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İstanbul Teknik Üniversitesi (2021)

Evaluating performance of different remote sensing techniques and various interpolation approaches for soil salinity assessment

GORJI Taha

Titre : Evaluating performance of different remote sensing techniques and various interpolation approaches for soil salinity assessment

Toprak tuzluluğu değerlendirmesi için farklı uzaktan algılama teknikleri ve çeşitli interpolasyon yaklaşımlarının performansının değerlendirilmesi

Auteur : GORJI Taha

Université de soutenance : İstanbul Teknik Üniversitesi

Grade : Doctorat 2021

Résumé partiel
Soil salinization is one of the drastic environmental phenomena due to its adverse effects on land productivity, plant growth and sustainable development especially in arid and semi-arid regions of the world. As population is growing fast, the demand for supplying food is increasing ; despite, plenty of arable land is abandoned due to primary and secondary soil salinization. Among primary sources of soil salinization, natural factors such as existence of parent material in soil structure, closeness of salty groundwater table to surface, weathering of the parent rock and sea water intrusion intensify soil salinity occurrence. In terms of secondary sources of soil salinization, irrigating agricultural land with water rich in salt, land clearing and using fertilizer containing nitrogen and potassium salts exacerbate salt accumulation in soil can be addressed. In many nations flood irrigating agriculture and lack of relevant drainage systems has caused environmental disturbances such as waterlogging, salinization, and depletion and pollution of water supplies and as a result it increased concern about the sustainability of irrigated agriculture. Indeed, exerting traditional irrigation approaches leads to acceleration of salt accumulation and water logging in soil. Accordingly, it is essential to monitor soil salinity on local, regional and global scale to track spatial variation of salt-affected soils particularly in places, which are more prone to soil salinization. Spatio-temporal soil salinity mapping is remarkably significant to support management strategies for soil related applications. Knowledge of spatiotemporal variation and probability of reoccurrence of salt-affected lands is critical to our understanding of land degradation and for planning effective remediation strategies in face of future climatic uncertainties. However, traditional approaches used for tracking the temporal and spatial distribution of soil salinity/sodicity are extensively localized, making estimations on a global scale very tough. projecting more soil salinity detecting and mapping along with monitoring spatial and temporal variation of salt-affected lands is necessary for taking relevant and prompt decisions to enhance the management practices and provide solutions to overcome or diminish soil salinity issues. Every soil salinity assessment requires two fundamental steps. Initially, it is essential to detect the areas where salts are accumulated and concentrated in the soil profile. In the next step, seasonal monitoring of the temporal and spatial alteration of salt-affected lands is required. In order to estimate periodical changes of soil salinity in large scale regions, it is essential to utilize rapid, fast and economical approaches. In that sense, Remote Sensing (RS) technologies, machine-learning algorithms and Geographical Information Systems (GIS) provide cost-effective, non-destructive, qualitative and quantitative spatio-temporal information on soil salinity changes. This research aimed to evaluate the performance of various RS techniques and interpolation methods for soil salinity mapping in three different geographical locations. Moreover, as a novelty to the study, a new soil salinity index was derived from visible and NIR bands, and it was applied for soil salinity mapping in all the three selected locations suffering from salinity. Capability of this new index was firstly compared with two other commonly used salinity indices independently .

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Page publiée le 30 décembre 2022