A planning tool for integrating crop choices with weed management in the Northern Great Plains
Abstract Crop production in the Northern Great Plains is rapidly changing because of no-till practices; producers now grow a diversity of crops with winter wheat to increase production as well as to manage weeds. With the multitude of crops available, producers are asking for guidelines to sequence crops in rotations that help weed management. We developed a planning tool that lists various choices with crops when designing a rotation; the choices are arranged by impact on weed dynamics as quantified by research in the region. The tool includes choices among crops, such as varying crops with different life cycles, planting dates, or row spacing, and choices within an individual crop, such as varying cultivar or planting date. Choices among crops impact weeds the most, whereas choices within an individual crop are less effective and usually lead to lower crop yield. For example, rotations comprised of two cool-season crops followed by two warm-season crops can reduce weed populations six- to 12-fold. In contrast, replacing a standard-height cultivar with a taller cultivar that is more competitive with weeds, is often inconsistent for weed management, whereas crop yield may be less. Producers associated with the Northern Plains Sustainable Agricultural Society felt that the planning tool would encourage long-range planning as well as help integrate weed management with the design of cropping systems. The purpose of the tool is to encourage ecologically based weed management, which can reduce herbicide inputs by 50% for Northern Great Plains producers.
Characterizing traits that enhance the competitiveness of winter wheat (Triticum aestivum) against jointed goatgrass (Aegilops cylindrica)
Our objective was to identify traits in winter wheat important to competitiveness against jointed goatgrass, measured as increased wheat yields and reduced jointed goatgrass seed production. Jointed goatgrass is an important winter annual grass weed that cannot be controlled selectively in winter wheat. Seven cultivars of soft white winter wheat were grown with and without competition from jointed goatgrass over two growing seasons. Measurements of numerous traits of winter wheat and jointed goatgrass were recorded throughout each growing season. The data were analyzed using path analysis with latent variables to determine which traits most enhanced competitiveness. In a drier year, increased rate of height development was important in maintaining wheat yields when wheat was growing in competition with jointed goatgrass. Increased rate of height development also was an important trait in reducing jointed goatgrass seed production. In a wet year compared to a dry year, the number of wheat heads per plant, the rate of water use, and weight gain were positively correlated to maintaining winter wheat yields. Jointed goatgrass seed production in the wet year was reduced overall compared to the dry year, but from the cultivars tested, there were no traits identified that were critical in enhancing this loss of seed production. This study suggests that cultivars with greater height development rates will be more competitive when growing in fields infested with jointed goatgrass.
An Introduction to Property Theory: Utilitarian Property Theories
As a leading property law casebook puts it, “[u]tilitarian theory is, without doubt, the dominant view of property today, at least among lawyers.” This is certainly true, but the story is also significantly more complicated. Although utilitarian analysis provides tremendous insight into the institution of property, it raises a number of important questions when treated as a comprehensive theory of property. Moreover, the term utilitarian masks a great deal of intellectual and methodological diversity. Rather than a single utilitarian theory, it is more appropriate to speak of a number of utilitarian (or even utilitarian-influenced) property theories . For our purposes, these utilitarian-influenced theories include many contemporary theories that refer to themselves as economic or welfarist . In this chapter, we will explore the broad outlines of these theories, focusing on their points of overlap and also on key areas of disagreement. A BRIEF INTRODUCTION TO UTILITARIANISM Utilitarianism is a consequentialist moral philosophy, that is, one that judges the rightness and wrongness of actions or rules or institutions by the goodness and badness of the consequences they bring about. Utilitarianism assesses the goodness or badness of consequences in terms of their tendency to maximize utility or welfare. Bernard Williams has observed that “[t]he fathers of utilitarianism thought of it principally as a system of social and political decision,” as opposed to “a system of personal morality.” As Williams correctly notes, it is sometimes hard to keep these two domains apart. Nevertheless, it is plainly as a theory of social choice that utilitarianism has been deployed in the context of property theory.