Publications (6)0 Total impact
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T. Smets, Jean Poesen,
Ranjan Bhattacharyya,
Michael A. Fullen,
Colin A. Booth,
Madhu Subedi,
Á. Kertész,
Z. Szalai,
A. Toth,
Benediktas Jankauskas,
G. Jankauskiene,
C. Bühmann,
A.J.T. Guerra,
J. F. R. Bezerra,
Yi Zheng,
Mattiga Panomtaranichagul
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ABSTRACT: Proceedings of the Green5 Conference, Vilnius, Lithuania 1 July - 4 July 2008 The objective of the work reported is to evaluate the effectiveness of selected types of biological geotextile in reducing runoff and soil lossin continental, temperate and tropical environments. Laboratory simulations used various rainfall intensities, flow shear stresses and slope gradient and field plot data were collected from seven countries. The laboratory experiments indicate that all tested biological geotextiles are effective in reducing interrill runoff (32-73% of the value for bare soil) and interrill erosion rates (5-27 % of the value for bare soil). Since simulated concentrated flow discharge sometimes flows below the geotextiles, their effectiveness in reducing concentrated flow erosion is significantly less (25-153% of the value for bare soil). On field plots, where both interrill and rill erosion occur, all tested geotextiles reduced runoff depth on average to 17-63 % of the control value for bare soil and in some cases, runoff depth increased compared to bare soil surfaces, which can be attributed to the impermeable and hydrophobic characteristics of some biological geotextiles. In the field, soil loss rates due to interrill and rill erosion were reduced on average to 5-20 % of the value of bare soil by the biological geotextiles. For all environmental conditions, the relative reduction of both runoff and soil loss by geotextiles compared to bare soil, increased with increasing rainfall depth. Runoff depths are significantly more reduced by Buriti and Rice straw geotextiles on the longer field plots (6-10 m) compared to the short interrill laboratory plots (0.9 m). Only the Rice straw geotextiles are significantly more effective in reducing soil loss on the longer field plots compared to the short interrill laboratory plot.
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ABSTRACT: Metadata only Despite geotextiles having potential for soil conservation, limited scientific data are available to assess the effects of geotextiles in reducing runoff and water erosion. Hence, the objective of this review is to analyse the effects of plot length (L) and other possible affecting factors [cover percentage (C, %), slope gradient (S), rainfall duration (D), rainfall intensity (I), sand, silt and clay contents, soil organic matter (SOM) content and geotextile type (natural or synthetic)] on the effectiveness of geotextiles in reducing soil and water loss, based on reported experimental data. From linear regressions, C (%) and soil sand, silt and clay contents are found to be the most important variables in reducing SLR (ratio of soil loss in bare plots to that in geotextile treated plots) for splash, C (%) for interrill and D (min) for rill and interrill erosion processes, respectively. Soil clay and silt contents and D are key variables in decreasing RR (ratio of runoff from bare plots to that from geotextile treated plots) for interrill, and clay content for rill and interrill erosion processes, respectively. The linear relationship between mean b-value (geotextile effectiveness factor in reducing soil loss) and L of all studies was not significant (PN0.05). The same is true for the relationship between L and SLR, and L and RR. However, when L is added to an equation as an interaction term with C (%), geotextile cover is significantly (Pb0.05) more effective in reducing SLR on shorter plots than longer ones for both interrill and rill and interrill erosion processes. Buffer strip plots (area coverage ∼10%) with Borassus and Buriti mats have the highest b-values.
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ABSTRACT: Despite geotextile-mats having the potential for soil conservation, field studies on the effects of geotextiles on soil properties are limited. Hence, the utilization of palm-mat geotextiles as a potential soil conservation technique was investigated at Hilton, east Shropshire, U.K. (52°33′5.7″ N, 2°19′18.3″ W). Geotextile-mats constructed from Borassus aethiopum (Borassus palm of West Africa) and Mauritia flexuosa (Buriti palm of South America) leaves are termed Borassus mats and Buriti mats, respectively. Field experiments were conducted at Hilton during 2007–2009, to study the impacts of Borassus and Buriti mats on selected properties of the topsoil (0–5 cm). Ten fixed plots (10×1 m on a 15° slope) were established, with duplicate treatments. The treatments were: (i) bare soil; (ii) permanent grassed; (iii) bare soil with 1 m Borassus-mat buffer strips (area coverage ~10%) at the lower end of the plots; (iv) bare soil with 1 mBuriti mat buffer strips (area coverage ~10%) at the lower end of the plots; and (v) completely-covered with Borassus mats. Initial and final soil samples of the topsoil were collected and analysed for bulk density, aggregate stability, soil organic matter (SOM), total soil C (TSC), total soil N (TSN) and pH. Results indicate that, apart from Borassus completely-covered plots, soil bulk density increased and aggregate stability decreased in all plots after two years. Despite decreases in SOM contents in bare plots, SOM content did not change after two years in the grassed and geotextile treated plots. Treatments had no effects on changes in pH, TSC or TSN. Both Borassus and Buriti mat-covers within the buffer strip plots had little impact on SOM, TSC and TSN changes compared with bare soils within the same plots. Thus, Borassus buffer strip plots were very effective in maintaining some soil properties (i.e. SOM, TSC, and TSN) after two years of erosion by water. In summary, utilization of Borassus mats as buffer strips was very successful in conserving soil properties on a loamy sand soil.
