Abstract

Soil erosion is a phenomenon that has existed throughout geological time, but lately human activities have accelerated it. It continues at slow rate in natural forests, but soil disturbances by several operations promote erosion in forest plantations. Though mechanical and cultural methods are avaliable for erosion control, current view is that low-cost cultural conservation practices are appropriate in forest plantations. This project was launched for preparation of a state-of-knowledge report on cultural practices suitable for managing soil erosion in forest plantations with special reference to Kerala. Soil loss in a region is the function of climate, soil erodibility, topography, vegetation cover and anti-erosion measures. While mechanical and cultural methods are accessible for erosion control, effects of the former are short-lived unless measures are taken to reduce exposure of soil to raindrops. Further, under tropical conditions a vegetation or mulch cover is the key factor in erosion management. An overview reveals that use of grass-legume mixtures, cover and under crops, mulches, minimum and zero tillage, contour cropping, gully control by vegetation and afforestation are the major cultural practices. In low-input forest plantations, prevention is better than cure approach is apt and here erosion management requires proper action at the proper time. As the time of worst vulnerability to erosion is during establishment period, maintenance of cover by taungya crops, undergrowth, under crops or mulches is crucial. Contour planting of seedlings and use of ridge and furrow system for tapioca planting can minimize erosion in forest plantations. Also, intercrops which provide good cover namely Leucaena leucocephala, Calliandra calothyrsus and Acacia auriculiformis may be tried during the post-taungya period to alleviate harmful effects of erosion