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• Analyzed physico-chemical and phytotoxic properties of biochars from tea pruning litter. • Pyrolysis of tea pruning litters improved NPK in prepared biochars. • Low pyrolysis temperature (300 °C) was optimal to get more stable biochar. • Biochar posed different half-life ranging from ≤100 years to >1000 years. • Overall effect of feeding materials is significant as indicated by MANOVA. The present study aimed to optimize the production of biochar from tea (Camellia sinensis L.) pruning litter. Characterization of biochar prepared from four tea pruning litters (mixed, Tocklai Vegetative 1, 22 and 25) at five pyrolysis temperatures (250, 300, 350, 400, 450, and 500 °C for 3 h) were documented. The results demonstrated that yield, total nitrogen, H:C, and O:C decreased steadily with increasing pyrolysis temperature. However, water holding capacity, ash content, fixed carbon, C:N, NH 4 +-N, NO 3 –-N, trace elements, total P and K, and germination index increased consistently with increasing pyrolysis temperature. All the prepared biochars are suitable for agriculture application as H:C and O:C ratios of prepared biochars are <0.6 and <0.4, respectively. Low pyrolysis temperature (<300 °C) was optimal to get more stable biochar with respect to essential nutrients. Biochar derived from Tocklai Vegetative 1 at 300 °C has more potential for agronomic applications. Principal component analysis showed >96% variability. [ABSTRACT FROM AUTHOR]

Field experiment was carried out for four years in mature tea (Camellia sinensis L.) growing plot to investigate the impacts of different doses of inorganic and organic fertilizers on aluminium (Al) distribution pattern in soil and different parts of tea plant, leaf pigment concentration, gas exchange parameters, as well as the yield of tea. Results indicated that application of 6 × 103 kg compost ha−1 significantly increased the dry matter yields of tea. Pluckable shoot of tea plant were markedly stimulated in the presence of Al irrespective of treatment imposed. Furthermore, Al induced growth stimulation in tea plant was facilitated by higher photosynthesis rate as well as gas exchange parameters. For the present experiment, Tea Research Association Heavy Metal Contamination Index (TRAHMCI) decreases with increase the fertilizer dose and all the experimental soils were found non-polluted with respect to Al. Localization of Al in the root apex predominantly accumulated in the cortex. The translocation of Al from root to shoot was driven by the gradient in hydrostatic pressure and water potential. In all tea infusions influenced by different treatments, Al concentrations were within the maximum permissible limit of Al in drinking water by Provisional Tolerable Weekly Intake (PTWI) established by the Joint FAO/WHO Expert Committee on Food Additives (JECFA, 2 mg kg−1 bw−1) and the tolerable weekly intake (TWI) established by EFSA (European Food Safety Authority, 1 mg kg−1 bw−1). Application of stepwise multiple regression model indicates that around 75% of the variability in the yield of the crop can be expressed by the selected parameters under study. The Hierarchical cluster analysis reveals that two homogenous groups of treatment can be formed based on all the studied parameters. • Compost amendments at moderate doses could be beneficial for tea yield • Beneficence of Al for the growth of tea plants is likely • Higher concentration of soil Al improves gas exchange parameters from tea leaf • The root apex predominantly accumulated Al in the cortex • Validation of TRAHMCI proposed by Karak et al. (2017b) (J. Haz. Mat. 338:250–264) was evaluated for Al Unlabelled Image [ABSTRACT FROM AUTHOR]

A mammoth amount of tea pruning litter (TPL) is generated through the pruning of the tea plant and kept on the soil surface which makes the soil sick due to the accretion of allelochemicals from it. Therefore, appropriate management of TPL is very much crucial. This study was conducted to assess the role of tea pruning litter biochar (TPLBC) as a soil conditioner towards the growth and regulations of two popularly grown tea cultivars (TV23 and S.3A/3) in India. Altogether twenty-nine (29) parameters comprising functional groups, plant biomass, and physiological and biochemical properties have been reported in this study to understand the feasibility of TPLBC for tea cultivation. TPLBC amendment of 400 kg ha−1 was best suited for the used cultivars, leading to an increase in chlorophyll content, photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency by 25.68%, 49.61%, 84.00%, 126.93%, and 3.87% respectively. The maximum increase in plant total biomass, shoot biomass, and root biomass was attended at 110%, 31%, and 117%, respectively at 400 kg TPLBC ha−1 over control. The results also revealed an increase in the content of sugar, starch, phenol, total polyphenol, and amino acids with an increasing dose of TPLBC up to 400 kg ha−1. However, with 500 kg ha−1 TPLBC, plant biomass, and polyphenol content were decreased but oxidative stress was increased. Considering all the 29 variables it can be concluded that the soil amendment with 400 kg TPLBC ha−1 was most promising for both TV23 and S.3A/3 clones. [Display omitted] • The first report of tea pruning litter biochar (TPLBC) in improving soil fertility. • TPLBC reduced soil sickness, thus impacting the growth and yield of tea plants. • 400 kg TPLBC ha−1 proved to be the best treatment based on 29 variables. • Application of more than 400 kg TPLBC ha−1 was found to be unsuitable. [ABSTRACT FROM AUTHOR]