The sale of cattle presents a significant opportunity to improve livelihoods for smallholder farmers in eastern Indonesia. An opportunity was identified to grow herbaceous forage legumes either in rotation with, or sown within, staple grain crops (maize, rice) to use surplus soil moisture to produce a feed bank for (mostly penned) cattle and potentially increase nitrogen supply to the grain crops. A series of experiments was conducted on Vertisol, Alfisol and Inceptisol soils in lowland and upland districts of eastern Indonesia to identify legumes from 18 taxa suitable for integrated crop-forage systems. Clitoria ternatea and Centrosema pascuorum were found to have best potential for these systems as they established reliably using local methods, consistently ranked highly for herbage yields 2–4 months after sowing and were relatively easy to harvest. Yields were highest on the Vertisol (greatest number of sites) and Inceptisol soils. Lablab purpureus, Macroptilium bracteatum and Mucuna pruriens also ranked high for yield on Vertisol soils. Clitoria ternatea regrew consistently after cutting and forage removal providing potential for extended forage production as growing conditions allow.

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.

Soil processes have a major impact on agroecosystems, controlling water and nutrient cycling, regulating plant growth and losses to the wider environment. Process-based agroecosystem simulation models generally encompass detailed descriptions of the soil, including a wide number of parameters that can be daunting to users with a limited soil science background. In this work we review and present an abridged description of the models used to simulate soil processes in the APSIM (Agricultural Production Systems sIMulator) framework. Such a resource is needed because this information is currently spread over multiple publications and some elements have become outdated. We list and briefly describe the parameters, and establish a protocol with guidelines, for building a soil description for APSIM. This protocol will promote consistency, enhancing the quality of the science done employing APSIM, and provide an easier pathway for new users. This compilation should also be of relevance to users of other models that require detailed soil information.•This paper presents a brief description of the models for simulating soil processes in the APSIM model.•The method stablishes guidelines to define the parameters for building a soil description for APSIM.

Context Increasing demand for livestock products in developing countries provides opportunities for smallholder farmers to increase and diversify their income through increased livestock production. However, livestock production in these systems is often limited by inadequate animal nutrition, and farmers need ways to increase the availability and quality of livestock feed without compromising yields of food crops or increasing the area of land planted to forages. Aim Using eastern Indonesia as a case study, we explore the potential for herbaceous legumes, integrated into existing mixed crop–livestock systems, to address specific production issues in smallholder beef systems. Methods Through a series of in-village feeding demonstrations, we tested three opportunities to increase livestock production through the use of herbaceous legumes: (i) increasing reproduction rates of cows by maintaining their liveweight (LW) and body condition score during the dry season; (ii) increasing the survival and LW gain of unweaned calves; and (iii) increasing LW gain of growing bulls. Key results Small amounts of legume (~10 g DM/kg LW) were enough to maintain LW of cows grazing poor-quality grasses and crop residues during the dry season. At higher levels of inclusion in the diet (~20 g DM/kg LW), feeding legumes increased the LW gain of growing cattle and survival of unweaned calves, providing benefits similar to a purchased concentrate, but at lower cost. Conclusions Our results demonstrate how strategic use of herbaceous legumes can increase beef production from low-input systems by maintaining LW of cows, and increasing survival of unweaned calves and LW gain of growing bulls. Implications Integration of herbaceous legumes into existing cropping systems removes many of the barriers to supplementary feeding. Improved livestock nutrition does not need to be based on purchased concentrates or increases in land used for forage production. The results are applicable to many other mixed crop–livestock systems throughout Southeast Asia.

