively), while the annual total outflow (mainly as livestock and crop products) remained nearly the same, indicating an improvement towards sustainable P management. Despite such a positive sign, there is still adequate room for improvement. This analysis indicates that over the study period, about 65,424 t P were accumulated (mainly as soil storage) that is approximately six times the mean annual P inflow as commercial fertilizer in this region; while approximately 3241 t P lost as soil erosion and runoff, indicating substantial adverse economic and environmental implications. Based on the findings of the current analysis, this paper outlines a wide range of policy and management interventions to reduce the downstream loss of P and other nutrients as well as the region's dependency on imported commercial fertilizers and grain based feed. This paper also presents new criteria for data quality analysis and a set of P concentration data of various materials that could be readily utilized in future SFAs of P at any geographical scale. This paper suggests that considering the inter-annual variations in P flow as assessed in this SFA, future research should focus on identifying the influence of socio-environmental, technological and political factors on the magnitude P flow in Gippsland. [ABSTRACT FROM AUTHOR]

Annual forecasts for the Australian macadamia crop have been issued since 2001, with varying (and not always improving) degrees of accuracy. Regression models using climate variables have formed the basis for these forecasts, with general linear model (GLM) ensembles being adopted more recently. This has proven to be a challenging task, as there are only a small number of observations (18) combined with a large number (90+) of independent variables – these being different climate measures for different times of the year (representing 'key physiological periods for macadamia trees'). Also, these 'assumedly-independent' variables contain various degrees of correlation. This study uses cross-validation, with the most recent data for the two dominant production regions of Australia (Lismore and Bundaberg), to investigate the relative performance of alternate modelling methods. These modelling methods were GLMs, partial least squares (PLS) regression and LASSO (least absolute shrinkage and selection operator) penalised regression. Model ensembles, which have been shown to be beneficial in many alternate disciplines, are used to advantage. Both GLMs and PLS produced quite-disappointing results, failing to meet the project's benchmarked accuracy of ±10% error. The optimal LASSO models performed notably better, with a further improvement when ensembles were incorporated. The lowest mean absolute error (MAE) rates here were 9.0% for Lismore and 5.9% for Bundaberg. Hence LASSO ensembles will be adopted for future forecasts of the Australian macadamia crop. • Since 2001 crop forecasts have been provided for the Australian industry to facilitate macadamia operations. • This paper reviews this process, and conducts a cross-validation comparison of some of the more modern regression methods. • These are also incorporated in with the new ensemble modelling methods, also known as 'wisdom of the crowds'. • Results from the ensemble LASSO penalised regressions show a marked improvement over the previous methods. • This method is now being adopted for the 2019 macadamia crop forecast. [ABSTRACT FROM AUTHOR]

Public and private research institutions are grappling with the challenges and opportunities of embedding dimensions of responsible innovation within their research and development programs, including those seeking to transform agricultural productivity and sustainability through digital technologies. Central to meeting this challenge is building institutional, organisational and professional capacity for anticipation and reflexiveness within multidisciplinary research communities. Foresighting methodologies provide a means by which this might be usefully and practically enabled, whilst also shedding light on the broader social and ethical implications of alternative agricultural technology development pathways under uncertain environmental and industry futures. This paper presents the results of a participatory foresighting exercise undertaken as part of a large, publicly funded multi-disciplinary research initiative designed to build a common big data infrastructure to harness the benefits of the digital revolution for the Australian agricultural and land sectors. We seek to explore what role digital technology will play in the future of Australian agriculture and to consider the social and ethical implications. We ran a one-day foresighting workshop comprised of four steps – 1) horizon scanning to identify trends 2) selecting two drivers of change 3) producing a matrix to generate scenarios 4) building and refining scenarios. Participants explored different possible futures of farming in Australia, with a focus on scenarios involving socio-technical dimensions of digital agriculture to consider the implications of these futures for research practice and for farming communities. Four scenarios were developed, distinguished by the interplay of two critical but uncertain drivers of change identified by participants, namely: the degree of resource security or insecurity that future agricultural enterprises are likely to experience; and the degree to which farming sectors maintain traditional farm business models and associated value chains or transition to more diverse or innovative business models. The process highlighted the need to increase the capacity and opportunity for more reflexivity in research and development, if positive outcomes were to be achieved. The scenarios we produced provide a catalyst for conversation about the implications of digital technology development in Australia and globally, for industry, policy and research and development. In particular, the scenarios highlight potential changes in farm business models, decision making, and beneficiaries and inequities of new technologies and other components of food value chains. The paper also serves as a guide and prompt for others, by demonstrating one way reflexivity can be achieved in organisations attempting innovation. [Display omitted] • We present findings from a workshop to develop four scenarios of digital agriculture futures in Australia. • The aim of the workshop was to identify trends about digital technologies for different forms of agriculture in Australia. • A crucial issue for digital technology is avoiding unintended adverse effects but foresight and reflexivity can help. • Our contribution is outlining a possible method to improve responsible digital innovation through foresighting. • We aim to start the conversation with researchers, industry and policy about achieving responsible digital innovation. [ABSTRACT FROM AUTHOR]

