1,720,959 research outputs found
Phosphorus Solubilizing Patterns of Different Phosphorus Sources in Rice Cultivation, Sri Lanka: A Case Study
Get PDFBiofilm enriched Eppawala Rock Phosphate (Biofilm-ERP) has been identified as a potential alternative for Triple Super Phosphate (TSP) application for rice cultivation in Anuradhapura, Sri Lanka. This is currently practiced in a few rice growing districts in Sri Lanka with the name of biofilm-ERP practice showing the most promising results in rice cultivation. This study was conducted to evaluate the Phosphorus (P) solubilizing patterns of biofilm-ERP over the Department of Agriculture (DOA) recommended full TSP dosage (2013)(CFE) for rice.
For the treatments, a modified chemical fertilizer (CFM) mixture was developed by replacing TSP in the DOA recommendation (CFE) from biofilm- ERP. Nitrogen (N) and potassium (K) levels were maintained as per the DOA recommendations and control was maintained without any fertilizer amendments. The experiment was arranged in a Completely Randomized Design (CRD) with three replicates. Soil pH, available N and P, organic matter (OM), and microbial biomass C were measured at the initially and end of the experiment. Solubilized P was recovered by leaching in two weekly intervals for up to three months. A significant effect was observed among the P solubilization patterns of treatments. Accordingly, the significantly (p<0.05) highest solubilized P was recorded with biofilm-ERP practice with a slightly increasing trend. Further, this pattern showed a slowly increasing trend over the solubilization period being caused by microbial assimilation of P and releasing of P into soil followed by microbial decomposition obviously with microbial biomass C measurements. The CFE solubilized the P also with a slightly increasing trend but it was significantly lower than the biofilm-ERP. In conclusion, biofilm-ERP was identified as the most outstanding P solubilizer with a sustained pattern for solubilized P. Hence, this biofilm-ERP would be an effective alternative for TSP for rice cultivation in near future. However, further field studies are needed for concrete findings
Potential of Phosphate Solubilizing Microorganisms for Efficient Phosphate Utilization with Eppawala Rock Phosphate : A Review
Get PDFPhosphorus (P) is a vital element in crop nutrition. In most soil, P remains as insoluble and only less than 10% is available for plants due to high P fixation. Phosphate solubilizing microorganisms (PSM) are capable of dissolving insoluble forms of phosphates into plant available forms. Triple Super Phosphate (TSP) is commonly used source of P fertilizer for many crops in Sri Lanka. However, TSP applied fields in Sri Lanka has recorded notable contents of certain heavy metals such as cadmium and arsenic. Eppawala Rock Phosphate (ERP) is a cheap, phosphate-rich source but due to its low solubility usages are limited for annual crops as a P fertilizer. However, PSM have shown the capability of solubilizing ERP and supplying P to plants. At present, several research studies pertaining to the application of PSM as inoculum for crops were condcuted. Hence this review based study is focused in identify the potential of PSM in agriculture. Literature reveled that PSM have shown their potential knack on solubilizing P in ERP with producing clear halo zones and organic acids proportionally. Thus more research studies have to be undertaken under field condition in order to optimize PSM innocula with ERP.Keywords: Halo zones, Eppawala rock phosphate, Organic acids, Phosphorous, Phosphate solubilizing microorganism
Performance Evaluation of Constructed Wetland Units for Domestic Greywater Treatment
Get PDFConstructed wetlands (CW) are an eco-friendly system which is mimic the functions of natural wetland. CW is now standing as a potential simple, low cost alternative system for the treatment of wastewater even up to domestic level. Therefore, this study was designed to assess the feasibility of pilot scale CW units on greywater treatment at domestic level. The sub surface flow constructed wetland units were designed using small plastic containers with the size of 55 cm length, 25 cm width, and 28 cm height and planted with selected plants such as Vetiver (Vetiveria zizanioides), Water spinach (Ipomoea aquatic L.), Lasia (Lasia spinosa L.) and soil without any amendments was served as a control. The experiment was conducted in a Completely Randomized Design (CRD) with three replicates in greenhouse conditions during two months period by using synthesized wastewater at the flow rate of 0.729l/h. The Hydraulic Retention Time of the system was 41 hours. The quality of the influent and each effluent were monitored at two weeks interval by analyzing water quality parameters such as Biological Oxygen Demand (BOD5), Total Dissolve Solids (TDS), pH, Electrical Conductivity (EC), PO4-3-P, NO3--N and NH4+-N. According to the results, Removal efficiency of contaminants increased throughout the monitoring period. Vetiver showed significantly (p<0.05) higher RE for BOD5, PO4-3-P, NO3--N, NH4+-N by 46%, 71%, 83% and 89% respectively. However Water spinach and Lasia showed significantly (p<0.05) higher RE for NO3--N and PO4-3-P by 77% and 68% respectively. Hence, it can be concluded that the pilot scale CW units are feasible technology for greywater treatment at domestic level with the combination of Vetiver, Water spinach and Lasia.Keywords: Constructed wetlands, Greywater treatment, Removal efficiencies, Wetland plant
