Effects of Palm-mat Geotextiles on the Conservation of Loamy Sand Soils in East Shropshire, UK

Abstract

Some 30% of world arable land has become unproductive, largely due to soil erosion. Considerable efforts have been devoted to studying and controlling water erosion. However, there remains the need for efficient, environmentallyfriendly and economically-viable options. An innovative approach has used geotextiles constructed from Borassus aethiopum (Black Rhun Palm of West Africa) leaves to decrease soil erosion. The effectiveness of employing palmmats to reduce soil erosion have been investigated by measuring runoff, soil loss and soil splash on humid temperate soils. Twelve experimental soil plots (each measuring 1.0 x 1.0 m) were established at Hilton, east Shropshire, UK, to study the effects of geotextiles on splash erosion (six plots completely covered with Borassus mats and six non-protected bare soil plots). Soil splash was measured (10/06/02-09/02/04; total precipitation = 1038 mm) by collecting splashed particles in a centrally positioned trap in each plot. An additional field study (25/03/02-10/05/04; total precipitation = 1320 mm) of eight experimental runoff plots (10 x 1 m on a 15o slope) were used at the same site, with duplicate treatments: (i) bare soil; (ii) grassed, (iii) bare soil with 1 m palm-mat buffer zones at the lower end of the plots and (iv) completely covered with palm-mats. Runoff volume and sediment yield were measured after each substantial storm. Results indicate that total splash erosion in bare plots was 34.2 g m-2 and mean splash height was 20.5 cm. The use of Borassus mats on bare soil significantly (P<0.05) reduced soil splash height by ~31% and splash erosion by ~50%. Total runoff from bare plots was 3.58 L m-2 and total sediment yield was 8.58 g m-2. Thus, application of geotextiles as 1 m protective buffer strips on bare soil reduced runoff by ~36% and soil erosion by ~57%. Although total soil loss from the completely covered geotextile plots was ~16% less than the buffer zone plots, total runoff volume from the completely covered plots was ~94% more than the buffer zone plots. Thus, palm-mat (buffer strips) cover on vulnerable segments of the landscape is highly effective for soil and water conservation on temperate loamy sand soils.