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Search Results: 1 - 10 of 401283 matches for " Upendra M. Sainju "
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Comparison of Net Global Warming Potential and Greenhouse Gas Intensity Affected by Management Practices in Two Dryland Cropping Sites  [PDF]
Upendra M. Sainju
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.69092
Abstract: Little is known about the effect of management practices on net global warming potential (GWP) and greenhouse gas intensity (GHGI) that account for all sources and sinks of greenhouse gas (GHG) emissions in dryland cropping systems. The objective of this study was to compare the effect of a combination of tillage, cropping system, and N fertilization on GWP and GHGI under dryland cropping systems with various soil and climatic conditions from 2008 to 2011 in western North Dakota and eastern Montana, USA. Treatments in western North Dakota with sandy loam soil and 373 mm annual precipitation were conventional till malt barley (Hordeum vulgarie L.) with 67 kg N ha-1 (CTB/N1), conventional till malt barley with 0 kg N ha-1 (CTB/N0), no-till malt barley-pea (Pisum sativum L.) with 67 kg N ha-1 (NTB-P/N1), no-till malt barley with 67 kg N ha-1 (NTB/N1), and no-till malt barley with 0 kg N ha-1 (NTB/N0). In eastern Montana with loam soil and 350 mm annual precipitation, treatments were conventional till malt barley-fallow with 80 kg N ha-1 (CTB-F/N1), conventional till malt barley-fallow with 0 kg N ha-1 (CTB-F/N0), no-till malt barley-pea with 80 kg N ha-1 (NTB-P/N1), no-till malt barley with 80 kg N ha-1 (NTB/N1), and no-till malt barley with 0 kg N ha-1 (NTB/N0). Carbon dioxide sink as soil C sequestration rate at the 0 - 10 cm depth was greater in NTB-P/N1 and NTB/N1 than the other treatments at both sites and greater in eastern Montana than western North Dakota. Carbon dioxide sources were greater with N fertilization than without and greater with conventional till than no-till. Soil total annual N2O and CH4 fluxes varied among treatments, years, and locations. Net GWP and GHGI were lower in NTB-P/N1 than the other treatments in western North Dakota and lower in NTB-P/N1 and NTB/N1 than the other treatments in eastern Montana. Net GWP across similar treatments was lower in eastern Montana than western North Dakota, but GHGI was similar. Annualized crop yield was greater in the treatments with N fertilization than without. Because of greater grain yield but lower GWP and GHGI, no-till malt barley-pea rotation with adequate N fertilization can be used as a robust management practice to mitigate net GHG emissions while sustaining dryland crop yields, regardless of soil and climatic conditions. Loam soil reduced GWP and crop yields compared with sandy loam soil.
Residue Placement and Rate, Crop Species, and Nitrogen Fertilization Effects on Soil Greenhouse Gas Emissions  [PDF]
Jun Wang, Upendra M. Sainju, Joy L. Barsotti
Journal of Environmental Protection (JEP) , 2012, DOI: 10.4236/jep.2012.329141
Abstract: High variability due to soil heterogeneity and climatic conditions challenge measurement of greenhouse gas (GHG) emissions as influenced by management practices in the field. To reduce this variability, we examined the effect of management practices on CO2, N2O, and CH4 fluxes and soil temperature and water content from July to November, 2011 in a greenhouse. Treatments were incomplete combinations of residue placements (no residue, surface placement, and incorporation into the soil) and rates (0%, 0.25%, and 0.50%), crop species (spring wheat [Triticum aestivum L.], pea [Pisum sativum L.], and fallow), and N fertilization rates (0.11 and 0.96 g.N.pot-1). Soil temperature was not influenced by treatments but water content was greater under fallow with surface residue than in other treatments. The GHG fluxes peaked immediately following water application and/or N fertilization, with coefficient of variation (CV) ranging from 21% to 46%, <50% of that reported in the field. Average CO2 and N2O fluxes across measurement dates were greater under wheat or fallow with surface residue and 0.96 g.N.pot-1 than in other treatments. Average CH4 uptake was greater under fallow with surface or incorporated residue and 0.11 g.N.pot-1 than in other treatments. Doubling the residue rate increased CO2 flux by 9%. Greater root respiration, N substrate availability, and soil water content increased CO2 and N2O emissions under wheat or fallow with surface residue and high N rate but fallow with low N rate increased CH4 uptake. Controlled soil and environmental conditions substantially reduced variations in GHG fluxes.
