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Context: The winter feed gap is a common problem for livestock grazing systems worldwide, and changes to climate have made these deficits more unpredictable and extreme. Dual-purpose crops are an important tool in many southern Australian mixed crop–livestock systems to help fill the winter feed gap. Providing more reliable feed over winter can remove feed constraints and allow for earlier lambing in autumn with potential whole-farm system benefits. Aims: We simulated a whole-farm livestock enterprise in the Agricultural Production Systems Simulator (APSIM) to examine the implications of spring- and autumn-lambing systems relying on a standard pasture-only feedbase compared with a farm where 25% of its grazed area is allocated to dual-purpose crops. Methods: Twelve simulations were run across four locations in New South Wales, Australia, that varied in climatic conditions (both rainfall total and distribution) including two lambing systems (spring vs autumn) × two feedbase types (100% pasture vs 75% pasture and 25% dual-purpose crops) × three stocking densities. Key results: For autumn-lambing systems, integrating dual-purpose crops helped to fill the winter feed gap and reduced supplement demand on average by ~28% compared with a pasture-only system. Compared with the standard pasture-only spring-lambing system, integrating dual-purpose crops into spring- and autumn-lambing systems more than doubled gross margin returns due to economic grain yield and lower supplement demand. A shift from spring- to autumn-lambing facilitated by dual-purpose crops also led to better reproductive performance of ewes in the subsequent year. In higher-rainfall, cooler environments, autumn-lambing systems with dual-purpose crops had the highest system gross margins, lowest economic risk and allowed for a safe increase in stocking density. In lower-rainfall, warmer environments, integration of dual-purpose crops into spring-lambing systems returned marginally higher gross margins than for the autumn-lambing system, but differences were less apparent at high stocking density. In lower-rainfall environments, dual-purpose crops helped to mitigate some of the economic risk, but the benefits were less clear. Conclusions: We show dual-purpose crops can help fill the winter feed gap and support earlier lambing in autumn across a range of environments, especially in higher-rainfall cooler environments, with significant improvements in total farm gross margins. Implications: Integrating dual-purpose crops will enable farmers to change their livestock system to mitigate their risks, reduce supplementary feeding and capitalise on other potential benefits, such as improved marketing and avoiding animal health problems. Whole-farm simulation modelling suggests that integrating dual-purpose crops of wheat and canola to 25% of the farm decreases the winter feed gap and facilitates autumn-lambing systems across environments. Spring- and autumn-lambing systems with dual-purpose crops achieved more than double the farm gross margins compared with the standard spring-lambing, pasture-only system. In higher-rainfall, cooler environments, autumn-lambing systems with dual-purpose crops returned higher gross margins due to grain production and lower supplement demand, but in lower-rainfall, warmer environments, spring-lambing systems were still more profitable. [ABSTRACT FROM AUTHOR]

