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Accueil du site → Doctorat → Royaume-Uni → 1994 → Analysis of the effects of water and nitrogen supply on the yield and growth of durum wheat under semi-arid conditions in Tunisia

University of Reading (1994)

Analysis of the effects of water and nitrogen supply on the yield and growth of durum wheat under semi-arid conditions in Tunisia

Latiri-Souki, Kawthar

Titre : Analysis of the effects of water and nitrogen supply on the yield and growth of durum wheat under semi-arid conditions in Tunisia

Auteur : Latiri-Souki, Kawthar

Université de soutenance : University of Reading

Grade : Doctor of Philosophy (Ph.D.) : 1994

Résumé
The objective of this work was to examine how water and nitrogen supply interact with growth and development of a durum wheat variety (Triticum durum Desf.,) cultivar Karim) in a Mediterranean environment. Experiments were carried out in 3 different years under various climatic and soil conditions ; plant production was related to soil water content, nitrogen uptake and to temperature and solar radiation.The main determinant of grain yield was grain number and to a smaller extent straw dry matter, showing the close relationship between reproductive and vegetative growth. Main effects on yield were related to nitrogen : an adequate supply of N increased photosynthetically active radiation use efficiency, and allowed more grains and more organs to be formed. Grain number was related to nitrogen absorption, mainly in the early stages of growth. Also high levels of nitrogen improved water use efficiency. The need for irrigation to prevent water deficits and to allow adequate N supply were also observed. The relative importance of changes in radiation, water and nitrogen use efficiencies were assessed.Contrast in the N and water effects between sandy and clay soils was large. The clay soil had a buffering effect both for nitrogen and water supply and these had large consequences on wheat growth and development.It is possible to improve durum wheat dry matter production and yield under semi-arid conditions in average climatic years by applying nitrogen early in the growing season. This allows establishment of a large grain number and improves water use efficiency for most of the growing season. Each when climatic conditions are very dry during the grain filling period, nitrogen improves yield. When crops are irrigated, water use efficiency should be improved by applying nitrogen and also by better control of the amount of water used through the use of several irrigations with smaller amounts of water

Mots clés : Grain yield ; Drought Agronomy Plant diseases Horticulture Agricultural engineering Ecology Agronomy

Présentation : Open Grey

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