scholarly journals Establishing the value of the deflection of the soil-piercing working body with an asymmetric tip when correcting the airway of movement

2021 ◽  
Vol 1 (92) ◽  
pp. 172
Author(s):  
Vladimir Suponyev ◽  
Sergiy Balesniy ◽  
Igor Pimonov
Keyword(s):  
Soil Compaction ◽  
Flat Surface ◽  
Sandy Loam ◽  
Front Surface ◽  
Transverse Component ◽  
Resistance Force ◽  
Permissible Stress ◽  
The World ◽  
Main Disadvantage ◽  
Heavy Clay

Trenchless laying of engineering communications is actively used in all countries of the world. Among the existing methods of formation of wells for the implementation of these technologies, the most popular is the method of ground penetration. The main disadvantage of this method is the poor accuracy of movement of the piercing head in the array. This requires constant adjustments to the trajectory of its movement. This process can be controlled by using a head with an asymmetrical tip and acting on it with translational and rotational motion. The transmission of these movements from the power unit by means of type-setting push rods. Therefore, it is important to choose a trajectory such that the deflection of the bar will be within the permissible stress range. If the bend goes beyond these limits, the rod may break and the puncture process will be interrupted. The conducted studies have established the regularities of the process of puncturing the soil with a head with an asymmetric tip in the form of an inclined flat surface. It has been established that the greatest deviation of the head from the action of the transverse component of the soil resistance force, which occurs when moving such a working body in the soil, will occur at an angle of inclination of the front surface of 25º, and the smallest deviation will occur at an angle of 55º. In addition, it was found that in heavy clay, deflection will occur almost 3 times worse than in a soup and 1.4 times worse than in a loam. It has been experimentally confirmed that at a distance of 10 m the puncture with a head with an inclined forehead surface in sandy loam was 40 mm, and in clay 20 mm. At an angle of inclination of 70º, a constant core of soil compaction is formed and the process of controlling the movement of the head stops.

The effects of changes in soil compaction and porosity on germination, establishment and yield of barley and globe beet

1967 ◽  
Vol 68 (2) ◽  
pp. 227-233 ◽  
Author(s):  
T. Kubota ◽  
R. J. B. Williams
Keyword(s):  
Organic Matter ◽  
Physical Properties ◽  
Soil Compaction ◽  
Sandy Loam ◽  
Pore Space ◽  
Silty Clay ◽  
Clay Loam ◽  
Silty Clay Loam ◽  
Heavy Clay

Two degrees of compaction, 'heavy' with a flattyred vehicle wheel, and 'light' with a ring roller, were given to the seed beds after sowing barley and globe beet on three contrasted soils. Changes in pore space of the soils and the responses of the crop to the changed physical properties were measured. The sites used were: Barnfield at Rothamsted, a heavy clay loam long under arable cultivation and having little organic matter; Pastures Field at Rothamsted, a field of silty clay loam ploughed after an 8-year ley; Stackyard field at Woburn, a light sandy loam long in arable cultivation and containing little organic matter.

scholarly journals How a tiger became a pussycat

2020 ◽  
Vol 71 (2) ◽  
pp. 173-199
Author(s):  
Miljenko Antić
Keyword(s):  
Economic Growth ◽  
Economic System ◽  
Mainland China ◽  
Economic Power ◽  
Market Reforms ◽  
The World ◽  
Main Disadvantage ◽  
Rates Of Growth

Based on capitalism and socialist measures, Taiwan not only achieved better results than Mainland China during the 1949-91 period, but also better results than any other country in the world in promoting economic growth. A lack of market was the main disadvantage of Mainland China during this period of time. However, its successful pro-market reforms and unsuccessful reforms in Taiwan (based on privatization), reversed the tide. During the last quarter of the century, Mainland China has more efficient economic system than Taiwan. As a result, Mainland China became the world’s leading economic power in 2014 and it continues to have higher rates of growth than Taiwan.

Influence of soil texture on fertilizer and soil phosphorus transformations in Gleysolic soils

2003 ◽  
Vol 83 (4) ◽  
pp. 395-403 ◽  
Author(s):  
Z. Zheng ◽  
L. E. Parent ◽  
J. A. MacLeod
Keyword(s):  
Soil Texture ◽  
Agricultural Soils ◽  
Sandy Loam ◽  
Clay Content ◽  
P Uptake ◽  
Hordeum Vulgare L ◽  
P Fractionation ◽  
Soil P ◽  
Plant P Uptake ◽  
Heavy Clay

