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Gewählte Master / Diploma Thesis:

Astrid Allesch (2011): Stickstoffumsetzung im Bodenwasser und in der bodennahen Luftschicht beim Zwischenfruchtanbau zur Biogasgewinnung.
Master / Diploma Thesis - Institut für Bodenforschung (IBF), BOKU-Universität für Bodenkultur, pp 112. UB BOKU obvsg FullText

Data Source: ZID Abstracts
The influences of intercrop cultivation on climate and environment were investigated on three fields in Austria. Experiments with different forms of crop residue management and mixtures of intercrops were established. On each field the tests were repeated three times. The thesis shows the results of the first year of research. During the period of intercrop growth and after the harvest, soil was sampled in the depths of 0-30, 30-60 and 60-90cm to determine the Nmin-content. The soil mineral nitrogen contents on areas with and without (control field) intercrops, as well as their different management methods (mulching, harvesting) were compared. The results on fields with intercrops show lower Nmin-contents than the control fields. On average the amount of Nmin can be reduced by 29kg/ha by cultivating intercrops. Application of plant residue mulch to the soil leads to mineralization processes and increases the Nmin-content whereas harvesting the intercrops can decrease the soil mineral content, reduce the nitrate leaching risk and protect the groundwater. The mulching fields result in Nmin-contents, that are circa 32 kg/ha higher than the Nmin-contents at harvesting fields.Through a literature study, important parameters to estimate the nitrous oxide emissions were identified. Correlations between nitrous oxide emissions and the clay-content, the water-content and the chemical quality of the intercrops were found. Two models were developed on the basis of 129 collected datasets to estimate the N2O-emissions on the three experimental fields and to assess the effects of harvesting or incorporating the intercrop residues. One model describes the N2O-background emissions from agriculturally used areas and the second model considers the different management methods.The N2O-background emissions depend on the factors soil water-, sand- and clay content. On average 1,8 kg N2O-N/ha/year emit from the three experimental fields. Additionally the factors N-input according to crop residues and fertilization were considerd when estimating the effects of different management methods. The incorporation of intercrop residues results in 3,5 kg N2O-N/ha/year. The estimated N2O-losses show that incorporating residues increases the nitrous oxide emission.

Beurteilende(r): Blum Winfried E.H.

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