1,480 research outputs found
Mikrobielle Carbonisierung und ihr Potential fĂŒr landwirtschaftliche Kompostierung : Untersuchung reduktiver Kompostierung als Ansatz fĂŒr die regenerative Landwirtschaft
The search for agronomic solutions to the decline of soil health, open-ended
nutrient cycles and greenhouse gas (GHG) emissions from agriculture, against
the background of impending climate change, were motivations for this thesis.
A composting trial on a Swedish farm was designed to find answers to the
overarching research question of how feasible and climate-friendly on-farm
composting using Microbial Carbonisation (MC) is, compared to conventional
windrow composting (CC). MC can be understood as the biological
transformation of biomass under mesophilic and anoxic conditions, in contrast
to CC, which is an aerobic and partly thermophilic decomposition process.
The investigation of the MC method was approached using natural and
social science methodologies. Field trials were carried out, accompanied by
substrate, soil, emission and pore-gas measurements, as well as records of
machinery use. In addition, interviews were conducted with farmers already
using MC in Germany, to gain a better insight into its practical application and
farmersâ needs.
The results suggest that MC substrates can be richer in nitrogen (N) and
carbon (C) after composting than CC. The machinery requirement of MC was
only one tenth of the more labour-intensive CC process, which is associated
with lower fossil emissions. A novelty of the present research was that nitrous
oxide (N2O) emissions were measured for the first time on a MC compost.
Overall, on a weight basis, MC showed 30 â 40 % lower GHG emissions
during composting, compared to CC. This advantage, however, was offset by
28 â 40 % higher emissions in the field on an area basis. In addition, GHG
balances are highly dependent on the appropriateness of the measurementmethodology,
the period under consideration and the reference unit in which
the emissions are expressed. As CC showed higher N-losses during the
composting process, MC overall emitted 5 â 29 % less GHG per kg N applied
to the field. It was therefore not entirely clear whether MC or CC performed
better in terms of GHG emissions.
As MC can provide N- and C-rich substrates in a cost-efficient way, it
appears promising for the use in regenerative agriculture. The farmersâ
interviews supported the results of MC being cost-efficient and practicable for
on-farm composting. Nevertheless, the field application of compost can
substantially increase the GHG balance of what at first sight appears to be a
climate friendly composting process. Future studies need to further address
this issue, as well as the impact of MC substrates on soil health.Die Suche nach ackerbaulichen Lösungen fĂŒr die Abnahme der
Bodengesundheit, offene NÀhrstoffkreislÀufe sowie Treibhausgasemissionen
(THG) der Landwirtschaft, vor dem Hintergrund des drohenden Klimawandels,
waren Motivation fĂŒr diese Studie. Ein Kompostierungsversuch auf einem
schwedischen Landwirtschaftsbetrieb sollte Antworten auf die ĂŒbergeordnete
Forschungsfrage liefern, wie praktikabel und klimafreundlich
landwirtschaftliche Kompostierung mittels Mikrobieller Carbonisierung (MC) im
Vergleich zur konventionellen Kompostierung (CC) ist. MC kann als
biologische Umwandlung von Biomasse unter mesophilen und anoxischen
Bedingungen verstanden werden, im Gegensatz zu CC, welchem ein aerober
und teilweise thermophiler Abbauprozess zugrunde liegt.
Die MC-Methode wurde mithilfe natur- und sozialwissenschaftlicher
Methoden untersucht. Es wurden Feldversuche durchgefĂŒhrt, begleitet von
Substrat-, Boden-, Emissions- und Porengas-Messungen, sowie
Aufzeichnungen des Maschineneinsatzes. DarĂŒber hinaus wurden Interviews
mit Landwirten gefĂŒhrt, welche MC in Deutschland bereits anwenden, um
einen besseren Einblick in die praktische Anwendung und die BedĂŒrfnisse der
Landwirte zu erhalten.
Die Ergebnisse deuten darauf hin, dass MC-Substrate nach der
Kompostierung reicher an Stickstoff (N) und Kohlenstoff (C) als CC-Substrate
sein können. Der Maschinenbedarf fĂŒr MC betrug nur ein Zehntel von CC, was
mit geringeren fossilen Emissionen einhergeht. Ein Novum war, dass zum
ersten Mal Lachgas-Emissionen (N2O) von MC gemessen wurden. Insgesamt
waren die THG-Emissionen bei MC wÀhrend der Kompostierung pro Tonne
Kompost um 30 â 40 % niedriger als bei CC. Dieser Vorteil wurde jedoch
durch 28 â 40 % höhere Emissionen (pro Hektar) auf dem Feld wieder
ausgeglichen. THG-Bilanzen sind in hohem MaĂe von der Messmethodik,
dem betrachteten Zeitraum und der Bezugseinheit abhÀngig, in der die
Emissionen ausgedrĂŒckt werden. Da CC wĂ€hrend der Kompostierung höhere
N-Verluste aufwies, emittierte MC insgesamt 5 â 29 % weniger THG pro auf
dem Feld ausgebrachtem kg N. Es war daher nicht eindeutig, ob MC oder CC
in Bezug auf die THG-Emissionen besser abschnitt.
Wie auch durch die Interviews bestÀtigt wurde, liefert MC auf
kosteneffiziente Weise N- und C-reiche Substrate und erscheint damit
vielversprechend fĂŒr den Einsatz in der regenerativen Landwirtschaft. Da die
Ausbringung des Komposts jedoch die THG-Bilanz eines auf den ersten Blick
klimafreundlichen Prozesses deutlich erhöhen kann, sollten kĂŒnftige Studien
sich mit dieser Problematik sowie mit den Auswirkungen von MC-Substraten
auf die Bodengesundheit nÀher befassen
Liquidity Risk and Monetary Policy
This paper provides a framework to analyse emergency liquidity assistance of central banks on financial markets in response to aggregate and idiosyncratic liquidity shocks. The model combines the microeconomic view of liquidity as the ability to sell assets quickly and at low costs and the macroeconomic view of liquidity as a medium of exchange that influences the aggregate price level of goods. The central bank faces a trade-off between limiting the negative output effects of dramatic asset price declines and more inflation. Furthermore, the anticipation of central bank intervention causes a moral hazard effect with investors. This gives rise to the possibility of an optimal monetary policy under commitment
Non-uniform and non-constant transaction costs as determinants of dispersed agricultural trade flows
A DISCOURSE ANALYSIS APPROACH TO EXPLAIN THE PATH DEPENDENCY OF SEASONAL FARM LABOUR REGULATIONS IN GERMANY
This article introduces discourse analysis as a theoretical concept and an empirical methodology that may enable the endogenization of path creation and path breaking changes in conventional models of political path dependencies. Economic criteria such as rents created by a policy do not always provide a comprehensive explanation for path dependent political decisions. Discourse theory implies that specific interpretative schemata and narratives, such as storylines in the mass media, heavily influence the political discourse. Discourses themselves exercise a constitutive power that constrains decision-making processes and, thus, influence the ensuing policy creation path. Hence, discourses must be taken into account when political path creation is analysed. In this paper we trace over time individual storylines that represent important elements of the discourse underlying the restriction of seasonal farm workers from central and eastern European countries in Germany. We illustrate how dominant speakers and their storylines have been and currently are interacting to shape this policy.Agricultural Policy, Path Dependencies, Discourse Analysis, Seasonal Farm Labour, Institutional and Behavioral Economics,
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