Conceptual design study of a Harrier V/STOL research aircraft

MCAIR recently completed a conceptual design study to define modification approaches to, and derive planning prices for the conversion of a two place Harrier to a V/STOL control, display and guidance research aircraft. Control concepts such as rate damping, attitude stabilization, velocity command, and cockpit controllers are to be demonstrated. Display formats will also be investigated, and landing, navigation and guidance systems flight tested. The rear cockpit is modified such that it can be quickly adapted to faithfully simulate the controls, displays and handling qualities of a Type A or Type B V/STOL. The safety pilot always has take command capability. The modifications studied fall into two categories: basic modifications and optional modifications. Technical descriptions of the basic modifications and of the optional modifications are presented. The modification plan and schedule as well as the test plan and schedule are presented. The failure mode and effects analysis, aircraft performance, aircraft weight, and aircraft support are discussed

Choosing corn hybrids

What management decision can make a 40 to 50 bushel per acre difference in grain yield without increasing input costs? If you\u27ve read the title to this article, you can probably guess the answer: hybrid selection! Hybrid selection is a critical component for achieving high yields and yet is not often given enough attention. Seed prices in Iowa are increasing about $1.30 per acre per year (Figure 1). This increase will continue as more genetic traits and stacks become available

Perceptions of wildlife damage and species conservation: lessons learned from the Utah prairie dog

The Utah prairie dog (Cynomys parvidens), a federally listed threatened species, causes damage to agricultural operations, yet little incentive exists for private landowners to conserve them. Therefore, we surveyed Utah residents to identify stakeholder attitudes regarding prairie dog management. We assessed how perceptions of wildlife damage affect respondent attitudes regarding conservation among agricultural producers, rural residents, and urban residents. Higher levels of perceived wildlife damage were reported for agriculture respondents (79%) than for urban (20%) or rural (45%) respondents. Compensation for damage caused by Utah prairie dogs was supported by those engaged in agricultural production but not by rural or urban respondents. Agricultural producers, rural residents and urban residents all stated a preference for private conservation organizations to fund damage compensation rather than a government agency. Most agricultural respondents (61%) and rural respondents (64%) believed that Utah prairie dogs should be only on public lands. Some agricultural respondents (23%) thought they should be on no land. Attitudes regarding the Utah prairie dog varied, with agricultural producers being the most negative and urban respondents the most positive. The negative attitude of rural residents and agricultural producers probably results from both the damage caused by Utah prairie dogs and land-use restrictions resulting from the species being listed as threatened. Acceptance of Utah prairie dogs by private landowners may be key to the recovery of the species, and our findings suggest that alleviation of damage issues may increase landowner acceptance of conservation measures to protect Utah prairie dogs.n

A Model for Testing New Seed Technologies

Extension specialists from several North Central states recently proposed a new approach to expedite and facilitate evaluation of new genetically modified organism (GMO) hybrids through multi-state testing. As an example of this approach, newly released GMO glyphosate tolerant (GT) corn hybrids were evaluated at multiple locations across five states in 1999 and nine states in 2001. This cooperative testing effort demonstrated that powerful sets of data across a range of production environments could be generated with a minimal amount of input and resource allocation for the individual states

Soybean Chlorosis Studies on High pH Bottomland Soils

Soybean varieties are different in tolerance to lime-induced chlorosis. Field trials were conducted to evaluate variety performance on soils where chlorosis in soybeans was a known problem. Thirty-six varieties out of 177 were identified as tolerant to soil conditions that cause chlorosis. Eleven varieties of these 36 were found to have the most consistent yield performance on high pH soils. Tolerant varieties must be planted at adequate densities for best performance. A seeding rate of 13.5 seeds per foot of row, the highest seeding rate employed, did not appear to maximize yield on soils where chlorosis was severe. On some soils, chlorosis is so severe that even tolerant varieties planted at adequate densities will not produce seed. Under conditions where soils cause moderate to severe chlorosis in tolerant varieties, yields were improved by the use of a high pH stable chelate (Fe-EDDHA) with the seed

Soybean Chlorosis Studies on High pH Bottomland Soils

Soybean varieties are different in tolerance to lime-induced chlorosis. Field trials were conducted to evaluate variety performance on soils where chlorosis in soybeans was a known problem. Thirty-six varieties out of 177 were identified as tolerant to soil conditions that cause chlorosis. Eleven varieties of these 36 were found to have the most consistent yield performance on high pH soils. Tolerant varieties must be planted at adequate densities for best performance. A seeding rate of 13.5 seeds per foot of row, the highest seeding rate employed, did not appear to maximize yield on soils where chlorosis was severe. On some soils, chlorosis is so severe that even tolerant varieties planted at adequate densities will not produce seed. Under conditions where soils cause moderate to severe chlorosis in tolerant varieties, yields were improved by the use of a high pH stable chelate (Fe-EDDHA) with the seed