ABSTRACT
A study to assess the profile distribution of important soil attributes in Alfisols and Entisols of West Bengal was conducted during 2016-17. Purposefully selected random sampling was carried out to collect the soils from different locations of two study sites, viz., Kalinagar (25º27'33.9"N, 88º19'10.2"E) from Malda district and Durganagar (26º09'62.7"N, 89º53'51.7"E) from Cooch Behar district of West Bengal at 0-15, 15-30, 30-45 and 45-60 cm depths. Understanding of vertical distribution of soil fertility indicators like soil organic carbon (SOC), total nitrogen (TN) and other important properties in two different soil and climatic conditions will provide an insight regarding the behaviour of soil with the change in environmental conditions. Soil bulk density (BD), porosity, pH, SOC, TN, C:N ratio and texture were determined using standard laboratory procedures and computations. Obtained results were subjected to statistical analyses. Soils of Kalinagar sites were slightly acidic in nature while soils of Durganagar were neutral in nature. Kalinagar soils were silt clay loam in texture where Durganagar soils classified as loam to sandy loam. Soil BD values increased with depth in both Kalinagar (Alfisol) and Durganagar (Entisol). The porosity percentage progressively decreased with an increase in depth. Soils of Durganagar reported higher soil porosity at all the depths studied. An increase in soil pH with increasing depth was observed in both the sites. The mean total organic carbon (TOC) content recorded maximum in surface soil and its concentration decreased with the depth. Kalinagar soils observed 7.63% higher TOC (17.94 g kg-1) content than Durganagar (16.57 g kg-1) at surface depth (0-15 cm) and its accumulation at the lower depths was also maximum in former soil. Mean TN values were also found to decrease by increasing the depth. The accumulation of total nitrogen at the subsequent depths was relatively higher in Kalinagar than Durganagar. Increase in C:N ratio with increasing depth was noticed in Kalinagar site but the opposite trend was accorded in case of Durganagar. Accumulation of SOC and TN throughout the soil depth was found to be greater in Alfisol (Kalingar) due to higher clay and silt fractions as compared to Entisol (Durganagar). There was a significant positive relation of TOC with clay and silt (r = 0.285, p<0.05, r = 0.314, p<0.01, respectively) and of TN with clay and silt (r = 0.328, p<0.01, r = 0.262, p<0.05, respectively) irrespective of soil orders. Alfisols with high bulk density have a greater capacity to accumulate SOC and TN throughout the soil profile due to higher clay and silt fractions in comparison to Entisols with loose textural properties.
ABSTRACT
Objective:To establish a method for the content determination of total nitrogen in Nidus Vespae by salicylic acid and sodium hypochlorite spectrophotometry. Methods:The content of total nitrogen in Nidus Vespae from different areas with various batches was detected. Nidus Vespae was treated with sulfuric acid and hydrogen peroxide, and colored by salicylic acid and sodium hypochlo-rite. Using ammonium chloride as the control sample, the content of total nitrogen in the samples was tested at 650 nm. To ensure the method reliability, single factor experiments were performed to study the effects of temperature, reaction time and reagent dosage; or-thogonal experiments were used to screen optimum amounts of phosphate buffer solution, sodium salicylate solution and sodium hypo-chlorite solution. Results:The results showed that the optimum temperature was ambient, and the optimum time was 1. 5h. The opti-mum amount of phosphate buffer solution , sodium salicylate solution and sodium hypochlorite solution was 4 ml,7 ml and 1. 5 ml, re-spectively. The linear range of total nitrogen was 0. 06-0. 78 μg·ml-1(r=0. 9998), and the average recovery was 100. 98% (RSD=2. 10%,n=6). Conclusion:The method can be used to determine the total nitrogen content in Nidus Vespae. The total nitrogen content in Nidus Vespae is various in various areas with different batches.
ABSTRACT
A cadmium column reduction-azo dyes spectrophotometric method based on micro sequential injection lab-on-valve was established for the determination of total nitrogen in seawater. The experimental parameters were optimized, and the interference experiment was carried out. The results showed that the interference of the main components and salinity in sea water could be eliminated by using a series of standard solution prepared by national standard seawater with certain salinity. The concentration of total nitrogen in seawater was linear with the absorbance in the range of 0 . 03-1 . 00 mg/L with a correlation coefficient of 0. 9993. When determining the national standard seawater at nitrogen concentration of 0. 20 mg/L, the relative standard deviation (RSD) was 4. 9%, the detection limit was 0. 010 mg/L, and the recoveries were 99. 5%-101 . 1%. There were not significance differences between the results of this method and national standard method in the t-test analysis. The method is suitable for the determination of total nitrogen in seawater.
