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Large changes have taken place in smallholder farming systems in South Asia's coastal areas in recent decades, particularly related to cropping intensity, input availability, climate risks, and off-farm activities. However, few studies have investigated the extent to which these changes have impacted farm-level crop productivity, which is a key driver of food security and poverty in rainfed, low-input, rice-based systems. The objective of this study was to conduct an integrated assessment of variables related to socioeconomic status, farm characteristics, and crop management practices to understand the major factors influencing crop productivity and identify promising leverage points for sustainable development in coastal Bangladesh. Using a panel survey dataset of 32 variables from 502 farm households located within polder (coastal embankment) and outside polder systems during 2005–2015, we employed statistical factor analysis to characterize five independent latent factors named here as Farming Challenges, Economic Status, Crop Management Practices, Asset Endowment, and Farm Characteristics. The factor Farming Challenges explained the most variation among households (31%), with decreases observed over time, specifically households located outside polders. Individual variables contributing to this factor included perceived cyclone severity, household distance to main roads and input-output markets, cropping intensity, and access to extension services. The most important factors for increasing crop productivity on a household and per unit area basis were Asset Endowment and Crop Management Practices, respectively. The former highlights the need for increasing gross cropped area, which can be achieved through greater cropping intensity, while the latter was associated with increased fertilizer, labor, and pesticide input use. Despite the importance of these factors, household poverty trajectory maps showed that changes in off-farm income had played the strongest role in improving livelihoods in this coastal area. This study can help inform development efforts and policies for boosting farm-level crop productivity, specifically through agricultural intensification (higher cropping intensity combined with appropriate and efficient use of inputs) and expanding opportunities for off-farm income as key pathways to bring smallholder households out of poverty. [ABSTRACT FROM AUTHOR]

Tar formation is one of the major problems during biomass gasification due to blocking and fouling processes in engines and turbines. Downstream gas cleanup process and conditioning are required to eliminate tar issues. For this reason, methods to reduce tar formation inside the gasifier are gaining more attention. In this work, a novel design for an inclined nozzle and a combustor was proposed and tested in a low-tar biomass (LTB) gasifier to evaluate the effect on tar reduction. The design process was based on a swirling flow created by an inclined nozzle that allows good mixing between pyrolysis gases and gasifying air. The swirl combustor created large internal annular and reverse flow zones with the help of swirl flow. Thus, the combustor had a positive effect on the combustion of the mixture of air and pyrolysis gases and induced thermal cracking in the partial oxidation zone. Recycling ratio (recycle gas/air, v/v) and combustion degree of volatiles were used to evaluate the performance of the inclined nozzle and combustor. The result showed that the tar yields in pyrolysis and partial oxidation zones were on average 1693 mg/Nm3 and 255 mg/Nm3, respectively which accounted for a reduction of 86.6% and 12.7% tar compounds in these zones, respectively. Besides, the producer gas leaving the gasifier had a tar content below 1%, and measured tar content was 7.4-27.14 mg/Nm3 for the tested biomass with moisture contents of 9–34%. Tar removal efficiency was found on average 84.9% after passing the pyrolysis gas through the partial oxidation zone, whereas tar in the producer gas was removed with an efficiency of 99.1% at the gas outlet zone. At an equivalence ratio of 0.35, the new design had the optimal performance with a recycling ratio of 0.35 and combustion degree of volatiles of 98.6%. The achieved producer gas could be directly fed to an internal combustion engine or a gas turbine at small to medium level power generation in remote rural off-grid areas. [Display omitted] • Inclined nozzle and combustor are introduced to reduce tar content of the producer gas (7.4 mg/Nm3). • Tar removal efficiency due to the effect of an inclined nozzle and combustor was 99.1%. • Recycling ratio and combustion degree of volatiles are key parameters of performance evaluation. • About 87% of tar compounds combusted in the partial oxidation zone by swirl flow effect. • Less than 1% tar content is observed at the gas outlet zone. [ABSTRACT FROM AUTHOR]

Many studies have examined the impact of climatic variability on agricultural productivity, although an understanding of these effects on farmland values and their relationship to farmers’ decisions to adapt and modify their land-use practices remains nascent in developing nations. We estimated the impacts of the deviation in our study year's (2012) temperature and precipitation patterns from medium-term (1980–2011) climatic patterns on farmland values in Pakistan. This was accomplished by employing a modified form of a Ricardian regression model. We also examined farmers’ perceptions of climate change during this period, as well as their perceptions of climate change impacts on farm productivity, in addition to past and anticipated farm adaptation strategies. Our results indicate that positive temperature deviation from the medium-term mean – indicative of climatic change – affects farmland values in Pakistan. Deviation in annual cumulative precipitation conversely appears to have no significant impact. Estimates of the marginal impact of temperature deviation suggested a slight but negative linear relationship with farmland values. The location of farms in areas where farmers can avail financial or extension services conversely had a positive impact on farmland values, as did the availability of irrigation facilities. Our analysis of farmers’ perceptions of climate change and their consequent adaptation behavior indicated a relatively high degree of awareness of climatic variability that influenced a number of proactive and future anticipated farm adaptation strategies. Examples included increased use of irrigation and farm enterprise diversification, as well as land-use change, including shifting from agriculture into alternative land uses. National policy in Pakistan underscores the importance of maintaining a productive rural agricultural sector. Our findings consequently highlight the importance of appropriate adaptation strategies to maintain both farm productivity and farmland values in much of Pakistan. The implications of increased extension and financial services to enhance farmers’ potential for climate change adaptation are discussed. [ABSTRACT FROM PUBLISHER]