Understanding the quantity and timing of labour to fulfill the goals of different cropping systems or crop rotations is critical, but poorly quantified and understood in many agricultural systems, including the grain-growing regions of eastern Australia. Yet, labour supply and demands are important considerations for farmers and can significantly influence their agronomic management and decisions to adopt modified crop rotation systems. Here, we investigated the extent to which crop rotation systems, that differed in their intensity (i.e. the proportion of time when crops were growing), and diversity (i.e. the range of crops grown) influence labour requirements and labour productivity. We used the Agricultural Production Systems sIMulator (APSIM) to simulate a set of different crop rotations and combined the output with farmer survey data and expert knowledge derived from farm advisers to compute the labour inputs for key crop operations (i.e. sowing, spraying, harvesting). This information was used to calculate the labour required and the timing of this demand for each cropping system. We showed that as the cropping intensity increases the labour demand also increases, and vice versa. However, only small differences in labour demands were identified between systems with differing crop diversity (i.e. range of crops grown). Thus, when it comes to labour demands, crop diversity is less critical than cropping intensity. Labour demand was highly seasonal, with peaks around the intense operations of sowing and harvesting. These peak demands constrained the area that could be managed by a unit of labour, particularly as the cropping intensity increased. Further, this analysis highlights that the most profitable systems may not necessarily be the most efficient in terms of labour productivity (i.e. return per unit of labour). This analysis shows that when labour is limiting, labour demands and especially peak periods may contribute to a farmer's choice of cropping systems, adding to other critical factors like risk aversion and profit maximisation. The analysis contributes to the literature on the role of labour in the context of influencing the implementation and adoption of what are seemingly more productive or profitable farming systems. In particular, the results demonstrate how labour as a critical farm resource (i.e. its quantity, seasonality and timing, and productivity) can influence the design of crop rotations. [Display omitted] • Many cropping systems in Australia are being modified by altering their intensities and crop diversity, but their labour demands are unknown. • Crop rotations with distinct intensity and diversity are simulated in APSIM to estimate their labour demands, seasonality, and economic returns. • Altering cropping intensity had stronger influence on labour demands and returns than changing the crop diversity in the rotation. • Labour demands between rotations is not substantial to influence a farmers decision on adopting alternative or modified cropping sequences. • Findings contribute to the growing discussion on the role of labour for the design and potential feasibility of innovative cropping systems. [ABSTRACT FROM AUTHOR]

Substantial initiatives are occurring in developing countries to integrate forage crops into crop-livestock systems to improve farmer livelihoods and reduce soil erosion. In particular, government authorities in western China focus on improving farmer livestock profits through greater forage crop production. We examined the whole-farm profit, downside risk, labour-use efficiency and feed balance effects of forage crop intensification on two simulated crop-livestock farm types in western China. Our methodology combined crop and livestock simulation modelling with whole-farm stochastic budgeting to capture both price and climate variability. We modelled the whole-farm effects of (1) introducing either forage vetch (Vicia sativa), forage oats (Avena sativa), or grain soybean (Glycine max) into current wheat (Triticum aestivum)-maize (Zea mays) systems and (2) replacing maize in current wheat-maize systems with either forage wheat, forage maize, or forage soybean. System intensification through incorporating a forage crop into current grain-cropping systems can increase average simulated profits without increasing downside risk on the simulated farms. As opposed to adding a forage crop into current grain-cropping systems, replacing a grain crop with a forage crop in current grain-cropping systems had a negative effect on profits, downside risk, and labour-use efficiency. Trade-offs existed between labour-use efficiency and profit as forage intensification increased labour demands. These effects were context specific, with greater positive profit effects of forage intensification for the higher-rainfall farm type. Overall, forage intensification in these systems benefited the households, but adoption will depend on household preferences and local agro-ecological and market factors. We demonstrated the importance of exploring proposed intensification options across different locations to capture impacts across diverse contexts. Providing these context-specific insights and exploring trade-offs within systems can help better understand livelihood improvement pathways. In locations with strong competing uses for labour, developing labour-saving practices appears critical. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mixing crops and livestock helps Australian farmers manage climate, price and soil variability. [•] Recent crop–livestock innovations can improve farm productivity, sustainability and reduce risk. [•] Potential for grazing dual-purpose cereal and canola crops or sacrificially grazing crops is unrealised. [•] Perennial pasture phases in grain crop rotations can provide multiple farm benefits. [•] Systems growing mixtures of crops and pastures and to utilise novel pasture species are evolving. [ABSTRACT FROM AUTHOR]

