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Swiss Federal Institute of Technology (Zurich) ETHZ 2021

Plant Water Relations in Response to Drought and Different Cropping Systems

Sun, Qing

Titre : Plant Water Relations in Response to Drought and Different Cropping Systems

Auteur : Sun, Qing

Etablissement de soutenance : Swiss Federal Institute of Technology (Zurich) ETHZ

Grade : Doctoral Thesis 2021

Résumé partiel
Agriculture is one of the main contributors to climate change and is also severely threatened by the consequences of the changing climate. To reduce the environmental pressure from agriculture, sustainable practices are urgently in need of evaluation and implementation. In croplands, organic farming and conservation tillage can reduce energy consumption, greenhouse gas emissions, and pollutant production as well as increase carbon sequestration, hence are considered more environmental-friendly and sustainable than conventional farming and intensive tillage. Moreover, organic farming and conservation tillage are shown to improve soil health such as physical structure, chemical conditions, and microbial functionalities. Therefore, these practices are also recommended as beneficial to mitigate climate change effects, such as crop drought stress. However, if organic farming and conservation tillage are truly climate-smart adaptations for cropping systems is still to be tested in different climate conditions. Extreme weathers, increasing in frequency and severity due to climate change, are posing extra challenges on food security in addition to the growing population. Drought as a top threat causes intense damage in agroecosystems, especially in rainfed agriculture. Crop water relations are highly responsive to drought stress, and directly linked to growth and productivity. Therefore, understanding crop water relations in response to drought can provide insights on assessing cropping systems for future climate. As introduced in Chapter 1, this thesis aims to bring insights on the effects of cropping systems and drought on plant water relations along the soil-plant-atmosphere continuum. This includes root water uptake patterns, stem xylem vulnerability and anatomy, leaf water status and physiological processes, phenology, growth, and yield. Combining different management practices, four cropping systems are studied : conventional intensive tillage, conventional no-tillage, organic intensive tillage, and organic reduced tillage. Simulated drought periods with portable shelters were carried out in Swiss rainfed cropland under temperate climate. During the 2018 growing season pea-barley mixture, an important fodder crop, was studied. Winter wheat, a globally important food source, was studied during 2019.

Mots clés : Organic farming ; Conservation tillage ; Drought ; Plant traits ; Stable water isotopes ; Pea ; Barley ; barley ; Winter wheat ; Water uptake depth

Présentation

Page publiée le 8 mars 2022