Major Soil Chemical Properties of the Major Tea-Growing Areas in India

Major chemical properties of tea-growing soils are of paramount importance for better management in a sustainable fashion.Therefore,this study was carried out to understand the major soil chemical properties of major tea(Camellia sinensis L.)-growing areas,Dibrugarh and Tinsukia districts,in the state of Assam,India.A total of 991 surface soil samples were collected from 15 large tea estates(TEs) for analysis of their major chemical properties.Soil pH ranged from 3.61 to 6.81.Total organic carbon and total nitrogen ranged from 2.4 to 47.3 and 0.24 to 3.60 g kg^(-1),respectively.All soils were sufficiently rich in plant-available potassium(as K_2O),which ranged from 127.71 to 252.33 mg kg^(-1),exceeding the amount prescribed for optimum tea yield of > 100 mg kg^(-1).Plant-available sulfur among soil samples widely varied from 4 to 129 mg kg^(-1).Results of hierarchical clustering analysis for homogenous grouping of the 15 TEs based on soil chemical properties showed that the 15 TEs could be classified into three distinct groups which consisted of6,8 and 1 TEs,respectively.Based on the Kolmogorov-Smirnov(K-S) test,the best fitted theoretical probability distributions were found out for different soil chemical properties.It could be concluded that a balanced fertilizer application would be needed as a part of tea improvement program using soil chemical test.

Comparative assessment for removal of anionic dye from water by different waste-derived biochar vis a vis reusability of generated sludge

In this study,four biochars prepared from different crop residue waste i.e.sugarcane bagasse(SBB),coconut shell(CNB),paddy straw(PDB),and distilled waste of lemongrass(LGB)were evaluated for removal of Remazol Brilliant Blue R from the aqueous system.The RBBR adsorption capacities of biochar were 97-79%for SBB,99.9-99.47%for CNB,66.1-48%for PDB,and 78-68%for LGB,dominantly controlled by their aromaticity and mineral content.The Langmuir and Freundlich isotherms and pseudo-second-order kinetic models have described the chemisorption of RBBR on biochar surfaces.The thermodynamic data suggested that adsorption was spontaneous and endothermic.These biochars demonstrated excellent reusability(till four cycles with 50-61%regeneration).The purified water and biochar dye sludge demonstrated no phytotoxicity.The findings obtained in this study may provide supports for the potential of biochars for anionic dye removal from water and utilization of generated sludge for zero waste-producing technologies in the future.