Suction Cup Samplers for Estimating Nitrate-Nitrogen in Soil Water in Irrigated Sugarbeet Production  [PDF]
Jay D. Jabro, William B. Stevens, William M. Iversen, Brett L. Allen, Upendra M. Sainju
Journal of Environmental Protection (JEP) , 2016, DOI: 10.4236/jep.2016.710117
Abstract: Efforts have increased to measure nitrate losses from farmland under different management practices due to environmental and public concerns over levels of nitrate-nitrogen (NO3-N) in surface and ground waters. This study evaluated the effect of conventional tillage (CT) and strip tillage (ST) practices and three N application rates on NO3-N concentrations in soil water at a 76 cm depth under irrigated sugarbeet (Beta vulgaris L.) in a clay loam soil. Nitrogen rates were applied as dry urea at 120, 150, 180 kg N ha-1 in 2006; 130, 160, 190 kg N ha-1 in 2007; and 110, 140, 170 kg N ha-1 in 2008. Soil water volumes were measured weekly during each growing season using three ceramic suction cup samplers per plot placed at a 76 cm depth below the soil surface under each tillage. Results indicated that NO3-N concentrations at the 76 cm depth in the soil profile were not significantly affected by either tillage practice or by N application rate due to soil variability across the field and due to suction cup samplers’ biased estimate of soil water. The three N rates under CT and ST practices maintained NO3-N concentrations below the root zone to levels exceeding the 10 mg L-1 safe drinking water maximum level in all three years. There were large variations in NO3-N concentrations among replicates within each tillage and N rate that were likely caused by variability in soil physical, hydraulic and chemical properties that impacted water movement through the soil profile, N dynamics and leaching below the root zone of sugarbeet. In conclusion, suction cup samplers are point water measurement devices that reveal considerable variability among replicates within each treatment due to the heterogeneity of field soils. Further, these samplers are not recommended in heterogeneous soils with preferential flow characteristics.
Agricultural Management Practices to Sustain Crop Yields and Improve Soil and Environmental Qualities
Upendra M. Sainju,Wayne F. Whitehead,Bharat P. Singh
The Scientific World Journal , 2003, DOI: 10.1100/tsw.2003.62
Abstract:
Tillage, Crop Rotation, and Cultural Practice Effects on Dryland Soil Carbon Fractions  [PDF]
Upendra M. Sainju, Andrew W. Lenssen, Thecan Caesar-TonThat, Jalal D. Jabro, Robert T. Lartey, Robert G. Evans, Brett L. Allen
Open Journal of Soil Science (OJSS) , 2012, DOI: 10.4236/ojss.2012.23029
Abstract: Information is needed on novel management practices to increase dryland C sequestration and soil quality in the northern Great Plains, USA. We evaluated the effects of tillage, crop rotation, and cultural practice on dryland crop biomass (stems and leaves) yield, surface residue, and soil C fractions at the 0-20 cm depth from 2004 to 2008 in a Williams loam in eastern Montana, USA. Treatments were two tillage (no-tillage [NT] and conventional tillage [CT]), two crop rotations (continuous spring wheat [Triticum aestivum L.] [CW] and spring wheat-barley [Hordeum vulgaris L.] hay-corn [Zea mays L.]-pea [Pisum sativum L.] [W-B-C-P]), and two cultural practices (regular [conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height] and ecological [variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height]). Carbon fractions were soil organic C (SOC), particulate organic C (POC), microbial biomass C (MBC), and potential C mineralization (PCM). Crop biomass was 24% to 39% greater in W-B-C-P than in CW in 2004 and 2005. Surface residue C was 36% greater in NT than in CT in the regular practice. At 5 - 20 cm, SOC was 14% greater in NT with W-B-C-P and the regular practice than in CT with CW and the ecological practice. In 2007, POC and PCM at 0 - 20 cm were 23 to 54% greater in NT with CW or the regular practice than in CT with CW or the ecological practice. Similarly, MBC at 10 - 20 cm was 70% greater with the regular than with the ecological practice in NT with CW. Surface residue, PCM, and MBC declined from autumn 2007 to spring 2008. No-tillage with the regular cultural practice increased surface residue and soil C storage and microbial biomass and activity compared to conventional tillage with the ecological practice. Mineralization reduced surface residue and soil labile C fractions from autumn to spring.
