Farm-Level Analysis of Risk Management Proposals, March 2000

This paper presents a detailed report of the representative farm analysis (summarized in FAPRI Policy Working Paper #01-00). At the request of several members of the Committee on Agriculture, Nutrition, and Forestry of the U.S. Senate, we have continued to analyze the impacts of the Farmers’ Risk Management Act of 1999 (S. 1666) and the Risk Management for the 21st Century Act (S. 1580). Earlier analysis reported in FAPRI Policy Working Paper #04-99 concentrated on the aggregate net farm income and government outlay impacts. The representative farm analysis is conducted for several types of farms, including both irrigated and non-irrigated cotton farms in Tom Green County, Texas; dryland wheat farms in Morton County, North Dakota and Sumner County, Kansas; and a corn farm in Webster County, Iowa. We consider additional factors that may shed light on the differential impacts of the two plans. 1. Farm-level income impacts under alternative weather scenarios. 2. Additional indirect impacts, such as a change in ability to obtain financing. 3. Implications of within-year price shocks. Our results indicate that farmers who buy crop insurance will increase their coverage levels under S. 1580. Farmers with high yield risk find that the 65 percent coverage level maximizes expected returns, but some who feel that they obtain other benefits from higher coverage will find that the S. 1580 subsidy schedule significantly lowers the cost of obtaining the additional coverage. Farmers with lower yield risk find that the increased indemnities from additional coverage will more than offset the increase in producer premium. In addition, because S. 1580 extends its increased premium subsidy percentages to revenue insurance products, farmers will have an increased incentive to buy revenue insurance. Differences in the ancillary benefits from crop insurance under the baseline and S. 1580 would be driven by the increase in insurance participation and buy-up. Given the same levels of insurance participation and buy-up, the ancillary benefits under the two scenarios would be the same.

Multilateral Trade and Agricultural Policy Reforms in Sugar Markets, September 2005

We analyze the impact of trade liberalization, removal of production subsidies, and elimination of consumption distortions in world sugar markets using a partial-equilibrium international sugar model calibrated on 2002 market data and current policies. The removal of trade distortions alone induces a 27% price increase while the removal of all trade and production distortions induces a 48% increase by 2011/12 relative to the baseline. Aggregate trade expands moderately, but location of production and trade patterns change substantially. Protectionist OECD countries (the EU, Japan, the US) experience an import expansion or export reduction and significant contraction in production in unfettered markets. Competitive producers in both OECD countries (Australia) and non-OECD countries (Brazil, Cuba), and even some protected producers (Indonesia, Turkey), expand production when all distortions are removed. Consumption distortions have marginal impacts on world markets and location of production. We discuss the significance of these results in the context of mounting pressures to increase market access in highly protected OECD countries and the impact on non-OECD countries.

Material and Construction Optimization for Prevention of Premature Pavement Distress in PCC Pavements, September 2004

The chemistry of today’s concrete mixture designs is complicated by many variables, including multiple sources of aggregate and cements and a plethora of sometimes incompatible mineral and chemical admixtures. Concrete paving has undergone significant changes in recent years as new materials have been introduced into concrete mixtures. Supplementary cementitious materials such as fly ash and ground granulated blast furnace slag are now regularly used. In addition, many new admixtures that were not even available a few years ago now have widespread usage. Adding to the complexity are construction variables such as weather, mix delivery times, finishing practices, and pavement opening schedules. Mixture materials, mix design, and pavement construction are not isolated steps in the concrete paving process. Each affects and is affected by the other in ways that determine overall pavement quality and long-term performance. Equipment and procedures commonly used to test concrete materials and concrete pavements have not changed in decades, leaving serious gaps in our ability to understand and control the factors that determine concrete durability. The concrete paving community needs tests that will adequately characterize the materials, predict interactions, and monitor the properties of the concrete.

