This paper presents a facile and effective method for the large-scale production of carbon dots (CDs) from diverse coconut wastes (fronds, husk and shell). On comparing two different methods, namely (i) hydrothermal carbonization and (ii) novel sequential synthesis processes (pyrolysis followed by sonication), the latter procedure recorded a higher recovery of CDs (14.0%) over the hydrothermal method (2.33%). Doping agents such as urea, polyethyleneimine (PEI) and hexamethylenetetramine (HMTA) were chosen at varying concentrations to synthesize surface-modified CDs (SMCDs) for enhanced antibacterial properties. Among these SMCDs, urea-doped CDs _(1:1) @ 1000 ppm registered significantly higher cytotoxicity (20.6%) against Escherichia coli (E. coli). Subsequently, to assess the applicability of CDs as a disinfectant in water purification systems, two products, namely (i) CD-infused chitosan beads and (ii) pelletized CDs, were developed to ensure the immobilization of CDs. Studies with lab-scale prototypes have revealed that CDs infused chitosan beads reduced the colonies of E. coli from 5.41 × 10² CFU/mL (control group) to 2.16 × 10² CFU/mL, in comparison with pelletized CDs that decreased to 3.30 × 10² CFU/mL. The biosafety of CDs was assessed against Eisenia fetida for 21 days, and the observations revealed no mortality, even at 2000 ppm. Overall, this research demonstrated that a waste biomass can be effectively transformed into a novel water disinfectant. Furthermore, this scientific endeavor opens up research avenues to evolve advanced water purifiers using low-cost and eco-friendly nanomaterials.

Background: Blackgram being important crop among pulse is gaining popularity and thus requiring suitable crop production practices especially under organic farming. In this context, this study was proposed with the objective to investigate the optimal nutrient management practices in organic blackgram by utilizing various organic nutrient sources. Methods: Field experiments were conducted at two different locations in spilt plot design. The treatments consisted of 4 levels of organic manure viz., Farm Yard Manure (FYM) @ 12.5 t ha-1, Vermicompost (VC) @ 2.5 t ha-1, Enriched FYM (EFYM) @ 750 kg ha-1 and Enriched VC (EVC) @ 1 t ha-1 as main plot treatments and five levels of foliar spray of liquid manure viz., two foliar sprays of Panchagavya @ 3% and Fermented egg extract (FEE), Fermented fish extract (FFE), Farmers effective microorganisms (FEM), Jeevamruth each @ 5%. Result: Results revealed that application of EFYM and VC, produced higher yield parameters and grain yield, respectively under main plot organic manure addition at site-I and II. Among the sub plots liquid manure treatments Panchagavya spray has produced higher grain yield along with the yield parameters at both the sites. Among the organic manures higher economic returns were obtained with the application of EFYM at both the sites while among the liquid manures better returns were obtained with the application of Panchagavya at site-I and Panchagavya or FEM spray at site-II.

Stabilizing GHG emissions in the agri-food sector is crucial for climate change mitigation. Tea is one of the most consumed drinks worldwide and such high levels of consumption necessitate for the carbon footprint (CF) assessment of its entire life cycle encompassing all six stages such as cultivation, processing, packaging, transportation, consumption and disposal to understand the environmental impact of tea industry at large. In this context, this study is a maiden attempt to quantify and compare CF for the entire life cycle of all three types of tea such as black, green and white tea in a single research paper by employing the life cycle assessment (LCA) method in significant tea growing areas of Tamil Nadu, India. The findings revealed that the consumption stage contributed the highest CO2 emissions, accounting for 45%-56% to overall CF. Black tea consumption contributed 45% (5.8 kg CO2-eq/kg of made tea) of the total CF, while green tea and white tea had higher CF (8.3 kg CO?-eq/kg of made tea), contributing 56% to the total CF. The processing stage was the second largest source, contributing 12-19% to overall CF, followed by packaging (15-17%) and cultivation (10-11%) stages. Overall, the total CF (cradle to grave) for black tea and white tea had a similar value of 12.9 kg CO2-eq/kg of made tea, whereas green tea registered a higher value of 14.79 kg CO2-eq/kg of made tea. Furthermore, this assessment identified hotspots of GHG emissions. It enabled the recommendation of CF reduction measures to promote carbon neutrality in tea sector while being a part of global climate change mitigation efforts.

