Seyed Masoud Soleimanpour; Majid Soufi; Mohammad Javad Rousta; Samad Shadfar; Ladan Jowkar; Hojatollah Keshavarzi
Abstract
Gully erosion is one of the main types of water erosion and is known as one of the destroying forms of land degradation and soil loss in the world. Therefore, knowing the most effective factors on extending this type of erosion is utmost important. Beside, management and control of gully erosion require ...
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Gully erosion is one of the main types of water erosion and is known as one of the destroying forms of land degradation and soil loss in the world. Therefore, knowing the most effective factors on extending this type of erosion is utmost important. Beside, management and control of gully erosion require knowing the most effective factors on gullies extension. So, the present study was performed to determine the most effective factors on gullies in Khorrambid Watershed, North of Fars Province through measuring the permanent gullies during 13 years (2004-2016). Results showed that the average of gully length extension was 21.67 m throughout this period. This data indicated that the length of gully extension was 1.67 m per year. Further, it is determined that the length expansion of permanent gullies in this region was a function of bare soil and saturated electrical conductivity, using SPSS and backward multivariable regression. In conclusion, it is suggested different management solutions to increase the soil resistance against the erosion be prioritized in management and implementation plans such as increasing adoptable cover vegetation for the natural condition of the region and exclude the area to restore vegetation cover and pay more attention to control erosion in gully head cuts.
Rohallah Taghizadeh Mehrjardi; Fereydoon Sarmadian; Mehdi Tazeh; Mahmood Omid; Norair Toomanian; Mohammad Javad Rousta; Mohammad Hassan Rahimian
Abstract
Recently, researchers are increasingly employed Digital Soil Mapping (DSM) techniques to overcome traditional soil mapping difficulties. Apparently, due to the large heterogeneity of soil environments, sampling may be the most important step in digital soil mapping studies. Therefore, in this research, ...
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Recently, researchers are increasingly employed Digital Soil Mapping (DSM) techniques to overcome traditional soil mapping difficulties. Apparently, due to the large heterogeneity of soil environments, sampling may be the most important step in digital soil mapping studies. Therefore, in this research, we employed three different sampling strategies including Latin hypercube, Fuzzy-K-Means and random sampling to achieve the best spatial distribution of soil samples in an area around 720 km2 located in Ardakan region, Yazd province, Iran. Auxiliary data that used in this study, were including terrain attributes, Landsat 7 ETM+ images and a geomorphologic surfaces map. Based on statistical criteria (i.e. mean and standard deviation), results showed that Latin hypercube is the best sampling method. For instance, in the selected points, the mean of wetness index is 18.19 which is the same as the mean of all area. Similarly, the mean of Multi-resolution Valley Bottom Flatness (MrRVF) in the points selected by Latin hypercube strategy is very similar to all area. Moreover, histogram of auxiliary data in selected points (samples) was more similar to histogram of auxiliary data in all area. Also, the results indicated that a good geographical coverage (Fuzzy-K-Means) does not adequately represent the distribution of the variables. Therefore, Latin hypercube is the best strategy to determine sample locations in our study area and hence, it is recommended that researchers apply Latin hypercube method in future digital soil mapping studies.
