Zohreh Azizzadeh; Majid Mohammad Esmaili; Ali Sattarian; Seyed Ali Hosseini; Bahareh Bahmanesh
Abstract
Soil moisture in the upper soil layers plays a vital role in water and soil resource management, directly influencing infiltration, runoff, agricultural productivity, and flood regulation. Its spatial variability is controlled by multiple factors, including climate conditions, topography, vegetation, ...
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Soil moisture in the upper soil layers plays a vital role in water and soil resource management, directly influencing infiltration, runoff, agricultural productivity, and flood regulation. Its spatial variability is controlled by multiple factors, including climate conditions, topography, vegetation, and soil characteristics. Neglecting these variations often leads to significant errors in hydrological and agricultural modeling. This study investigates the relationship between geomorphometric indices as a proxy of topography and topsoil moisture across five sub-basins of the Simineh and Zarrineh rivers in northwest Iran, using both field observations and satellite data. Soil moisture measurements from 287 points (2015–2017) were compared with Soil Moisture Active Passive (SMAP) satellite estimates to produce high-resolution spatial maps. Several geomorphometric indices were derived, including the Topographic Wetness Index (TWI), Topographic Position Index (TPI), Wind Exposure Index (WEI), flow direction (Flow_D), flow accumulation, and Analytical Hillshading (AH). The Random Forest (RF) model was applied to determine the importance of geomorphometric attributes. Validation results revealed a strong correspondence between SMAP data and field observations, with July showing the highest correlation (r = 0.77, soil moisture = 0.18 cm³·cm⁻³), and May the lowest (r = 0.50). The RF model achieved robust performance (R² > 0.7, RMSE = 0.04%). Among the indices, WEI and TWI exhibited the greatest importance (>16%), followed by AH (13%), while Flow_D had the lowest influence (8.9%). These findings confirm the significant role of topographic and hydrological features in controlling soil moisture distribution. The integration of SMAP data with machine learning and geomorphometric indices provides a reliable framework for soil moisture monitoring, offering valuable insights for agricultural management, hydrological modeling, and environmental planning in similar watersheds.
Reza Siahmansour; Nadia Kamali
Abstract
Fire is the fastest cause of extensive changes in vegetation. The purpose of this research is to examine some of these changes. SO, after determining key area of four 200m transects and a distance of 100 m from each other, 10 plots 1m2 fixed on each of them, formed sample units in each field. This site ...
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Fire is the fastest cause of extensive changes in vegetation. The purpose of this research is to examine some of these changes. SO, after determining key area of four 200m transects and a distance of 100 m from each other, 10 plots 1m2 fixed on each of them, formed sample units in each field. This site burned in 2011 and 2013, in 2018 and 2019, random-systematic statistical collection was carried out in it. Results showed, in fire treatment the dominance of production and cover is with invader plants. Production of this class 52.05 and 209.1gr/m2 has been preserved in burnt area compared to control. Also, annual grasses have significant average difference in terms of production and canopy compared to other species. However, annual forbs had 1.5 times more production in fire than control. Although the amount of production in burnt area is more than control but, it doesnt mean an increase in the amount of allowable forage. The plant type in the burned fundamental change compared to the control by replacing annuals instead of permanent species. As result production, density and canopy cover of different palatability classes and growing forms also found fundamental changes. Fire is cause of changing in rangeland condition from excellent to average, the trend is positive in both treatments. The management of burnt fields is very specialized, and according to the existing conditions, it is strongly not recommended to create a fire either intentionally or accidentally in this area is vegetation zone form of Iran.
Kobra Karimi; esmaeel karami dehkordi; khalil aghajanlu
Abstract
Assessment of rangeland management projects enables policy makers and planners to understand their impacts from different environmental, social, human, and economic aspects. The aim of this research is to assess rural households’ perspective regarding the impact of rangeland management projects ...
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Assessment of rangeland management projects enables policy makers and planners to understand their impacts from different environmental, social, human, and economic aspects. The aim of this research is to assess rural households’ perspective regarding the impact of rangeland management projects on their social capital. Using a survey methodology, respondents were asked to assess the indicators before and after the implementation of the projects. A randomized multi-stage sampling technique was utilized to select a sample of 204 out of 1280 rural pastoralists in Mahneshan County of Zanjan Province. Data was collected utilizing a structured interview technique and questionnaire. From pastoralists’ points of view, these projects have had considerable impacts on increasing relationships, collaboration, and social norms for collective actions. They have also been slightly effective in terms of reducing emigration, increasing job opportunities and participation in decision-making. Nevertheless, these projects had no effect in establishing or strengthening non-governmental organizations. Therefore, planning for rangeland management projects necessitates more attention to improving their effectiveness and their social institutionalization potential.
