Impact of Soil Rehabilitation of Tea Soils and Development of an Index

Abstract

A study was undertaken to evaluate four soil parameters, soil bulk density, available water content, organic carbon content and microbial biomass , in rehabilitated field and adjacent old tea field in 40 tea estates, representing all tea growing areas of Sri Lanka. While BD showed significant reduction after planting grasses, AWC, MBC and C showed significant increase. A soil quality index (SQI) was developed after standardization of above parameters between 0-10 and using the following formula SQI = 0.36BD + 0.14AWC + 0.34C + 0.16MBC Accordingly, minimum SQI requirement for skipping the grass planting was proposed as 5.0 fpr Low elevation, 6.0 for Mid elevations and 7.0 for Uva and Up elevations in tea growing regions of Sri Lanka. This study proved the beneficial effects of grass planting prior to replanting and developed a standard index to evaluate the soil fertility.

Keywords: tea soil, rehabilitation, standard index.