158 research outputs found

    Maize (Zea mays L.) response to subsoil compaction and nitrogen fertilization under semi-arid irrigated conditions

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    The present investigation was carried out to access the optimal N dose and its impact on growth, yield and yield attributes of hybrid maize (Zea mays. L) under subsoil compaction condition. The experiment was conducted at Research Farm, Department of Soil Science, Punjab Agricultural University, Ludhiana during the summer seasons of the year 2012 and 2013. The experiment comprised three subsoil compaction treatments in main plots and three nitrogen levels in sub plots following split-plot design with three replications. Plant height, leaf area index and dry matter accumulation were negatively affected by subsoil compaction. However nitrogen fertilization mitigates the negative effect of subsoil compaction on growth of maize. Cob length was recorded lower with higher cob barrenness under higher degree of subsoil compaction. The grain yield was reduced by 13-16 per cent and biomass yield by 10-17 per cent due to subsoil compaction. The total N uptake was 14.6 and 18.2 per cent higher under C0 treatment than that in highly compacted subsoil (C2), while N2 treatment had improved the total N uptake by 18.6 and 14.9 per cent as compared to N0 treatment during the year 2012 and 2013, respectively. The results revealed that N1 fertilization level can be recommended under subsurface compacted soils as compared to N0 and N2 rates. This study further suggests the management option should be explored in addition to deep tillage to maximize yield of maize

    Phenology and thermal indices of maize (Zea mays L.) influenced by subsoil compaction and nitrogen fertilization under semi-arid irrigated conditions

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    The magnitude of yield reduction due to soil compaction is variable and depends on the soil type, fertility status and other soil and environmental factors. The present investigation was carried out at the research farm, Department of Soil Science, Punjab Agricultural University, Ludhiana. The experiment was conducted to evaluate the effect of different levels of subsoil compaction and nitrogen fertilization on maize phenology, yield and heat use efficiency. The C2 (subsoil bulk density (Db)= >1.8 Mg m-3) treatment reduced yield by 15.5 and 24.3 % and heat use efficiency (HUE) by 15.2 and 20.9 % than that in C0 (subsoil Db=1.55-1.65 Mg m-3) treatment during the year 2012 and 2013, respectively. The tasseling and silking stage was delayed, while physiological maturity was advanced under C2 subsoil compaction treatment than that in C0 treatment. The N2 treatment improved the yield by 14.9 and 13.9 % and HUE by 15.2 and 14.3 % than that in N0 treatment during the year 2012 and 2013, respectively. Maize took more days to reach physiological maturity under N2 treatment as compared to N0 treatment. Phenothermal index (PTI) showed that crop reached different stages earlier under C1 and C2 than that of C0. The data emphasized the need to take care of soil strength and soil temperature related parameters along with weather conditions for better yield prediction using thermal time

    Quantification of surface runoff in Patiala-Ki-Rao watersheds using modified NRCS model: a case study

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    Quantification of the surface runoff in a watershed is of vital importance for solution of many water resource problems. It can be quantified by employing large number of estimation approaches. Of these, SCS-CN approach is quite simple effective and requires less number of parameters. Thus, the objective of the study was to employ soil conservation service-curve number (SCS-CN) approach and their modifications to estimate surface runoff for Patiala-Ki-Rao watershed, district SAS, Nagar, Punjab and to choose the best model of the 8-different employed models. Soil moisture retention parameter was characterised and optimised by using the descriptive statistics and later used in the models. The mean and median valueof soil moisture retention parameter was 47.2 mm and 35.9 mm for June to September months and 35.4 to 30.8 mm for October to March months. The models were evaluated on the basis of Root Mean Square Error (RMSE), Nash- Scutcliffe Efficiency (NSE), Coefficient of Determination (R2) and Per cent Bias (PB). Of the evaluated and tested models, NRCS model (M5) performed best with the highest score of 32 and 31 by employing mean andmedian values of soil moisture retention parameter in Patiala-Ki-Rao watersheds over the other models. Further, the results of the study suggested in evaluating the performance of NRCS model (M5) in other treated micro-watersheds at Patiala-Ki-Rao, Punjab, over the control

    TWO NOVEL FLAVONE C-GLYCOSIDES ISOLATED FROM AFROCARPUS GRACILIOR: POM ANALYSES AND IN VITRO CYTOTOXIC ACTIVITY AGANIST HEPATOCELLULAR CARCINOMA

