Florian Diekmann

Certified Crop Advisors’ Perceptions of Giant Ragweed (Ambrosia trifida) Distribution, Herbicide Resistance, and Management in the Corn Belt

Abstract Giant ragweed has been increasing as a major weed of row crops in the last 30 yr, but quantitative data regarding its pattern and mechanisms of spread in crop fields are lacking. To address this gap, we conducted a Web-based survey of certified crop advisors in the U.S. Corn Belt and Ontario, Canada. Participants were asked questions regarding giant ragweed and crop production practices for the county of their choice. Responses were mapped and correlation analyses were conducted among the responses to determine factors associated with giant ragweed populations. Respondents rated giant ragweed as the most or one of the most difficult weeds to manage in 45% of 421 U.S. counties responding, and 57% of responding counties reported giant ragweed populations with herbicide resistance to acetolactate synthase inhibitors, glyphosate, or both herbicides. Results suggest that giant ragweed is increasing in crop fields outward from the east-central U.S. Corn Belt in most directions. Crop production practices associated with giant ragweed populations included minimum tillage, continuous soybean, and multiple-application herbicide programs; ecological factors included giant ragweed presence in noncrop edge habitats, early and prolonged emergence, and presence of the seed-burying common earthworm in crop fields. Managing giant ragweed in noncrop areas could reduce giant ragweed migration from noncrop habitats into crop fields and slow its spread. Where giant ragweed is already established in crop fields, including a more diverse combination of crop species, tillage practices, and herbicide sites of action will be critical to reduce populations, disrupt emergence patterns, and select against herbicide-resistant giant ragweed genotypes. Incorporation of a cereal grain into the crop rotation may help suppress early giant ragweed emergence and provide chemical or mechanical control options for late-emerging giant ragweed. Nomenclature: Glyphosate; giant ragweed; Ambrosia trifida L. AMBTR; common earthworm; Lumbricus terrestris L.; corn; Zea mays L.; soybean, Glycine max (L.) Merr.

Data Practices of Agricultural Scientists: Results from an Exploratory Study

This qualitative study examines data practices of agricultural scientists. A series of individual, semi-structured interviews were conducted with researchers from multiple agricultural disciplines to identify commonalities of data management approaches, to document currently available data management infrastructure, and to explore experiences and attitudes toward sharing of research data. The study highlights the challenges and obstacles agricultural scientists face when managing research data. It shows how barriers to data access and sharing jeopardize usability and longevity of potentially valuable and unique agricultural data sets.

Tractors on eBay: Differences between Internet and In-Person Auctions

We provide a systematic examination of the differences between Internet and in-person auction prices for used tractors. A hedonic model estimated with transactions pooled between eBay and in-person auctions reveals statistically distinct price surfaces for the two auction venues and predicts significantly lower prices for comparable equipment sold on eBay, though this difference is attenuated for tractors fully covered by eBays buyer protection program and is fully absent for the most frequently traded tractor. An endogenous venue selection model reveals that larger, more valuable tractors from states with more valuable stocks of machinery are more likely to be offered on eBay. Copyright 2008, Oxford University Press.

Staying in touch through Extension: an analysis of farmers' use of alternative Extension information products.

The U.S. farming industry is evolving quickly. It is therefore important that state Extension services be prepared to evolve as well. This study uses data collected in a 2007 survey of Ohio farmers to evaluate likelihood and frequency of use of various services offered by Extension as well as overall satisfaction with Extension services. Results indicate that tailoring of topics and communication methods to type of farm and/or farmer informational needs could improve the use of Extension resources. This implies that targeting of information products and methods may improve the performance of Extension education programs and customer satisfaction.

Small Grain Cereals

Small grain cereals—wheat, barley, oat, rye, and triticale—are among the most important cultivated plant species, essential to human and livestock nutrition, and grown in greater quantities than any other crop. The importance of small grains is related to their biological characteristics that allow for systematic cultivation and development of an efficient production technology. Small grain cereals are relatively easy to plant, cultivate, and harvest. Because of their low water content, they are also well-suited for transportation and long-term storage. Compared to grain crops from other families, such as legumes, yields of cereals are relatively high. All cereals possess a high nutritional value and are a rich source of energy, protein, and dietary fiber. Because of their large genetic variability, small grain cereals are extremely adaptable to different environments. Production can be found in most regions of the world, from the arctic circle to the equator, ranging in altitudes from a few feet to more than 10,000 feet above sea level, and in areas with between 10 and 70 inches of rainfall (Gooding & Davies, 1997; Satorre & Slafer, 1999). Botanically, cereals are annual grasses cultivated for their grains that complete their life cycle in less than a year. All cereals belong to the monocot Poaceae family (also called Gramineae), tribe Triticae (Zohary & Hopf, 2000). The origin of agriculture in the Old World is closely associated with cereal domestication (Araus, Ferrio, Buxo, & Voltas, 2007). Wheat and barley have been traditional staple foods of Europe and Western Asia and are the principal crops that inspired Western agriculture in the Fertile Crescent (Smith, 1998; Salamini, Ozkan, Brandolini, Schafer-Pregl, & Martin, 2002). An important step in the development of wild cereal species to domesticated crops was the selection of mutant forms with larger grains, a tendency for

Economics of Technology for Precision Weed Control in Conventional and Organic Systems

Regardless of the crop production system used, weeds must be controlled at or below an economic threshold in order to achieve an acceptable level of profitability. The best method of weed control will depend on a number of factors, including labor, fuel and machinery cost, crop prices, and farmer’s willingness to accept production risks. In this chapter, we discuss economic factors that drive innovation in precision weed control technologies for agriculture and influence producer adoption of those technologies. We present a theoretical framework to help explain the economic incentives or disincentives to adoption of these emerging technologies. We also introduce the concept of externalities – costs or benefits realized by groups other than producers – which, if internalized to farm firms through taxes, subsidies, or restrictions, may influence producer adoption of a specific technology. We conclude with highlighting a number of important farm-level economic impacts of precision weed technology adoption.

Research Practices of Agricultural Scientists at The Ohio State University

ABSTRACT The Ohio State University Libraries was one of 19 institutions collaborating in the Ithaka S+R Research Support Services for the Field of Agriculture study. Based on a series of individual, semistructured interviews with faculty researchers affiliated with the agricultural sciences at the Ohio State University, the study gathered information about current research practices. The study highlighted challenges of the agricultural research process and identified opportunities for improving research support services for agricultural scientists.

Bibliometric Analysis of the Literature on Giant Ragweed (Ambrosia trifida L.)

Giant ragweed (Ambrosia trifida L.) has become one of the most persistent and problematic weeds to farmers and allergy sufferers in North America over the last decades. This study aims to identify and assess the scholarly literature using a bibliometric analysis approach. Based on bibliographic records retrieved from the Web of Science database, the study describes the periodic growth of literature, scientific fields and journals, author productivity and collaborations, institutions and countries, and topical focus and uses article citation analysis to identify the most influential works in this research field during the period of 1903 to 2012.