Digitalization and the use of Smart Farming Technologies are considered a major opportunity for the future of agriculture. However, realisation of full benefits is constrained by: (1) farmers' interest in and use of big data to improve farm decision making; (2) issues of data sovereignty and trust between providers and users of data and technology; (3) institutional arrangements associated with the governance of data platforms. This paper examines the case of Australia's dairy herd milk recording system, arguably one of agriculture's first cases of 'big data' use, which collects, analyses and uses farm-level data (milk production, lactation and breeding records) to provide individual cow and herd performance information, used by individual farmers for farm management decisions. The aim of this study was to 1) examine the use of big data to add value to farm decision making; and 2) explore factors and processes, including institutional arrangements, which influence farmer engagement with and use of big data. This paper traces the Australian history of the organisation of dairy herd recording (established in 1912 and digitalized in late 1970s) and then uses findings from a longitudinal study of 7 case study dairy farms, which were incentivised to become involved in herd recording in 2015. Applying a conceptual framework linking path dependency in farm decision making and collaborative governance capacity, we find three new important dimensions of the farm user context influencing farmer demand for big data applications: 1) the transition to a new business stage; 2) the additionality farmers seek from data generated in one component of the farm system to other subsystems, and 3) the use of data in long term or strategic decision making. Further, we identified critical attributes of support services in addressing digital literacy, capacity and capability issues at farm level, including diversity in data presentation formats and facilitation of the on-farm transition process through intermediary herd test organisations. The role of farmers as governance actors, or citizens in the decisions of the trajectory of big data applications, adds to understanding of the nature of collaborative governance arrangements that support farm engagement. • Farmer interest in data relates to business stage and the decision's importance. • Cooperative governance structures facilitate farmer trust and use of big data. • Support services reduce the impact of low digital literacy, capacity and capability. • Inter-dependence occurs between existing data processes and optimising data use. [ABSTRACT FROM AUTHOR]

Over the past three decades major changes have occurred in Australia's beef industry, affecting productivity and potentially the amount of resources used and environmental impacts from production. Using a life cycle assessment (LCA) approach with a 'cradle-to-farm gate' boundary the changes in greenhouse gas (GHG) emission intensity and key resource use efficiency factors (water use, fossil fuel energy demand and land occupation) are reported for the 30 years from 1981 to 2010, for the Australian beef industry. The analysis showed that over the three decades since 1981 there has been a decrease in GHG emission intensity (excluding land use change emissions) of 14% from 15.3 to 13.1 kg CO2-e/kg liveweight (LW). The improvement was largely due to efficiency gains through heavier slaughter weights, increases in growth rates in grass-fed cattle, improved survival rates and greater numbers of cattle being finished on grain. However, the increase in supplement and grain use on farms, and the increase in feedlot finishing, resulted in a twofold increase in fossil fuel energy demand for beef production over the same time. Fresh water consumption for beef production dropped to almost a third from 1465 L/kg LW in 1981 to 515 L/kg LW in 2010. Three contributing factors for this dramatic reduction in water use were: (i)an increase in the competitive demand for irrigation water, resulting in a transfer away from pasture for cattle to higher value industries such as horticulture, (ii) an initiative to cap free flowing artesian bores in the rangelands, and (iii) an overall decline in water available for agriculture compared to industrial and domestic uses. While there was higher uncertainty relating to estimates of land occupation and emissions from land use (LU) and direct land use change (dLUC), an inventory of land occupation indicated a decline in non-arable land occupation of about 19%, but a sevenfold increase in land occupation for feed production, albeit from a low base in 1981. GHG emissions associated with LU and dLUC for grazing were estimated to have declined by around 42% since 1981, due largely to legislated restrictions on broad-scale deforestation which were introduced progressively between 1996 and 2006. This paper discusses the prospects and challenges for further gains in resource use efficiency and reductions in greenhouse gas intensity for Australian beef production. [ABSTRACT FROM AUTHOR]