Integration of tropical forage legumes into cropping systems may improve subsequent crop nitrogen (N) supply, but removal of legume biomass for forage is likely to diminish these benefits. This study aimed to determine: (i) under irrigated conditions, the potential N inputs that can be provided by different tropical forage legumes to a subsequent cereal crop; and (ii) the residual N benefits once fodder had been removed. Available soil mineral N following tropical forage legumes lablab (Lablab purpureus), centro (Centrosema pascuorum), butterfly pea (Clitoria ternatea) and burgundy bean (Macroptilium bracteatum) and grain legume soybean (Glycine max) was compared with a maize (Zea mays) control when legume biomass was retained or cut and removed (phase 1). An oat (Avena sativa) cover crop was then grown to ensure consistent soil-water across treatments (phase 2), followed by a maize grain crop (phase 3) in which N uptake, biomass production and grain yield were compared among the phase 1 treatments. To determine N-fertiliser equivalence values for subsequent maize crop yields, different rates of fertiliser (0–150 kg urea-N/ha) were applied in phase 3. Retained biomass of butterfly pea, centro and lablab increased phase 3 unfertilised maize grain yield by 6–8 t/ha and N uptake by 95–200 kg N/ha compared with a previous cereal crop, contributing the equivalent of 100–150 kg urea-N/ha. When legume biomass was cut and removed, grain yield in the phase 3 maize crop did not increase significantly. When butterfly pea, centro and lablab biomass was retained rather than removed, the maize accumulated an additional 80–132 kg N/ha. After fodder removal, centro was the only legume that provided N benefits to the phase 3 maize crop (equivalent of 33 kg urea-N/ha). Burgundy bean did not increase subsequent crop production when biomass was either retained or removed. The study found that a range of tropical forage legumes could contribute large amounts of N to subsequent crops, potentially tripling maize grain yield. However, when these legumes were cut and removed, the benefits were greatly diminished and the legumes provided little residual N benefit to a subsequent crop. Given the large N trade-offs between retaining and removing legume biomass, quantification of N inputs under livestock grazing or when greater residual biomass is retained may provide an alternative to achieving dual soil N–fodder benefits.

The Coal Seam Gas (CSG) extraction industry is developing rapidly within the Surat Basin in southern Queensland, Australia, with licenses already approved for tenements covering more than 24,000 km(2). Much of this land is used for a broad range of agricultural purposes and the need for coexistence between the farm and gas industries has been the source of much conflict. Whilst much research has been undertaken into the environmental and economic impacts of CSG, little research has looked into the issues of coexistence between farmers and the CSG industry in the shared space that is a farm business, a home and a resource extraction network. We conducted three workshops with farmers from across a broad region undergoing CSG development to explore farmers' perceptions of some of the issues arising from large scale land use change. Workshops explored the importance of place identity and landscape aesthetics for farmers, farmers' acceptance and coping with change, and possible benefits from off-farm income. We found that farmers believed that place identity was not well understood by CSG staff from non-rural backgrounds and that farmers struggled to explain some concerns because of the different way they interpreted their landscape. Furthermore, high staff turnover, and the extensive use of contractors also impacted on communications. These factors were the cause of much frustration and farmers felt that this has led to severe impacts on mental health and wellbeing. Farmers felt that a change in culture within the CSG companies will be required if engagement with farmers is to improve and that efforts to employ local people in these communications was helping this. The workshops also identified a range of issues perceived by farmers arising from increased traffic volumes, impacts to mental health and wellbeing, place identity and loss of water resources for farmers. Finally, it was suggested that scientists and agricultural industry groups will need to work closely with farmers to develop understanding of these emerging issues and to develop solutions that are timely and relevant.

This report presents data and analysis from the “Markets and Policy” component of ACIAR Project LPS-2009-036 “Enhancing smallholder beef production in East Timor” (20012-15). The report aims to provide a rigorous, up-to-date and comprehensive account of structures and development issues in the Timor Leste beef industry for industry stakeholders, including policy-makers, development agencies, researchers and members of LPS-2009-036.

With high levels of seasonal climatic variability impacting on the consistency of rice production in Cambodian rainfed, lowland systems, there is a need to identify strategies that improve farmer food security and better meet national domestic and export demands. While there is a substantial gap between actual and potential rice yield, little research has been undertaken in Cambodia to improve rainfed rice agronomy or the efficiency of use of natural resources which, in a climate constrained environment can hold the key to better productivity and food security.On-station and on-farm research, in combination with farming systems simulation and social research provide the capacity to evaluate cropping options through the lens of climate variability. The testing of technologies and strategies, including the use of modern, short and medium duration varieties, opportunistic timing of crop establishment, mechanisation, supplementary irrigation and improved agronomic practice has shown that there is potential to mitigate the effects of variable climate on farm productivity and household income. However, this requires an increased level of farmer/systems flexibility to allow for near to real-time changes in cropping response to observed seasonal conditions. These factors differentiate this research and provide the opportunities to improve the individuals' livelihood and in meeting national rice production targets. (C) 2016 Elsevier B.V. All rights reserved.