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ABSTRACT: Soil erosion by concentrated flow can cause serious environmental damage. Erosion-control geotextiles have considerable potential for reducing concentrated flow erosion. However, limited data are available on the erosion-reducing potential of geotextiles. In this study, the effectiveness of three biological geotextiles in reducing soil losses during concentrated flow is investigated. Hereto, runoff was simulated in a concentrated flow flume, filled with an erodible sandy loam on three slope gradients (13·5, 27·0 and 41·5%). Treatments included three biological geotextiles (borassus, buriti and bamboo) and one bare soil surface. Darcy–Weisbach friction coefficients ranged from 0·01 to 2·84. The highest values are observed for borassus covered soil surfaces, followed by buriti, bamboo and bare soil, respectively. The friction coefficients are linearly correlated with geotextile thickness. For the specific experimental conditions of this study, borassus geotextiles reduced soil detachment rate on average to 56%, buriti geotextiles to 59% and bamboo geotextiles to 66% of the soil detachment rate for bare soil surfaces. Total flow shear stress was the hydraulic parameter best predicting soil detachment rate for bare and geotextile covered surfaces (R² = 0·75–0·84, p < 0·001, n = 12–15). The highest resistance against soil detachment was observed for the borassus covered soil surfaces, followed by buriti, bamboo and bare soil surfaces, respectively. Overall, biological geotextiles are less effective in controlling concentrated flow erosion compared with interrill erosion. Copyright © 2009 John Wiley & Sons, Ltd.
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Madhu Subedi,
Michael A. Fullen,
Colin A. Booth,
Robert W. Sarsby, Jean Poesen,
Á. Kertész,
Benediktas Jankauskas,
Ranjan Bhattacharyya,
R. Kugan,
T. Smets,
A. Toth,
Z. Szalai,
Genovaitė Jankauskienė
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ABSTRACT: Field and laboratory experiments has shown that geotextile mats made from palm leaves are an effective, sustainable and economically-viable soil conservation method, with huge global potential. The EU-funded BORASSUS Project (2005-09; Contract Number INCO-CT-2005-510745) is evaluating the long-term effectiveness of biogeotextiles in controlling soil erosion and assessing their sustainability and economic viability. These experiments are in progress in 10 countries, both in the ‘industrial north’ (in Europe) and in the ‘developing south’ (Africa, South America and South-East Asia). This paper discusses the significance of geotextile palm mats in European countries (Belgium, Hungary, Lithuania and the UK). Geotextile mats were effective in reducing splash erosion, runoff and soil erosion on arable sloping land in Shropshire, UK. The use of Borassus-mats on bare soil reduced soil splash height by ~31% and splash erosion by ~42%. The application of Borassus-mats as complete cover on bare soil reduced runoff by ~49% and soil erosion by ~75%. Borassus and Buriti mats as 1 m buffer strips reduced runoff by ~56 and 34%, respectively, and soil erosion by ~83 and 77%, respectively. Results from selected types of vineyards in Hungary suggest that the geotextile mats are effective in reducing soil erosion, particularly erosive rainfall. The geotextiles mats are also helpful in maintaining moisture and temperature conditions in the surface soil at levels particularly conducive to the establishment and growth of young plants. Experiments in Lithuania show that geotextile mats are effective in encouraging the establishment and growth of natural vegetation, thereby reducing erosion on roadside slopes. Simulated experiments in controlled laboratory conditions in Belgium suggest that palm-leaf geotextiles are effective in increasing infiltration rates and reducing interrill runoff and erosion rates on medium (i.e. 15%) and steep (i.e. 45%) slope gradients. The effectiveness of geotextile mats when used as technical materials for the construction industry in ground strengthening was investigated. Generally, the tensile strength of the Buriti mats was approximately twice that of the Borassus mats. The tensile strength of the palm-leaf geotextile mats is influenced by the mat strip formation pattern. Research and development activities of the BORASSUS Project have improved our knowledge on the effect of palm geotextile mats on the micro- and macro- soil environments and at larger scales through controlled laboratory and field experiments in diverse environments.
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ABSTRACT: Palm-leaf geotextiles could be an effective and cheap soil conservation method with enormous global potential. However, there are very few data on the effectiveness of palm geotextiles in reducing soil erosion by water. This study investigates the effectiveness of two types of palm geotextiles and the effect of geotextile mesh size on infiltration, run-off and inter-rill erosion rate and soil surface roughness on a medium and steep slope. A well-defined protocol was developed to conduct laboratory experiments. Rainfall was simulated for 90 min with an intensity (I) of 45 and 67 mm h−1 on an inter-rill erosion plot, filled with an erodible sandy loam and having slope gradients (S) of 15 and 45%. Two palm-leaf geotextiles (Borassus aethiopum and Brazilian Buriti Palm) and three simulated geotextiles (polyethylene tarpaulin) with different mesh sizes (1 × 1, 5 × 5 and 12 × 12 cm) were tested on a simulated fine tilth. Calculated k values from the Horton infiltration equation ranged from 0.025 to 0.145 and decreased linearly on both slopes with geotextile cover. Geotextiles are more effective in reducing the run-off coefficient on a medium slope (15%) compared with that on a steep slope (45%), ranging from 76.4 to 17.9%. Mean b values from the mulch cover equation equalled 0.024 for a 15% slope and 0.045 for a 45% slope, indicating a higher effectiveness of geotextiles in reducing total inter-rill soil loss on gentler slopes compared with commonly used mulches. Erosion-induced soil surface roughness at the end of each experiment increased linearly with geotextile cover percentage and this increase was not significantly different between the two slope gradients. (Blackwell Publishing)
