Contributions to the Knowledge of Sandy Soils from Oltenia Plain

2020 ◽  
Vol 71 (1) ◽  
pp. 192-200
Author(s):  
Anca-Luiza Stanila ◽  
Catalin Cristian Simota ◽  
Mihail Dumitru

Highlighting the sandy soil of Oltenia Plain calls for a better knowledge of their variability their correlation with major natural factors from each physical geography. Pedogenetic processes specific sandy soils are strongly influenced by nature parent material. This leads, on the one hand, climate aridity of the soil due to strong heating and accumulation of small water reserves, consequences emphasizing the moisture deficit in the development of the vegetation and favoring weak deflation, and on the other hand, an increase in mineralization organic matter. Relief under wind characteristic sandy land, soil formation and distribution has some particularly of flat land with the land formed on the loess. The dune ridges are less evolved soils, profile underdeveloped and poorly supplied with nutrients compared to those on the slopes of the dunes and the interdune, whose physical and chemical properties are more favorable to plant growth.Both Romanati Plain and the Blahnita (Mehedinti) Plain and Bailesti Plain, sand wind shaped covering a finer material, loamy sand and even loess (containing up to 26% clay), also rippled with negative effects in terms of overall drainage. Depending on the pedogenetic physical and geographical factors that have contributed to soil cover, in the researched were identified following classes of soils: protisols, cernisols, cambisols, luvisols, hidrisols and antrosols.Obtaining appropriate agricultural production requires some land improvement works (especially fitting for irrigation) and agropedoameliorative works. Particular attention should be paid to preventing and combating wind erosion.

2021 ◽  
Author(s):  
R.F. Khasanova ◽  
G.T. Isanbayeva ◽  
I.N. Semenova ◽  
M.B. Suyundukova ◽  
G.R. Ilbulova ◽  
...  

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Sergio Arias Quintero ◽  
Joshua Schmitt ◽  
Richard Blair ◽  
Jayanta Kapat

Historically, gas turbine fuels have been procured based on availability and low cost criteria. However,in the past few decades, with the growing concern over the negative environmental impacts produced by emissions, alternative fuels have been developed and tested under the objective of reducing such negative effects. The physical properties and broad chemical composition of fuels, including trace elements, may result in engine performance issues found only after extensive operation. This, in turn, results in higher maintenance and operation costs. This paper studies the feasibility of several renewable fuels for microturbine application, identifying key relationships between the physical and chemical properties, thermal stability, materials compatibility, and turbine performance.


1932 ◽  
Vol 5 (2) ◽  
pp. 110-116
Author(s):  
F. Kirchhof

Abstract The application of the long-known Friedel-Crafts reaction to rubber hydrocarbons led to a new type of condensation products which may be called provisionally aral cyclorubbers (“benzylidene rubbers”), since their benzylidene groups are probably condensed with the polyprene skeleton to cyclic systems. It would not have been foreseen without further work that rubber would form this type of condensation product with aral halides in the presence of aluminum chloride, since on the one hand benzyl chloride is known to form, by the action of aluminum chloride in the Friedel-Crafts reaction, an amorphous, apparently high molecular hydrocarbon of the empirical composition (C7H6)x, and on the other hand rubber in solution is transformed by the metal chlorides, especially aluminum chloride, into amorphous polycyclorubbers. Under definite conditions of condensation with aluminum chloride aral groups are combined with the skeleton of the rubber hydrocarbon with the formation of white to yellowish amorphous bodies which contain, in addition to a small proportion of organically combined chlorine, only carbon and hydrogen, and are therefore to be regarded as hydrocarbons. In their physical and chemical properties these substances resemble the already known amorphous substance of the empirical formula (C7H6)x, which doubtless is polybenzylidene, probably hexabenzylidene.


