Details zur Publikation |
| Kategorie | Textpublikation |
| Referenztyp | Qualifizierungsarbeiten |
| Volltext | Publikationsdokument |
| Titel (primär) | Methods, potentials, and challenges in the determination of soil water balance parameters for dry steppe soils: case studies from southwest Siberia and Kazakhstan |
| Autor | Haselow, L. |
| Quelle | PhD Dissertation |
| Erscheinungsjahr | 2021 |
| Department | BOSYS |
| Band/Volume | 3/2021 |
| Seite bis | 97 |
| Sprache | englisch |
| Topic | T5 Future Landscapes |
| Keywords | Soil water balance parameter; Dry steppe soil; Southwest Siberia; Kazakhstan; Soil management; Climate change |
| UFZ Bestand | Leipzig, Bibliothek, Berichtsammlung, 00537490, 21-0149 F/E |
| Abstract | The ongoing climate change characterised by increasing temperatures will pose a challenge for many nations. Especially agriculture as an often keystone of a system, both by the food security and also in the securing of economic livelihoods, is facing its effects since decreasing water resources lead to crop losses and contribute to the global food crisis. In particular semiarid regions, where water scarcity is already a reality, the issue will still increase in the future, and water in any form becomes essential. As a result, agriculture is forced to adapt to climate and sustainability by adjusting current land management practices to regional conditions. Within the context, this study focus on the soil water balance of semiarid steppe soils whose optimisation may contribute to increasing yields. Through field studies conducted in the steppes of southwest Siberia and Kazakhstan, attempts were made to determine the regional soil water balance to derive recommendations for sustainable soil management. The aim is to store the available water that is naturally fed into the soil and provide it for plant production. For this purpose, pedo-hydrological information is needed to quantify the soil water balance. To fulfill these objectives, monitoring networks were established to enable long-term in situ measurements at the study sites. These networks relied on the use of weighable gravitation lysimeters that turned out as a suitable method to investigate pedo-hydrological processes. Through the high-resolution weighing technique, it is possible to detect minor mass changes, which are caused by water input (precipitation) or water output (evapotranspiration, outflow). Using two lysimeters comparative analyses were conducted to quantify the demand for soil water as a function of the land management. The monolithically extracted soil columns were characterised by different vegetation cover and soil management. They stemmed from fallow sites covered by pristine steppe grass and arable land, which was continuously cultivated by the regional dominating crop. It was shown that the determination of individual soil water balance parameters was a scientific challenge. It emerged that weighable lysimeters provide high-resolution data at the determination of soil water balance parameters. A comparison of methods indicated that weighable lysimeters are an optimal instrument at precipitation measurements, contrary to the initial purpose. The record of actual evapotranspiration proved to be difficult under given conditions. During summer, edge effects accompanied by the vegetation on the lysimeter and in the surrounding area could distort the determination of the evapotranspiration, whereas snow and wind showed a considerable impact on its measurement. Although there are widely accepted and suitable models for the estimation of evapotranspiration, common approaches were not able to estimate reliable evapotranspiration rates due to the dryness and the properties of the steppe vegetation. Furthermore, the often neglected sublimation of snow as part of evapotranspiration is also an essential aspect. The cold and snowy winter periods have made it impossible to get full-year measurements so far. Since in particular, the high snow volume is a considerable water reservoir, it is also necessary to determine the amount of evapotranspiration during winter. Having established that snow and ice affect the lysimeter weighing, a technique was developed to prevent the impairments and enable reliable measurements during winter periods for the first time for this climate. Unfortunately, the technique proved to be unsuitable. Although the frost effects could be minimised, a significant impact on the natural soil water balance could be observed. Even though these studies did not produce long-term and continuous time series, an overview of the soil water balance could be nonetheless gained. According to the steppe climate, the evapotranspiration exceeded the precipitation. Thus, a negative water balance was identified at both study sites. It could be observed that the high snow amounts led to an increase of soil moisture in spring, but the soil was not able to store the water in the long-term under the current soil management. Finally, it can be stated that there is a potential to use the steppe landscape as arable land with which an increase in yields could be achieved. However, a transformation from grassland to arable land is only possible by the consideration of the climate conditions and soil characteristics. Thus, adapted soil management should allow the securing of the areas as farmland in future. |
| dauerhafte UFZ-Verlinkung | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=24902 |
| Haselow, L. (2021): Methods, potentials, and challenges in the determination of soil water balance parameters for dry steppe soils: case studies from southwest Siberia and Kazakhstan Dissertation, Martin-Luther-Universität Halle-Wittenberg, Naturwissenschaftliche Fakultät III - Agrar- und Ernährungswissenschaften, Geowissenschaften und Informatik PhD Dissertation 3/2021 Helmholtz-Zentrum für Umweltforschung - UFZ, Leipzig, 97 pp. |
|