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Gewählte Master / Diploma Thesis:

Anne Kathrin Leonhard (2017): Nährstoffbilanzen von Phosphor und Kalium auf biologisch wirtschaftenden Marktfruchtbetrieben in Österreich - Eine Erstellung von Hoftorbilanzen zur Identifizierung möglicher Bodenverarmungsrisiken im biologischen Landbau.
Master / Diploma Thesis - Institut für Ökologischer Landbau (IFÖL), BOKU-Universität für Bodenkultur, pp 145. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Agricultural soils in general and organically cultivated soils in particular are highly vulnerable to the risk of nutrient depletion. Due to the deficiency of suitable fertilizers in organic agriculture this especially applies to the nutrients of phosphorous and potassium. For this reason this the-sis conducted 15 so called “farm gate balances” on 15 different Austrian organic stockless farms selected from the five most important national production areas. The data has been gathered by the use of qualitative and quantitative interviews with the farmers. The compari-son of nutrient inputs (i.e. additionally purchased fertilizers as well as seeding material) and nutrient outputs (i.e. marketed harvest products) for each farm exclusively resulted in nega-tive balances associated with very high nutrient efficiencies. Most of the balances for both phosphorous and potassium have been classified as “slightly deficient”. Based on these defi-cient balances long-term risks of soil nutrient depletion could not be preempted. Additionally, scattered chemical analyses also indicated decreasing values for both phosphorous and po-tassium. The results of this thesis furthermore suggested that good nutrient efficiencies do not implicate well-balanced nutrient balances, and vice versa. Regarding the balances for phospho-rous the farms are rather dependent on (commercial) organic fertilizers, while potassium bal-ances are rather influenced by organic fertilizers of animal origin. Due to the relatively small sample size it has not been possible to draw any conclusions on the influence of regional vari-ation. The results are however emphasizing the necessity of improving the nutrient manage-ment on organic farms in order to guarantee a sustainable cultivation in line with the principles of organic agriculture. The development of fertilizers enabling the recirculation of phospho-rous and potassium into the cultivated soils is in this regard more than essential.  

Beurteilende(r): Friedel Jürgen Kurt

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