Rice production is the major source of food security in Cambodia where 85% of the total arable land is cultivated to rice with traditional transplanted medium and later maturity varieties accounting for >70% of the plantings during the monsoon period. Climate change poses risks and opportunities to the sustained productivity of rice based farming systems in Cambodia. The objective of this study is to evaluate adaptation strategies that support the replacement of traditional low input systems with a 'response' farming approach for better temporal utilisation of available labour, land and water resources. Options include replacing a traditional transplanted crop with short duration varieties, more efficient crop establishment methods and better agronomic and fertiliser management that responds to timing, intensity and longevity of the monsoon and has potential to mitigate effects of current and future climate variability. To achieve this, we apply the APSIM farming systems model to evaluate how adaptation options for smallholder farmers can increase or maintain overall productivity within present day climate variability and future climates, using downscaled GCM baseline and 2030 climate scenarios. To extend beyond the 2030 climate change scenarios, we also assess production risk from an increase in ambient air temperature of 1.4-4.3 degrees C, atmospheric CO2 concentration of 545-885 ppm and variation in rainfall, for rainfed and irrigated systems to 2090. Modelled scenarios indicate a yield response to elevated CO2 of 17.5% at a concentration of 680 ppm for current temperature and rainfall and are consistent with established physiological effects of CO2 on crop yields. In response to temperature, yields decreased by 4% per degree increase from an average annual baseline temperature of 28 degrees C. Adaptation strategies involving deployment of short duration rice varieties, in conjunction with direct seeding and better N management, indicate comparable and improved production can be achieved to 2030 under likely future climate projections. However, beyond 2030, the distribution and timing of rainfall has a significant influence on rainfed lowland rice in Cambodia. In this case a more transformational approach involving widespread provision of irrigation water will be required to offset climate change impacts. (C) 2016 Elsevier B.V. All rights reserved.

SUMMARYAchieving export growth in rice production from variable rainfed lowland rice ecosystems is at risk if depending on conventional breeding or genetic development alone. Sustained, long-term production requires building adaption capacity of smallholder farmers to better manage the challenges of seasonal climate variability and future climate change. Better understanding of the risks and constraints that farmers face in managing their current cropping system helps develop strategies for improving rice production in Cambodia. System models are now considered valuable assessment tools for evaluating cropping systems performance worldwide but require validation at the local level. This paper presents an evaluation of the APSIM-Oryza model for 15 Cambodian rice varieties under recommended practice. Data from a field experiment in 2011, conducted in a non-limiting water and nutrient environment, are used to calibrate varietal-specific coefficients and model input parameters. An independent dataset is then used to validate the model performance for a ‘real-world’ situation using on-farm data for six rice varieties planted in 54 farmer fields on 32 farms in two villages of Southeastern Cambodia. From this analysis, the APSIM-Oryza model is shown to be an acceptable tool for exploring the mismatch between current on-farm yields and potential production through yield gap analysis and the exploration of cropping system options for smallholder farmers to increase production, adapt to seasonal climate variability and be prepared for potential climate changes.

Agricultural systems models worldwide are increasingly being used to explore options and solutions for the food security, climate change adaptation and mitigation and carbon trading problem domains. APSIM (Agricultural Production Systems sIMulator) is one such model that continues to be applied and adapted to this challenging research agenda. From its inception twenty years ago, APSIM has evolved into a framework containing many of the key models required to explore changes in agricultural landscapes with capability ranging from simulation of gene expression through to multi-field farms and beyond.Keating et al. (2003) described many of the fundamental attributes of APSIM in detail. Much has changed in the last decade, and the APSIM community has been exploring novel scientific domains and utilising software developments in social media, web and mobile applications to provide simulation tools adapted to new demands.This paper updates the earlier work by Keating et al. (2003) and chronicles the changing external challenges and opportunities being placed on APSIM during the last decade. It also explores and discusses how APSIM has been evolving to a "next generation" framework with improved features and capabilities that allow its use in many diverse topics. Crown Copyright (C) 2014 Published by Elsevier Ltd. All rights reserved.

