Using alterative whole-farm modelling approaches to assess farm enterprise selection, risk and welfare

Using an expected mean-variance model the changes in farm enterprise levels and indirect utility were examined under conditions of risk aversion, budget constraints and gross margin variance. An extension of the comparative statics of the expected mean-variance model was adopted by introducing a budget constraint into the constrained optimisation problem. A 10-year expected mean-variance whole-farm model was solved for a farm in the wheat-sheep zone of Australia to provide an empirical example. Results were obtained using no planning horizon (the static model) and then with a five-year rolling planning horizon (the dynamic model). In addition, enterprise levels were constrained to match levels observed on the farm so as to compare incomes between the constrained and unconstrained models. For a cash constrained, risk averse, farmer it was found that they are likely to have larger expenditures than less risk averse operators in order to obtain the same indirect utility. Enterprise levels differed between the dynamic and static models, and a dynamic model was used to help explain inter-temporal decision-making. Risk aversion reduced the set of possible welfare improving production activities available to a farmer.Whole-farm modelling, enterprise selection, risk., Farm Management, Q12, C61,

A heterogeneous-agent model with district-level constraints: an application to livestock development in Gansu, China

This paper develops a heterogeneous-agent model to assess the impacts of removing lucerne growing subsidies, increasing livestock numbers and including district-level equilibrium conditions on optimal farm plans in the Qingyang district of Gansu Province, China. The model is a five-year dynamic linear program that solves across 96 farm households whilst incorporating district-level constraints. The approach used allows us to observe seasonal variations in incomes, infer the distribution of a policy shock among households and highlight trade patterns at the district level. The results suggest that without lucerne growing subsidies the total area of lucerne grown by all modelled households falls by 18%. Increasing livestock numbers by 25% reduces net household incomes by 17% as changes to labour allocations reduce off-farm employment opportunities. When external trade in forages is included in the model, total livestock numbers held by all 96 households rise from 502 to 838, this highlights the benefits of integrated feed markets. Shadow prices for crop production rise when livestock numbers increase, implying that benefits exist to improving crop yields.Heterogeneous-agent model, district-level constraints, livestock, China., Farm Management,

A review of types of risks in agriculture: What we know and what we need to know

This study examines the scope and depth of research on the five major types of risks in agriculture, and the extent to which those studies have addressed the impacts of, and policies to mitigate individual types of risk as opposed to more holistic analyses of the multiple sources of risk with which farmers have to cope with. Risk is at the center of new paradigms and approaches that inform risk management initiatives and shape investments in many countries. Although the literature includes several substantive reviews of the methods available for risk analysis and their empirical applications have been extensively scrutinized, limited information exists about which types of risks have received sufficient attention, and which have not. This limited information is perplexing because farmers manage multiple risks at the same time and unanticipated events continue to have substantial impacts on farmers. We identify 3283 peer-reviewed studies that address one or more of the five major types of risk in agriculture (production risk, market risk, institutional risk, personal risk, and financial risk) published between 1974 and 2019. We conduct a literature search and then apply an eligibility criteria to retain eligible studies from the search. We then classify those eligible studies based on risk type and geographic focus. We placed no limit on the temporal scale, geographic focus, or study method for inclusion in our search. Results show that 66% of the 3283 studies focused solely on production risk, with only 15% considering more than one type of risk. Only 18 studies considered all five types of risk and those either asked how farmers perceived the importance of each risk or were focused on conceptual issues, rather than assessing how exposure to all the risks quantitatively affects farm indicators such as yields or incomes. Without more detailed analyses of the multiple types of risks faced by farmers, farmers and policymakers will lack the information needed to devise relevant risk management strategies and policies. A shift in research focus towards the analysis of multiple contemporaneous types of risk may provide a basis that gives farmers greater options for coping with and managing risk. We discuss some of the challenges for studying multiple risks simultaneously, including data requirements and the need for probability distributions and the role of simulation approaches

Trade-offs and synergies associated with maize leaf stripping within crop-livestock systems in northern Ghana

Open Access Article; Published online: 09 Jul 2021CONTEXT The accessibility and availability of forages is a common concern in crop-livestock systems in West Africa; however, options to increase forage production may entail trade-offs within the farm system that can be challenging to quantify explicitly. OBJECTIVE This study examined how maize (Zea mays L.) leaf stripping affected maize and sheep productivity and associated labour requirements, and farm system trade-offs and synergies in four communities in the Northern Region of Ghana. METHODS Maize leaf stripping involved removing almost senesced leaves from maize plants below the cob level at silking. We combined data from three sources: on-farm maize trials with 28 farmers from two seasons (2017 and 2018), on-farm sheep feeding trials where the pasture-based diets of weaner sheep were supplemented with stripped maize leaves fed in pens (conducted in 2019), and farm survey data from 117 households (conducted in 2014), seven of which were in the on-farm maize trials and owned sheep. We examined the trial data using linear mixed-effects models. RESULTS AND CONCLUSIONS Maize leaf stripping had no significant effect on maize grain yield but had a significant positive effect on maize forage protein yield from leaf and stover. Offering maize leaves to weaner sheep had a significant positive effect on average daily liveweight gain, estimated marginal mean was 29.3 g with maize leaves and −10.9 g without maize leaves. For the maize-sheep systems of the seven households, non-inferential statistics suggested that on average maize leaf stripping reduced total maize grain production by 12% (range −46 to 38) and increased maize forage protein production from leaf and stover by 90% (range −16 to 298). Stripping the maize leaves from one hectare of land took an extra 34 h (range 27 to 42) of labour, which was counterbalanced by reduced labour time for grazing as sheep were fed the maize leaves in pens. For the 117 farmers, heterogeneity in maize areas planted and livestock numbers resulted in heterogeneous production and labour effects of maize leaf stripping. Farmers qualitatively described how maize leaf stripping released labour so children could spend more time at school rather than shepherding. SIGNIFICANCE We quantified in northern Ghana how maize leaf stripping altered crop and livestock productivity and associated trade-offs and synergies in the farm system, including labour. Changes in crop management often have implications beyond the crop's field and examining these implications can provide insights into the suitability of alternative farm management options. Graphical abstract Unlabelled Image Download : Download high-res image (97KB)Download : Download full-size imag

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

Systems thinking : an approach for understanding 'eco-agri-food systems'

The TEEBAgriFood ‘Scientific and Economic Foundations’ report addresses the core theoretical issues and controversies underpinning the evaluation of the nexus between the agri-food sector, biodiversity and ecosystem services and externalities including human health impacts from agriculture on a global scale. It argues the need for a ‘systems thinking‘ approach, draws out issues related to health, nutrition, equity and livelihoods, presents a Framework for evaluation and describes how it can be applied, and identifies theories and pathways for transformational change

Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente