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The coconut-based agricultural wastes have gained wide attention as an alternative adsorbent for the removal of diverse pollutants from the industrial effluents. This paper presents the zinc chloride activation of adsorbent carbon and the utilization as an adsorbent for the removal of malachite green dye from aqueous solution. The characterisation of activated carbon was performed to get an insight into the adsorption mechanism. The ZnCl2 activated carbon acquired a higher specific surface area (544.66 m2 g−1) and stability (−32.6 mV). The impact of process parameters including contact time (20–220 min) and initial dye concentration (20–80 mg L−1) were evaluated on the effectiveness of activated carbon for the dye removal. The results concluded that zinc chloride activated carbon showed a significant dye adsorption (39.683 mg g−1) at an initial concentration of 20 mg L−1 after 3 hours. Based on the correlation coefficient (R2), Freundlich isotherm model (0.978–0.998) was best fitted for the experimental data followed by the intraparticle diffusion model (0.88–0.929) as most appropriate model for the malachite green dye removal. Additionally, the energy and thermogravimetric analysis portrayed the suitability of the carbon material to be used as an energy alternative to coal.

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Oil palm (Elaeis guineensis) has proven to be a phytolith-occluded carbon (PhytOC)-rich species that plays a vital role in acting as a carbon sink for reducing atmospheric carbon dioxide (CO 2 ) concentration. The present research estimated the silicon, phytolith, and PhytOC contents in four (OP4), eight (OP8), and fifteen (OP15)-year-old oil palm plantations. Qualitative analysis using a scanning electron microscope (SEM) revealed the presence of abundant globular echinate phytoliths with varied diameter (8.484−10.18 μm) in fronds, empty fruit bunches, and roots. Furthermore, a wide band (400−490 cm −1 ) underlined a higher relative abundance of Si−OH groups in empty fruit bunches, fronds, and roots, which emphasized the amorphous nature of silica. Quantitative analysis revealed that the phytolith (phytolith/dry biomass), PhytOC (PhytOC/phytolith), and PhytOC (PhytOC/dry biomass) contents in all oil palms differed significantly (p < 0.05) and increased with age. The PhytOC stock showed significant variation, with the trend of OP15 > OP8 > OP4. The belowground biomass of OP4 (16.43 g kg −1 ) and OP8 (17.13 g kg −1 ) had a maximum PhytOC concentration compared to the aboveground biomass, and the belowground proportion varied from 20.62 to 20.65%. The study demonstrated a positive correlation between the phytolith and PhytOC contents of oil palm; thereby, oil palm should be cultivated for enhanced long-term sequestration as a phytolith accumulator.

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On-farm trials were conducted during 2010 and 2011 to evaluate the effect of different interventions on productivity and profitability of rainfed farming systems of small and marginal farmers in Seethagondhi cluster, Adilabad district. Averaged across six farmers' fields, the cotton equivalent yield (CEY) of cotton + pigeonpea intercropping was 7.99 q/ha with farmers' practice. The CEY increased by 17.5% due to herbicide use for weed control, 28.3% with application of recommended NPK, and 35.8% with use of both herbicide and recommended NPK compared to farmers' practice. Use of herbicide for weed control coupled with application of recommended NPK gave higher net return (` 10,300/ha) compared to other management practices. Among the farming systems of marginal farmers, integrated farming system involving crop production (cotton + pigeonpea intercropping) and livestock rearing (4 bullocks, 3 desi cows and 1 buffalo) gave higher net return (` 40,180/year) compared to other farming systems. Similarly, among the three farming systems of small farmers, integrated farming system involving crop production (cotton + pigeonpea intercropping) and livestock rearing (2 bullocks, 1 desi cow and 40 goats) performed better with a net return of ` 89,937/year compared to other farming systems.

This paper was attempted to examine the effect of temperature and rainfall on the productivity of two important crops-pigeonpea and cotton in Andhra Pradesh following panel data regression approach. Using the district level time series data, the yield of each of these two crops was regressed on maximum temperature during kharif, rainfall quantity and number of rainy days for the period 1990-2002, in a one-way and two-way fixed effect models of panel regression using Least Squares Dummy Variable Method. Comparison of district specific effects revealed statistically significant differences between districts in case of pigeonpea. The response coefficients for rainfall and number of rainy days were found significant at 5 per cent level. A positive impact on yield of pigeonpea at the rate of 1.9 kg/ha was observed for a 10 mm rise in rainfall. The number of rainy days was found to have a significant negative relationship with yield. In case of cotton, half of the major cotton growing districts differed significantly in mean yield levels. A significant reduction in yield at a rate of 13 kg/ha for every 1 0 C rise in the maximum temperature was observed. The yield of cotton was found to increase by 0.7 kg/ha for every 10 mm increase in the rainfall.