MADRAS AGRICULTURAL JOURNAL

Effect of Weed Management Practices on Crop Growth, Yield and Economics of Direct Seeded Rice Ecosystems

Abstract

                               A field trial was carried out in Central Farm of Agricultural College and Research Institute, Madurai during rabi (late samba), 2018-19 to study the effect of weed management on crop growth, yield and economics of rice under various ecosystems. The experiment was laid out in strip plot design with twenty-eight treatment combinations and replicated thrice. The results revealed that among sowing methods, plant height, LAI, LAD, CGR, DMP and yield were observed higher under wet seeded condition whereas, in weed management practices weed free upto panicle initiation stage and the application of Bensulfuron methyl (0.6%) + Pretilachlor (6% GR) (10 kg ha-1) fb 2,4-D (1.25 kg a.i. ha-1) + one hand weeding at 45 DAS showed higher results. The economic analysis revealed that among the methods of sowing, net income and B:C ratio was found higher in puddled condition. Among various weed management practices, higher net return and B:C ratio was observed with the application of Bensulfuron methyl (0.6%) + Pretilachlor (6% GR) (10 kg ha-1) fb 2,4-D (1.25 kg a.i. ha-1) + one hand weeding at 45 DAS. It was followed by the application of Pendimethalin (2.5 kg a.i. ha-1) + Bispyribac sodium (50 g a.i. ha-1) fb one hand weeding at 45 DAS.

Key words : Aerobic rice, Economics, Puddled, Unpuddled, Wet seeded, Weed control efficiency

Copyright @ 2019 Madras Agricultural Journal | Developed by Crystalpro All right reserved.

MADRAS AGRICULTURAL JOURNAL

Biosorption of Chromium (III) from Aqueous Solution by Water Hyacinth Biomass

Abstract

                                Release of heavy metals into the environment is a matter of global concern for the past few years and it should be removed from industrial waste waters before discharge for maintaining water quality standards. This study involved the use of water hyacinth biomass as biosorbent for removal of Cr(III) from aqueous solution. The biosorbent was characterized by FTIR, SEM with EDAX. Batch experiments were conducted to determine the sorption isotherms, effect of solution pH, adsorbate concentration, contact time, biosorbent dosage and size. The results confirmed that water hyacinth biomass can remove Cr(III) from aqueous solution. The maximum sorption occurs at pH =5.0, biosorbent size= 0.2mm, biosorbent dosage=2.0g 100ml-1 of adsorbate, adsorbate / solute concentration= 100 mg L-1 Cr(III) at 25ºC at 250 rpm after 24 hrs. The rate of adsorption was rapid and equilibrium attained at 24hrs. Langmuir, Freundlich and Temkin isotherm models were used to analyze the equilibrium adsorption data. Langmuir isotherm fitted the data well with R2 value of 0.999. Overall, the powdered water hyacinth biomass could be utilized as effective low cost adsorbent for the removal of Cr(III) from waste water.

Key words : Adsorption, Cr Removal, Release kinetics, Water hyacinth

Copyright @ 2019 Madras Agricultural Journal | Developed by Crystalpro All right reserved.

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