The effect of phosphorus amendments on nitrogen fixation and growth of trees on salt-affected croplands in the lower reaches of Amu Darya, Uzbekis [Elektronische Ressource] / Dilfuza Djumaeva. Landwirtschaftliche Fakultät

Zentrum für Entwicklungsforschung _______________________________________________________________ The effect of phosphorus amendments on nitrogen fixation and growth of trees on salt-affected croplands in the lower reaches of Amu Darya, Uzbekistan Inaugural-Dissertation zur Erlangung des Grades Doktor der Agrarwissenschaften (Dr. agr.) der Hohen Landwirtschaftlichen Fakultät der Rheinischen Friedrich-Wilhelms-Universität zu Bonn vorgelegt am 29. April 2011 von DILFUZA DJUMAEVA aus URGENCH, UZBEKISTAN To my husband John Lamers, our daughter Nicole Anna Cecilia, and our son Daniel Hendricus Ronald ABSTRACT Afforestation, particularly with the use of N -fixing trees (NFTs), is an option for ecological 2restoration of salinized, irrigated croplands in the lower reaches of the Amu Darya River. But current knowledge of enhanced juvenile tree growth and their N fixation rates is sparse for the marginal 2irrigated croplands of the Khorezm Region of Uzbekistan. A superior understanding would increase productivity of such lands, improve soil fertility status and increase profits for farmers. A two-factorial field experiment was therefore conducted during 2006-2008 to compare the effect of three phosphorus (P) amendments on N fixation, biomass and growth rates of actinorhizal Elaeagnus 2 15angustifolia L. and leguminous Robinia pseudoacacia L.