نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
This study aims to investigate fluctuations in surface and root-zone soil moisture for rainfed wheat and to generate soil moisture stress maps under various wet and dry year scenarios in Qazvin Province. It is the first research in the country to utilize Level-4 soil moisture products from the Soil Moisture Active Passive (SMAP) satellite for this purpose. A total of 22,800 raster images from SMAP hourly data spanning a seven-year period (2015–2021) were analyzed. The extracted surface soil moisture values from these images were compared against field-measured soil moisture data at depths of 0–5 cm and 5–10 cm. To generate soil moisture stress layers for each 10-day period during the rainfed wheat growing season, 10-day average soil moisture maps derived from SMAP data were integrated with raster layers representing wilting point moisture content. This process produced layers for plant-available water and readily available water. By subtracting the readily available water from the net irrigation requirement table for rainfed wheat, soil moisture stress layers were calculated for 26 ten-day periods in each year of the study (2015–2021). The standardized soil moisture stress index identified the years 2017–2018 and 2019–2020 as the driest and wettest years, respectively. The spatial extent of soil moisture stress across the study years fluctuated between a minimum of 5.9% and a maximum of 43.3% of the province’s total area during wet and dry periods. The maximum area affected by moderate to extreme soil moisture stress was calculated to be 27.7% of the province during dry years, with the highest intensity observed in the central, southern, and western regions. One of the key limitations of this study is the relatively short duration of available SMAP satellite data and the lack of ground-based soil moisture monitoring stations at various depths, which could impact the accuracy of the results. These findings can be utilized to optimize water resource management, determine the appropriate timing for supplementary irrigation, and mitigate soil moisture stress to enhance the productivity of rainfed crops.
کلیدواژهها English
Zhu, H., Zhao, H. L., Jiang, Y. Z., & Zang, W. B. (2018). Studies and application of remote sensing retrieval method of soil moisture content in land parcel units in irrigation area. The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 42, 2583-2589