scholarly journals Phosphorus requirements of some selected soil types in the Fiji sugarcane belt

2014 ◽  
Vol 32 (1) ◽  
pp. 1 ◽  
Author(s):  
M.S. Goundar ◽  
R.J. Morrison ◽  
C. Togamana
Keyword(s):  
Soil Phosphorus ◽  
Strong Association ◽  
Clay Content ◽  
Limiting Factors ◽  
Soil Types ◽  
Strong Positive Correlation ◽  
P Leaching ◽  
Phosphorus Requirements ◽  
Physical And Chemical

The availability of phosphorus (P) in soil is perceived to be one of the limiting factors to sustainable sugarcane production in Fiji. The main objective of this research was to ascertain the amount of bioavailable phosphorus in some Fiji sugarcane growing area soils; this will be valuable in improving the determination of the required amount of inorganic fertilizer to be applied to the soil. In this study, twelve different soils were selected from the sugarcane belt of Fiji and phosphorus buffer index (PBI) and phosphorus isotherm experiments were performed. Soil physical and chemical parameters were also measured and Pearson’s correlation tests used to identify patterns. It was found that Oxisols had the highest PBI values ranging from 134 to 170 while Inceptisols had the lowest ranging from 33 to 54. The PBI data followed a similar pattern to the generated isotherm curves of the different soil types. Most interest was in identifying soils with low PBIs as they have greater potential for P leaching through runoff into waterways. Clay content showed a strong positive correlation with PBI (R = 0.76, p ≤ 0.005). There is strong association with phosphorus fixation in soil with increasing levels of Al and Fe in the soil. Phosphorus availability and P fixation varied with soil types.

scholarly journals Properties and Constraints of Red-Yellow and Volcanic Ash Soils Planted to Rootcrops in the Philippines

2007 ◽  
Vol 07 (1) ◽  
pp. 52-78
Author(s):  
Anabella Tulin ◽  
Keyword(s):  
Volcanic Ash ◽  
Chemical Properties ◽  
Clay Content ◽  
The Philippines ◽  
P Availability ◽  
Compacted Soils ◽  
Soil Constraints ◽  
Physical And Chemical ◽  
Volcanic Ash Soils

Soil samples representing hightly weathered Red-Yellow and Volcanic Ash soils were collected from 45 pedons of different rootcrop producing provinces in the Philippines. This research was conducted to provide a comprehensive data on the properties and constraints of Red-yellow and Volcanic Ash soils planted to rootcrops through determination of the soils' various morphological, physical, and chemical properties. Some of the identified soil constraints associated with Red-Yellow and Volcanic Ash soils planted to rootcrops include : low organic matter, soil acidity, Al toxicity, low CEC, low amounts of exchangeable bases such as Ca, K, Mg, and Na, low P availability, high clay content, and highly compacted soils.

scholarly journals Soil characterization for adobe mixtures containing Portland cement as stabilizer

2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Lucas Miranda Araújo Santos ◽  
José Anselmo da Silva Neto ◽  
Aline Figueirêdo Nóbrega de Azerêdo
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Distribution Curve ◽  
Cement Content ◽  
Clay Content ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Physical And Chemical ◽  
Method Analysis

ABSTRACT One of the most economical ways to build with soil is to use adobe technique. There are several types of soils and most of them are not suitable for using to construct buildings. Physical and chemical characteristics of the soils will influence on its performance to use for buildings. This work aims to characterize physically, chemically and mineralogically two soil samples and study the dosage of mixtures for adobe using Portland cement as stabilizer. It was studied three different Portland cement content (6%, 9% and 12%) in the soil. The results showed that compressive strength of up to 5 MPa at 28 days for both type of soils studied with 12% of Portland cement. In addition, a comparison between two methods used for the particle size analysis of the soils. It was observed that the results differed in each method analysis. Overall this work has shown that to use these soils for adobe bricks, 9% of Portland cement is enough to reach the minimum compressive strength required by standard. Furthermore, this research brings results about the determination of the clay content of the soil, indicating that the traditional method to determine the size distribution curve by sieving and sedimentation may not be the most suitable to check this clay content.