Soil available water capacity (AWC) is the main source of water for vegetation and it is the potential amount of water available for atmospheric exchange. Studying its spatial distribution is crucial for agricultural planning and management and for use in biophysical modelling. The aim of this work is to obtain a continuous spatial prediction of AWC over Australia's wheatbelt (about 1.75millionkm2), using digital soil mapping techniques. We used a data set of 806 soil profiles which have field measurements of drainage upper limit (DUL) and crop lower limit (CLL). We mapped AWC at five depth intervals (0–5, 5–15, 15–30, 30–60, and 60–100cm) with the help of different combinations of environmental information (topographic, climatic, soils, landsat imagery, gamma-ray spectrometry) as covariates. The modelling techniques used were symbolic regression (GP), Cubist, and support vector machines (SVM). We also tried two averaging methods to generate an ensemble model. We observed decreasing RMSE values with the addition of extra covariates and also an expected decreasing soil depth. In general, SVM produced the best accuracy. We were able to improve the predictions using one of the ensemble techniques, based on a weighted average of GP, Cubist and SVM model. The map generated with the optimal ensemble model was an unrealistic representation of AWC therefore we decided to present a sub-optimal model as the final map. We stress the need to not only focus on the numerical performance in order to obtain a flexible and stable model, but also a coherent visual representation without anomalies.

The FARMSCAPE Information System emerged in a long-running research program aimed at making simulation models useful to Australian farmers in managing climatic variability. This paper is about how well it has worked. This is reported in relation to two standards: (1) the value to thinking and action expressed by farmers and their consultants, (2) correspondence with theory about learning and judgement in uncertain external environments. The former utilises recorded narrative interviews with participants over many years. The latter uses a cognitive framework drawn from theory of judgment and decision making featuring the relationship between intuition and analysis (McCown, 2011).The cognitive theory framework makes sense of several evaluation surprises. The first was high enthusiasm by largely-intuitive farmers for an analytic approach to soil water in conjunction with a newly-appreciated "bucket" metaphor for water balance. The second surprise was the virtual absence of soil water measurement 10 years later. This had been replaced by various intuitive estimates, calibrated to maintain a heuristic relationship with regard to the "bucket" as a resource.Farmers and their advisers were facilitated in using simulation for thought experiments and planning under climatic uncertainty. Benchmarking enabled problem solving in documented conditions. Scenario analysis using historical climate records supported thought experiments by providing probability distributions that were valued for shaping expectations as a "history of the future". In retrospective evaluation interviews, researchers were surprised to find that yield forecasting and tactical decision making, anticipated to be analyses that were both site- and season-specific forecasts, had served farmers as "management gaming" simulations to aid formulating action rules for such conditions, thus reducing the need for an on-going decision-aiding service. Equipped with their soil monitoring techniques and with their heuristic rules, farmers still reserved a place for simulation "when you've got a planting situation out of the ordinary." (C) 2011 Elsevier Ltd. All rights reserved.

Economic and climatic pressures are forcing many Australian dryland farmers to reassess their management of soil resources and climatic risk. FARMSCAPE intervention has offered enhanced soil characterisation and monitoring as a contribution to soil water and nitrogen inventory, and simulation as a contribution to interpretation of locally measured environmental data in stochastic production terms. This paper relates the journey taken by the farmers, their consultants, and the researchers as they worked together to assess the value to farming and consulting practice of these scientific tools and techniques. Ten years after FARMSCAPE interactions commenced, a sample of participant farmers and consultants was interviewed to evaluate effects on thinking and practice. Understandings and concepts gained in FARMSCAPE continued to guide thinking and action. Early simulations in response to ‘what if…?’ enquiries of strategic importance, such as crop sequencing and rotation choice, were still referred to as learnings of continuing value. However, techniques and practices varied markedly between individuals and organisations. Monitoring of soil resources varied from continued use of the relatively complex tools and techniques provided by the researchers through to the use of much-simplified techniques that provided adequate information to satisfy the conceptual models. Methods for interpreting soil water ranged from use of the simulator, APSIM, to simple water-use efficiency ‘rules of thumb’.