Behavior of subsistence producers in response to technological change- The elasticity of cassava production and home consumption in Benin

The welfare effects of GM (genetic modification)-led productivity growth for cassava producers are partly affected by the characteristics of individual cassava producing households. Those household characteristics include the elasticity of production and home consumption of cassava. Some studies assume the inelastic home consumption when conducting ex-ante welfare effects analysis for subsistence crops. This study modifies the estimation methods used in the past literature to estimate both elasticities using the dataset from Benin. Several assumptions are also tested regarding the heterogeneity of cassava producers. On estimation of elasticities, the paper tests the hypothesis that on-farm sellers are characteristically different from off-farm sellers by employing the double hurdle model. The findings contribute to the literatures analyzing the distributional effects of welfare effects from GM-led productivity growth for cassava, which are gaining importance in the context of the policy impacts on poverty reduction.cassava, subsistence, double-hurdle, non-nested test, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies, Q11, Q12,

Sensitivity of welfare effects estimated by equilibrium displacement model: a biological productivity growth for semi-subsistence crop in Sub-Sahara African market with high transactions costs

This paper discusses the application of the equilibrium displacement model (EDM) to estimate ex-ante the welfare effects of biological productivity growth for semi-subsistence crop and its impact on poverty reduction. The conventionally used EDM is compared with an alternative model (alternative EDM) that reflects arguably more realistic assumptions for African semi-subsistence crops, such as the shape and shift of supply curve, significant margins due to high transportation costs between farmgate and consumption market, as well as between different consumption markets, and the degree of precisions of estimated structural parameters. The application to the dataset for Benin cassava farmers provides an example that the conventional EDM may significantly overestimate the total welfare gains, and may also lead to very different interpretation of how pro-poor the technology is.equilibrium displacement model, pivotal shift, cassava, semi-subsistence, market margins, double buffering, Agricultural and Food Policy, Consumer/Household Economics, Food Security and Poverty, International Development, Productivity Analysis, Research Methods/ Statistical Methods, C65, D13, D31, D60, Q11, Q12,

Market and climatic risks and farmers' investment in productive assets under the Second Fadama Development Project in Nigeria:

The majority of African farmers lack the means to mitigate the impact of risks such as those associated with rainfall and commodity prices. Because most farmers in Sub-Saharan Africa are risk-averse, they may be willing to invest in productive assets that can mitigate the impacts of such risks if their capital constraints are relaxed through external financial assistance. We test this hypothesis using panel data on Nigerian farmers' investment behaviors collected during the Second National Fadama Development Program (Fadama II), which provided financial assistance to farmers in obtaining various productive assets, as well as historical data on rainfall and white gari price in various locations in Nigeria. The results support the hypothesis. Under the Fadama II, farmers facing higher rainfall risk (coefficient of variation in annual rainfall) were more likely to invest in irrigation pumps that can mitigate the impact of rainfall risk, and those facing higher risks on white gari price were more likely to invest in milling machines that enable them to process cassava into flour instead of gari.poverty trap, rainfall risk, price risk, irrigation pump, milling machine, Risk aversion,

Assessing Complementarities Among Farm Machineries Through Farmers' Investment Behaviors Under An External Capital Injection – Implications on Agricultural Mechanization and Tractorization In Sub-Saharan Africa

Agricultural Finance, Farm Management,

Sales location and supply response among semisubsistence farmers in Benin

In much of rural Africa, high transaction costs limit farmers’ market participation and thus their potential for income growth. Transaction costs can affect not only whether a farmer sells product but also whether sales occur at the farm gate on at a market. If production behavior is related to a chosen sales location, then analysis of interventions can be improved by explicit consideration of the decision of where to sell. This paper develops a double-selection model that explains consumption and production decisions by semi-subsistence farmers who first decide whether to be a seller and then whether to sell at the farm gate or at an off-farm location before deciding on production and consumption. The study tests the validity of this dual-criteria model against a single criterion model in which a grower first decides to be a seller and then decides production, consumption and sales location simultaneously. Dual-criteria and single-criterion models are compared while correcting inconsistency in estimations due to violation of homoskedasticity and normality assumptions in selection equations. The results suggest that the dual-criteria model provides more information than the single-criterion model using a sample of cassava producer in Benin.agricultural supply response, Development strategies, dual-criteria, sales location, Transaction costs,