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
An Assessment of Land Use on Water Quality in Different Inlet and Outlet Canals Connected to Nuwarawewa in Anuradhapura
Get PDFWater quality is a term used to describe the chemical, physical and biological characteristics of water. Water quality parameters in various hydrologic systems have been closely linked to the types of land use within a watershed which are closely related to the characteristics of human activities. As water drains from the land surface, it carries the residues from the land and these residues carried into hydrologic systems through drainage or runoff processes. Hence, this study aimed to assess the impacts of land use on water quality in inlet and outlet water canals connected to Nuwarawewa in Anuradhapura. Seven major inlets and one outlet canals connected to Nuwarawewa were identified. Water samples were collected from each selected location in one-month interval for three months period. Soil samples (0-30cm) were collected from each location at second time point and reference soil samples were collected from the nearby locations. Water quality parameters such as pH, EC, DO, TDS, NO3--N, NH4+-N, available phosphorus (Av.P), alkalinity and heavy metals (Cd and As) concentrations were determined in each water sample. Soil samples were analyzed for pH, EC, NO3--N, NH4+-N, Av.P, total Cd and total As. The results showed that pH, DO, TDS, NH4+-N, and Av.P of some of the water samples tested were higher and other parameters were within permissible levels according to WHO drinking water standards. Higher average N and average P were observed in all soil samples compared to the reference values in literature. Soil As level was within the permissible levels according to European Regulatory Standards for soils and Cd were not at detectable level. A temporal variation of water quality parameters was observed in the inlet and outlet canals during the study period. The results conclude that, impacts of surrounded land use on water pollution in inlet water canals connected to Nuwarawewa are higher and implementation of pollution management plan is required to prevent further pollution by conducting future researches.Keywords: Land use, Nuwarawewa, Water pollution, Water qualit
Can Biofilm-Enriched Eppawala Rock Phosphate Replace the Use of Triple Super Phosphate in Rice Cultivation?
Get PDFEppawala Rock Phosphates (ERP) has a greater potential to be used as an alternate for Triple Super Phosphate (TSP) if phosphorous (P) biosolubility is increased. A certain biofilm (BF3) has been identified as the most efficient P biosolubiliser for ERP. Thus, this study was designed to test the potential of replacing TSP from biofilm-enriched ERP in rice cultivation. Two experiments were conducted; soil leaching tube and pot experiments under controlled conditions. A modified chemical fertiliser (CFM) mixture was developed by replacing TSP from ERP, in the existing chemical fertiliser (CFE) mixture for rice recommended by the Department of Agriculture (DOA). Eleven treatments were used with all possible combinations of CFE and CFM at rates of 50% or 100% alone or together with the BF3. Soil alone was used as the control. Treatment of 50% CFM+BF3 was denoted as biofilm-enriched ERP. The experiments were conducted in a completely randomized design (CRD) with three replicates. Data were statistically analyzed using analysis of variance (ANOVA) followed by mean separation using Turkey’s HSD test. Solubilised P was recovered by leaching in every two weeks for three months. Available soil P, total plant P and grain yields were evaluated at the end of the pot experiment. Biofilm enriched ERP showed no added advantage over the CFE, with lower cumulative solubilized P in leachates. At the end of the pot experiment; biofilm-enriched ERP showed significantly (p<0.05) higher P retention in soil and significantly (p<0.05) lower grain yield comparison to the CFE. However, biofilm-enriched ERP showed no any significant (p>0.05) difference in total plant P. The overall results conclude that the biofilm-enriched ERP performed poorly in comparison to the DOA recommended TSP dosages. Thus, further studies are required to enhance the performance of biofilm-enriched ERP to use as an alternate for TSP in rice cultivation.Keywords: Biofilm, Eppawala Rock phosphate, Rice cultivation, Triple super phosphat
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