By developing meta-frontier efficiency and structural equation models, the paper examines whether farm economic viability is positively associated with technical efficiency in a highly food insecure context, such as that of rural Sierra Leone. The findings show that technical efficiency can be a sufficient but not necessary condition in determining economic viability of smallholder farming. It is possible to breach reproductive thresholds at the cost of reduced technical efficiency, when the crop diversification strategy of smallholders includes market-oriented high-value crops. This calls for a dual policy approach that addresses farmers' internal needs for self-consumption (increasing efficiency of food crop production) while encouraging market-oriented cash crop production (diversification assisted through the reduction of associated transaction costs and the establishment of accessible commercialization channels of export related crops and/or high-value crops). The work also calls out for a move-up or move-out strategy for small holders to create viable farming systems in developing world. [ABSTRACT FROM AUTHOR]

Sustainable intensification (SI) is envisioned as an effective strategy for developing countries to increase farm productivity while reducing negative environmental and social externalities. The development of regionally appropriate SI options however requires accounting for the knowledge and preferences of key stakeholders. In Bangladesh, the Government has requested international donors to support the development of dry season rice expansion in the coastal region. Policies however tend to be made without adequate study of farmers' preferences and ambitions; this can render crop intensification efforts ineffective. Understanding farmers' preferences for alternative crops and crop management practices are therefore crucial for success where agricultural development investments aim at incorporating the principles of SI. Using coastal Bangladesh as a case study– we aim to (1) quantify farmers' preferences for alternative irrigated crop and crop management options in comparison to the status quo (land fallowing), (2) analyze whether farmers' preferences are conditioned by concerns regarding the cost and availability of irrigation and fertilizer inputs in comparison to expected net revenues, (3) understand how the heterogeneity in preferences can be attributed to farmer and/or farm characteristics, institutional, and biophysical factors, (4) determine how much farmers' are willing to invest in different crops and crop management options – including those reliant and not reliant on irrigation. Taking 300 farmers in two diverse coastal environments, a choice experiment (CE) was employed to explore the heterogeneity in farmers' preferences for different dry " rabi " season intensification options (' boro ' rice, maize, wheat and mungbean) against the status quo (dry season land fallowing after harvest of the monsoon season rice crop). Analyses included random parameter logit modeling followed by willingness-to-invest and profit simulations. Analyses revealed strong farmer preferences against rice and in favor of irrigated maize, and also in favor of rainfed or partially irrigated mungbean as an alternative to land fallowing. Irrespective of their location and environmental conditions, respondents had largely a negative preference for irrigation and fertilizer use due to high investment costs and associated production risks in the dry season. Nonetheless, a significant positive effect on their willingness-to-intensify cropping was observed where farmers felt it feasible to provide in-field drainage to limit waterlogging risks. The study signifies the importance of accounting for farmers' preferences while developing context-specific SI policies. Improving agronomic investments, tenure security, market, credit and extension support are likely prerequisites, alongside targeted diffusion of stress-tolerant mungbean and maize varieties for SI in coastal Bangladesh. Unlabelled Image • Government's policy encourages intensified cropping in the coastal region of Bangladesh. • Analyze farmers' preferences for alternative crop intensification options using a choice experiment. • Preferences against rice and in favor of mungbean, and maize as alternative to land fallowing. • Farmers' preference for non-rice crops in place of dry season land fallowing conflicts ongoing policy favoring rice. • Agronomic investments, tenure, markets, credit, and extension are prerequisites for sustainable intensification. [ABSTRACT FROM AUTHOR]