The ecology of Bathyporeia pilosa (Amphipoda: Haustoriidae) in the Tay Estuary. I. Factors influencing the distribution on Tayport and Tentsmuir beaches

1980 ◽  
Vol 78 (3-4) ◽  
pp. s109-s119 ◽  
Author(s):  
N. H. Khayrallah ◽  
A. M. Jones
Keyword(s):  
Particle Diameter ◽  
Clay Content ◽  
Sedimentary Characteristics ◽  
Median Particle Diameter ◽  
Median Particle ◽  
Distribution Studies ◽  
Chemical Characters ◽  
Physical And Chemical ◽  
Sediment Preference

SynopsisThe distribution of Bathyporeia pilosa is discussed in relation to variations in a number of physical and chemical characters of the sediment on eight transects. Relationships were found between density and median particle diameter, silt content, and water content of the sediment, but stability of the beach appeared to be the main parameter influencing B. pilosa distribution. Sediment preference experiments showed that sediments varied in attractiveness, medium and fine grade sands being preferred: coarse sands and muds were avoided as were sediments with a high silt and clay content. Attractiveness in laboratory conditions was not correlated with observed field densities in some cases, indicating that other parameters were important in determining the distribution. Studies of swimming behaviour demonstrated the importance of current speed during the pelagic phase and it is concluded that hydrological conditions may be as important as sedimentary characteristics in the determination of the distribution of this species.

THE IMPORTANCE OF THE RED BOOK OF SOILS FOR MONITORING AND JUSTIFICATION OF CONSERVATION MEASURES

2020 ◽  
Author(s):  
O.S. Bezuglova ◽  
Keyword(s):  
Chemical Properties ◽  
Natural State ◽  
Soil Maps ◽  
Rostov Region ◽  
Conservation Measures ◽  
Background Data ◽  
The Russian Federation ◽  
Physical And Chemical ◽  
And Chemical Properties

Rostov Region belongs to the highly protected natural territories characterized by the continuous plowing. There territories are the only reserves with the soils preserved in their natural state. However, these areas often lack detailed information about the soils quality and composition. Surveying soils on these territories is crucial for determination of their basic physical and chemical properties. The resulted compilation of soil maps could lay a foundation for creating the Red Book of Soils and the formation of a section in the soil-geographical database of the Russian Federation. Subsequently, such information can be used as a background data for the main types of soils in the region. It will be also valuable during monitoring and justification of conservation measures.

scholarly journals Treated wastewater irrigation effects on soil hydraulic conductivity and aggregate stability of loamy soils in Israel

2015 ◽  
Vol 63 (1) ◽  
pp. 47-54 ◽  
Author(s):  
Karsten Schacht ◽  
Bernd Marschner
Keyword(s):  
Hydraulic Conductivity ◽  
Chemical Properties ◽  
Aggregate Stability ◽  
Treated Wastewater ◽  
Soil Aggregate Stability ◽  
Irrigation Effects ◽  
Physical And Chemical ◽  
The Impact

Abstract The use of treated wastewater (TWW) for agricultural irrigation becomes increasingly important in water stressed regions like the Middle East for substituting fresh water (FW) resources. Due to elevated salt concentrations and organic compounds in TWW this practice has potential adverse effects on soil quality, such as the reduction of hydraulic conductivity (HC) and soil aggregate stability (SAS). To assess the impact of TWW irrigation in comparison to FW irrigation on HC, in-situ infiltration measurements using mini disk infiltrometer were deployed in four different long-term experimental orchard test sites in Israel. Topsoil samples (0-10 cm) were collected for analyzing SAS and determination of selected soil chemical and physical characteristics. The mean HC values decreased at all TWW sites by 42.9% up to 50.8% compared to FW sites. The SAS was 11.3% to 32.4% lower at all TWW sites. Soil electrical conductivity (EC) and exchangeable sodium percentage (ESP) were generally higher at TWW sites. These results indicate the use of TWW for irrigation is a viable, but potentially deleterious option, as it influences soil physical and chemical properties.