Background: Cotton, a popular fiber crop, is in high demand for textiles due to its natural properties. It plays a vital role in biological cycles and sustainable yield. A field experiment to compare natural, organic farming and integrated crop management to assess cotton fiber qualities was conducted in Tamil Nadu Agricultural University, Coimbatore, for two years (2021-22 and 2022-23) in Cotton cv. CO 17. Methods: The experiment had nine treatments, arranged in a Randomized Block Design and replicated thrice. A complete Zero Budget Natural Farming Practices were used, including Ghanajeevamirit as Basal, seed treatment with Beejamirit, Jeevamirit applied twice a month through irrigation, intercropping, mulching and Whapasa (Alternate Furrow irrigation). Organic and Integrated plots were also included. Result: The use of beejamirit, jeevamirit and ghanajeevamirit in natural farming led to substantial seed cotton yield of 1287 kg ha-1 in 2021-22 and 1364 kg ha-1 in 2022-23, comparable to organic plots of 1695 kg ha-1 in 2021-22 and 1768 kg ha-1 in 2022-23, while improving soil health, biodiversity and pest management. Quality characteristics did not significantly differ among the different farming practices.

Background: Traditional organic formulation bijamrith prepared from fresh urine and dung of cow is an important element in natural farming and extensively applied in modern agriculture practices to improve the soil fertility, control pest and disease in plants. The scientific validation of the biologically active compounds in bijamrith is unexplored. Methods: Bijamrith was prepared from excrements of Gir cow. Since, the volatile low molecular weight organic compounds from cow wastes could be derived from the solvent extract using GC-MS effectively, the compounds were separated by liquid-solvent extraction method using diethyl ether solvent and analyzed by GC-MS. Result: GC-MS analysis revealed the elution of about 40 different compounds in bijamrith formulation. Among them, fatty acid namely 9-octadecenoic acid (Z)-, an ester compound 2,3-dihydroxypropyl occupied higher concentration with peak area of 13.96% at 29.29 minutes of retention time which were reported to possess antifungal, antibacterial and anti-inflammatory activity. The other biologically active compounds eluted were antioxidants, plant growth hormones, nematicidal agents for defense mechanism and improvement of plant health.

Background: A series of field experiments were conducted at the Tapioca and Castor Research Station (TCRS), Tamil Nadu Agricultural University, Yethapur, Salem from 2022 to 2023. The purpose was to investigate the growth dynamics and economics of short-duration cassava under different nutrient management practices including both integrated and organic approaches. Methods: Twelve treatments were carried out consisting of various combinations of organic manures, liquid organic foliar sprays, integrated nutrient management treatments and a control treatment (no manures/fertilizers/sprays). The experiments were carried out in a randomized block design (RBD) with three replications at the same location. Results: The results revealed that the different nutrient management practices had a significant impact on the physiological response throughout the various stages of plant growth. Based on the average data from two experiments, the INM treatment (FYM @ 25 t ha-1 + 100% recommended dose of fertilizers and cassava booster spray) showed the highest physiological response during the final phase of growth. This treatment showed superior performance in terms of leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), tuber bulking rate (TBR) and mean TBR. The organic treatment (wood ash @ 2 t ha-1 and 3% panchagavya foliar spray) recorded comparable performance to the INM treatment in major parameters such as LAI, CGR, RGR and NAR. However, it followed the INM treatment in terms of mean TBR. Economic analysis revealed that the INM treatment yielded the highest net income and benefit-cost ratio (BCR), followed by the organic treatment. The control resulted in the least returns. In conclusion, the findings highlight the effectiveness of the INM treatment and the promising performance of the organic treatment which can contribute to sustainable and profitable cassava cultivation.