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Subject: Microbiology × Author: Manpreet Kaur × End date: 2019 × Start date: 2012 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Synthesis and characterization of nanosilica particles from rice husk and its effect on soil microbes and vegetative growth in tomato
    (Punjab Agricultural University, Ludhiana, 2016) Manpreet Kaur; Kalia, Anu
    Rice husk, a waste by-product of rice sheller industry, has serious disposal problems. Turning this waste into nanosilica particles (SiNPs) is an ecologically as well as economical prudent technology. The SiNPs were synthesized from rice husks of 3 basmati and 6 parmal rice varieties by giving the acid pre-treatment using conventional heating and microwave irradiation techniques prior to charring in muffle furnace at 7000 C. The particle size ranged from 20 to 80 nm of individual and 150 to 200 nm of the agglomerated particles for the tested varieties. The synthesized SiNPs along with other micro silica sources (i.e. Rice Husk Ash (RHA), Kaolinite and Sodium Silicate) were applied to soil at six different concentrations to assess their effect on soil properties, total microbial population, soil enzymatic activities and vegetative growth of tomato. The SiNPs and RHA application caused decrease in pH, OC and EC while enhanced the soil available Nitrogen (N). The SiNPs significantly enhanced the soil microbial population, soil dehydrogenase, acid and alkaline phosphatase activities while significantly decreased the urease activity. A numerical increase in shoot and root length, number of laterals and total chlorophyll content of tomato cv. Chhuhara and a significant increase in rhizospheric microbial populations occurred by foliar application of SiNPs. The applied SiNPs remained on leaf surface as aggregates and were observed to be internalized through stomata as confirmed by Scanning EM and SEM-EDS studies. The tomato root-endophytic fungal interactions remained unaffected which further accentuates the beneficial effects of SiNP application in tomato.