Grassland soil moiture utilising Sentinel 2 imagery and agricultural applications
Basu, Rumia
Basu, Rumia
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Publication Date
2024-06-12
Type
doctoral thesis
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Abstract
Soil moisture is an essential climate variable that affects the climate system through its impact on evapotranspiration, which in turn affects, land, water and energy balances as these are coupled through evapotranspiration. At the surface, soil moisture controls the partitioning of incoming solar energy into latent and sensible heat fluxes, which affects the water and energy cycles. Additionally, soil moisture is also linked to biogeochemical cycles such as the carbon and nitrogen cycles through plant transpiration and photosynthesis. It is especially significant for agriculture and farm management. Information on soil moisture at high spatial and temporal resolution is crucial for an overall management of land and water resources. In this thesis, Sentinel-2 data was used to estimate normalised surface soil moisture (nSSM) at a high spatial resolution of 10 m for two Irish farms using a modified Optical Trapezoid Model (OPTRAM). These farms are dominated by soils that are poorly draining, remaining wet for large parts of the year and the major crop is grass. The modelled nSSM was validated against in-situ volumetric soil moisture data from sensors. Two applications were developed for farm management whereby, a) a proof of concept was developed for an improved decision support system using the concept of soil moisture deficit and nSSM safeguarding both soil and crop health and b) Nitrogen fertiliser application was analysed using high resolution soil moisture threshold maps and weather data suggesting that soil moisture should be considered an important variable for framing rules and policies around nutrient management. The methodology developed in this thesis can be applied globally for precision agriculture strategies and serves as an important starting point for application on other land cover categories.
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University of Galway
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Attribution-NonCommercial-NoDerivatives 4.0 International