ECONOMIC AND ENVIRONMENTAL BENEFITS OF VARIABLE RATE APPLICATION OF NITROGEN TO CORN FIELDS: ROLE OF VARIABILITY AND WEATHER

The use of meta-response functions based on EPIC-generated data resulted in comparisons between variable (VRAT) and uniform rate application technologies for 36 simulated fields. VRAT was more profitable and less nitrogen was lost to the environment in most cases. When spatial variability was small, uniform rate application techniques were adopted. However, when nitrogen use is restricted, VRAT is used on all simulated fields.Precision farming, site-specific farming, spatial variability, nitrogen restriction, rainfall, EPIC, crop growth simulation model, meta-response functions, Environmental Economics and Policy, Research and Development/Tech Change/Emerging Technologies, Resource /Energy Economics and Policy,

ASSESSING SPATIAL BREAK-EVEN VARIABILITY IN FIELDS WITH TWO OR MORE MANAGEMENT ZONES

Farmers are interested in knowing whether applying inputs at variable rates across a field is economically viable. The answer depends on the crop, the input, their prices, the cost of variable rate technology (VRT) versus uninform rate technology (URT), and the spatial and yield response variability within each field. Methods were investigated for determining the range of spatial variability over which the return to VRT covers its additional cost compared with URT in fields with multiple management zones. Models developed in this article, or variants thereof, could be used to help farmers make the VRT adoption decision.management zones, nitrogen, precision farming, site-specific management, spatial break-even variability proportions, spatial variability, variable rate technology, yield response variability, Farm Management,

Ignition and combustion of lunar propellants

The ignition and combustion of Al, Mg, and Al/Mg alloy particles in 99 percent O2/1 percent N2 mixtures is investigated at high temperatures and pressures for rocket engine applications. The 20 micron particles contain 0, 5, 10, 20, 40, 60, 80, and 100 weight percent Mg alloyed with Al, and are ignited in oxygen using the reflected shock in a shock tube near the endwall. Using this technique, the ignition delay and combustion times of the particles are measured at temperatures up to 3250 K as a function of Mg content for oxygen pressures of 8.5, 17, and 34 atm. An ignition model is developed which employs a simple lumped capacitance energy equation and temperature and pressure dependent particle and gas properties. Good agreement is achieved between the measured and predicted trends in the ignition delay times. For the particles investigated, the contribution of heterogeneous reaction to the heating of the particle is found to be significant at lower temperatures, but may be neglected as gas temperatures above 3000 K. As little as 10 percent Mg reduces the ignition delay time substantially at all pressures tested. The particle ignition delay times decrease with increasing Mg content, and this reduction becomes less pronounced as oxidizer temperature and pressure are increased

EVALUATING THE RETURNS TO VARIABLE RATE NITROGEN APPLICATION

Potential benefits of variable rate nitrogen application are illustrated and information needs identified. Lower costs of precision farming services, higher crop prices, and greater divergence in yield response potentials across management zones reduce the spatial variability required for profitable variable rate application. Information needs include identification and measurement of management zones within a field and estimation of management zone yield response functions, crop and input prices, and the cost of precision farming services.production economics, management zones, nitrogen, precision farming, spatial break-even variability proportions, variable rate applications, yield response variability, Crop Production/Industries,

Economic Feasibility of Kenaf Production in Three Tennessee Counties

Since the 1940s, kenaf has been viewed as a potential source of fiber, mainly for newsprint and high quality paper. Kenaf research has once again risen to the forefront due to the recent USDA tobacco buyout. Many states and farmers dependent upon tobacco revenues have been seeking alternative crops for a number of years. This study seeks to expand the current literature by examining the economic feasibility of growing kenaf within three counties in Tennessee. Nitrogen meta-yield response functions for kenaf and four traditional crops were developed for 30 soils through crop growth simulation modeling and used to compare optimal crop budgets for each soil. Results reveal that kenaf would not compete favorably with traditional crops on any soil at prices below $49/ton, while profit-maximizing farmers could supply as much as 1,385,700 tons of kenaf if the price were$55/ton.alternative crop, economic feasibility, enterprise budgeting, kenaf, plant growth modeling, yield response functions, Agribusiness, Crop Production/Industries,

The Variable-Rate Decision for Multiple Inputs with Multiple Management Zones

Research has evaluated the relative profitability of variable-rate versus uniform-rate application of a single input in fields with multiple management zones. This paper addresses the variable-rate decision for multiple inputs. The decision-making framework is evaluated for nitrogen and water applied to irrigated cotton in fields with three management zones.Crop Production/Industries,

Economic Feasibility of Kenaf Production in Three Tennessee Counties

This article seeks to expand current literature by discussing the economic feasibility of growing kenaf within three counties in Tennessee. Results revealed that kenaf would not compete with traditional crops at prices below $49/ton, while profit-maximizing farmers could supply as much as 1,385,700 tons of kenaf at prices of$55/ton.Crop Production/Industries,

The Variable-Rate Input Application Decision for Multiple Inputs with Interactions

Research has evaluated the relative profitability of variable-rate (VRT) versus uniform-rate (URT) application of a single input in fields with multiple management zones. This study addresses map-based VRT decisions for multiple inputs in fields with multiple management zones. The decision-making framework is illustrated for nitrogen and water applied to irrigated cotton in fields with three management zones. Results suggest traditional methods of determining VRT application of a single input may by suboptimal if interactions exist among VRT inputs and URT inputs. Implications are that a systems approach to multiple-input VRT decisions can produce increased net returns to VRT.breakeven analysis, cotton, economic feasibility, multiple-inputs, precision farming, variable-rate technology, Crop Production/Industries,

Adoption of Conservation-Tillage Methods and Genetically Modified Cotton

Adoption of herbicide-tolerant cotton and conservation tillage may be simultaneously related. Bayes' theorem and a two-equation logit model were used to test the simultaneity hypothesis. Evidence for Tennessee suggests that adoption of these technologies reduced residual herbicide use and soil erosion more than if adoption of these technologies were independent.Bayes' theorem, conservation tillage, cotton, genetically modified crops, herbicide tolerant crops, simultaneous logit model, technology adoption, Crop Production/Industries, Q12, Q16, Q24, O33,

Pushing boundaries: Women in Sport and Exercise Conference, St Mary’s University, Twickenham, June 11–12, 2019

The Women in Sport and Exercise Academic Network (WiSEAN) was established in 2016 to grow, strengthen and promote research on women in sport and exercise, with the ultimate goal of optimising women’s athletic success and their participation