Private Agricultural Land Base by Producing Areas for Year 2000

A prime resource in the production of agriculture commodities is land. Individuals throughout the United States have become increasingly concerned over the loss of agricultural land to nonagricultural purposes such as urban sprawl, roads and airports facilities and mining etc. Reduction in the agricultural land base due to urban expansion and other nonagricultural uses could result in less agricultural production unless the reduced land base is compensated by other resources in production. Over time, two viewpoints on this issue have surfaced, one group feels the reduction of agricultural land will be a definite threat to agriculture in the future Because once a piece of land is converted for urban build-up or any other use; chances of reclaiming that land to agricultural production are slim. Another group feels that the conversion rate of agricultural land to other uses is not significant enough to affect future agricultural production With increasing research on crop genetics and resource substitutions, compensation for the loss of land can occur. Few studies have been carried out at regional or at national levels that determine the extent of loss of land and its effect on agricultural production. The objective of this study is to estimate the loss of agricultural land in years ahead. These estimates will be incorporated in the Center for Agricultural and Rural Development linear programming models or right-hand-sides. They will serve as production restraints on the agricultural system

Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering

Recent microphysical studies suggest that geoengineering by continuous stratospheric injection of SO<sub>2</sub> gas may be limited by the growth of the aerosols. We study the efficacy of SO<sub>2</sub>, H<sub>2</sub>SO<sub>4</sub> and aerosol injections on aerosol mass and optical depth using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA). We find increasing injection rates of SO<sub>2</sub> in a narrow band around the equator to have limited efficacy while broadening the injecting zone as well as injecting particles instead of SO<sub>2</sub> gas increases the sulfate burden for a given injection rate, in agreement with previous work. We find that injecting H<sub>2</sub>SO<sub>4</sub> gas instead of SO<sub>2</sub> does not discernibly alter sulfate size or mass, in contrast with a previous study using a plume model with a microphysical model. However, the physics and chemistry in aircraft plumes, which are smaller than climate model grid cells, need to be more carefully considered. We also find significant perturbations to tropospheric aerosol for all injections studied, particularly in the upper troposphere and near the poles, where sulfate burden increases by up to 100 times. This enhanced burden could have implications for tropospheric radiative forcing and chemistry. These results highlight the need to mitigate greenhouse gas emissions rather than attempt to cool the planet through geoengineering, and to further study geoengineering before it can be seriously considered as a climate intervention option

Two-week joint mobilization intervention improves self-reported function, range of motion, and dynamic balance in those with chronic ankle instability

We examined the effect of a 2-week anterior-to-posterior ankle joint mobilization intervention on weight-bearing dorsiflexion range of motion (ROM), dynamic balance, and self-reported function in subjects with chronic ankle instability (CAI). In this prospective cohort study, subjects received six Maitland Grade III anterior-to-posterior joint mobilization treatments over 2 weeks. Weightbearing dorsiflexion ROM, the anterior, posteromedial, and posterolateral reach directions of the Star Excursion Balance Test (SEBT), and self-reported function on the Foot and Ankle Ability Measure (FAAM) were assessed 1 week before the intervention (baseline), prior to the first treatment (pre-intervention), 24–48 h following the final treatment (post-intervention), and 1 week later (1-week follow-up) in 12 adults (6 males and 6 females) with CAI. The results indicate that dorsiflexion ROM, reach distance in all directions of the SEBT, and the FAAM improved (p < 0.05 for all) in all measures following the intervention compared to those prior to the intervention. No differences were observed in any assessments between the baseline and pre-intervention measures or between the postintervention and 1-week follow-up measures (p > 0.05). These results indicate that the joint mobilization intervention that targeted posterior talar glide was able to improve measures of function in adults with CAI for at least 1 week

Future Crop Prices and Quantities: Influence of Alternative Crop Yields

Many people have tried to analyze what the future holds for continued increases in crop yields. After studying time series of average U.S. yields for 19 crops, Lin and Seaver [6] concluded that 12 crops including corn, cotton, and wheat have reached yield plateau, and the seven remaining crops including hay and soybeans yields have had a slowdown in their rate of growth. On the other hand, after presenting some of the possible new technologies or changes in existing technologies that could boast yields, Wittwer [15] concluded that it is reasonable to expect possible large increases in yields. Wittwer\u27s list of possible technologies included: changes in the plants\u27 ability to withstand environmental stress; changes in the plants\u27 ability to utilize fertilizer including the possibility of more plants with nitrogen fixation capabilities; increases in the plants\u27 photosynthetic efficiency; and increases in the use of chemical growth regulators. Heady [5], after reviewing a host of other studies, observed that probably the best that can be hoped for in the future is the continuation of the current absolute increases in yields

Agriculture and Changing Natural Gas Prices

For the period of analysis, 1982 through 1987, the impacts on agriculture that result from increasing natural gas prices are examined. Two types of models are used in the analysis -- econometric and linear programming. These models are linked together so that a short-run multi-period analysis can be conducted. The econometric model represents national demand for agricultural commodities and projects next year\u27s price while the linear programming component is an agricultural supply model

Implications of Soil Loss Control Policies upon the Long-run Sustainability of Agricultural Production within the State of Iowa

There is a growing tendency in the United States for decentralized public policymaking concerning agricultural production and resource use. Regional differences in climate, soil characteristics, water resource development, and input factor costs present each region with a unique situation. Individual regions have an incentive to develop a framework for analyzing both the impacts of national farm policies upon their own area, and in formulating region-specific policy programs which take explicit account of important local problems

Analysis of Demand and Supply for some U.S. Crops through Tatonnement Modeling

During the last decade, two concerns have been raised about the future of U.S. crop production. These concerns are: A) Will the United States have enough land available in the future that is suitable for crop production? and b) What will future crop yields be? Future U.S. crop production is highly dependent upon both these issues. The real problem may not be the quantity of future crop production, but rather the price of the quantity that is available. The development of a model to answer this question is one of the objectives of this study. The other objective is the projection of prices and quantities for barley, corn, oats, sorghum, soybeans, and wheat for the year 2000 under alternative yield and land availability assumptions

Information for Conservation Decisions: The IIASA Approach

Sound policy decisions concerning the complex interrelationships between sustainable agricultural production potential, resource use, technical change, and the environment, require much detailed information on the site-specific nature of resource inputs and alternative land-use practices over time. Realizing that these information requirements transcend geographic, economic, and potential boundaries, the Food and Agriculture program (FAP) of the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria, has initiated a series of case studies directed at examining the relationships for the United States (Iowa), Hungary, U.S.S.R. (Stavropol Regions0), Czechoslovakia (Nitra Region), Italy (Tuscany Region), Northeastern Bulgaria, and Japan. The purpose of this paper is to provide an overview of the objectives, methodological framework, and potential information available from this aspect of FAP\u27s research, with emphasis on the Iowa Case Study

A Tatonnement Model for Determining Future Market Prices and Quantities for some U.S. Crops

People concerned with planning and analysis of the agricultural sector are faced with two general problems which in turn gives rise for two general types of models. One problem involves positive or predictive models which attempt to predict the real world as it actually exists based on response functions. Models directed towards these types of predictions are usually based on time series observations and use statistical estimation techniques such as regression equations. The second problem involves normative models, which ask the question: what conditions could prevail if certain conditions and goals were to be met? Frequently, these conditions have never prevailed in the past and time series observations do not exist. Problems of this type cannot be handled by time-series regression models but more nearly involve some type of operations research methods. Specific techniques in the set of possibilities include mathematical programming and systems simulation. Mathematical programming models lend themselves to great detail on spatial characteristics of agriculture that cannot be accomplished with time-series regression models