ESTIMATING MARKETING MARGIN COST COMPONENTS: AN APPLICATION OF SIMULATION TO PRODUCTS OF THE VEGETABLE OIL INDUSTRY

Demand and Price Analysis,

DEMAND AND SUPPLY OF VEGETABLE OIL PRODUCTS IN THE UNITED STATES: A SHORT-RUN ANALYSIS

Demand and Price Analysis,

DYNAMICS OF FOOD PRICE INFLATION

A supply-shift concept of food price inflation is offered as an explanation of why food prices have increased in recent years. This view is consistent with cost-push theories of inflation. The effects of higher farm product prices on food prices are analyzed using Pascal distributed lag models of the price adjustment process. Estimates are presented for 23 selected food products. The results indicate that higher farm prices are passed through to the retail level most quickly for food products which are not highly processed.Demand and Price Analysis,

The Study of the Heisenberg-Euler Lagrangian and Some of its Applications

The Heisenberg-Euler Lagrangian is not only a topic of fundamental interest, but also has a rich variety of diverse applications in astrophysics, nonlinear optics and elementary particle physics etc. We discuss the series representation of this Lagrangian and a few of its applications in this study. [In an appendix, we discuss issues related to the renormalization - and the renormalization-group invariance - of the Heisenberg-Euler Lagrangian and its two-loop generalization.]Comment: 12 pages, LaTeX; Proceedings of the MRST-2003 conference; talk given by S. R. Vallur

Age spreads in star forming regions?

Rotation periods and projected equatorial velocities of pre-main-sequence (PMS) stars in star forming regions can be combined to give projected stellar radii. Assuming random axial orientation, a Monte-Carlo model is used to illustrate that distributions of projected stellar radii are very sensitive to ages and age dispersions between 1 and 10 Myr which, unlike age estimates from conventional Hertzsprung-Russell diagrams, are relatively immune to uncertainties due to extinction, variability, distance etc. Application of the technique to the Orion Nebula cluster reveals radius spreads of a factor of 2--3 (FWHM) at a given effective temperature. Modelling this dispersion as an age spread suggests that PMS stars in the ONC have an age range larger than the mean cluster age, that could be reasonably described by the age distribution deduced from the Hertzsprung-Russell diagram. These radius/age spreads are certainly large enough to invalidate the assumption of coevality when considering the evolution of PMS properties (rotation, disks etc.) from one young cluster to another.Comment: To appear in "The Ages of Stars", E.E. Mamajek, D.R. Soderblom, R.F.G. Wyse (eds.), IAU Symposium 258, CU

Cotton, tomato, corn, and onion production with subsurface drip irrigation: A review

Citation: Lamm, F. R. (2016). Cotton, tomato, corn, and onion production with subsurface drip irrigation: A review. Transactions of the Asabe, 59(1), 263-278. doi:10.13031/trans.59.11231The usage of subsurface drip irrigation (SDI) has increased by 89% in the U.S. during the past ten years according to USDA-NASS estimates, and over 93% of the SDI land area is located in just ten states. Combining public entity and private industry perceptions of SDI in these ten states, the major crops were tentatively identified as cotton, processing tomato, field corn, and onion. An extensive literature review of SDI usage for these four crops was performed concentrating on irrigation system comparisons, water and/or nutrient management, and SDI system design criteria. Although many crops potentially can be grown with SDI, the results presented here may be a relatively representative crosssection of the various opportunities and challenges of SDI for general crop production. © 2016 American Society of Agricultural and Biological Engineers

Net Returns for Grain Sorghum and Corn under Alternative Irrigation Systems in Western Kansas

This study evaluates seven irrigation systems for use in production of grain sorghum and corn. These systems are medium pressure center-pivot (MPCP), low pressure center-pivot (LPCP), low drift nozzle center-pivot (LDN) , low energy precision application center-pivot (LEPA), furrow flood (FF) , surge flood (SF), and subsurface drip (SD). After-tax net present value estimates from investing in and using each system over a 10-year period to produce grain sorghum and corn are compared. The surge flood system, has the highest net returns under typical conditions for irrigation of both grain sorghum and corn. The furrow flood system generates the next highest net returns for both crops, followed by the subsurface drip system. The medium pressure center-pivot system is the least profitable for both crops. Of the center-pivot systems, the low pressure system has the highest net return, but is followed very closely by the low drift nozzle system. The results of the sensitivity analysis indicate that the net return estimates and ranking of the subsurface drip system are very sensitive to the yield response to irrigation. Lower than average crop prices also have a substantial impact on the ranking of this system. The original investment cost is also an important determinant of its net return.Crop Production/Industries,

The Importance of Irrigation Scheduling for Marginal Capacity Systems Growing Corn

Citation: Lamm, F. R., & Rogers, D. H. (2015). The Importance of Irrigation Scheduling for Marginal Capacity Systems Growing Corn. Applied Engineering in Agriculture, 31(2), 261-265. Retrieved from ://WOS:000353671300011Many irrigators in the Central Great Plains region do not use science-based irrigation scheduling for a variety of reasons, many of which are not strongly related to the technical feasibility. Evapotranspiration (ET)-based irrigation scheduling has been shown to be an acceptable irrigation scheduling method within the region. Many irrigators have expressed the rationale that there is no need to implement irrigation scheduling because their marginal capacity irrigation must be ran continually throughout the season to meet corn irrigation needs. ET-based irrigation schedules were simulated using 43 years (1972-2014) of weather data for Colby, Kansas, to determine irrigation needs as affected by irrigation capacity, center pivot sprinkler system application efficiency and the initial soil water condition at corn emergence. Adoption of ET-based irrigation scheduling with an initial soil water condition of 85% of field capacity and 95% application efficiency potentially could save on average 212 mm of water for a 25.4 mm/4 days irrigation capacity and 71 mm for a severely deficit 25.4 mm/8 day irrigation capacity. As application efficiency was decreased from 95% to 80% these savings for similar initial soil water conditions decreased from 176 to 67 mm for the greater and smaller irrigation capacities, respectively. Potential irrigation savings using an application efficiency of 95% were reduced but still appreciable when the initial soil water condition was 60% of field capacity averaging 154 and 25 mm for the 25.4 mm every 4 or 8 days irrigation capacities, respectively. Irrigators with marginal capacity systems should adopt science-based irrigation scheduling to make best use of their limited irrigation and should not discount their opportunity to save irrigation water even when their system restrictions are severe

Key considerations for a successful subsurface drip irrigation (SDI) system

Presented at the Central Plains irrigation conference on February 17-18, 2004 in Kearney Nebraska