不同覆盖措施对黄土高原旱作农田N2O通量的影响
刘全全,王俊,付鑫,刘文兆,Upendra M. Sainju
- , 2016, DOI: 10.7606/j.issn.1000-7601.2016.03.18
Abstract: 为研究秸秆和地膜覆盖条件下旱作冬小麦田N2O通量变化及水热状况,在中国科学院长武农业生态试验站采用静态箱-气相色谱法测定了冬小麦种植期间覆盖处理(CK)、地膜覆盖处理(PM)、全年覆盖秸秆处理4 500 kg·hm-2(M4500)和全年覆盖秸秆9 000 kg·hm-2处理(M9000)土壤N2O排放通量,并同步测定了土壤水分、土壤温度和气温。研究表明:CK、PM、M4500和M9000处理生育期内N2O通量范围分别为17.24~321.86、19.03~388.00、21.57~344.53 μg·m-2·h-1和24.77~348.42 μg·m-2·h-1,生育期内N2O平均排放通量分别为110.64、146.48、131.31 μg·m-2·h-1和142.26 μg·m-2·h-1,与CK相比,PM、M4500和M9000处理N2O平均排放通量分别提高了32.29%、18.68%和28.57%,其中,PM和M9000处理与CK之间差异达极显著水平(P<0.01)。PM处理N2O累积排放量(7.25 kg·hm-2)较CK处理(5.18 kg·hm-2)提高了40%(P<0.05),秸秆覆盖处理M4500(6.30 kg·hm-2)和M9000(7.17 kg·hm-2)N2O累积排放量较CK处理分别提高23%和38%(P<0.05),PM和M9000处理N2O累积排放量显著高于M4500,PM和M9000处理之间显著差异。不同覆盖条件下生育期N2O通量表现出明显的季节变化特征,小麦生长季始末期较高中期较低,N2O排放受降水影响明显。生育期N2O累积通量主要源于冬小麦拔节期至收获期,PM、M4500和M9000处理拔节期至收获期N2O排放量分别占整个生育期的41%、40%和43%,均高于CK(38%)处理。土壤温度变化可以解释69%~76%土壤N2O通量变化,土壤水分仅解释了37%~51%的土壤N2O通量变化。回归分析表明覆盖时,土壤水分是影响土壤N2O排放的关键因子,秸秆覆盖和地膜覆盖条件下土壤温度是影响土壤N2O排放的关键因子。覆盖秸秆4 500 kg·hm-2是黄土旱塬区较为适宜的冬小麦栽培模式。
RHINACANTHUS NASUTUS (LINN.) KURZ: A COMPREHENSIVE REVIEW
M.Upendra Rao
International Journal of Pharmaceutical Research and Development , 2010,
Abstract: Rhinacanthus Nasutus (Linn.) Kurz is an important medicinal plant, is widely distributed in some parts of the sub-continent India, China and in the region of Southeast Asia including Thailand. The plant contains several chemical constituents like rhinacanthin-C, rhinacanthin-D, rhinacanthin-N, rhinacanthin-Q, rhinacanthins (A- D, G-Q) and rhinacanthone. The plant is claimed to possess anti-microbial activity, anti-allergic activity, anti-inflammatory activity, anti-viral activity, anti-mutagenicity, anti-proliferative activity, anti-tumor activity and anti-platelet effect. The present article reveals the detailed exploration of phytoconstituents and pharmacological activities of Rhinacanthus Nasutus is an attempt to provide for further research.
