1- Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan, Iran , saadati.nas@gmail.com
2- Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
2- Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan, Iran
Abstract: (13 Views)
Background and Objective: Plants’ root exudates have diverse effects on structural stability and water repellency of their surrounding soil. Few studies have been available about the effect of rangeland plants on soil physical quality. Therefore, this study was conducted to investigate the root zone’s structural stability and water repellency of selected rangeland plants in a greenhouse experiment.
Methods: Tillers of tall fescue (F. arundinacea genotypes 75B and 75C), B. inermis and B. tomentellus were planted in the columns of a sandy clay loam soil with three replicates in a completely randomized design. Six months later, undisturbed soil samples were collected from the root zone and bulk soil in the planted and non-planted (control) columns, respectively. Soil water repellency was determined by the intrinsic sorptivity method. Soil structural stability was measured by high-energy moisture characteristic (HEMC) and wet single-sieve methods.
Results: Presence of rangeland plants’ roots increased ethanol sorptivity (SE) and decreased water sorptivity (SW) in the rhizosphere. Water repellency index (R) in the rhizosphere was, on average, about two times greater than that in the bulk soil. The highest R was recorded in the root zone of B. inermis, followed by tall fescue genotype 75C, B. tomentellus, and tall fescue genotype 75B, and the lowest value was measured in the non-planted soil. The HEMC indices were greater in the rhizosphere when compared to the control soil. The presence of plant roots significantly increased the percent of water-stable aggregates (WSA) in comparison with the control soil. The root zone of B. inermis had the highest WSA, while no significant difference with tall fescue was observed. The positive and significant correlation between HEMC and WSA indices with R indicates a strong linear relationship between sub-critical water repellency and soil structural stability.
Conclusion: The findings of this study indicated the beneficial influence of rangeland plants’ roots on soil physical quality and structural stability. Slight (sub-critical) water repellency in the rhizospheric soil triggers aggregate stability against environmental stresses. Overall, B. inermis and tall fescue genotype 75C had greater effects on improving soil physical quality and structural stability among the studied species.
Methods: Tillers of tall fescue (F. arundinacea genotypes 75B and 75C), B. inermis and B. tomentellus were planted in the columns of a sandy clay loam soil with three replicates in a completely randomized design. Six months later, undisturbed soil samples were collected from the root zone and bulk soil in the planted and non-planted (control) columns, respectively. Soil water repellency was determined by the intrinsic sorptivity method. Soil structural stability was measured by high-energy moisture characteristic (HEMC) and wet single-sieve methods.
Results: Presence of rangeland plants’ roots increased ethanol sorptivity (SE) and decreased water sorptivity (SW) in the rhizosphere. Water repellency index (R) in the rhizosphere was, on average, about two times greater than that in the bulk soil. The highest R was recorded in the root zone of B. inermis, followed by tall fescue genotype 75C, B. tomentellus, and tall fescue genotype 75B, and the lowest value was measured in the non-planted soil. The HEMC indices were greater in the rhizosphere when compared to the control soil. The presence of plant roots significantly increased the percent of water-stable aggregates (WSA) in comparison with the control soil. The root zone of B. inermis had the highest WSA, while no significant difference with tall fescue was observed. The positive and significant correlation between HEMC and WSA indices with R indicates a strong linear relationship between sub-critical water repellency and soil structural stability.
Conclusion: The findings of this study indicated the beneficial influence of rangeland plants’ roots on soil physical quality and structural stability. Slight (sub-critical) water repellency in the rhizospheric soil triggers aggregate stability against environmental stresses. Overall, B. inermis and tall fescue genotype 75C had greater effects on improving soil physical quality and structural stability among the studied species.
Keywords: Rhizosphere, Soil sorptivity, Water repellency index, High energy moisture characteristic, Soil stability ratio, Percent of water-stable aggregates.
Type of Article: Research |
Subject:
Root effects on soil properties and biophysical and biochemical processes
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Journal of Soil and Plant Interactions by http://jspi.iut.ac.ir is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License which allows users to read, copy, distribute and make derivative works for non-commercial purposes from the material, as long as the author of the original work is cited properly.
This work is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License which allows users to read, copy, distribute and make derivative works for non-commercial purposes from the material, as long as the author of the original work is cited properly.
