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| DOI：10.13522/j.cnki.ggps.20190101 |
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| Multifractal Analysis of Shrinkage and Fracture in Farmland Under the Influence of Crop Root System |
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ZHANG Meng, SHEN Tongqing, MA Rong, ZHU Lei
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1.School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, China; 2.Efficient Use of Water Resources in Arid Modern Agriculture Ministry of Educational Engineering Research Center, Yinchuan 750021, China
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| Abstract: |
| 【Objective】Analyze the effect of crop root system on soil fissure network in farmland.【Method】Soil fissure digital image was obtained through outdoor soil fissure experiment.Generalized fractal dimension Dq, multifractal singular exponent αand fractal spectrum function f(α) were calculated and analyzed by using digital image processing technology and programming.【Result】The area density of crop-free fissure image was larger than that of the image containing crop, which indicated that the width of soil fissure without crop was larger. The length density and euler number of the images of soil fissures without crop roots were larger than those of soil fissures with crop roots, indicating that the soil fissures without crop roots were longer and more closed networks were formed. The overall variation range of the generalized fractal dimension was that the spectral width of the cracks without crop roots was larger than that of the cracks with crop roots, and the spectral width of the cracks with crop roots was smaller than that of the cracks without crop roots. Under the influence of crop root system, the crack D0 value was greater than that of crop-free soil. Under the influence of root system, soil crack D1 was larger. The difference between D0 and D2 was the smallest in the cranny produced by crop-free soil, indicating that the distribution was better non-uniform.【Conclusion】The anchoring action of crop root system did not make soil fissure lose its non-uniform distribution characteristic, and the non-uniform distribution of soil fissures network was obvious. Under the influence of root system, the heterogeneity of soil fissure distribution is smaller; When the measurement scale is 25/8~50 cm, the fractal structure of crop-free fissures is more complex. Multi-fractal parameters can be used as an important indicator to compare the non-uniformity of cracks and crop-free fractures under the influence of crops. |
| Key words: soil fracture network; crop root system; multifractal; probability measure |
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