• Tropical forage legumes were grown in rotation or relays with maize and rice. • Subsequent maize yields increased by up to 80 % if legumes were retained as mulch. • Maize yield increased less (15−35% higher) after legume forage was harvested. • Forage legumes grown in rotation with rice increased subsequent yields by 40–70 %. • Clitoria ternatea proved the most beneficial forage legume for diverse systems. In temperate systems, it is well known that forage legumes can improve both nitrogen (N) supply and yields of subsequent cereal crops. While this is assumed to be true in tropical systems, it is less well tested, particularly in smallholder settings where forage is often cut and removed from the field. This paper confirms the potential of short phases of tropical forage legumes to provide N to subsequent crops in seasonally dry tropical farming systems. Across five experiments, maize and rice grain yields increased by up to 80 % after 4−8 month rotations of forage legumes, but the benefits were smaller when legume growth was reduced, biomass was removed for forage, or the yield potential of cereal crops was lower. We found that the additional N cycling from legumes can last for at least 2 years, although the benefit diminishes with time. When all legume material was retained as mulch, the estimated additional N provided to subsequent no-till maize crops was the equivalent of 9−15 kg urea-N per tonne of above-ground legume biomass produced but fell to 1.5−3 kg urea-N/t if forage was removed. After shoot removal, more legume N cycled to a subsequent rice crop (equivalent of 11–13 kg urea-N/t of legume biomass) than to a no-till maize crop, presumably because more below-ground material mineralised. Of the legumes tested, Clitoria ternatea grew best across a variety of environments and use patterns and provided the largest yield benefits to subsequent crops. This research demonstrates the potential to integrate short phases of tropical herbaceous forage legumes into smallholder crop-livestock systems in the seasonally dry tropics, and, in doing so, improve or maintain staple grain crop production and household food self-sufficiency. [ABSTRACT FROM AUTHOR]

Abstract: Soil damage by livestock on cropped land is a concern for mixed crop-livestock producers. The hypothesis that livestock-induced soil damage does not effect subsequent crop productivity was investigated in three ways; a review of existing literature; two experimental studies in southern Australia; and based on these, use of a farming system model to simulate likely consequences of changes to soil conditions on crop productivity under a variety of seasonal conditions. The literature suggests that treading by livestock increases soil strength and bulk density and reduces macro-porosity and infiltration rate. Yet, the effects are confined to the soil surface (0–0.1m) and are short-lived due to amelioration through natural processes or tillage. Despite the potential for soil damage, few studies report yield penalties in following crops, possibly because effects are too small in magnitude or depth to influence plant growth significantly, or because of the highly season-dependent nature of crop response. Two recent field experiments in southern Australia also found no effect of sheep grazing on subsequent crop growth or yield, despite evidence of surface compaction and reduced infiltration rate. Using reviewed literature and this experimental evidence, we adjusted soil parameters in APSIM (Agricultural Production Systems Simulator) to reflect mild, moderate and severe reductions in surface root growth and surface water infiltration. The predicted sensitivity of wheat crop productivity to these simulated impacts was investigated at 6 locations in eastern Australia. Consistent with experimental evidence, predicted average grain yield was reduced by <10% (+3 to −10%) under mild and moderate scenarios typical of those reported experimentally. Crop yields were reduced by lower rainfall infiltration and fallow efficiency in locations with summer-dominant-rainfall, and by reduced root exploration at locations with winter-dominant-rainfall. Lower residue cover levels amplified reductions in rainfall infiltration, especially reducing the accumulation of soil water during summer fallow. Predicted grain yield was only reduced substantially (up to 43% on average) when severe changes in soil parameters were implemented (e.g. 90% reduction in rate of root exploration in surface layers). Overall, most experiments support our hypothesis that grazing livestock have little effect on subsequent crop yields. Long-term simulations suggest that soil impacts generating large reductions in root growth and infiltration rate are required to reduce subsequent crop yields substantially. Such impacts are unlikely where current best-practice grazing management occurs, but would be possible on structurally degraded soils where surface cover is allowed to fall below critical levels. [Copyright &y& Elsevier]

Pulses have emerged as important rotation crops in Australia. Some are in demand in agricultural production systems due to their high potential market value, because of their roles as grain or forage crops, their nitrogen fixation capability, and because they provide a disease break or improve soil health. While several pulse crops have been identified for winter-season cropping, there are few adapted legumes apart from mungbean that are appropriate for dryland summer cropping. Currently, short-duration crops of mungbean are commonly used, but yields are highly variable and susceptible to drought. Here, we propose that cowpea has the potential to become an alternative rotation crop in dryland summer cropping zones, providing a competitive and profitable alternative pulse crop option where its drought tolerance could enable better performance under inconsistent in-crop rainfall. We demonstrate that cowpea has nutritional properties and putative uses that could prove valuable in emerging plant-based protein and aquaculture markets. [ABSTRACT FROM AUTHOR]

