Soil conservation using palm-mat geotextiles on loamy sand soils in the United Kingdom

Abstract

Geotextile-mats constructed from Borassus aethiopum (Borassus Palm) and Mauritia flexuosa (Buriti Palm) leaves have the potential to decrease soil erosion. In the U.K., field experiments are being conducted on the effectiveness of palm-mats to reduce soil erosion at Hilton, east Shropshire. Twelve plots (each plot measuring 1.0 x 1.0 m; 6 plots were completely covered with Borassus mats, and the other 6 plots were bare) were established to study the effects of geotextile-mats on splash erosion. Eight runoff plots (10 x 1 m on a 15o slope) were used, with duplicate treatments: (i) bare soil; (ii) grassed, (iii) bare soil with 1 m Borassus-mat buffer zones and (iv) completely covered with Borassus mats. Runoff volume and sediment yield were measured after each substantial storm from 25/03/02-10/05/04 (total precipitation = 1320 mm). Results indicate that palm-mats on bare soil significantly reduced total soil splash erosion by ~50% compared with bare soil (34.2 g m-2; during 10/06/02-09/02/04, total precipitation = 1038 mm). Total runoff from bare plots was 3.58 litres m-2 and total sediment yield was 8.58 g m-2. Borassus mats as buffer strips reduced runoff by ~36% and soil erosion by ~57%. Total soil loss from the completely covered plots was only ~16% less than the buffer zone plots. To confirm the results, another set of runoff experiments are in progress at Hilton, with one additional treatment (bare soil with 1 m Buriti-mat buffer zones) compared with the earlier experiment. Results (08/01/07-24/08/07; total precipitation = 702 mm) indicate that total runoff from bare plots was 21.2 litres m-2 and total sediment yield was 2302 g m-2. Borassus and Buriti mats as 1 m buffer strips reduced runoff by ~86 and 61%, respectively, and soil erosion by ~93 and 98%, respectively. Buffer strips of Borassus mats are as effective as complete cover of the same mats and are more effective in reducing runoff water than the buffer strips of Buriti mats. Combined results from both sets of runoff experiments (total precipitation = 2022 mm) suggest that application of Borassus mats as 1 m protective buffer strips on bare soil reduced runoff by ~77% and soil erosion by ~93%. Thus, Borassus-mat (buffer strips) cover on vulnerable segments of the soilscape is highly effective for soil and water conservation on temperate loamy sand soils.