Charles F. Nicholson

Modeling the Impact of Natural Resource-Based Poverty Traps on Food Security in Kenya: The Crops, Livestock and Soils in Smallholder Economic Systems (CLASSES) Model

We investigate the interactions between natural resource-based poverty traps and food security for smallholder farms in highland Kenya using a recently developed system dynamics bio-economic model. This approach permits examination of the complex interactions and feedback between farm household economic decision-making and long-term soil fertility dynamics that characterize persistent poverty and food insecurity among smallholders in rural highland Kenya. We examine the effects of changing initial endowments of land and stocks of soil organic matter on smallholders’ well being, as reflected in several different indicators. We show that larger and higher quality land endowments permit accumulation of cash and livestock resources and conservation of soil organic matter relative to smaller or more degraded farms. This suggests the existence of asset thresholds that divide food secure households from food insecure ones.

Subsidized Vehicle Acquisition and Earned Income in the Transition from Welfare to Work

Availability and affordability of reliable transportation – either through public transportation or individual ownership of automobiles – appears necessary to support a successful transition from welfare to work. One approach adopted by state and local governments is to subsidize vehicle acquisition by welfare recipients in transition. To date there are no empirical studies that analyze the impacts or effectiveness of these vehicle subsidy programs. The objective of this study is to examine the extent to which participation in a small-scale vehicle donation-and-sales program in Vermont increases earned income by individuals in transition from welfare to work. Using reduced-form random effects and censored regression models to account for the simultaneity of decisions to work and participate in welfare programs, we examine the impacts of this vehicle acquisition program for a small group of individuals. Our analyses indicate that the program results in a statistically significant increase in both earned income and the probability of employment.

Environmental Impacts of Livestock in the Developing World

(2001). Environmental Impacts of Livestock in the Developing World. Environment: Science and Policy for Sustainable Development: Vol. 43, No. 2, pp. 7-17.

Spatial Price Equilibrium Models with Discriminatory Ad Valorem Tariffs: Formulation and Comparative Computation Using Variational Inequalities

Ad valorem tariffs are a trade policy instrument used by nearly all nations to restrict imports of a wide variety of commodities. Recent emphasis on tariffication as a means of trade liberalization underscores the importance of appropriately incorporating discriminatory ad valorem tariffs (tariffs imposed by the importing country that vary according to the exporting country) into spatial economic models. Both the recently-approved North American Free Trade Agreement (NAFTA) and the General Agreement on Tariffs and Trade (GATT) negotiations specify tariffication as a mechanism to lower trade barriers.

Environmental and Economic Impacts of Localizing Food Systems: The Case of Dairy Supply Chains in the Northeastern United States

We developed and evaluated an empirical model of the U.S. dairy supply chain with a high degree of spatial and product disaggregation to assess the impacts of increasing localization of the northeast regions fluid milk supply on food miles, supply chain costs, greenhouse gas and criteria pollutant emissions, economic activity, and employment. Evaluation included comparison to regional production values and sensitivity analysis of demand and unit cost assumptions. Our analysis compares a baseline to two localization scenarios based on state boundaries and multiple-state subregions. Localization scenarios increased total distances fluid milk traveled by 7-15%, overall supply chain costs by 1-2%, and emissions of greenhouse gases (CO2 equivalent) criteria pollutants such as oxides of nitrogen and particulate matter smaller than 2.5 μm associated with fluid milk transportation by 7-15% per month. The impacts of localization on employment and economic activity are positive, but changes are small on a percentage basis. Our analyses indicate that the definition used for localization has an impact on outcomes and that efforts to localize food systems may benefit from a more systems-oriented approach.

Massively Parallel Computation of Large-Scale Spatial Price Equilibrium Models With Discriminatory Ad Valorem Tariffs

In this paper, we develop a perfectly competitive spatial equilibrium model in price and quantity variables in the presence of discriminatory ad valorem tariffs, a widely used trade policy instrument. We derive the equilibrium conditions and formulate them as a variational inequality problem. An algorithm is then proposed for the computation of the equilibrium pattern and convergence results established. The algorithm resolves the problem into very simple subproblems, each of which can be solved simultaneously and in closed form. Finally, the algorithm is implemented on the massively parallel Thinking Machines CM-2 and CM-5 architectures, known as the Connection Machines, and numerical results presented.

Economic analysis of alternative nutritional management of dual-purpose cow herds in central coastal Veracruz, Mexico.

Market information was combined with predicted input–output relationships in an economic analysis of alternative nutritional management for dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. Cow productivity outcomes for typical management and alternative feeding scenarios were obtained from structured sets of simulations in a companion study of productivity limitations and potentials using the Cornell Net Carbohydrate and Protein System model (Version 6.0). Partial budgeting methods and sensitivity analysis were used to identify economically viable alternatives based on expected change in milk income over feed cost (change in revenues from milk sales less change in feed costs). Herd owners in coastal Veracruz have large economic incentives, from

Limitations and potentials of dual-purpose cow herds in Central Coastal Veracruz, Mexico

584 to

Effects of weed control and manure application on nutrient fluxes in the shifting cultivation milpa system of Yucatán

1,131 in predicted net margin, to increase milk sales by up to 74% across a three-lactation cow lifetime by improving diets based on good quality grass and legume forages. This increment is equal to, or exceeds, in value the total yield from at least one additional lactation per cow lifetime. Furthermore, marginal rates of return (change in milk income over feed costs divided by change in variable costs when alternative practices are used) of 3.3 ± 0.8 indicate clear economic incentives to remove fundamental productivity vulnerabilities due to chronic energy deficits and impeded growth of immature cows under typical management. Sensitivity analyses indicate that the economic outcomes are robust for a variety of market conditions.

Assessing policy options for agricultural livestock development: A case study of Mexico’s sheep sector

Feed chemical and kinetic composition and animal performance information was used to evaluate productivity limitations and potentials of dual-purpose member herds of the Genesis farmer organization of central coastal Veracruz, Mexico. The Cornell Net Carbohydrate and Protein System model (Version 6.0) was systematically applied to specific groups of cows in structured simulations to establish probable input–output relationships for typical management, and to estimate probable outcomes from alternative management based on forage-based dietary improvements. Key herd vulnerabilities were pinpointed: chronic energy deficits among dry cows of all ages in late gestation and impeded growth for immature cows. Regardless of the forage season of calving, most cows, if not all, incur energy deficits in the final trimester of gestation; thus reducing the pool of tissue energy and constraining milking performance. Under typical management, cows are smaller and underweight for their age, which limits feed intake capacity, milk production and the probability of early postpartum return to ovarian cyclicity. The substitution of good-quality harvested forage for grazing increased predicted yields by about one-third over typical scenarios for underweight cows. When diets from first parturition properly supported growth and tissue repletion, milk production in second and third lactations was predicted to improve about 60%. Judiciously supplemented diets based on good quality grass and legume forages from first calving were predicted to further increase productivity by about 80% across a three-lactation cow lifetime. These dual-purpose herd owners have large incentives to increase sales income by implementing nutritional strategies like those considered in this study.