ABSTRACT
Mycotoxins are considered as the most hazardous fungal metabolites for human, animals and plant health. Recently, more attention has been paid on the occurrence of this group of fungi in different water sources throughout the globe. In this study, Aspergillus parasiticus ATCC strain was used as representative strain producing aflatoxins in drinking water. This study aimed to investigate the activation of fungi in drinking water and their ability to produce aflatoxins (B1, B2, G1, and G2) in water under different ratios of C:N using different concentrations of total organic carbon (TOC) and total nitrogen (TN). Glucose and ammonium sulphate were used for changing the levels of TOC and TN in the selected water media. Similarly, the effects of different water pH levels from 4.5 to 8.2 on the growth of this group of fungi and aflatoxins production were also investigated. The results indicate that the growth of fungi was highest, at C:N ratio of 1:1 as compared to other selected ratios. Furthermore, the findings indicate that the pH levels 5.5-6.5 showed best growth of fungi as compared to other pH levels. Aflatoxin concentrations were measured in the water samples using HPLC technique, but selected fungi were not able to produce aflatoxins in water at applied concentrations of TOC and TN mimicking the ratios and concentrations present in the natural aquatic environment.
ABSTRACT
Present investigation was carried out in Cachar district of Assam over a period of two years (May 2007 - April 2009) to understand the seasonal ecology of Isotomina thermophila (Axelson, 1900) in secondary succession and homegarden ecosystems. Population was found to be maximum during July 2008 (7949.05 No. m-2) and September 2008 (7949.05 No. m-2) in homegarden whereas the peak was recorded in secondary succession during September 2008 (13656.05 No. m-2). Least population was encountered during March 2008 (1222.93 No. m-2) and April 2008 (1630.57 No. m-2) in homegarden and secondary succession, respectively. It may be due to the fact that, vital activity of this species effected in the dry period or migrate towards lower soil profile in search of food and moisture. Linear regression analysis established the hypothesis that all the environmental variables showed positive and significant influence on the population dynamics whereas in homegarden, rainfall (r= 0.36, p>0.05) did not show any influence. In multiple regression analysis positive and significant influences (p<0.05) were recorded for both the investigated sites. Rainfall, relative humidity and temperature facilitated the soil moisture, microbial activity, litter decomposition may favour the reproduction and growth rate of the species. Among microclimatic conditions except soil pH all other parameters exhibited significant correlations (p<0.05) with population. Based on the present investigation, it can be concluded that I. thermophilia does not differ much with the general ecology of collembolans in this sub humid climate.
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Lake Uluabat, which is located in Marmara region, is one of the most productive lakes in Turkey. Due to concerns about potential pollution resulting from watershed sources and adjacent agricultural lands, a study of the trophic state of lake Uluabat was conducted during the period February 2003 to January 2004. Total nitrogen (TN), total phosphorus (TP), Secchi disc depth (SD) and chlorophyll a (Chl a) were analyzed monthly in order to assess the trophic state of the lake. According to calculated nutrient ratios, phosphorus was found to be the primary limiting nutrient in lake Uluabat. Carlson’s trophic state index values, based on TP, SD and chl a, indicated that lake Uluabat is an eutrophic system.
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[Objective] To measure the nitrogen content in Agrocybe cylindracea R.Maire,compare the advantages of Kai's Nitrogen-testing method and Spectrophotometric method.[Method]Take Kai's Nitrogen-testing method and Spectrophotometric method.[Result]The two methods were almost the same in the measurement of nitrogen,i.e.30.70mg/g,which had no marked difference by t test.[Conclusion]Spectrophotometric method is simple and convenient for operation,quickly and correctly,and can be used for measurement of total nitrogen.
ABSTRACT
O experimento foi realizado com a cv. Gewürztraminer proveniente de Santana do Livramento e de Garibaldi, e submetidas a diferentes tratamentos nitrogenados realizados durante o período vegetativo de 1992-1993. Os mostos obtidos foram divididos em quatro lotes e microvinificados com diferentes leveduras. A fertilização nitrogenada causou um aumento na concentração de nitrogênio total no mosto, variando entre um mínimo de 376, 1mg/l e um máximo de 695,8mg/l. Em todas as microvinificações foram observadas grandes diminuições na concentração de nitrogênio total durante a fermentação; o consumo variou entre 49,3 por cento e 83,7 por cento. Diferentes leveduras mostraram diferenças no consumo de nitrogênio total.
The experiment was done with the grape variety Gewürztraminer from two regions of Rio Grande do Sul; different nitrogen treatments were done in the vineyard during the season of 1992-1993. The musts, of each treatment, were divided into four lots. Each lot was fermented with a different yeast. There was an increasing in the total nitrogen of the musts with the increase of nitrogen fertilization; these values ranged from a minimum of 376.1 mg/l to a maximum of 695.8 mg/l. In all small fermentation lots there was a decrease in the must total nitrogen; yeast used anywhere from 49.3 percent to 83.7 percent of nitrogent. Different yeasts showed difference in total nitrogen uptake.