Highlights • Delaying sowing date shortened time of emergence of maize, Sudan grass, foxtail millet and Japanese millet. • Variation of leaf area per plant of three forage crops was caused by leaf area elongation rate (LAER). • The relationship between final leaf number on main culm and climatic conditions varied with forage species. • Maize, Sudan grass, foxtail millet and Japanese millet displayed a strong phenotypic plasticity. Abstract Annual forage crops attract more attention to researchers for it can be used as both forage in animal production and ethanol production in industry. Sowing date are critical to increase crop yield potential in semi-arid environments. Successful establishment and canopy develop are two key aspects ensuring the final yield of forage crop. Therefore, emergence time, leaf appearance and solar radiation interception by the canopy were measured with four annual forage grasses [maize (Zea mays), Sudan grass (Sorghum sudanense Stapf., S), foxtail millet (Setaria italic) and Japanese millet (Echinochloa crus-galli var. frumentacacea)] during the period of 2011–2013 in the western Loess Plateau of China. The results showed that a delay of sowing date could decrease the time for crop emergence. In addition, a decrease in the final leaf number (FLN) and the individual leaf area (ILA) (maize, foxtail millet and Japanese millet) from delayed sowing resulted in less light interception (RI). The variation FLN was closely related to day length (DL) and initial soil water and rainfall at flowering (W s +R f) for maize and foxtail millet, thermal time (TT), DL and W s +R f for Sudan grass and Japanese millet. Changes in leaf area per plant (LA single) in Sudan grass, foxtail millet and Japanese millet were caused by leaf area elongation rate (LAER). Sowing date did not affect leaf appearance rate (LAR) in Japanese millet while decreased in Sudan grass and increased in foxtail millet when the sowing date was delayed, mainly due to changes in DL, TT and W s +R f. Variations in individual leaf area (ILA) and LAER indicated the strong plasticity of the four crop species. Therefore, the results of this study improved the understanding of the relationship between sowing date and canopy development and provide important information in crop management and breeding to increase the crop yield. [ABSTRACT FROM AUTHOR]

• Effect of sowing date on biomass partition varied with forage crop species. • Aboveground biomass at flowering was dependent on rainfall and solar radiation. • Aboveground biomass at maturity more reliant on temperature and rainfall. • Allometric approach should be used in the analysis of allocation pattern. Biomass production and partitioning are important for crop production and is influenced by environmental conditions. Sowing date can profoundly influence biomass production and portioning in crop plants depending upon the local climatic conditions. However, the accumulation of biomass in different plant components in annual forages in response to changes in sowing date has not been quantified, especially for semiarid farming systems. A field experiment was conducted during 2011–2013 to investigate how sowing date (early, mid, late) influences biomass partitioning and the interrelationships with environments in four warm-season annual crops in the Loess Plateau of China. The aboveground biomass of all four crops was more reliant on rainfall and solar radiation at flowering and temperature and rainfall at maturity. Solar radiation, rainfall, and temperature had a combined effect on belowground biomass (0–0.3 m), depending on the forage crop. Reductions in biomass in the late-sown treatment were mostly attributed to plant size; the 'allometry' among plant components did not change. The changes of shoot: root and leaf: stem ratios were related to the relationship between biomass accumulation and rainfall, temperature and intercepted radiation. It is evident that dry matter allocation patterns in crops must be analyzed using a dynamic approach (allometry) and relate with environmental conditions, rather than a static approach using ratios. The results from this study provide references for crop management in forage production and breeding in semiarid areas. [ABSTRACT FROM AUTHOR]