Evaluating the Contribution of the Physical and Biochemical Effects of Root on Detachment for the Coarse-Textured Soil f
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OIL BIOLOGY
Evaluating the Contribution of the Physical and Biochemical Effects of Root on Detachment for the Coarse-Textured Soil from the Three Gorges Reservoir, China Ping Guoa, Zhenyao Xiaa, b, Feng Gaoa, Md Sahidul Islamb, Hai Xiaoa, b, *, Mingyi Lib, Yueshu Yangb, and Wennian Xua, b a
Key Laboratory of Geological Hazards on Three Gorges Reservoir Area (China Three Gorges University), Ministry of Education, Yichang 443002, People’s Republic of China b Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, People’s Republic of China *e-mail: [email protected] Received February 6, 2020; revised February 15, 2020; accepted April 4, 2020
Abstract—Plant roots have great effect on the process of soil detachment, but the contribution of the physical and biochemical effects of root on soil detachment have not been sufficiently evaluated. For the purpose to distinguish the relative contribution of the root physical effect and biochemical effect to soil erosion resistance, three kinds of treatment, soil samples without roots, dead roots and live roots, were chosen to simulate the condition of no root effect, the root’s physical effect and the root’s whole effect on the soil detachment, respectively. The Cynodon dactylon and purple soil in Three Gorges Reservoir Area in China were selected to conduct the scouring experiment under condition of five slope gradients (17.63%, 26.79%, 36.40%, 46.63% and 57.73%) and three runoff rates (1, 2 and 3 L min-1). The soil detachment process under different treatment conditions was analyzed. The effects of slope gradient and the runoff rate on soil detachment rate were also estimated for different treatment conditions and the contributions of the physical and biochemical effects of root on soil detachment were also evaluated. The results indicated that detachment rate showed a dramatically decrease initially, followed by gradual decrease until to a stable stage for all treatments. The soil detachment rate can be effectively described with the slope gradient and the runoff rate by using the power function, which was more influenced by slope gradient than by runoff rate for all the treatment conditions in this study. Plant roots could effectively diminish the soil detachment rate, and the contributions of physical and biochemical effects of root on detachment were 59.64%–82.09% and 17.91%–40.36%, with mean values of 68.92% and 31.08%, respectively. The root’s physical effect is the main reason strengthens soil erosion resistance. Keywords: biochemical effect, coarse-textured soil, Cynodon dactylon, physical effect, soil detachment DOI: 10.1134/S1064229320090069
INTRODUCTION Soil erosion is a threat to soil sustainability [24, 30] and vegetation can effectively reduce and control the accelerated soil erosion rates in agricultural lands [35, 47, 50]. The presence of plants increases soil resistance against soil erosion by its above-ground leaves and stems and underground roots [9]. The le
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