Utilization of Palm-mat Geotextiles to Conserve Agricultural Soils.

Abstract

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.