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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]

Abstract: Australia has a long history of mixed farming. This paper examines the integration of Australian cropping and livestock production from three perspectives: as a factor in land use change, a consequence of individual management practices and a means of meeting farmers’ multiple objectives. Since about 1995, the proportion of cropped land has increased on Australian cropping farms while livestock numbers have decreased. Land use in the north-eastern, central and south-western regions of the cropping zone have diverged. Despite these changes, mixed farms still dominate Australia’s broadacre farming regions. Previous accounts of the dimensions in which farming enterprises are integrated can be simplified for Australian broadacre agriculture. For most purposes it is sufficient to consider a nested set of four integration options: “specialization” (not integrated organizationally), “separation” (integrated organizationally only), “rotation” (integrated organizationally and spatially, but not temporally) and “synchronization” (integrated in all three dimensions). We illustrate these integration options with a short survey of agronomic practices that affect crop–livestock integration. We review the farmer objectives that enterprise integration can meet and the constraints that limit it, seeking to balance social, economic and agronomic factors. We use a dynamic simulation model to make a first quantification of the economic risk reduction provided by enterprise diversification. Constraints imposed by limited labour, capital, and management attention cannot be overlooked; this is especially relevant in Australia where labour is increasingly in short supply. We characterize our surveyed set of agronomic practices with respect to the farmer objectives they affect. We find that farmers generally have the option of meeting a particular objective through different practices that affect different dimensions of integration. Practices that result in closer integration in time and space generally require greater management attention; practices that do not integrate in space typically require an increase in external inputs. History suggests that current commodity price ratios may be sufficient to slow or reverse the overall land use trend away from livestock production. In the longer term, forecast increases in worldwide demand for meat, energy costs and soil resource constraints will all encourage Australian cropping farmers to maintain mixed systems; however reduced availability of labour relative to capital will push land use toward specialized systems. Valuing the benefits and costs associated with differing degrees of enterprise integration is a major research challenge that will require insightful application of both biophysical and economic models. [Copyright &y& Elsevier]

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]

Failing grain crops are sometimes sacrificed for grazing by mixed farmers, a decision involving a complex range of factors. This simulation study used two APSIM (Agricultural Production Systems Simulator)-based approaches to investigate the circumstances under which more revenue might be obtained by sacrificing a wheat crop for grazing rather than harvesting it for grain in Western Australia's grainbelt. First, we developed a simple partial budget calculation to estimate and compare revenue from grain or grazing alternatives using data for grain yield and standing biomass at flowering. This was simulated for a factorial of soil types and locations varying in mean annual rainfall. We then simulated wheat quality and livestock production on spring wheat grazed at different stages of crop development and at a range of stocking rates. Dynamic simulations of grazing showed that livestock production increased as grazing was delayed; stocking rate had little impact at this time. Grazing earlier necessitated lighter stocking rates but surprisingly had little benefit for animal performance. Partial budgets showed that under average commodity prices, grazing a wheat crop could be more profitable 40-75% of the time on poorer soil types in lower rainfall environments. In these situations, by tactically grazing when grain yield is below a critical level economic returns could be increased by more than A$50/ha in 30-40% of years and over the long term average revenues could be increased by A$30/ha.year. This critical grain yield ranged from 1.3 to 1.7 t/ha on shallow gravel soil and 1.9 to 2.2 t/ha on a deep sand. In higher rainfall environments and on better soil types grazing was rarely a better option unless livestock prices were high relative to grain. This approach, combining crop simulation with partial budgets, was useful for developing simple management rules for a complex system. Overall, the findings of this study suggest that making tactical use of a wheat crop for forage in situations with low grain yield prospects is a major opportunity to increase profitability and help respond to climate variability in mixed farms in many areas of the Western Australian wheatbelt. [ABSTRACT FROM AUTHOR]

A central concern of the Grain & Graze research, development and extension program has been improving the management of the feedbase on mixed farms through addressing 'feed gaps' -- times of year during which the supply of forage is insufficient to meet livestock demand. In this review, we use the available data on pasture growth and quality, supplemented by modelling results, to describe the characteristic timing of feed gaps across the Australian cereal-livestock zone. Feedbase interventions studied during the Grain & Graze program have mainly addressed the supply side of the feed balance equation. We review these studies, paying particular attention to the time scale of the variability in the feed balance that each intervention is intended to address. We conclude that grazing of cereals (either dual-purpose or forage crops) is the most promising means of alleviating winter feed gaps in regions where they are important. Reducing feed gaps in summer by relying on unpredictable summer rainfall events will increase year-to-year variability in forage production and will therefore require more flexible livestock management systems to exploit it. The use of forage shrubs offers a practical tool for increasing the predictability of summer and autumn feed supply, but given their moderate capacity for providing additional metabolisable energy it remains important to carefully manage livestock over autumn and to manage the herbaceous inter-row pasture. Feed gaps mainly arise from an interaction between biology and economics. We find, however, that the options studied in the Grain & Graze program for addressing feed gaps require either greater complexity in pasture and grazing management or more opportunistic livestock trading; they therefore come at a cost to the manager's limited decision-making time. Times with feed gaps are also times when particular natural resource management risks (especially erosion) need to be managed. Supply-side interventions to relieve feed gaps will generally use more soil water, which will often have positive effects on natural resource management outcomes. [ABSTRACT FROM AUTHOR]