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    Objective: Cancer is considered as one of the top reasons of death and the number of cases increasing gradually. Cancer is severe clinical difficulty to the health caution system. This study explored two novel polyphenols of Afrocarpus gracilior Pilger growing in Egypt and evaluated their cytotoxic activity. Methods: Methanolic (80%) extract of the leaves of A. gracilior was subjected to column chromatography; the chemical structures of the isolated compounds were established by advanced spectral techniques: UV, 1H, 13C NMR, two dimensional NMR (2D NMR) and electron spray ionization mass spectroscopy (ESI-MS). Compounds 1 and 2 were studied for their cytotoxic activity against hepatocellular carcinoma (Hep-G2) using sulforhodamine B (SRB) assay. Furthermore the pharmacokinetics profiles of these molecules were accessed by employing Petra/Osiris/Molinspiration (POM) analyses. Results: Two novel C-flavonoid glycosides were isolated [1: Apigenin 8-C-β-D-glucopyranosyl-(1```→4``)-O-β-D-glucopyranoside] and [2: 7-O methyl-luteolin 8-C-β-glucopyranosyl-(1```→4``)-O-β-D-glucopyranoside]. They exhibited significant cytotoxic activity (IC50 = 9.02 and 15.61 µg/ml, respectively) against Hep-G2 cells. The POM analyses revealed that the activity of these two compounds depends on the presence of glucosyl and alkyl groups at the internal and terminal atmosphere of the compounds. Conclusion: These findings demonstrated that the leaves of A. gracilior contain a series of bioactive polyphenolic compounds with significant cytotoxic properties against hepatocellular carcinoma and may be used as alternative anticancer agents for doxorubicin. On the basis of POM calculations, it will be interesting to develop some alternative flavones because the deglucosylated derivatives have a better drug score than parent molecules. This preliminary study will be extended to other strains of cancer

    Inhibitory effect of Acacia hamulosa methanolic extract on the corrosion of mild steel in 1 M hydrochloric acid

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    The flora of Saudi Arabia comprises about 18 species of Acacia species including Acacia hamulosa Benth. The methanolic extract of the flowering tops of A. hamulosa was tested for its radical scavenging activity toward 2,2-diphenyl-1-pricylhydrazyl (DPPH) radical and the activity was compared with L-ascorbic acid, quercetin and Trolox as standards. The total phenolic content was determined using Folin-Ciocalteu method. In addition the methanolic extract has been evaluated as a corrosion inhibitor for steel in 1 M HCl solution by means of weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Tafel polarization study revealed that extract of Acacia hamulosa acts as a cathodic type inhibitor. Inhibition was found to increase with increasing concentration of the extract of Acacia hamulosa. Values of inhibition efficiency calculated from weight loss, Tafel polarization curves, and EIS are in good agreement. The effect of temperature on the corrosion behaviour of mild steel in 1 M HCl with addition of extract was also studied and thermodynamic parameters were determined and discussed.               KEY WORDS: Acacia hamulosa, Extract, Polyphenols, Antioxidant corrosion, Electrochemical study Bull. Chem. Soc. Ethiop. 2018, 32(2), 323-335.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1

    Studies of Catecholase Activities of N-donor Bidentates Ligands derivated from Benzoxazole with Copper (II) Salts

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    Three functional, N-donorbidentates ligands, L1: 2-(pyridin-2-yl)benzoxazole L2: 2-(quinolin-2-yl)benzoxazole and L3: 2-(4-(trifluoromethyl)pyridin-2-yl)benzoxazole have been examined for their catalytic oxidative activities. The dioxygen complexes of Cu(II) were generated in situ by stirring copper salts and bidentates ligands derivated from benzoxazole. It has been found that these compounds are very efficient to give o-quinone. The nature of the ligands, the counter anion copper (II) salts and solvent have been investigated. These three parameters have an important effect on the oxidation reaction rate

    Hydrogen effect modeling on Ziegler-Natta catalyst and final product properties in propylene polymerization

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    Hydrogen, as chain transfer agent, effects on kinetic of propylene polymerization; consequently variation of hydrogen concentration leads to change final product properties and also activates site of used catalyst. This phenomenon is one of the most important process variables is to adjust the final product properties and optimize the operating conditions. This work has attempted to present a mathematical model that cable to calculate the most important indices of end used product, such as melt flow index, number and weight average molecular weight and poly dispersity index. The model can predict profile polymerization rates determining important kinetic parameters such as the activation energy, lumped deactivation reaction initial reaction rate and deactivation constant. The mathematical model was implemented in Matlab/Simulink environment for slurry polymerization in laboratory scale. The modeling approach is based on polymer moment balance method in the slurry semi-batch reactor. In addition, in this work have provided a model that calculating fraction activated sites catalyst via hydrogen concentration. The model was validated by experimental data from lab scale, reactor. The experimental and model outputs were compared; consequently, the errors were within acceptable range.               KEY WORDS: Mathematical modeling, Propylene polymerization, Kinetics study, Hydrogen response, population balance Bull. Chem. Soc. Ethiop. 2018, 32(2), 371-386.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1
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