The P dynamics in soils should be quantified in agricultural soils to improve fertilizer P (FP) efficiency while limiting the risk of P transfer from soils to water bodies. This study assessed P transformations following FP addition to Gleysolic soils. A pot experiment was conducted with five soils varying in texture from sandy loam to heavy clay, and receiving four FP rates under barley (Hordeum vulgare L.)-soybean (Glycine max L.) rotations. A modified Hedley procedure was used for soil P fractionation. Soil resin-P and NaHCO3-Pi contents were interactively affected by texture and FP. The NaHCO3-Po, NaOH-Po, HCl-P and H2SO4-P were only affected by soil texture. Proportions of 78 and 90% of the variation in labile and total P were, respectively, related to soil clay content. The FP addition increased resin-P, NaHCO3-Pi and NaOH-Pi and -Po contents in coarse-textured soils, but the amount added was not sufficient to mask the initial influence of soil texture on the sizes of soil P pools. Plant P uptake was proportional to FP rate but less closely linked to clay content. The average increase in labile P per unit of total FP added in excess of plant exports was 0.85, 0.8 2 , 0.73, 0.55 and 0.24 for the sandy loam, loam, clay loam, clay and heavy clay soil, respectively. The results of this study stress the important of considering soil texture in Gleysolic soils when assessing P accumulation and transformations in soils, due to commercial fertilizers applied in excess of crop removal. Key words: P fractions, clay content, fertilizer P, plant P uptake, soil texture

scholarly journals Soil compaction during harvest operations in five tropical soils with different textures under eucalyptus forests

2018 ◽  
Vol 42 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Paula Cristina Caruana Martins ◽  
Moacir de Souza Dias Junior ◽  
Ayodele Ebenezer Ajayi ◽  
Ernesto Norio Takahashi ◽  
Diego Tassinari
Keyword(s):  
Bearing Capacity ◽  
Soil Compaction ◽  
Sandy Loam ◽  
Traffic Intensity ◽  
Compression Tests ◽  
Load Bearing Capacity ◽  
Undisturbed Soil ◽  
Load Bearing ◽  
Structure Degradation ◽  
Precompression Stress

ABSTRACT Traffic of farm machinery during harvest and logging operations has been identified as the main source of soil structure degradation in forestry activity. Soil susceptibility to compaction and the amount of compaction caused by each forest harvest operation differs according to a number of factors (such as soil strength, soil texture, kind of equipment, traffic intensity, among many others), what requires the adequate assessment of soil compaction under different traffic conditions. The objectives of this study were to determine the susceptibility to compaction of five soil classes with different textures under eucalyptus forests based on their load bearing capacity models; and to determine, from these models and the precompression stresses obtained after harvest operations, the effect of traffic intensity with different equipment in the occurrence of soil compaction. Undisturbed soil samples were collected before and after harvest operations, being then subjected to uniaxial compression tests to determine their precompression stress. The coarse-textured soils were less resistant and endured greater soil compaction. In the clayey LVd2, traffic intensity below four Forwarder passes limited compaction to a third of the samples, whereas in the sandy loam PVd all samples from the 0-3 cm layer were compacted regardless of traffic intensity. The Feller Buncher and the Clambunk presented a high potential to cause soil compaction even with only one or two passes. The use of soil load bearing capacity models and precompression stress determined after harvest and logging operations allowed insight into the soil compaction process in forestry soils.

The effects of soil compaction, soil moisture and soil type on growth and nodulation of soybean and common bean

1998 ◽  
Vol 78 (4) ◽  
pp. 571-576 ◽  
Author(s):  
B. R. Buttery ◽  
C. S. Tan ◽  
C. F. Drury ◽  
S. J. Park ◽  
R. J. Armstrong ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Adverse Effects ◽  
Plant Growth ◽  
Water Supply ◽  
Common Bean ◽  
Soil Type ◽  
Soil Compaction ◽  
Sandy Loam ◽  
Clay Loam ◽  
Reduced Water

In field tests we have observed year-to-year differences in the severity of the effects of soil compaction on nodulation and growth of common bean; these differences appeared to be related to the amount of rainfall during the growing season. We decided to use better controlled conditions in the greenhouse, and extend the scope of the study to another legume crop and a different soil type, in order to investigate the hypothesis that copious water supply alleviates the adverse effects of soil compaction on nodulation and plant growth.The effects of two levels of soil compaction and of high and low water supply on the growth and nodulation of common bean and soybean were investigated in separate pot tests using a Fox sandy loam and a Brookston clay loam soil.Root growth of both species was severely restricted by dry compacted conditions. Plant growth as a whole was clearly reduced by both increased compaction and by reduced water supply, presumably mediated by the effects on root growth. The effect of reduced water supply was more severe in the highly compacted pots, and more severe in the clay loam than in the sandy loam.In the sandy loam, low moisture reduced nodule numbers and weights in both species, while increased bulk density reduced the numbers of nodules but not the dry weights. In the clay loam, nodule weights and numbers were very low, presumably, owing to high levels of nitrate, which may have resulted from mineralization of soil organic matter during storage.A generous supply of water obviously alleviated some of the adverse effects of soil compaction on plant growth. This is in general agreement with results of earlier field trials, where severity of the effects of soil compaction varied with the quantity of rainfall. Key words: Soybean, common bean, soil compaction, soil moisture, nodulation, bulk density

COMPARISON OF TILLAGE AND DIRECT DRILLING FOR ITALIAN RYEGRASS ON THE PROPERTIES OF A FINE SANDY LOAM SOIL

1986 ◽  
Vol 66 (2) ◽  
pp. 197-207 ◽  
Author(s):  
M. R. CARTER ◽  
H. T. KUNELIUS
Keyword(s):  
Soil Compaction ◽  
Soil Structure ◽  
Sandy Loam ◽  
Soil Strength ◽  
Phleum Pratense ◽  
Italian Ryegrass ◽  
Organic C ◽  
Fine Sandy Loam ◽  
Permanent Pasture ◽  
Direct Drilling

