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Universität Hohenheim (2013)

Environmental effects on physical properties of Geohumus and effects of its application on drought responses in maize

Duong, Van Nha

Titre : Environmental effects on physical properties of Geohumus and effects of its application on drought responses in maize

Umwelteinflüsse auf die physikalischen Eigenschaften von Geohumus und Auswirkungen von dessen Anwendungen auf Trockenstressantworten von Mais

Auteur : Duong, Van Nha

Université de soutenance : Universität Hohenheim

Grade : Doctor of Philosophy (PhD 2013

Résumé
Geohumus belongs to a new generation of soil melioration/hydrophilic polymers ; however, evidence is limited with regard to both, the ability of Geohumus to store water in variable abiotic environments and the effects of Geohumus or other hydrophilic polymers on plant genotypes in response to drought condition. Therefore, this study aims at providing necessary and complementary information for improving Geohumus usage under field condition, and to improve our ecophysiological understanding of the interactions between Geohumus, plant genotype and the growing environment. Three series of experiments were conducted to investigate (1) how abiotic factors affect the water holding capacity and restorability of Geohumus, (2) how the application of Geohumus affects plant morphological and physiological traits in response to different irrigation scenarios such as full irrigation, water deficit, and re-watering and (3) how the application of Geohumus in different soil types affects drought induced plant root-shoot communication. Water holding capacity (WHC) and restorability of Geohumus in mL water g-1 was determined by immersing teabags with fresh and used Geohumus in prepared media under laboratory conditions. A greenhouse experiment was carried out in order to analyze morphological and physiological responses of the two maize cultivars Mikado and Companero to progressive drought or full irrigation (field capacity) as affected by Geohumus. To obtain in depth information on Geohumus-plant interactions, a split root system experiment was conducted as a tool to investigate hydraulic and bio-chemical root-shoot communication of Mikado and Companero under full irrigation, partial rootzone drying, and deficit irrigation.

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Page publiée le 24 juin 2013, mise à jour le 11 mai 2019