• Maize and wheat are proposed for diversification, but irrigation advice is limited. • Soil moisture content was above or near drained upper limit for depths below 0.5 m. • A significant effect of irrigation on yield was observed for maize only, in one year. • One irrigation, in addition to a starter irrigation, generally is sufficient to grow a crop. • Low-input maize cultivation is not always profitable and low fertilizer rates increase risk of negative returns. Further efforts are needed to combat poverty and agricultural productivity problems in the delta region of Bangladesh. Sustainable intensification of crop production through irrigation and production of cash crops such as maize and wheat might be a promising option to increase income and diversify food production. Only limited research has however been conducted on the potential of using surface water from canals as an irrigation source for maize and wheat production in the delta region. To better understand the contribution of shallow groundwater to crop production and number of irrigations needed for maize and wheat in this unique coastal environment, we conducted multi-locational trials on farmers' fields over three rabi seasons. In addition to soil moisture and salinity, we recorded the depth and salinity of the shallow water table throughout these experiments. Maize in particular requires considerable capital investment for seeds, fertilizer, irrigation and labor. Although farmers express wide interest in maize – which can be sold as a profitable cash crop into Bangladesh's expanding poultry feed industry – many of them are reluctant to invest in fertilizer because of the high entry costs. We therefore also investigated the profitability of growing maize under low and high (recommended) fertilizer regimens. Volumetric soil moisture at sowing and during the grain filling phase or at maturity indicated that there is ample supply of water in the profile. Most measurements were above the drained upper limit (DUL). We attributed this to the generally shallow water table depths, which never exceeded 2.75 m at any location, but generally stayed between 1–2 m depth throughout the season. The region's soil texture classes (clay loams, silt loams and silty clay loams) are all conducive for capillary rise of water into the rooting zone. Consequently, irrigation had a significant effect on maize yield in the driest winter only, whereas for wheat, it had no effect. The key for a successful maize and wheat production in the delta region of Bangladesh is to ensure a good crop establishment, which can be achieved with a starter and an additional irrigation at crown root initiation for wheat and at V6-8 for maize. Maize however is not always profitable. Compared to low fertilizer rates, higher rates reduced losses in low yielding site-years and increased profits in high-yielding site years. This indicates that it is advisable for farmers not to reduce fertilizer rates. Low-risk financial credit with rationally structured interest rates that allow farmers to invest in maize could potentially offset these constraints. [ABSTRACT FROM AUTHOR]

South Asia is the world’s most poverty-dense region, where climate change and climate variability are expected to result in increased heat stress and erratic precipitation patterns that affect agricultural productivity. Considerable evidence has been generated on the effects of these stresses on crop yield, though previous research has not yet examined their influence on the economic efficiency of cereal producers. Surveying 240 farmers across eight of Pakistan’s twelve agro-ecological zones, we examined the impact of temperature and precipitation anomalies – as indicators of climatic variability – and the number of days when temperature exceeds crop specific heat stress thresholds on the economic efficiency of rice and wheat production. To this end, we employed first-stage stochastic production frontier (SPF) models and second-stage ordinary least square (OLS) and quantile regression models. Both OLS and quantile regressions indicated that terminal heat >34 °C has a significant negative impact on wheat production economic efficiency. Small positive deviation (0.54 °C ± 0.16 SD) of the wheat season’s mean temperature from the medium-term historical mean also significantly and negatively affected economic efficiency across all regression models. Heat stress >35.5 °C during rice flowering in the monsoon also had a significant and negative impact. A slight positive deviation in temperature averaging 0.38 °C (±0.11 SD) above the medium-term mean also had significant negative effects across all regressions. Cumulative precipitation conversely had significant yet contrary effects, by offsetting farmers’ investment in supplementary irrigation and increasing economic efficiency. Our results highlight the fact that indicators of climatic variability and heat stress negatively affect the economic efficiency of both rice and wheat producing farmers. Farmers’ education and access to financial and extension services were however both positively associated with economic efficiency. Our findings point to the importance of developing interlinked agronomic, economic and socio-ecological policy strategies to adapt and increase the resilience of Pakistan’s cereal systems to climatic variability. [ABSTRACT FROM AUTHOR]

Several studies estimate the immediate impact of climate change on agricultural societies in terms of changes in crop yields or farm income, though few studies concentrate on the immediate secondary consequences of climate change. This synthetic analysis uses a set of indicators to assess the repercussions of predicted income reductions resulting from climate change on food consumption, nutrition, health expenditure, education, and recreation in Zimbabwe, Cameroon, South Africa and Ethiopia. We also assess the potential decline in human development potential among smallholder dryland farmers in these sub-Saharan African countries. In contrast to previous efforts, the current study directly integrates the uncertainties in estimations of income changes and secondary consequences through a weighting scheme. The results reveal moderate to high levels of secondary impacts which could lead to increased vulnerability to diseases, susceptibility to nutritional disorders, deprivation of educational opportunities, and ultimately to a reduction in human and societal development potential among the considered nations. The article concludes by proposing a portfolio of policy options for ameliorating the secondary impacts of climate change in these sub-Saharan African countries. [ABSTRACT FROM AUTHOR]

Growing populations, changing market conditions, and the food security risks posed by rainfed cropping and climate change collectively indicate that Sub-Saharan African nations could benefit from transforming agricultural production to more intensive yet resilient and sustainable systems. Although highly underutilized, emerging evidence indicates that groundwater may be more widely available than previously thought, highlighting its potential role in facilitating such a transformation. Nevertheless, the possibility for such a transition is conditioned by number of complex factors. We therefore construct a transition index that integrates data considering groundwater and energy availability and cost, market access, infrastructural needs, farm conditions and natural resource stocks, labor availability, climate, population density, as well as economic and political framework variables, using a principal component analysis based methodology. Using the consequent multi-dimensional transition index and constituent intermediate indices, we provide an assessment of groundwater irrigation potential discussed in consideration of Burkina Faso, Ghana, Malawi, Ethiopia, Nigeria, Zambia, Namibia, Cameroon, and Zimbabwe. Our results, though preliminary, provide a methodology for conducting such an integrated assessment, while deriving a holistic set of policy options considering the transition towards appropriate use of groundwater for agricultural development. [ABSTRACT FROM AUTHOR]