2020 ◽  
Vol 33 (02) ◽  
pp. 476-789
Author(s):  
Hengameh Javadi ◽  
Reza Sokouti ◽  
Ebrahim Pazira ◽  
Mohammad Hassan Massihabbadi

Different soils with various properties and sometimes with different types of limitations can be formed which is necessary to investigate the conditions of soil formation and evolution for their optimal use. In this study, we studied the relationship between soil, topography in terms of slope and elevation, and parent material with the land morphology and physical and chemical properties of soil, how the soil formed and evolved. From 19 control soil profiles, 57 soil samples were obtained from three layers and some soil characteristics including Acidity, Salinity, Gypsum, Lime, Texture and Organic matter were measured. Using NEWHALL software, the soil temperature and moisture regime was determined. To study the conditions of topography, the digital elevation map and slope was prepared, the characteristics of geological formations were determined and based on the Gower index and Jacquard index, the relationship between soil evolution factors with topography and parent materials were studied. The diversity of soils classification was studied using richness, uniformity of Shannon and Simpson indices. Based on the results obtained from Gower and jacquard similarity indices, the effect of topography and parent materials on soil diversity was proved. Soil diversity indices showed an increasing trend from the soil order level to the soil family. The increase in the Richness index was higher at the soil family level, so that the highest soil diversity observed at the soil family level. Also, soil diversity is mainly affected by intrinsic factors and to some extent by environmental factors. Soil profile development is mostly influenced by slope, parent materials and in some areas by groundwater level.


2017 ◽  
pp. 87-104
Author(s):  
Roland Rallos ◽  
Victor Asio ◽  
Faustino Villamayor

Studies on soil-landscape relationships are necessary to improve our understanding of the spatial distribution and variation of soils for their sustainable management. This study evaluated the relationship between soil properties and landscape position in the northern volcanic mountain of Leyte, Philippines. Five soil profiles located on summit, shoulder, backslope and footslope positions were evaluated. Findings revealed that the degree of soil development as well as the soil morphophysical and chemical properties varied with landscape position. The soil in the most stable position (summit) had thicker solum and slightly more developed soil profile than the soils in other landscape positions. On the other hand, soils in the unstable position (backslope) generally had thinner solum. All the five soils also revealed the influence of the andesitic volcanic parent material on their properties. They all showed some properties typical of Andisols such as low bulk density and high pH in NaF although they were classified as Andic Dystrudept. The soils all possessed physical and chemical constraints for crop production.


2021 ◽  
Vol 8 (7) ◽  
pp. 214-220
Author(s):  
Long Tong ◽  
◽  
Hongyan Li ◽  
Xiaoming Liu ◽  
Bin Li ◽  
...  

The continuous obstacle of Dictyophora indusiata has become the one of the main factors affecting the healthy development of D. indusiata industry. In order to study the effects of continuous cropping of D. indusiata on the soil environment, four treatments were used in this study: no planted (CK), planted for 1 years (1Y), continuous cropping for 2 years (2Y) and continuous cropping for 3 years (3Y), to determined of the yield of D. indusiata, soil physical and chemical properties, microbial content and enzyme activity. The results showed that the yield and soil pH value decreased with the increase of continuous cropping years, and the contents of organic matter, total nitrogen, total phosphorus and total potassium, C/N and C/P also increased with the increase of continuous cropping years. Soil availability decreased with the increase of continuous cropping years, the content of alkaline nitrogen, available phosphorus and available potassium decreased by 12.25%, 28.91% and 24.86% at 3Y compared with 1Y, respectively. The biomass of bacteria, actinomycetes and fungi and the total amount of microorganism in soil increased at 1Y compared with CK, but with the increase of continuous cropping years, the biomass of bacteria and actinomycetes and the total amount of microorganism decreased significantly, while the biomass of fungi increased significantly; the continuous cropping of D. indusiata also decreased the value of bacteria/fungi in soil. The enzyme activities of the soil were higher than those of the unplanted plots, however, the activities of urease, catalase, peroxidase, sucrase, phosphatase and protease decreased with the increase of continuous cropping years. In a word, with the increase of continuous cropping, the acidity of rhizosphere soil increased, the availability of soil nutrients and the activity of soil enzymes decreased, the biomass of soil microorganisms, bacteria and actinomycetes decreased. However, the increase of fungal biomass led to the decline of soil texture.


