270 research outputs found

    The social networks of manureshed management

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    Manureshed management—the strategic use of manure nutrients that prioritizes recycling between livestock systems and cropping systems—provides a comprehensive framework for sustainable nutrient management that necessitates the collaboration of many actors. Understanding the social dimensions of collaboration is critical to implement the strategic and technological requirements of functional manuresheds. To improve this understanding, we identified aspirational networks of actors involved in manureshed management across local, regional, and national scales, principally in the United States, elucidating key relationships and highlighting the breadth of interactions essential to successful manureshed management. We concluded that, although the social networks vary with scale, the involvement of a common core set of actors and relationships appears to be universal to the successful integration of modern livestock and crop production systems necessary for functional manuresheds. Our analysis also reveals that, in addition to agricultural producers, local actors in extension and advisory services and private and public sectors ensure optimal outcomes at all scales. For manureshed management to successfully integrate crop and livestock production and sustainably manage manure nutrient resources at each scale, the full complement of actors identified in these social networks is critical to generate innovation and ensure collaboration continuity

    Soil erosion assessment—Mind the gap

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    Accurate assessment of erosion rates remains an elusive problem because soil loss is strongly nonunique with respect to the main drivers. In addressing the mechanistic causes of erosion responses, we discriminate between macroscale effects of external factors—long studied and referred to as “geomorphic external variability”, and microscale effects, introduced as “geomorphic internal variability.” The latter source of erosion variations represents the knowledge gap, an overlooked but vital element of geomorphic response, significantly impacting the low predictability skill of deterministic models at field‐catchment scales. This is corroborated with experiments using a comprehensive physical model that dynamically updates the soil mass and particle composition. As complete knowledge of microscale conditions for arbitrary location and time is infeasible, we propose that new predictive frameworks of soil erosion should embed stochastic components in deterministic assessments of external and internal types of geomorphic variability.Key PointsSoil loss response to runoff is strongly controlled by “geomorphic internal variability”: microscale factors intrinsic to geomorphic systemPredictive skill of deterministic soil loss models at event scale is likely to remain poorErosion estimates must communicate uncertainty due to geomorphic external and internal types of variabilityPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/136017/1/grl55374-sup-0001-Supplementary.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136017/2/grl55374.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/136017/3/grl55374_am.pd

    Land Application of Organic Fertilizers or Amendments

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    4 pp., 5 photosApplying organic materials to your land can add beneficial nutrients to the soil. But when too much is applied, or when it is applied incorrectly, organic material can cause environmental problems. This publication will help you select the proper application rate, calibrate equipment so that the correct rate is applied, and learn how location, water, soil and tillage can all affect the process

    Ensemble evaluation of hydrological model hypotheses

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    It is demonstrated for the first time how model parameter, structural and data uncertainties can be accounted for explicitly and simultaneously within the Generalized Likelihood Uncertainty Estimation (GLUE) methodology. As an example application, 72 variants of a single soil moisture accounting store are tested as simplified hypotheses of runoff generation at six experimental grassland field-scale lysimeters through model rejection and a novel diagnostic scheme. The fields, designed as replicates, exhibit different hydrological behaviors which yield different model performances. For fields with low initial discharge levels at the beginning of events, the conceptual stores considered reach their limit of applicability. Conversely, one of the fields yielding more discharge than the others, but having larger data gaps, allows for greater flexibility in the choice of model structures. As a model learning exercise, the study points to a “leaking” of the fields not evident from previous field experiments. It is discussed how understanding observational uncertainties and incorporating these into model diagnostics can help appreciate the scale of model structural error

    Political Party Mortality in Established Party Systems:A Hierarchical Competing Risks Approach

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    Existing scholarship offers few answers to fundamental questions about the mortality of political parties in established party systems. Linking party research to the organization literature, we conceptualize two types of party death, dissolution and merger, reflecting distinct theoretical rationales. They underpin a new framework on party organizational mortality theorizing three sets of factors: those shaping mortality generally and those shaping dissolution or merger death exclusively. We test this framework on a new data set covering the complete life cycles of 184 parties that entered 21 consolidated party systems over the last five decades, resorting to multilevel competing risks models to estimate the impact of party and country characteristics on the hazards of both types of death. Our findings not only show that dissolution and merger death are driven by distinct factors, but also that they represent separate logics not intrinsically related at either the party or systemic level

    GPS network monitor the Western Alps deformation over a five year period: 1993-1998

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    GPS surveys in the Western Alps, performed in the time span 1993-2003, estimated the current crustal deformation of this area.Published63-763.2. Tettonica attivaJCR Journalreserve

    Attacks by a piercing-sucking insect (Myzus persicae Sultzer) or a chewing insect (Leptinotarsa decemlineata Say) on potato plants (Solanum tuberosum L.) induce differential changes in volatile compound release and oxylipin synthesis

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    Plant defensive strategies bring into play blends of compounds dependent on the type of attacker and coming from different synthesis pathways. Interest in the field is mainly focused on volatile organic compounds (VOCs) and jasmonic acid (JA). By contrast, little is known about the oxidized polyunsaturated fatty acids (PUFAs), such as PUFA-hydroperoxides, PUFA-hydroxides, or PUFA-ketones. PUFA-hydroperoxides and their derivatives might be involved in stress response and show antimicrobial activities. Hydroperoxides are also precursors of JA and some volatile compounds. In this paper, the differential biochemical response of a plant against insects with distinct feeding behaviours is characterized not only in terms of VOC signature and JA profile but also in terms of their precursors synthesized through the lipoxygenase (LOX)-pathway at the early stage of the plant response. For this purpose, two leading pests of potato with distinct feeding behaviours were used: the Colorado Potato Beetle (Leptinotarsa decemlineata Say), a chewing herbivore, and the Green Peach Aphid (Myzus persicae Sulzer), a piercing-sucking insect. The volatile signatures identified clearly differ in function with the feeding behaviour of the attacker and the aphid, which causes the smaller damages, triggers the emission of a higher number of volatiles. In addition, 9-LOX products, which are usually associated with defence against pathogens, were exclusively activated by aphid attack. Furthermore, a correlation between volatiles and JA accumulation and the evolution of their precursors was determined. Finally, the role of the insect itself on the plant response after insect infestation was highlighted

    Why Parties Narrow their Representative Profile: Evidence from Six European Democracies

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    This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this recordIn this paper, we analyse the conditions under which political parties narrow their representative profile (defined by the scope of the issues or the constituencies they represent). This strategy has been neglected in the party literature, which is mainly focused on the adoption of catch-all strategies among mainstream parties or the tendency to stick to core issues among niche parties. In this paper, we develop a theoretical framework that includes central external and internal drivers of party change and we empirically test this framework using novel survey data covering 121 parties across six European democracies: The United Kingdom, Norway, Germany, Switzerland, Italy and Ireland.European Commissio
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