Assessment of Soil and Groundwater Quality as influenced by continuous monoculture of Tea Camellia sinensis in the Upper Brahmaputra Valley Zone UBVZ of Assam

Abstract

Tea (Camellia sinensis) is one of the most important perennial cash crops of Assam used for domestic consumption and export. Assam produces 55% of the tea produced in India and 1/6th of the tea produced in the world. Most of the small tea gardens are confined to Upper Brahmaputra Valley Zone (UBVZ). Tea crop is cultivated since years and predictions are made that due to prolonged monoculture it may be deteriorating soil health and depletion of nutrients or nutrient imbalance compounded by poor physical, chemical and biological conditions of the soils appear to contribute significantly. So the present investigation was undertaken to find out the soil and water qualities of the tea gardens in five districts viz. Golaghat, Jorhat, Sivsagar, Dibrugarh and Tinsukia with a special reference to the age groups (0-5, 5-30, 30-45, gt45) years of cultivation in identifying the key quality indicators for assessing the effect of continuous monoculture of tea on soil and water quality and the concentration of Aluminium and Fluoride in tea plant and their correlation with yield. Through identification of Minimum Data Set (MDS) for soil and water quality with principal component analyses, the critical soil quality indicators were identified in continuous tea cultivation in reference to the age. newlineIn Golaghat district the SQI was found to be 17.29, 16.68, 14.46 and 12.50 for the age groups of 0-5, 5-30, 30-45, gt45 years of continuous tea cultivation with MDS. Similarly, in Jorhat, Sivsagar, Dibrugarh and Tinsukia the SQI values were 16.41, 14.08, 10.57, 10.32; 14.01, 12.71, 11.25, 10.97; 13.57, 12.59, 11.97, 11.62; 11.31, 10.22, 10.13, 9.01 under 0-5, 5-30, 30-45, gt45 years of continuous cultivation, respectively with MDS. The most sensitive indicators of soil quality were pH, Avl N, Avl P2O5, Avl K2O, OM, Zn, Ex Al and Avl S which contributes the most towards SQI in all the districts. newlineWater Quality Index (WQI) indicates the quality of water and the best quality was being found in Dibrugarh (54.37) followed by Tinsukia (44.40), Siva