Activated carbon produced from coconut shells has been gaining interest in wastewater treatment as a potential carbon source for adsorption with desired porosity, surface area, and stability requirements. Acid activation has been preferred for activated carbon production due to its superiority over adsorption of malachite green dye. This study involved in the acid activation of coconut shell derived carbon and its characterisation was performed to study the surface functionalities, thermal stability, textural and structural morphologies. The activated carbon was used for the adsorption of malachite green dye from aqueous solutions and with a special insight by varying contact time (20–220 min) and initial dye concentration (20–80 mg L⁻¹) for adsorption study. Phosphoric acid-activated carbon has shown maximum adsorption capacity (X_m) of 32.787 mg g⁻¹ at initial malachite dye concentration of 20 mg L⁻¹ after 3 hours. All the adsorbents followed Freundlich isotherm with intra particle diffusion model as the rate-limiting step.

Tamil Nadu in particular is a key rice-producing region in peninsular India. Hydrochemistry, viz., redox potential (Rh), soil temperature and dissolved oxygen (DO), of rice soils can determine the production of greenhouse gas methane (CH₄). In recent decades, the cultivation of crops organically became a viable option for mitigating climate change. Hence, this study aimed to investigate the effects of different organic amendments on CH₄ emission, Rh, DO, and soil and water temperature (T) in relation to the yield of paddy. The treatments composed of viz., control, blue-green algae (BGA), Azolla, farm yard manure (FYM), green leaf manure (GLM), blue-green algae + Azolla, FYM + GLM, BGA + Azolla + FYM + GLM, vermicompost and decomposed livestock manure. With the addition of BGA + Azolla, the highest reduction in CH₄ emission was 37.9% over the control followed by BGA. However, the same treatment had a 50% and 43% increase in Rh and DO, respectively, over the control. Established Pearson correlation analyses showed that the CH₄ emission had a positive correlation with soil (r = 0.880 **) and water T (r = 0.888 **) and negative correlations with Rh (r = −0.987 **) and DO (r = −0.963 **). The higher grain yield of 26.5% was associated with BGA + Azolla + FYM + GLM application. Our findings showed that there are significant differences in CH₄ emissions between different organic amendments and that hydro-parameters may be a more important controlling factor for methane emissions than temperature. The conclusion has been drawn based on valid research findings that bio-fertilization using BGA and Azolla is an efficient and feasible approach to combat climate change, as it assists in reducing methane emissions while simultaneously boosting crop yield by fixing nitrogen into the soil in the studied agro-climatic zone.

An experiment was conducted at Woodhouse farm, Horticultural Research Station, Ooty, during October 2017 to March 2018 to quantify the impact of elevated ozone and ozone protectant spray on plant growth, nutrients, biochemical and yield properties of turnip crop. The experiment was laid out in a factorial completely randomized block design and was replicated thrice. Elevated ozone exposure on turnip significantly reduced the plant height, tuber size, tuber weight, chlorophyll ‘a,’ chlorophyll ‘b’ and total chlorophyll content as well as the nutrient content of plant, viz., total nitrogen, total potassium, total manganese, iron, zinc and copper, also affected. Elevated ozone exposure significantly increased the antioxidant enzyme activity like catalase and peroxidase activity in addition to increment in total phosphorus content in leaf tissues. However, ozone protectants played a major role in nullifying the tropospheric ozone effect on growth and development, physiological traits and yield of turnip while tested with panchagavya performed better followed by neem oil and ascorbic acid.

Agriculture, very often falls victim of climate change around the world. Adopting a cost efficient system of agricultural production with minimal environmental impacts, depends on the selection of best cropping system and associated farming practices. The coconut farming and coconut agroecosystem is one of the country’s largest agricultural systems and sectors that could substantially preserve carbon dioxide (CO₂) through sequestration. Tamil Nadu state is one of the largest growers of coconut with an area of 443000 ha. In the present investigation the Vellore district was chosen as study area. Coconut data such as tree diameter and tree height were collected from the Tall (Aliyar nagar 1), Dwarf (Chowghat Orange Dwarf (COD)) and Chowghat Green Dwarf (CGD) varieties at different ages (five, fifteen, twenty and twenty-fifth years) at various plantations of Vellore district. The carbon sequestered by five, ten, fifteen, twenty and twenty-five-years old coconut tall variety trees were found to be 1.32, 1.97, 2.11, 3.10 and 3.96 tons per acre per year, respectively. Similarly, five, ten, fifteen, twenty and twenty-five-year-old coconut dwarf variety could able to sequester 1.45, 1.27, 1.58, 2.03 and 2.63 tons per acre per year, respectively in Vellore district. The C sequestration potential of ten year old coconut tree (Tall or Dwarf) were 18 to 28 kg per tree per year approximately. The fifteen years (2003-04 to 2017-18) coconut plantation of both tall and dwarf varieties in Vellore district had sequestered 1.15 million tons of carbon from the atmosphere.

The impact of climate change on methane (CH₄) emissions from rice production systems in the Coimbatore region (Tamil Nadu, India) was studied by leveraging field experiments across two main treatments and four sub-treatments in a split-plot design. Utilizing the closed-chamber method for gas collection and gas chromatography analysis, this study identified significant differences in CH₄ emissions between conventional cultivation methods and the system of rice intensification (henceforth SRI). Over two growing seasons, conventional cultivation methods reported higher CH₄ emissions (range: from 36.9 to 59.3 kg CH₄ ha⁻¹ season⁻¹) compared with SRI (range: from 2.2 to 12.8 kg CH₄ ha⁻¹ season⁻¹). Experimental data were subsequently used to guide parametrization and validation of the DeNitrification–DeComposition (DNDC) model. The validation of the model showed good agreement between the measured and modeled data, as denoted by the statistical tests performed, which included CRM (0.09), D-index (0.99), RMSE (7.16), EF (0.96), and R² (0.92). The validated model was then used to develop future CH₄ emissions projections under various shared socio-economic pathways (henceforth SSPs) for the mid- (2021–2050) and late (2051–2080) century. The analysis revealed a potential increase in CH₄ emissions for the simulated scenarios, which was dependent on specific soil and irrigation management practices. Conventional cultivation produced the highest CH₄ emissions, but it was shown that they could be reduced if the current practice was replaced by minimal flooding or through irrigation with alternating wetting and drying cycles. Emissions were predicted to rise until SSP 370, with a marginal increase in SSP 585 thereafter. The findings of this work underscored an urgency to develop climate-smart location-specific mitigation strategies focused on simultaneously improving current water and nutrient management practices. The use of methanotrophs to reduce CH₄ production from rice systems should be considered in future work. This research also highlighted the critical interaction that exists between agricultural practices and climate change, and emphasized the need to implement adaptive crop management strategies that can sustain productivity and mitigate the environmental impacts of rice-based systems in southern India.