How Much “Safety” Is Available under the U.S. Proposal to the WTO?, November 2005

Critics of the U.S. proposal to the World Trade Organization (WTO) made in October 2005 are correct when they argue that adoption of the proposal would significantly reduce available support under the current farm program structure. Using historical prices and yields from 1980 to 2004, we estimate that loan rates would have to drop by 9 percent and target prices would have to drop by 10 percent in order to meet the proposed aggregate Amber Box and Blue Box limits. While this finding should cheer those who think that reform of U.S. farm programs is long overdue, it alarms those who want to maintain a strong safety net for U.S. agriculture. The dilemma of needing to reform farm programs while maintaining a strong safety net could be resolved by redesigning programs so that they target revenue rather than price. Building on a base of 70 percent Green Box income insurance, a program that provides a crop-specific revenue guarantee equal to 98 percent of the product of the current effective target price and expected county yield would fit into the proposed aggregate Amber and Blue Box limits. Payments would be triggered whenever the product of the season-average price and county average yield fell below this 98 percent revenue guarantee. Adding the proposed crop-specific constraints lowers the coverage level to 95 percent. Moving from programs that target price to ones that target revenue would eliminate the rationale for ad hoc disaster payments. Program payments would automatically arrive whenever significant crop losses or economic losses caused by low prices occurred. Also, much of the need for the complicated mechanism (the Standard Reinsurance Agreement) that transfers most risk of the U.S. crop insurance to the federal government would be eliminated because the federal government would directly assume the risk through farm programs. Changing the focus of federal farm programs from price targeting to revenue targeting would not be easy. Farmers have long relied on price supports and the knowledge that crop losses are often adequately covered by heavily subsidized crop insurance or by ad hoc disaster payments. Farmers and their leaders would only be willing to support a change to revenue targeting if they see that the current system is untenable in an era of tight federal budgets and WTO limits.

Evalution of Hot Mix Asphalt Moisture Sensitivity Using the Nottingham Asphalt Test Equipment, July 2005

Moisture sensitivity of Hot Mix Asphalt (HMA) mixtures, generally called stripping, is a major form of distress in asphalt concrete pavement. It is characterized by the loss of adhesive bond between the asphalt binder and the aggregate (a failure of the bonding of the binder to the aggregate) or by a softening of the cohesive bonds within the asphalt binder (a failure within the binder itself), both of which are due to the action of loading under traffic in the presence of moisture. The evaluation of HMA moisture sensitivity has been divided into two categories: visual inspection test and mechanical test. However, most of them have been developed in pre-Superpave mix design. This research was undertaken to develop a protocol for evaluating the moisture sensitivity potential of HMA mixtures using the Nottingham Asphalt Tester (NAT). The mechanisms of HMA moisture sensitivity were reviewed and the test protocols using the NAT were developed. Different types of blends as moisture-sensitive groups and non-moisture-sensitive groups were used to evaluate the potential of the proposed test. The test results were analyzed with three parameters based on performance character: the retained flow number depending on critical permanent deformation failure (RFNP), the retained flow number depending on cohesion failure (RFNC), and energy ratio (ER). Analysis based on energy ratio of elastic strain (EREE ) at flow number of cohesion failure (FNC) has higher potential to evaluate the HMA moisture sensitivity than other parameters. If the measurement error in data-acquisition process is removed, analyses based on RFNP and RFNC would also have high potential to evaluate the HMA moisture sensitivity. The vacuum pressure saturation used in AASHTO T 283 and proposed test has a risk to damage specimen before the load applying.

Economies of Feedlot Scale, Biosecurity, Investment, and Endemic Livestock Disease, September 2006

Infectious livestock disease creates externalities for proximate animal production enterprises. The distribution of production scale within a region should influence and be influenced by these disease externalities. Taking the distribution of the unit costs of stocking an animal as primitive, we show that an increase in the variance of these unit costs reduces consumer surplus. The effect on producer surplus, total surplus, and animal concentration across feedlots depends on the demand elasticity. A subsidy to smaller herds can reduce social welfare and immiserize the farm sector by increasing the extent of disease. While Nash behavior involves excessive stocking, disease effects can be such that aggregate output declines relative to first-best. Disease externalities can induce more adoption of a cost-reducing technology by larger herds so that animals become more concentrated across herds. For strategic reasons, excess overall adoption of the innovation may occur. Larger herds are also more likely to adopt biosecurity innovations, explaining why larger herds may be less diseased in equilibrium.