The nutritive value of annual pasture legumes changes with phenology during each season, with a progressive decrease in feeding value as plants accumulate structural carbohydrates and nutrients are diluted. However, these changes differ widely among annual legume species, affecting the pattern of nutrient availability and production in a grazing enterprise. This paper set out to examine the implications of differences in the nutritive value of annual pasture legumes in relation to their economic value for mixed farming systems of southern Australia. Calibrated GrassGro™ plant models with data generated from field experiments to represent Dry Matter Digestibility (DMD) profiles of six annual legume species; Medicago truncatula Gaertn. (barrel medic), B. pelecinus L. (biserrula), Trifolium spumosum L. (bladder clover), Ornithopus sativus Brot. (French serradella), Medicago littoralis Rhode ex Loisel. (strand medic) and Trifolium subterraneum L. (subterranean clover). The plant models were used in a modelling study to support a self-replacing Merino sheep enterprise, which was simulated at seven locations across southern Australia, where annual pasture species are heavily relied on for livestock production. Modelled values of DMD of green material, averaged across all phenological stages, ranged from approximately 62% (French serradella) to 73% (bladder clover), with little variation due to location. Pastures with higher nutritive value had a reduced requirement for supplementary feeding of sheep. Variation in nutritive value had a greater effect on supplementary feeding costs and gross margins than differences in biomass production among the annual legume species. Differences in the levels of supplementary feeding required in systems with the different legumes was most pronounced during the period from May to July (late autumn to winter). For sheep enterprises compared at the same stocking rate, the total supplementary feed required was 18% lower with bladder clover pastures, and 9% lower in subterranean clover pastures, compared with an average of the remaining four pasture species. This is the first study to compare the effects of variation in nutritive value among the annual pasture legumes developed for the soils and climatic conditions of southern Australia. Our results demonstrated that the magnitude of differences in nutritive value among annual pasture legumes are economically important and that the establishment of higher nutritive value legumes will reduce supplementary feeding costs in extensive grazing systems, in some cases even where their biomass production is lower. [Display omitted] • The nutritive value of annual pasture legumes varies widely among species and varieties. • We calibrated Dry Matter Digestibility in six annual legume models to represent their year-round nutritive value. • Mean Dry Matter Digestibility of pastures ranged from 62% to 73% over the year among the six species modelled. • The supplementary feeding cost in a sheep enterprise decreased by up to 20% when higher quality legumes species were grown. • Differences in nutritive value among pasture legumes are important in extensive livestock production. [ABSTRACT FROM AUTHOR]

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]

Mixed crop-livestock farms are important production systems worldwide and dominate Australia's broadacre agricultural regions. While integration of crops and livestock can offer many benefits, these are often intertwined and are hard to quantify explicitly. This paper set out to examine specifically the financial risk and return implications from operating a farm portfolio involving segregated crop and livestock enterprises considering both production variability and commodity price variability. Crop and livestock production from representative systems were simulated over 40 years at six locations spanning Australia's crop-livestock zone using coupled biophysical production simulation models, APSIM for cropping enterprises and GRAZPLAN for livestock enterprises. Time series of varying prices and costs for the same period were derived using historical data. Annual gross margins for each enterprise and different proportional land allocations to the farm were calculated either allowing both production and price to vary or keeping either constant at average values. At all locations the livestock enterprise had less downside risk than the cropping enterprises (as measured by conditional value at risk). Across both enterprises, the impact of production variability was greater than price variability at 5 of the 6 locations. Annual gross margins from the modelled crop and livestock enterprises were not well correlated with each other. Hence, even in the absence of biophysical interactions, the risk-efficient frontier included mixtures of crops and livestock enterprises at most sites. At two sites, a mix of 20–40% crop resulted in the lowest downside risk, while at other sites there was a clear trade-off between maximising farm returns and minimising risk across a range of crop-livestock mixtures. This is the first study to explicitly quantify and show across a diversity of environments in Australia's mixed farming systems that operating a mixture of even segregated crop and livestock enterprises in a farming business can help farmers optimise their risk-return trade-off. Similar risk mitigation benefits may be achieved through crop-livestock systems in other agricultural regions exposed to high climate and price variability. Unlabelled Image • Risk mitigation benefits of mixed farming examined across 6 locations in Australia. • Long-term variability in returns from crop and livestock enterprises were modelled. • Down-side risk was lower from livestock than cropping enterprises. • Annual returns from crop and livestock enterprises were weakly or not correlated. • Mixed farms were more risk efficient than those specialising on a single enterprise. [ABSTRACT FROM AUTHOR]

