Deterioration of soil quality with continuous plantation of teak (Tectona grandis)

Abstract

A study was carried out at Rathmale teak Plantation, Thalawa to investigate the cause for the poor growth of teak saplings in a selected area. The study hypothesized that the poor growth and development of second rotation teak is a result of poor physical and chemical properties of the soil that gradually developed after the conversion of natural forest to plantation. Three sites, poorly grown teak plants, normally grown teak plants, natural forest land were selected. Soil samples from top and sub layer were analysed for pH, Electrical conductivity (EC), Nitrogen, Phosphorus, Potassium, CEC, Soil organic matter (SOM), Texture and Bulk density (BD). Bulk density, SOM and EC were Session I – Forest and Natural Resource Management Significantly different between site one and site two. Higher BD, lower SOM and EC are key components of the soil quality and the changes may have led to the poor growth of Teak in site one. It was therefore clearly evident that the change in soil quality as a result of the conversion of natural forest to teak plantation is linked with the poor growth of teak saplings in the area under investigation.