Biogeotextiles constructed from the leaves of Borassus aethiopum and Mauritia flexuosa are investigated at the Kaltinėnai Research Station of the Lithuanian Institute of Agriculture, which is participating in the EU-funded BORASSUS Project. Biogeotextiles are potentially excellent biodegradable and environmentally-friendly materials useful for soil conservation. Field studies on a steep (21–25°) roadside slope in Lithuania suggest biogeotextile mats are an effective and sustainable soil conservation technique. Biogeotextiles have a potential as a biotechnical soil conservation method for slope stabilization and protection from water erosion on steep industrial slopes and may be integrated with the use of perennial grasses to optimize protection from water erosion. The investigations demonstrated that a cover of Borassus and Buriti mats improved the germination and growth of sown perennial grasses. The biomass of perennial grasses increased by 52.0–63.4% under cover of Borassus mats and by 18.6–28.2% under cover of Buriti mats. Over 2 years, the biogeotextiles (Borassus and Buruti, respectively) decreased soil losses from bare fallow soil by 90.8% and 81.5% and from plots covered by perennial grasses by 87.9% and 79.0%, respectively.

Previously, most studies on the effectiveness of geotextiles on soil erosion rates and processes were conducted in laboratory experiments for <1 h. Hence, at Hilton (52o33' N, 2o19' W), East Shropshire, UK, we investigated the effectiveness of employing palm-mat geotextiles (Borassus and Buriti mats) to reduce rainsplash erosion, runoff and soil loss under field conditions. This study is a component of the European Union-funded BORASSUS Project. The effects of Borassus mats on rainsplash erosion were studied for ~2 years (2002-2004), and re-established in January 2007 on a 0o slope. There were 12 experimental plots (six plots completely-covered with mats and six bare plots; each measuring 1.0 x 1.0 m). Runoff-plot studies were also conducted on the loamy sand soil at Hilton for 2 years (2002-2004) with duplicate treatments: (i) bare soil; (ii) grassed, (iii) bare soil with 1 m Borassus-mat buffer zones at the lower end of the plots and (iv) completely-covered with Borassus-mats. Each plot was 10 x 1 m on a 15o (26.6%) slope. To confirm the results, another set of experiments have been in progress at Hilton since January 2007, with one additional treatment (bare soil with 1 m Buriti-mat buffer zones) compared with the earlier experiment. Runoff and soil erosion were collected from each plot in a concrete gutter, leading to a 0.02 m3 (20 liters) capacity receptacle placed inside a 0.14 m3 (140 liters) capacity container. Results (06/10/02-02/09/04; total precipitation = 1038.3 mm) showed Borassus mats on bare soil reduced total rainsplash erosion by ~50% compared with bare plots (9.64 kg m-2; 1.97 lb ft-2). The use of Borassus mats on bare soil (during 01/22/07-01/21/08; total precipitation = 919.2 mm) also reduced soil splash erosion by ~90%. During 03/25/02-05/10/04 (total precipitation = 1319.8 mm) complete cover of Borassus mats on bare soil reduced total runoff by ~19% and soil erosion by ~64%. Furthermore, Borassus mats as 1 m buffer strips on bare soil reduced runoff by ~36% and soil erosion by ~57%. During 01/08/07-01/14/08 (total precipitation = 923.4 mm), plots with Borassus and Buriti mats as buffer strips on bare soil reduced sediment yield by ~93 and 98%, respectively, and runoff by ~83 and 63%, respectively. Buffer strips of Borassus mats were also as effective as complete cover of the same mats. Thus, utilization of palm-mat geotextiles as buffer strips on bare plots (area coverage ~10%) is highly effective for soil and water conservation.

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.