At least 25% of lambs born in Australia die before marking. Research across southern Australia has demonstrated that reducing mob size at lambing by 100 ewes will, on average, increase the survival of single-born lambs by 0.8% and twin-born lambs by 2.2%. In this paper we assessed the economic value of lambing ewes in smaller mobs to improve lamb survival. The analysis considered scenarios for Merino and non-Merino flocks where producers subdivided lambing paddocks using temporary or permanent fencing, or where ewes were reallocated within existing paddocks based on ewe pregnancy status. Optimum mob sizes were most sensitive to the type of fencing used for subdivision, whether ewes were single- or twin-bearing, whether the effect of paddock size on potential stocking rate was included and the target return on investment. Breed, ewe stocking rate, scanning percentage and lamb price also impacted optimum mob size but had a smaller effect. The optimum mob size for twin-bearing Merino and non-Merino ewes was between 34% and 60% that of single-bearing ewes and this was similar for scenarios where paddocks were subdivided or ewes were reallocated within existing paddocks. Permanent subdivision of paddocks also presents an opportunity to increase stocking rate by capitalising on the benefits of improved pasture utilisation in smaller paddocks. The relationship between paddock size and pasture utilisation is not well quantified but it has an important effect on optimum mob and paddock size. The value of reallocating ewes within existing paddocks was greatest at a scanning percentage of 150% as this presents the greatest opportunity to alter mob sizes for single- and twin-bearing ewes. The economic return from adjusting the relative mob size of twin-bearing ewes from 100% to 50% that of single-bearing ewes was up to $0.27/Merino ewe/yr and $0.44/non-Merino ewe/yr with lamb at $6/kg carcass weight. Overall, these analyses demonstrate that reducing mob size at lambing can be a profitable strategy for improving lamb survival depending on the current size of lambing mobs. However, it is difficult to provide generic recommendations to producers for the optimum mob size of ewes and value of paddock subdivision because these are dependent on enterprise-specific factors. • The optimum mob size for ewes and value of paddock subdivision are enterprise-specific. • Optimum mob size was smaller for twin-bearing ewes compared with single-bearing ewes. • Optimum mob size was smaller where the costs of paddock subdivision were reduced. • The return on investment was greater when splitting up larger mobs. [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]

Digitalisation is widely regarded as having the potential to provide productivity and sustainability gains for the agricultural sector. However, there are likely to be broader implications arising from the digitalisation of agricultural innovation systems. Agricultural knowledge and advice networks are important components of agricultural innovation systems that have the potential to be digitally disrupted. In this paper, we review trends within agricultural knowledge and advice networks both internationally and in Australia, to anticipate and prepare for potential transformations in these networks. Through a combined structured and traditional review of relevant literature, we come to three key conclusions regarding the state-of-the-art. First, the connectivity of humans and technologies in agricultural knowledge and advice networks and value chains will likely continue to increase. Second, transparency of agricultural practices and informational interaction between farmers, advisors, agri-businesses, consumers and regulators will drive and be driven by growing connectivity. Finally, there are likely to be challenges balancing the priorities of various agricultural stakeholders as agricultural innovation systems digitalise. These findings have implications for the oversight of international agri-food sectors. • Research concerning the digitalisation of agricultural innovation systems is reviewed. • Dominant trends concerning agricultural advisory services are presented. • Connectivity, transparency and governance are found to be key themes. • Australian agricultural knowledge and advice networks provide further context for analysis. [ABSTRACT FROM AUTHOR]