The soil physical, biological, and chemical condition was assessed under cultivated and direct-drilled systems for the annual establishment of Italian ryegrass (Lolium multiflorum Lam.) on Prince Edward Island. After 3 yr, the degree of tillage-induced soil compaction and change in soil biological and chemical properties were determined over the 0- to 24-cm soil depth, and compared with the soil structure under a permanent timothy (Phleum pratense L.) pasture. The study was conducted at two sites on a Charlottetown fine sandy loam, an Orthic Humo-Ferric Podzol (Haplorthod). Although the tillage comparisons produced significant changes in soil porosity, pore-size distribution, pore continuity, aggregation and soil strength, the range in physical properties was within the range considered optimum for soil structure. Soil strength was shown to exhibit marked temporal variation over the growing season. Changes in the distribution of soil microbial biomass C and N, percent organic C, pH and plant nutrients were evident between the establishment methods. Generally, soil chemical and biological conditions under direct-drilling were similar to those under permanent pasture. Comparison of the actual with the estimated maximum bulk density down the soil profile indicated that the propensity for soil consolidation or compaction was the same under the direct-drilling and cultivated systems and similar to that measured under permanent pasture. The annual establishment of Italian ryegrass, for 3 yr, by direct-drilling did not adversely affect soil structure or increase soil compaction. Key words: Direct-drilling, Italian ryegrass, soil structure, soil biological properties, tillage

RELATIVE MEASURES OF SOIL BULK DENSITY TO CHARACTERIZE COMPACTION IN TILLAGE STUDIES ON FINE SANDY LOAMS

1990 ◽  
Vol 70 (3) ◽  
pp. 425-433 ◽  
Author(s):  
M. R. CARTER
Keyword(s):  
Grain Yield ◽  
Bulk Density ◽  
Soil Compaction ◽  
Sandy Loam ◽  
Soil Bulk Density ◽  
Moisture Regime ◽  
Density Level ◽  
Soil Consolidation ◽  
Fine Sandy Loam ◽  
Relative Compaction

Field studies concerned with soil physical properties require methods to quantify and characterize soil compaction, especially for tillage experiments. The bulk densities of a Charlottetown and Gowanbrae fine sandy loam were related to a maximum or standard compaction state for each soil to obtain a measure of relative compaction. The two soils were both classified as Orthic Humo-Ferric Podzols. Relative compaction was closely related to the volume of macropores (r2 = 0.85). Over a 3-yr period, mouldboard ploughing loosened the soil to give an average relative compaction of 77%. Subsequent soil consolidation and settling increased relative compaction to 84% over the growing season. Direct-drilling maintained relative compaction at a limited range of 88–91%. Relative grain yield of cereals was related (r2 = 0.69) using a polynomial curve to relative compaction. A range of 77–84% relative compaction was associated with a relative grain yield ≥ 95%. A relative compaction of 84–89% was considered the equilibrium soil density level for the two soils under study. This range was related to a macropore volume of 13.5–10% which is adequate for permeability but possibly inadequate for optimum soil aeration under a humid soil moisture regime. Overall, relative compaction provided a useful index or standard to assess changes in soil bulk density and proved to be a biologically meaningful soil physical parameter. Key words: Soil compaction indices, relative compaction, Podzolic soil, fine sandy loam, cereal yield

scholarly journals Evaluation of Groundwater Vulnerability to Contamination in Coimbatore District

2019 ◽  
pp. 1-17
Author(s):  
P. Meenakshi ◽  
A. Ganesh
Keyword(s):  
Sandy Loam ◽  
Low Cost ◽  
Groundwater Resources ◽  
Groundwater Vulnerability ◽  
Shallow Water Table ◽  
Point Of Use ◽  
Coimbatore District ◽  
The World ◽  
Gis Environment ◽  
Alternate Source

Groundwater usage in the world is widely reported to increase because of the uncertainties attached with the availability of surface water. Groundwater resources are looked upon as the alternate source of freshwater on account of its widespread and continuous availability in proximity to the point of use or living place, less vulnerability to contamination and low cost of extraction in both urban and rural area of developed and developing countries of the world. Such a scenario has led to the degradation and depletion of groundwater resources in many parts of the world. The study area, Coimbatore district, is a rapidly urbanizing and industrializing city in the southern part of India which relies upon the groundwater resources for meeting the agricultural, industrial and domestic requirements. In view of this evaluation of groundwater resources and an understanding of the vulnerability of the aquifer to contamination become essential for the effective management of groundwater resources. The vulnerability of the groundwater to contamination is assessed using DRASTIC and Pesticide DRASTIC index in the GIS environment. The study showed that the high vulnerability areas are characterized by shallow water table of less than 4 m, gentle topography, sandy loam soils, thinner vadose zone and underlying geologic formations with well-developed fissures and fractures.

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