Changing Diets in China’s Cities: Empirical Fact or Urban Legend, November 2006

China’s economic reforms, which began in 1978, resulted in remarkable income growth, and urban Chinese consumers have responded by dramatically increasing their consumption of meat, other livestock products, and fruits and by decreasing consumption of grain-based foods. Economic prosperity, a growing openness to international markets, and domestic policy reforms have changed the food marketing environment for Chinese consumers and may have contributed to shifts in consumer preferences. The objective of this paper is to uncover evidence of structural change in food consumption among urban residents in China. Both parametric and nonparametric methods are used to test for structural change in aggregate household data from 1981 to 2004. The tests provided a reasonably clear picture of changing food consumption over the study period.

Crash Data Validation: An Iowa Case Study, February, 2007

With the quickening pace of crash reporting, the statistical editing of data on a weekly basis, and the ability to provide working databases to users at CTRE/Iowa Traffic Safety Data Service, the University of Iowa, and the Iowa DOT, databases that would be considered incomplete by past standards of static data files are in “public use” even as the dynamic nature of the central DOT database allows changes to be made to both the aggregate of data and to the individual crashes already reported. Moreover, “definitive” analyses of serious crashes will, by their nature, lag seriously behind the preliminary data files. Even after these analyses, the dynamic nature of the mainframe data file means that crash numbers can continue to change long after the incident year. The Iowa DOT, its Office of Driver Services (the “data owner”), and institutional data users/distributors must establish data use, distribution, and labeling protocols to deal with the new, dynamic nature of data. In order to set these protocols, data must be collected concerning the magnitude of difference between database records and crash narratives and diagrams. This study determines the difference between database records and crash narratives for the Iowa Department of Transportation’s Office of Traffic and Safety crash database and the impacts of this difference.

2007 Greenhouse Gas Emissions from Selected Iowa Source Categories

The Department’s 2007 Greenhouse Gas Inventory is a refinement of previous statewide inventories. It is a bottom-up inventory of two sectors – fossil fuel combustion at federally-recognized major sources of air pollution and fossil fuel combustion and ethanol fermentation at dry mill ethanol plants. This is the first bottomup greenhouse gas inventory conducted for Iowa and the first bottom-up greenhouse gas inventory of ethanol plants in the nation that the Department is aware of. In a bottom-up inventory, facility-specific activity data is used to calculate emissions. In a top-down inventory, aggregate activity data is used to calculate emissions. For example, this bottom-up inventory calculates greenhouse gas emissions from the fossil fuel combustion at each individual facility instead of using the total amount of fossil fuel combusted state-wide, which would be a top-down inventory method. The advantage to a bottom-up inventory is that the calculations are more accurate than a top-down inventory. However, because the two methods differ, the results from a bottom-up inventory are not directly comparable to a top-down inventory.

Evaluation of PCC Long-Term Durability Using Intermediate Sized Gravels to Optimize Mix Gradations, April 2010

With the implementation of the 2000 Q-MC specification, an incentive is provided to produce an optimized gradation to improve placement characteristics. Also, specifications for slip-formed barrier rail have changed to require an optimized gradation. Generally, these optimized gradations have been achieved by blending an intermediate aggregate with the coarse and fine aggregate. The demand for this intermediate aggregate has been satisfied by using crushed limestone chips developed from the crushing of the parent concrete stone. The availability, cost, and physical limitations of crushed limestone chips can be a concern. A viable option in addressing these concerns is the use of gravel as the intermediate aggregate. Unfortunately, gravels of Class 3I durability are limited to a small geographic area in Mississippi river sands north of the Rock River. Class 3 or Class 2 durability gravels are more widely available across the state. The durability classification of gravels is based on the amount and quality of the carbonate fraction of the material. At present, no service histories or research exists to assess the impact of using Class 3 or 2 durability gravels would have on the long-term durability of Portland cement concrete (PCC) pavement requiring Class 3I aggregate.