Temporal variability in the availability of forage reduces the production and economic performance of livestock systems. The marginal value of feed (MVF, the possible gross economic benefit of additional feed on offer during an annual cycle), was assessed under the expected variability of climate and prices in a cow-calf operation from the Flooding Pampas, Argentina. Herbage mass accumulation (HMA) was simulated on a daily basis over 20 different years with DairyMod, grouped by month and season and where the HMA was equal or below 50% of its long-term average, it was tagged as “Dry”. Typical monthly pasture growth rates were synthetically depicted for average years (Average), or with dry autumn (D-Au), winter (D-Wi), spring (D-Sp) or summer (D-Su) conditions. These pasture growth curves were incorporated into whole-farm scenarios which were modelled with SIMUGAN, a bio-economic whole-farm model. Farm scenarios were baseline (unchanged HMA) or with additional 10% of the annual HMA. This additional feed was either evenly distributed across each month of the year (all year), or the full amount provided in one of the four seasons. These scenarios were repeated in a factorial design across a range of stocking rates (SR; 0.9–1.3 cows/ha) on an average year or years including one dry season (D-Au, D-Wi, D-Sp orD-Su). SIMUGAN results were fed to an ad-hoc built model to calculate production and market risk profiles. In years with average HMA, MVF were always below 0.05 US$/kg DM but the presence of a dry season caused significantly higher MVF. Years with dry autumn presented the highest economic responses when the extra feed was fed during autumn or winter. MVF analyses showed a positive impact of additional forage only above 1.1 head/ha and this increased with SR, whereas MVF at the low SR were mostly negative due to extra hay making costs. At 1.1 and 1.2 head/ha, allocating additional feed in autumn produced a higher return (0.04 and 0.08 US$/kg DM) than feed provided at other times of the year (averaging 0.02 and 0.05 US$/kg DM). Otherwise, at 1.3 SR extra feed in winter always had the highest MVF (up to 0.19 US$/kg DM). Bio-physical variables of livestock demand and seasonality of pasture growth were the main drivers of MVF variability. Overall, the framework developed by integrating forage, livestock and economic models “in a series” effectively identified the economic feasibility of changes to the farm feed-base under different climatic and livestock management conditions. [ABSTRACT FROM AUTHOR]

Abstract: Simulation models can help to identify the whole-farm economic and biophysical impacts of smallholder farmers altering their farming systems. Incorporating long-term climate-induced variability in crop and livestock production enables the implications for agricultural household income and risk to be explored over a range of seasonal conditions. In this study, a simulation model is used to answer the following question: can reducing the area used for grain production by allocating more land to lucerne (Medicago sativa) and increasing livestock numbers improve total net farm income, reduce income variability and maintain grain self-sufficiency for farmers in the Qingyang Prefecture of Gansu Province, China? This was examined for three representative farm types found in the region: a low land-labour ratio farm household, a subsistence-oriented farm household, and a livestock-focused farm household. The Integrated Analysis Tool (IAT), a simulation model of a household farming system, was used to combine crop and forage production simulations, a livestock production model and a household socio-economic model to explore the impact of changes to farming systems over a 40year simulation period. Data from 90 surveyed households were used to define the structure of the three farm household types and to calibrate the IAT model specifically for Qingyang Prefecture. Additional livestock increased total household net incomes, increased net livestock incomes and reduced net crop incomes for the subsistence-oriented and livestock-focused farm households. For these households, the greater commitment to livestock also reduced grain self-sufficiency due to increased frequency of purchasing grain for home-consumption. Nevertheless, additional livestock reduced income variability for these households whilst improving total net income. The methodology used is useful for understanding changes in farming systems as it focuses on the feasibility and profitability of alternative enterprise mixes and incorporates climate variability. The results support current debates on targeting livestock policies towards smallholders as subsistence-oriented farm households appear to be the largest beneficiaries from livestock interventions. The analysis demonstrates that tradeoffs between net income and grain self-sufficiency are important for households, especially when they are moving from subsistence-based to market-based production. [Copyright &y& Elsevier]