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Dissertation
Effects of the application of biochar and organic fertilizers as well as temperature on soil carbon and aggregate dynamics
(2017-11-27)
Soil aggregate formation is an important process for long-term carbon storage in soils. While it has been shown that plant residues exert a positive influence on aggregate formation, the effects of organic fertilizers such as cattle slurry or manure as well as the effects of biochar application to soil are less clear. Furthermore, little is known about the role of increased soil temperatures in aggregate dynamics.
The main objectives of this thesis were to analyse the effects of (i) cattle slurry and manure, (ii) ...
Dissertation
Role of grassland in phosphorus-flows in mixed organic farms
(2017-09-28)
The aim of the study is to analyze the role of grassland in phosphorus (P) flows in mixed organic farms. The research farm of the Thünen Institute of Organic Farming, Trenthorst, located in northern Germany was used for the analyses. The farm converted to organic farming in 2001 and had no P-fertilizer import. Grassland-related P flows (by grazing and harvesting) were estimated with a specific method using a calibrated rising plate meter (DM = 100.41 x h + 1 (r²=0.7549; n=396)). Inner farm nutrient cycles were ...
Dissertation
Conservation agriculture in organic farming: Impacts on weeds and plant-parasitic nematodes during the transition
(2017-10-12)
Der Bodenschutz ist eine der wichtigsten Anforderungen an die Landwirtschaft im 21. Jahrhundert. Daher sind nicht-wendende Bodenbearbeitungssysteme, basierend auf dem Anbau von Untersaaten und Zwischenfrüchten, verstärkt in den Fokus der europäischen Agrarwirtschaft geraten. Allerdings können diese neuartigen Systeme das Spektrum und die Abundanz gewisser Krankheiten, Schädlinge und Unkräuter grundlegend verändern. Ein Beispiel ist die Zunahme von Unkräutern und ihren Samenbanken während der Übergangsphase von ...
Dissertation
Amount, composition and turnover of organic matter in topsoils and subsoils under mature beech forest
(2017-12-15)
Two-third of the terrestrial carbon (C) is stored in soils, and up to 63 % of the soil organic C (SOC) is stored in subsoils (i.e. below 30 cm soil depth). Forest soils account for nearly 70 % of the global SOC, demonstrating their great importance regarding the global carbon cycle. The higher average age of the OC stored in subsoil indicates that the subsoil OC is more stable against microbial decomposition. The capability of soil to stabilize OC is affected by substrate characteristics (e.g. size, distribution, ...