Identification of the effective policy for the improvement of food security -The comparison of the impacts of domestic food production, economic growth and trade liberalization

Food insecurity and undemutrition are serious problems in many countries. The identification of the efficient way to improve the food security condition has become a primary political issue for each country. Domestic food production growth, economic growth and trade liberalization have been listed as major solutions, with the increasing weight on the latter two. All of these three factors may improve each country\u27s food security condition to some extent. However, the significance of the impact of each of these factors has not fully been compared. It is assumed one of these three factors has stronger impact on food security than the others have, and also the size and the significance of the impact may change under the different agricultural population ratio and the population size of the country. The identification of the most efficient factor is therefore helpful for policymakers to formulate the most effective policy to improve food security. According to the analysis based on the historical trend, it is assumed that the domestic food production growth is generally more significant than economic growth and trade liberalization, and may be the only significant factor under the high agricultural population ratio. Countries with severer and more widespread undemutrition today generally have high agricultural population ratio. Therefore the result of this analysis suggests that the policies in countries with severe and widespread undemutrition today should be directed more toward the domestic food production growth, than toward economic growth and trade liberalization

Nigerian Farmers' Preferences On Specific Timing and Channel for Cereals and Legume Seeds Delivery–An Empirical Estimation of Willingness to Pay (WTP) through Mixed Preference Models

Crop Production/Industries, Farm Management,

Sensitivity of welfare effects estimated by equilibrium displacement model: A biological productivity growth for semisubsistence crops in Sub-Sahara African market with high transaction costs

equilibrium displacement model, pivotal shift, Cassava, semisubsistence, market margins, double buffering, Development strategies,

Convergence in Food Demand and Delivery: Do Middle-Income Countries Follow High-Income Trends?

This study uses food expenditures and food-sales data from 1990 to 2004 to examine whether food-consumption patterns and food-delivery-mechanism trends are converging across 47 high- and middle-income countries. Results point to a high degree of convergence in global food systems. Middle-income countries appear to be following trends in high-income countries. Convergence is apparent in most important food-expenditure categories and in indicators of food-system modernization such as supermarket and fast food sales.Food Consumption/Nutrition/Food Safety,

頸椎症性脊髄症における椎間関節変性の有病率と臨床的影響：CT新分類での検討

Objective: To evaluate cervical facet joint degeneration using a newly developed classification, investigate its prevalence and relationship with cervical degenerative spondylolisthesis, and clarify its clinical significance in patients with degenerative cervical myelopathy (DCM). Methods: This study included 145 consecutive patients with DCM who underwent surgical treatment. Clinical variables and radiological findings were analyzed. A new 6-grade computed tomography (CT) classification for cervical facet joint degeneration was adapted, and its prevalence was evaluated by categorizing the joints into those at responsible and those at nonresponsible spinal segmental levels. We evaluated the association between rapidly progressive myelopathy and the presence of significant facet joint degeneration or spondylolisthesis at the responsible segmental level. Results: Finally, 140 patients with a mean age of 64.1±12.8 years were analyzed. The prevalence of grade 1, 2, 3, 4, 5A, and 5B classification in all facet joints was 72.0%, 9.5%, 10.9%, 4.3%, 2.9%, and 0.4%, respectively. There was a statistically significant difference in the distribution of CT grades between the joints at the responsible and nonresponsible segmental levels (p<0.001), with a high prevalence of grade 4 or 5B degeneration at the responsible segmental level, reflecting articular irregularity. There was also a statistically significant relationship between rapidly progressive myelopathy and grade 4 or 5B degeneration at the responsible segmental level (p<0.001), but not between rapidly progressive myelopathy and spondylolisthesis (p=0.255). Conclusion: This novel CT classification for facet joints deserves additional evaluation in patients with DCM. Abnormal findings on the articular surfaces might be related to the progression of myelopathy.博士（医学）・甲第870号・令和5年3月15