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20132
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Subject: Chemistry × End date: 2013 × Start date: 2013 ×
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    ThesisItemOpen Access
    CHEMISTRY AND POTENTIAL OF VETIVER OIL AS STORED GRAIN PROTECTANT
    (PAU Ludhiana, 2013) Amanpal Kaur Sandhu; K. K., Chahal
    The present investigation deals with Chemistry and potential of vetiver oil as stored grain protectant. Vetiver oil was subjected to column chromatography to have non polar and polar fractions. Different fractions were subjected to thin layer chromatography in order to find the number of compounds present in different fractions. Rearing of Tribolium castaneum (Herbst) adults were carried out. Vetiver oil, its non-polar and polar fractions were tested for their bioefficacy against adults of Tribolium castaneum by releasing them in wheat grains spiked with various concentrations of vetiver oil, its non-polar and polar fractions viz. 30,000, 35,000, 40,000, 45,000, and 50,000 μg g-1 respectively. The observations of mortality were noted every 24 hrs till complete or constant mortality was obtained. The corrected per cent mortality was calculated using Abbott’s formula. Vetiver oil was found to be effective at all concentrations tested. The non-polar fraction of petroleum ether was found to be most active whereas the acetone fraction was least active. The corrected per cent mortality increased with increase in concentration and time of application. The most active petroleum ether fraction was subjected to extensive column chromatography to isolate the pure compounds. Khusinol having melting point 73oC was isolated as pure compound. The compound was characterized by FT-IR, 1H NMR and 13C NMR spectroscopy and mass spectrometry.
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    ThesisItemOpen Access
    Nitrogen mineralization kinetics in rice and wheat residue amended soils under long-term saline and sodic water irrigation
    (Punjab Agricultural University, 2013) Vikram Verma
    Laboratory incubation experiments were conducted to study the influence of crop residue incorporation on soil properties and to assess the N-mineralization kinetics under long-term irrigation with saline (SaW) and sodic water (SW). Irrigation with SaW and SW significantly increased the pH, EC and ESP while application of gypsum and crop residues improved these properties. N-mineralization in different soils ranged from 233 to 392 mg N kg-1 in case of field addition and 84 to 285 mg N kg-1 in case of fresh addition of crop residues during incubation. Relative to canal water (CW) treatment, SW significantly decreased the mineral-N followed by SaW treatment. Application of gypsum and incorporation of crop residues in the field resulted in increase in mineral-N. Maximum cumulative N mineralization was observed in wheat straw (WS) amended treatment except in SW+G treatment. Fresh addition of crop residues resulted in net N immobilization and lower rate of N mineralization compared to unamended treatments. In SaW, SW and SW+G treatments, a dip in mineral-N was observed at 28 days in the amended treatments. Among the kinetic models,only first order model (FO) provided realistic solutions but with poor R2values (0.18 to 0.57). Nitrogen mineralization potential (N0) ranged between 171 and 383 mg N kg-1 and the rate constant (k) ranged from 0.020 to 0.411 day-1in different treatments.In case of fresh additions of residues, even FO model didnot provide solutions to any of the amended treatments. Compared to CW treatment, both SW and SaW irrigation significantly decreased the grain yield and N uptake by wheat. Incorporation of crop residues significantly improved the grain yield over the unamended treatment but increase in N uptake was not significant.