Roger Pierre-Armand auteur aut IRD Kurihara Y. auteur aut IRD text bookSection eng text/pdf reformatted digital access The first part of the review deals with the components of the ecosystem (floodwater, photosynthetic aquatic biomass, and fauna), their properties and activies. Variations of the major physical and chemical properties of the floodwater (temperature, pH, 02 concentration, N content...) during the crop cycle are summarized. The section on photosynthetic aquatic biomass considers composition, nutrient contribution, and effects on N dynamics, namely : biological N2 fixation, N immobilization, N recycling, N accumulation at the soil surface, N supply to rice crop, and N losses by NH3 volatilization in relation to pH increase due to photosynthetic activity in the floodwater. The section on fauna emphasizes grazing and nutrient recycling by ostracods and snails, and the role of tubificid worms on floodwater ecology. The second part deals with the agronomic management of the floodwater ecosystem. It reviews cultural practices that take advantage of the agronomic potential of the floodwater ecosystem (decreasing losses due to NH3 volatization, promoting photodependent BNF, recycling of nutrients), and the effects of crop intensification on floodwater ecology and possible related effects on soil fertility. (Résumé d'auteur) specialized RIZIERE ECOLOGIE ALGUE FIXATION BIOLOGIQUE DE L'AZOTE CYCLE DE L'AZOTE MICROBIOLOGIE DU SOL FAUNE DU SOL FERTILISATION DU SOL PESTICIDE EAU D'IMMERSION BIOMASSE PHOTOSYNTHETIQUE AQUATIQUE 082ECOSYS 074 2 211-233 Bangkok IBSRAM 1991 2 https://www.documentation.ird.fr/hor/fdi:38316 [F B38316] https://www.documentation.ird.fr/hor/fdi:38316 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_6/b_fdi_33-34/38316.pdf IRD - Base Horizon / Pleins textes 1993-11-03 2006-05-31 fdi:38316 fre