Agropedology ◽  
2019 ◽  
Vol 30 (2) ◽  
Author(s):  
R. Srinivasan ◽  
◽  
R. Vasundhara ◽  
M. Lalitha ◽  
B. Kalaiselvi ◽  
...  

Four typical pedons representing major mango growing soils, developed from granite gneiss parent material were studied for their morphological, physical and chemical properties. The soils were moderately shallow (50-75 cm) to very deep (>150 cm) in depth, loamy sand to sandy clay loam in texture, sub-angular blocky in structure, reddish brown to dark red in colour, slightly acidic to moderately alkaline in reaction, non-saline, very low to high in organic carbon content (0.09 to 1.29%), low AWC (3.36 to 7.80%), low to medium in cation exchange capacity (2.90 to 19.36 cmol (p+) kg-1) and high base saturation (78 to 98%). The soils also had high amounts of coarse fragments in P1 and P2 and high clay content in P4 and P2. Among the exchangeable cations, calcium was found to be high in most of the soils, followed by magnesium, sodium, and potassium. Based on the soil characteristics, the mango growing soils were classified as Typic Haplargids and Typic Paleargids in subgroup level. Varying soil and site characters i.e., poor rainfall, shallow soil depths, excess gravel contents, low AWC, poor nutrient status and severe soil erosion are limiting the growth and development of mango plantation. Developing site-specific soils based suitable management practices can improve the productivity of mango crops.


2018 ◽  
Vol 36 (0) ◽  
Author(s):  
Lj. ŠANTRIC ◽  
Lj. RADIVOJEVIC ◽  
J. GAJIC-UMILJENDIC ◽  
M. SARIC-KRSMANOVIC ◽  
R. ÐUROVIC-PEJCEV

ABSTRACT: The effects of the nicosulfuron and glyphosate herbicides on microbial activity in two soils with different physical and chemical properties (loam and sand) were investigated. Nicosulfuron was applied at the rates of 0.3, 0.6, 3.0 and 30.0 mg kg-1 soil and glyphosate at 32.6, 65.2, 326.0 and 3260.0 mg kg-1 soil in the laboratory. Changes in dehydrogenase and urease activity, as well as in microbial biomass carbon, were examined. Samples for the analysis were collected at 3, 7, 14, 30 and 45 days after herbicide application. The results showed that the effects of nicosulfuron and glyphosate depended on treatment rate, duration of activity, test parameters and soil types. In general, application of the herbicides significantly increased the activity of dehydrogenase and urease. Nicosulfuron had a stimulating activity on microbial biomass carbon in loam, while both herbicides demonstrated negative effects on the parameter in the sandy soil.


The Copley Medal is awarded to Sir Derek Barton, F. R. S. Among Sir Derek Barton's many distinguished contributions to organic chemistry, outstanding is his conception and development of conformational analysis, which represents the most important advance in this century in the understanding of the stereochemistry of organic compounds, and for which he received a Nobel Prize in 1969. Originally devised for cyclohexane derivatives, the concept was rapidly extended to other ring systems, and is of major importance in interpretation of the physical and chemical properties of a wide range of natural products. Sir Derek has also contributed greatly to the understanding of biosynthesis, and in many cases demonstrated the validity of his hypotheses by labelling experiments in vivo . In particular, his ideas on the nature of phenolic coupling, involving one-electron oxidative processes, formed the basis of a very large number of successful biosynthetic studies, especially in the alkaloid field. He has also applied his ideas to the simulation of natural biosynthetic sequences, the one-step synthesis of the complex usnic acid from a simple monocyclic precursor providing one of the most striking examples.


Soil Research ◽  
1981 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
AJ Koppi

A common toposequence on Bunya Phyllite in south-east Queensland was studied in detail at a representative site. Four sample profiles on the slope are described, and some physical and chemical properties are given. The clay minerals, derived from the weathering of the quartz-sericite-chlorite phyllite, comprise dioctahedral mica, dioctahedral vermiculite, an interstratification of these minerals, and kaolin. Properties are related to the slope; and the clay-rich horizon of the middle and lower slopes is considered to be formed mostly by in situ weathering. The classification of the genetic unit given by the slope and parent material is discussed.


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