A Laboratory Investigation into the Effects of the Aggregated Related Facts of Critical VMA in Asphalt Paving Mixtures, June 2000

This report summarizes research conducted at Iowa State University on behalf of the Iowa Department of Transportation, focusing on the volumetric state of hot-mix asphalt (HMA) mixtures as they transition from stable to unstable configurations. This has raditionally been addressed during mix design by meeting a minimum voids in the mineral aggregate (VMA) requirement, based solely upon the nominal maximum aggregate size without regard to other significant aggregate-related properties. The goal was to expand the current specification to include additional aggregate properties, e.g., fineness modulus, percent crushed fine and coarse aggregate, and their interactions. The work was accomplished in three phases: a literature review, extensive laboratory testing, and statistical analysis of test results. The literature review focused on the history and development of the current specification, laboratory methods of identifying critical mixtures, and the effects of other aggregate-related factors on critical mixtures. The laboratory testing involved three maximum aggregate sizes (19.0, 12.5, and 9.5 millimeters), three gradations (coarse, fine, and dense), and combinations of natural and manufactured coarse and fine aggregates. Specimens were compacted using the Superpave Gyratory Compactor (SGC), conventionally tested for bulk and maximum theoretical specific gravities and physically tested using the Nottingham Asphalt Tester (NAT) under a repeated load confined configuration to identify the transition state from sound to unsound. The statistical analysis involved using ANOVA and linear regression to examine the effects of identified aggregate factors on critical state transitions in asphalt paving mixtures and to develop predictive equations. The results clearly demonstrate that the volumetric conditions of an HMA mixture at the stable unstable threshold are influenced by a composite measure of the maximum aggregate size and gradation and by aggregate shape and texture. The currently defined VMA criterion, while significant, is seen to be insufficient by itself to correctly differentiate sound from unsound mixtures. Under current specifications, many otherwise sound mixtures are subject to rejection solely on the basis of failing to meet the VMA requirement. Based on the laboratory data and statistical analysis, a new paradigm to volumetric mix design is proposed that explicitly accounts for aggregate factors (gradation, shape, and texture).

Reclaimed Fly Ash as Select Fill Under PCC Pavement, November 1999

With the support of the Iowa Fly Ash Affiliates, research on reclaimed fly ash for use as a construction material has been ongoing since 1991. The material exhibits engineering properties similar to those of soft limestone or sandstone and a lightweight aggregate. It is unique in that it is rich in calcium, silica, and aluminum and exhibits pozzolanic properties (i.e. gains strength over time) when used untreated or when a calcium activator is added. Reclaimed Class C fly ashes have been successfully used as a base material on a variety of construction projects in southern and western Iowa. A pavement design guide has been developed with the support of the Iowa Fly Ash Affiliates. Soils in Iowa generally rate fair to poor as subgrade soils for paving projects. This is especially true in the southern quarter of the state and for many areas of eastern and western Iowa. Many of the soil types encountered for highway projects are unsuitable soils under the current Iowa DOT specifications. The bulk of the remaining soils are Class 10 soils. Select soils for use directly under the pavement are often difficult to find on a project, and in many instances are economically unavailable. This was the case for a 4.43-mile grading (STP-S- 90(22)-SE-90) and paving project in Wapello County. The project begins at the Alliant Utilities generating station in Chillicothe, Iowa, and runs west to the Monroe-Wapello county line. This road carries a significant amount of truck traffic hauling coal from the generating station to the Cargill corn processing plant in Eddyville, Iowa. The proposed 10-inch Portland Cement Concrete (PCC) pavement was for construction directly on a Class 10 soil subgrade, which is not a desirable condition if other alternatives are available. Wapello County Engineer Wendell Folkerts supported the use of reclaimed fly ash for a portion of the project. Construction of about three miles of the project was accomplished using 10 inches of reclaimed fly ash as a select fill beneath the PCC slab. The remaining mile was constructed according to the original design to be used as a control section for performance monitoring. The project was graded during the summers of 1998 and 1999. Paving was completed in the fall of 1999. This report presents the results of design considerations and laboratory and field testing results during construction. Recommendations for use of reclaimed fly ash as a select fill are also presented.

