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| Distribution characteristics of the content of available Mn in Yingwugou watershed,Shaanxi Province |
| Tang Hui1, Li Zhanbin1,2, Song Xiaoqiang3, Tong Xinqi3, Wang Tian1, Yang yuanyuan1, Yao Jingwei1 |
| 1. Key Laboratory of Northwest Water Resources and Environment Ecology of Ministry of Education, Xi忆an University of Technology,710048, Xi忆an, China; 2. Key Laboratory of Soil Erosion and Dry鄄land Farming on the Loess Plateau, Institute of Soil and WaterConservation, Chinese Academy of Sciences and Ministry of Water Resources, 712100, Yangling, Shaanxi, China;3. Shaanxi Bureau ofSoil and Water Conservation, 710004, Xi忆an, China |
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Abstract Manganese (Mn) is one of important elements in soil and its transportation process is an reflection of soil and water loss. In order to understand more deeply about the process of soil and water loss, the content of available Mn in Yingwugou watershed located in Shaanxi Province was investigated.This study employed DTPA-atomic absorption fire spectrophotometry to measure the content of available Mn in different topography and land use types of the watershed. Then fractal dimension of the content of available Mn in a few directions was calculated and finally the distribution of the content of available Mn was clarified. The results showed that the content of soil available Mn at the Yingwugou watershed ranged from 7.43-57.67 mg/kg, 39-52 mg/kg on average. 1) Middle elevation had the highest content(41-61 mg/kg) and the value of the coefficient variation (CV) from high to low was ordered distinctively as low, middle, and high, suggesting that the available Mn in soil is moved from high to low elevations by runoff in the watershed after leaching, gathers at middle or low elevation are as, and finally the available Mn at low elevation are as is carried away by flowing river. The highest content of available Mn(43.32mg/kg) could be found on slopes with degree ranging from 8-14° and the value of CV from high to low was ranked as very gentle slope, micro-slope, very steep slope, steep slope and gentle slope; the available Mn was easier to aggregate at very gentle slope, micro-slope, and steep slope. The upslope position had the highest content (42-16mg/kg) and the value of CV from high to low was ordered as downslope, middle slope, upslope, indicating that runoff is the main force to move the available Mn. 2) The woodland had the highest content of 42.07mg/kg and the value of CV from high to low was ranked as farmland, woodland, grassland. The woodland and the grassland had more complicated soil structures because of more biocenoses and less disturbance. The grass roots have a high ability to utilize the available Mn and the soil texture of farmland is highly uniform. All of these reasons lead to the current distribution characteristics of content of available Mn in the different landuse types. 3) The fractal characteristics wereobvious at the 45° direction, and extent of variation was the highest. The high content of Mn was distributed in the west, south, and north of the watershed. The total spatial pattern of the watershed was that the content of available Mn increased from east to west and then decreased, but still higher than the east. These results would provide reference to describe the process of soil and water loss.
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Received: 15 May 2015
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