Mixed crop-livestock farming systems provide food for over half of the global population. However, some important food exporting countries, like Australia, are predicted to be vulnerable to climate change and may require transformative adaptations if they are to continue their role in food exportation. This paper assesses the potential impacts of projected climate change by 2030 (0.4–1.6° increase in mean temperature) on Australian mixed crop-livestock systems and examines the consequences of shifts in land allocations to cropping and grazing, in these systems, as an adaptation option. Farm bio-economic simulation models were developed for these mixed enterprise systems in several regions of Australia. These models were based on biophysically coupled crop, pasture, and livestock simulation models that in turn drew on site-based downscaled climate projection datasets. The farm models calculated farm profitability and risk measures. A range of land use changes was investigated. At drier locations facing adverse climate change, results showed a transition towards a greater emphasis on livestock production could be beneficial when assessed against multiple criteria of farm profit, downside financial risk, and environmental damage. We highlight some industry and government actions and policies that could facilitate these preferred adaptation strategies at such locations. • Temperature increase of 0.4–1.6° affect mixed crop-livestock systems in Australia. • Transition towards a greater emphasis on livestock production is often desirable. • Financially optimal land allocations vary between historical and future climate. • Increase in the land devoted to pasture is a strategy to manage future climate risk. [ABSTRACT FROM AUTHOR]

• The value of extra pasture DM for livestock production can be estimated using several different methods. • The two-price market value method can be an efficient way to estimate the value of extra seasonal dry matter yield of pasture grown and used. • To demonstrate its application, the method is used to value the seasonal yield of 19 perennial ryegrass cultivars grown in temperate Australia. • The value of extra pasture estimated using the two-price market value method can be easily generalised across a range of farming systems. The challenges of estimating the value of growing and using extra pasture to the farm business often necessitates using complex systems modelling of individual farms. In this paper, a straightforward market value method is outlined, where technical substitutes for which there is a defined market price are used as proxies to estimate an equivalent value for extra pasture used in a farm system. The method can be useful for all grazed livestock production systems where substitutes for pasture are purchased and sold. The two-price approach presented advances on previous applications of using market values by accounting for differences in the value of extra pasture DM used on farm in different seasons. The value per extra kg DM harvested in seasons when pasture typically limits livestock production, for example during summer/autumn in temperate environments, and used on farm equates to the market price of the replacement cost as purchased supplementary feed. This is the maximum the extra pasture DM could be worth when used in the farm system. Conversely, the value per extra kg DM harvested in spring when extra pasture is likely to be in surplus of livestock requirements, equates to its market price if sold, as standing hay for example, termed the salvage value. This two-price approach was applied to value the previously published seasonal DM yield differences of 19 perennial ryegrass cultivars, compared to an industry standard cultivar, grown in three regions of Victoria, Australia. Results were then compared to the value of extra pasture DM previously estimated using system simulation analyses of three farms and applied to the same perennial ryegrass data set. The difference in the value of extra pasture DM estimated using the two methods ranged from $0.01/kg DM to $0.24/kg DM. Overall, the two-price method estimated an extra $24 to $200/ha.year benefit over the industry standard cultivar for the 19 cultivars across the three regions, similar to the extra $0 to ∼ $180/ha.year estimated by the previous system simulation analysis. The two-price market value method can be an efficient way to estimate the value of extra seasonal DM yield of pasture, with results easily generalised across a range of farming systems. [ABSTRACT FROM AUTHOR]

Lucerne (Medicago sativa L.) is valued by producers with integrated crop-livestock systems. The multiple benefits of periods of lucerne leys to either livestock or to crop production have been widely reported; however, the importance of managing lucerne leys to whole farm profit and production has not and is best suited to a whole of system modelling study. This paper reports a simulation study aimed at better understanding the mixed farming systems that include short-term (3-year) phases of lucerne: specifically, the effects of terminating lucerne leys at different times prior to cropping. Simulations of mixed farming systems with the same soil type, crop rotation and proportional land use were conducted along a rainfall transect in a temperate environment in south-eastern Australia. Spring versus summer termination of the lucerne ley prior to cropping in autumn were compared. Although farming systems where lucerne was terminated in spring had higher crop production (mostly because of increased N at sowing) than those where lucerne was terminated in summer, the opposite was true for livestock production. Livestock production was higher in systems with summer termination mostly because of higher ewe condition scores at mating. When these sometimes positive and sometimes negative effects were evaluated at the whole of farm scale, in cases except the low rainfall site, allowing the lucerne ley to grow as late as possible prior to cropping was the most profitable management strategy in medium to high rainfall systems as it resulted in more lambs that were sold at heavier weights and the systems were more profitable, less costly, more efficient and less risky than those where leys were terminated in spring. • The decision when to remove lucerne in leys requires a whole farm analysis. • Differences in removal dates at the farm level were small and yet significant. • Land in transition presents opportunities for increasing water and N use efficiency. • Summer termination of lucerne was overall more profitable, efficient and less risky. • Perennial legume pastures need to be seen as a whole-of-farm resource. [ABSTRACT FROM AUTHOR]