ECN Congestion Control Mechanism in IP Networks
Subarna Shakya,Anup Sainju
Journal of the Institute of Engineering , 2011, DOI: 10.3126/jie.v8i1-2.5093
Abstract: Explicit Congestion Notification (ECN) is a newer method for congestion control in TCP IP networks. Network Simulator 2 (NS2) software has been used to compare the performance of ECN packet marking to other older and newer congestion control schemes, such as DropTail and Random Early Detection (RED), in both LAN and WAN schemes. During the simulations different parameters including proportion of packet drops, window size variation, queue size, and throughput were measured to evaluate the performance. The overall objective was to independently and comparatively study ECN in a wide range of situations to better understand its advantages and disadvantages. The results of these simulations showed that when all the network prerequisites were met (i.e. all the nodes including being ECN-aware), ECN reduced packet drops and thereby optimized network resource utilization and data throughput. Key Words : Explicit Congestion Notification; Network Simulator; Random Early Detect; DropTail DOI: http://dx.doi.org/10.3126/jie.v8i1-2.5093 Journal of the Institute of Engineering Vol. 8, No. 1&2, 2010/2011 Page : 12-24 Uploaded Date : 19 July, 2011
Quantitative Application to a Polypill by the Development of Stability Indicating LC Method for the Simultaneous Estimation of Aspirin, Atorvastatin, Atenolol and Losartan Potassium  [PDF]
Satheesh K. Shetty, Koduru V. Surendranath, Pullapanthula Radhakrishnanand, Roshan M. Borkar, Prashant S. Devrukhakar, Johnson Jogul, Upendra M. Tripathi
American Journal of Analytical Chemistry (AJAC) , 2010, DOI: 10.4236/ajac.2010.12008
Abstract: Polypill is a fixed-dose combination (FDC) containing three or more drugs in a single pill with the intention of reducing the number of tablets or capsules that need to be taken. Developing a single analytical method for the estimation of individual drugs in a Polypill is very challenging, due to the formation of drug-drug and drug-excipients interaction impurities. Here an attempt was made to develop a new, sensitive, single stability-indicating HPLC method for the simultaneous quantitative determination of Aspirin (ASP) Atorvastatin (ATV), Atenolol (ATL) and Losartan potassium (LST) in a polypill form in the presence of degradation products. Efficient chromatographic separation was achieved on a C18 stationary phase with simple mobile phase combination of buffer and Acetonitrile. Buffer consists of 0.1% Orthophosphoric acid (pH 2.9), delivered in a gradient mode and quantitation was carried out using ultraviolet detection at 230 nm with a flow rate of 1.0 mL/min. The retention times of Atenolol, Aspirin, Losartan potassium, and Atorvastatin were 3.3, 7.6, 10.7 and 12.9 min respectively. The combination drug product are exposed to thermal, acid/base hydrolytic, humidity and oxidative stress conditions, and the stressed samples were analyzed by proposed method. The method was validated with respect to linearity; the method was linear in the range of 37.5 to 150.0 µg/mL for ASP, 5.0 to 20.0 µg/mL for ATV and 25.0 to 100.0 µg/mL for ATL and LST. Acceptable precision and accuracy were obtained for concentrations over the standard curve ranges. The validated method was successfully applied to the analysis of Starpill tablets constituting all the four drugs; the percentage recoveries obtained were 99.60% for ASP, 99.30% for ATV, 99.41% for ATL and 99.62% for LST.
Stress Degradation Behavior of a Polypill and Development of Stability Indicating UHPLC Method for the Simultaneous Estimation of Aspirin, Atorvastatin, Ramipril and Metoprolol Succinate  [PDF]
Satheesh Kumar Shetty, K.V Surendranath, P Radhakrishnanand, Roshan M Borkar, Prashant S Devrukhakar, Johnson Jogul, Upendra Mani Tripathi
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.24049
Abstract: A novel, sensitive and precise UHPLC method has been developed and validated for the simultaneous determination of the all the active components of a Polypill viz Zycad, i.e., Aspirin (ASP) Atorvastatin (ATV), Ramipril (RMP) and Metoprolol (MTP) in Zycad tablet dosage form in the presence of degradation products. Forced degradation of individual as well as combination of all the drug substances components of Polypill was conducted in accordance with ICH guidelines. Acidic, basic, neutral, and oxidative hydrolysis, thermal stress, and photolytic degradation were used to assess the stability-indicating power of the method. Use of 100 × 2.1 mm, 1.7 µm stationary phases with simple mobile phase combination buffer consisting of 0.1% Perchloric acid (adjusted to pH 2.5) and Acetonitrile, delivered in a gradient mode and quantitation was carried out using ultraviolet detection at 215 nm with a flow rate of 0.6 mL?min–1. The method was optimized using samples generated by forced degradation studies. The method was validated for linearity, accuracy (recovery), precision, Specificity and robustness. The method was linear in the range of 37.5 to 150.0 µg?mL–1 for ASP, 5.0 to 20.0 µg?mL–1 for ATV and 2.5 to 10.0 µg?mL–1 for RMP and 25.0 to 100.0 µg?mL–1 for MTP.
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