Field evaluation of using coconut husk and fibre to control slope erosion

Abstract

One of the most common temporary measures to control soil slope erosion is the placement of synthetic geotextile or biological cover over the sloping surface. However, synthetic geotextiles have some disadvantages. Firstly, they are much expensive compared to biological materials. Secondly, synthetic geotextiles made of polymeric materials are not biodegradable and are likely to cause soil pollution. The use of natural bio-resources, such as coconut husk and fibre, is less costly and they are readily available in tropical countries. It is environmentally friendly and also durable and will not decompose as fast as live mulches due to its high carbon to nitrogen ratio and lignin content. A field experiment is set up to test two designs of coconut mulches, coconut fibre net and coconut husk using onsite experimental erosion plots with a slope gradient of 27°. The results showed that the coconut husk placed in the correct orientation is effective in reducing soil loss (980 grams), produced two times less soil loss compared to the control plot of bare soil (2465 grams) and coconut fibre net (2410 grams). Both the mulch covers also enhanced soil and water holding capacity promoting vegetation growth.