Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Sustainable fertilization through co-application of biochar and chemical fertilizers improves yield, quality of Andrographis paniculata and soil health Ajoy Saha a,b, ⁎ , B.B. Basak a, ⁎ , N.A. Gajbhiye a , K.A. Kalariya a , P. Manivel a a ICAR-Directorate of Medicinal and Aromatic Plants Research, Anand 387310, India b ICAR-Central Inland Fisheries Research Institute, Bangalore Research Centre, Hesaraghatta Lake Post, Bangalore 560089, India ARTICLE INFO Keywords: Biochar Chemical fertilizer Medicinal herb Crop performance Soil biological activity ABSTRACT Cultivation of medicinal plants by maintaining sustainable environment with low chemical inputs is attempted through a pot culture experiment by integrating the biochar prepared from lemongrass (Cymbopogon flexuosus) distillation waste and chemical fertilizers (CF) in different ratios. The objective was to find out the influence on yield, physiology and quality of Andrographis paniculata (kalmegh) herb and on soil chemical/biological prop- erties. All the growth parameters and yield were significantly influenced by the integrated biochar and CF application. Biochar application, remarkably improved the soil carbon content, cation exchange capacity and nutrients accessibility. However, significantly higher fresh herbage yield (140.8 g plant -1 ) was recorded in the treatment receiving biochar (5 t ha -1 ) combined with recommended dose of CF (60:20:40 NPK kg ha -1 ). The same treatment resulted in higher soil microbial biomass C, fluorescein diacetate hydrolytic, dehydrogenase and alkaline phosphatase activity. Total phenol/flavonoid contents and antioxidant (DPPH and ABTS) activities, were higher in sole biochar treated plant and increased further in combination with CF. Sole application of biochar or CF did not have any significant influence on leaf andrographolide content, however their combination increased the content but the effects were not significant on stem andrographolide. The reduction in stomatal conductance and higher water use efficiency after biochar application indicates it’s potential to mitigate water deficit stress. Results indicate that use of only biochar was not enough to improve the plant growth and soil health. Therefore, to achieve environmentally safe and quality herb production, it is recommended to use combination of biochar and CF which not only improve crop yield and quality but also improves the soil quality. 1. Introduction Biochar, a carbon rich pyrogenic substances considered as an ideal soil amendment for sustainable crop and environmental management. Biomass resources like, agricultural wastes, wood waste, forest residues and food waste are more frequently used as a precursor material for biochar preparation. Farmers in India are encouraged to grow high demanding essential oil bearing aromatic crops. Lemon grass (Cymbopogon flexuous), an important essential oil containing aromatic plant, are extensively cultivated in different parts of India. After ex- traction of essential oil, the waste residues are either mulched or burnt, which led to emission of green house gases (GHGs). So, conversion of this spent material through effective valorization process will not only reduced the environmental hazard but also increases the farmer’s in- come. The conversion of this essential oil distillation waste into value added soil amendment like biochar will be a best alternative strategy for their effective management. Use of biochar as soil amendments is constantly gaining importance as it improves crop productivity and maintains soil fertility (Lehmann et al., 2003). However, Hussain et al. (2016) apprised that biochar only enhances the yield of crops when they are grown in unfertile/ barren land and in fertile soil the effects are not so prominent. Therefore, biochar incorporation along with chemical fertilizer (CF) could be an appropriate option for yield improvement when crops are grown in cultivated soil (Sadaf et al., 2017). This combined application may enhance the availability and uptake of plant nutrients supplied through chemical fertilizer and also reduces the leaching loss of nutrients by minimizing the requirement of CF. Hence, co-application of biochars and CF or mixing them in different proportions is necessary (Sadaf et al., 2017). Though, importance of integrated use of biochar along with CF has been reported in different food crops (Sadaf et al., 2017; Khan et al., 2017), there is no reported work on its effects on medicinal plant like Andrographis paniculata Nees (kalmegh) along with its quality and soil health. https://doi.org/10.1016/j.indcrop.2019.111607 Received 28 January 2019; Received in revised form 19 July 2019; Accepted 25 July 2019 ⁎ Corresponding authors at: ICAR-Directorate of Medicinal and Aromatic Plants Research, Anand 387310, India. E-mail addresses: ajoysahacob@gmail.com (A. Saha), biraj.basak@icar.gov.in (B.B. Basak). Industrial Crops & Products 140 (2019) 111607 0926-6690/ © 2019 Elsevier B.V. All rights reserved. T