Evaluation of Hot Mix Asphalt Moisture Sensitivity Using the Nottingham Asphalt Test Equipment, July 2005

Moisture sensitivity of Hot Mix Asphalt (HMA) mixtures, generally called stripping, is a major form of distress in asphalt concrete pavement. It is characterized by the loss of adhesive bond between the asphalt binder and the aggregate (a failure of the bonding of the binder to the aggregate) or by a softening of the cohesive bonds within the asphalt binder (a failure within the binder itself), both of which are due to the action of loading under traffic in the presence of moisture. The evaluation of HMA moisture sensitivity has been divided into two categories: visual inspection test and mechanical test. However, most of them have been developed in pre-Superpave mix design. This research was undertaken to develop a protocol for evaluating the moisture sensitivity potential of HMA mixtures using the Nottingham Asphalt Tester (NAT). The mechanisms of HMA moisture sensitivity were reviewed and the test protocols using the NAT were developed. Different types of blends as moisture-sensitive groups and non-moisture-sensitive groups were used to evaluate the potential of the proposed test. The test results were analyzed with three parameters based on performance character: the retained flow number depending on critical permanent deformation failure (RFNP), the retained flow number depending on cohesion failure (RFNC), and energy ratio (ER). Analysis based on energy ratio of elastic strain (EREE ) at flow number of cohesion failure (FNC) has higher potential to evaluate the HMA moisture sensitivity than other parameters. If the measurement error in data-acquisition process is removed, analyses based on RFNP and RFNC would also have high potential to evaluate the HMA moisture sensitivity. The vacuum pressure saturation used in AASHTO T 283 and proposed test has a risk to damage specimen before the load applying.

Greenhouse Gas and Nitrogen Fertilizer Scenarios for U.S. Agriculture and Global Biofuels, June 2011

This analysis uses the 2011 FAPRI-CARD (Food and Agricultural Policy Research Institute–Center for Agricultural and Rural Development) baseline to evaluate the impact of four alternative scenarios on U.S. and world agricultural markets, as well as on world fertilizer use and world agricultural greenhouse gas emissions. A key assumption in the 2011 baseline is that ethanol support policies disappear in 2012. The baseline also assumes that existing biofuel mandates remain in place and are binding. Two of the scenarios are adverse supply shocks, the first being a 10% increase in the price of nitrogen fertilizer in the United States, and the second, a reversion of cropland into forestland. The third scenario examines how lower energy prices would impact world agriculture. The fourth scenario reintroduces biofuel tax credits and duties. Given that the baseline excludes these policies, the fourth scenario is an attempt to understand the impact of these policies under the market conditions that prevail in early 2011. A key to understanding the results of this fourth scenario is that in the absence of tax credits and duties, the mandate drives biofuel use. Therefore, when the tax credits and duties are reintroduced, the impacts are relatively small. In general, the results show that the entire international commodity market system is remarkably robust with respect to policy changes in one country or in one sector. The policy implication is that domestic policy changes implemented by a large agricultural producer like the United States can have fairly significant impacts on the aggregate world commodity markets. A second point that emerges from the results is that the law of unintended consequences is at work in world agriculture. For example, a U.S. nitrogen tax that might presumably be motivated for environmental benefit results in an increase in world greenhouse gas emissions. A similar situation occurs in the afforestation scenario in which crop production shifts from high-yielding land in the United States to low-yielding land and probably native vegetation in the rest of the world, resulting in an unintended increase in global greenhouse gas emissions.

Engineering Study Iowa Highway Resarch Board Project HR-223 Maintaining Granular Surfaced Roads, February 1981

Approximately 65% of Iowa's roads are surfaced with aggregates composed of crushed limestone and/or gravel. Rural Iowan's regard these roads as a very important part of their lives. Therefore, the slide-tape presentation, "Maintaining Granular Surfaced Roads" was developed to aid the motor grader operator to better understand the procedures required t o maintain aggregate surfaced roads. A typical cross-section is presented with the proper nomenclature assigned to the roadway features to facilitate the operator's understanding of the basic terms used the program. The following areas are expanded: safety , dragging, cutting, intersections , superelevations, and reporting any discrepancies. The operator's attention to detail can enhance the economy of the state and contribute to the savings of lives on rural highways.