Enzymes and Their Forms Used in Detection of Organophosphorus Compounds

2021 ◽  
pp. 22-41
Keyword(s):  
Organophosphorus Compounds ◽  
Degradation Products ◽  
Rapid Development ◽  
Hydrolytic Enzymes ◽  
Immobilized Enzymes ◽  
Amino Acid Sequences ◽  
Practical Implementation ◽  
Scientific Results ◽  
Physical And Chemical

Еnzymes are able to effectively interact with various organophosphorus compounds (OPC), entering into (bio)chemical reactions with them. Changes in the initial activity of enzymes as a result of their inhibition by OPC, the formation of OPC degradation products under the action of hydrolytic enzymes, etc. can be determined using different physical and chemical methods and used in bioanalytic systems to determine the concentrations of OPC. The purpose of the review is to analyze the main scientific results achieved over the past 10 years in the development of analytical systems based on enzymes intended for the determination of OPC. It is shown in the article, that the requirements for the sensitivity of biosensors are based on the norms of the content of the analyzed substances detected in/at the objects of mandatory control. The cholinesterases compose a basis for the development of the largest number of ultra-sensitive biosensors, although other enzymes can be successfully used as a biosensitive element. The most technologically advanced solution that is close to the practical implementation seems to be bioanalytical systems using immobilized enzymes. Improving the detection limits of the OPC can be achieved by using nanoobjects together with modern methods of signal transducers, for example, with nanomechanical detectors and signal converters. This combination of technical solutions ensures the sensitivity of the OPC analysis up to pg/l. At present, «reagentless» systems have received significant development, which have become the basis for the production of a large number of commercially available strips for the express determination of OPC. Modern demands stimulate the rapid development of portable and, especially, wearable biosensors that can be attached to various surfaces, including a clothing. The progress in the development of affine amino acid sequences, in the future, will allow the creation of enzyme biosensors on any surface.

Molecular characterization of plasmid-mediated quinolone resistance (PMQR) and ESBLs-producing Klebsiella pneumonia isolated from an Iranian teaching hospital

2021 ◽  
Author(s):  
Hamid Talebzadeh ◽  
Hamid Mellali ◽  
hamid solgi
Keyword(s):  
Teaching Hospital ◽  
Strong Association ◽  
Control Measures ◽  
Klebsiella Pneumonia ◽  
The Public ◽  
Isfahan Province ◽  
Clonal Distribution ◽  
Cross Transmission

Abstract Background The spread of plasmid-mediated multidrug resistance in Klebsiella pneumonia is a serious threat to the public health. We investigated the clinical characteristics and molecular epidemiology of K. pneumoniae isolated at a teaching hospital in Iran. Methods A total of 50 third-generation cephalosporins resistant K. pneumoniae strains were collected from patients’ clinical cultures. Antibiotic susceptibility testing and determination of MIC values for ceftazidime, cefotaxime and ciprofloxacin were performed. PCR and DNA sequencing were used to assess the presence of ESBL genes (blaCTX−M, blaTEM, blaSHV) and PMQR genes (qnrA, qnrB, qnrS, qepA, oqxA, oqxB and aac(6)-Ib-cr). Multilocus sequence typing (MLST) was performed on the strains to assess homology. Results Our results showed that the rates of resistance to all of antibiotics is high. All 50 K. pneumoniae strains harboured at least one of the ESBL resistance determinants. The blaCTX−M−15 gene was the major ESBLs determinant found in K. pneumoniae (88%; 44/50). PMQR was detected in 96% of the isolates and aac(6′)-Ib-cr was the most common (78% 39/50) followed by oqxA 36 (72%), oqxB 34 (68%), qnrS 20 (40%), qnrB 14 (28%) and qepA 1 (2%). MLST identified seven sequence types (STs), with the most common being ST11 (19/39). There was a strong association between PMQR genes (especially aac(6′)-Ib-cr) and ESBL genes. Conclusion The widespread detection of ESBLs-producing K. pneumoniae that co-carried PMQR determinants has become a threat to the treatment of infections in Isfahan Province of center Iran. Our findings suggest that K. pneumoniae ST11 and ST893 has a clonal distribution in our hospital. Therefore, this study highlighted the crucial need for implementing strict control measures to prevent cross transmission of these endemic clones.

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