Modeling Soil Shrinkage Curve across a Wide Range of Soil Types

2005 ◽  
Vol 69 (3) ◽  
pp. 584-592 ◽  
Author(s):  
X. Peng ◽  
R. Horn
Keyword(s):  
Soil Types ◽  
Shrinkage Curve ◽  
Wide Range ◽  
Soil Shrinkage

scholarly journals Predictive modelling of soils’ hydraulic conductivity using artificial neural network and multiple linear regression

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Charles Gbenga Williams ◽  
Oluwapelumi O. Ojuri
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Hydraulic Conductivity ◽  
Linear Regression ◽  
Multiple Linear Regression ◽  
Coarse Grained ◽  
Soil Types ◽  
Wide Range ◽  
Artificial Neural ◽  
Input Variables

AbstractAs a result of heterogeneity nature of soils and variation in its hydraulic conductivity over several orders of magnitude for various soil types from fine-grained to coarse-grained soils, predictive methods to estimate hydraulic conductivity of soils from properties considered more easily obtainable have now been given an appropriate consideration. This study evaluates the performance of artificial neural network (ANN) being one of the popular computational intelligence techniques in predicting hydraulic conductivity of wide range of soil types and compared with the traditional multiple linear regression (MLR). ANN and MLR models were developed using six input variables. Results revealed that only three input variables were statistically significant in MLR model development. Performance evaluations of the developed models using determination coefficient and mean square error show that the prediction capability of ANN is far better than MLR. In addition, comparative study with available existing models shows that the developed ANN and MLR in this study performed relatively better.

The undrained strength of some thawed permafrost soils

1979 ◽  
Vol 16 (2) ◽  
pp. 420-427
Author(s):  
John F. Nixon ◽  
Alan J. Hanna
Keyword(s):  
Undrained Shear Strength ◽  
Soil Types ◽  
Density Range ◽  
Mackenzie Delta ◽  
Sample Depth ◽  
Wide Range ◽  
Permafrost Soils ◽  
Undrained Strength ◽  
Water Contents ◽  
Undrained Shear

A large number of undrained shear strengths have been measured for thawed, undrained permafrost samples obtained from the Niglintgak Peninsula area of the Mackenzie Delta, N.W.T. The samples are mostly deltaic silts, with a few clay tills, and cover a wide range of depths, water contents, and frozen density. The undrained shear strengths of the thawed samples have been correlated with water content, frozen density, and sample depth. For these soil types, the strength is shown to decrease to zero at frozen densities of less than about 1670 kg/m3 and at water contents greater than about 35–42%. In the Niglintgak area, the undrained shear strength of the thawed samples below a depth of 10 m becomes relatively constant in the range of 23–43 kPa. This corresponds to a frozen density range of 1780–1870 kg/m3, and previous experience with soils of this nature indicates that the corresponding thaw settlement at these depths would be less than 10%.

Some aspects of fertilizer application to grassland in the Soviet Union

1968 ◽  
Vol 5 (5) ◽  
pp. 197-201
Author(s):  
N. G. Andreev ◽  
E. E. Ljubimova
Keyword(s):  
Soviet Union ◽  
Present Article ◽  
Fertilizer Application ◽  
Soil Types ◽  
The Soviet Union ◽  
Wide Range

Grasslands in the Soviet Union amount to about 370 million hectares, of which some 70 million are devoted to hay, the remaining 300 million being grazed. That the wide range of climate and soil types should be reflected in the variety of grassland problems is inevitable. The present article reviews the contributions of the Timiryazev Agricultural Academy and discusses many of the problems related to the use of fertilizers on grassland in the Soviet Union.

Physiological and biomass partitioning shifts to water stress under distinct soil types in Populus deltoides saplings

2020 ◽  
Vol 13 (5) ◽  
pp. 545-553
Author(s):  
Senlin Yang ◽  
Jian Shi ◽  
Lianghua Chen ◽  
Jian Zhang ◽  
Danju Zhang ◽  
...  
Keyword(s):  
Exchange Rate ◽  
Drought Stress ◽  
Gas Exchange ◽  
Nitrogen Metabolism ◽  
Populus Deltoides ◽  
Soil Types ◽  
Soil Conditions ◽  
N Assimilation ◽  
Wide Range ◽  
Gas Exchange Rate

Abstract Aims Although soil environments exist extensive heterogeneity for many plants with a wide range of distribution, researches about effects of soil conditions on plants’ tolerance and adaptation are particularly inadequate. In our study, the aims are to reveal physiological strategies of Populus deltoides against drought stress under different soil conditions and to select the most suitable soil type for P. deltoides plantation. Methods Under controlled conditions, we used P. deltoides as a model species to detect differences in gas exchange rate, antioxidative capacity, nitrogen metabolism and biomass accumulation and partitioning in response to drought stress under three mineral soil types with distinct physicochemical characters, i.e. red soil (RS), yellow soil (YS) and yellow-brown soil (BS). Important Findings Exposure to 25% of field water holding capacity in soil for 3 months had significantly decreased biomass of all organs, photosynthetic rate, enzyme activities related to N assimilation, but increased H2O2, malondialdehyde and content of both NO3− and NH4+, when P. deltoides was planted in both RS and YS. In contrast, under BS, there are slightly negative effects exerted by water deficit on total biomass, gas exchange rate, activities of enzymes related to nitrogen metabolism and membrane damage caused by reactive oxygen species, which can be associated with a consistent increase in superoxide dismutase, peroxidase and catalase, and a higher ratio of root mass to shoot mass. It is concluded that, such higher capacity in tolerance and adaptation against drought stress under BS relative to both RS and YS could be accounted for more sufficient nutrient provision in soil parental materials and better soil aeration conditions which play a vital role in plant acclimation to water shortage. Our study also revealed that, distribution areas of BS might be preferable for cultivation of P. deltoides, when compared with those of RS and YS.

ANALYSIS OF EMPIRICAL COMPRESSION INDEX EQUATIONS USING THE WATER CONTENT

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Amir W. Al-Khafaji ◽  
Krishnanand Y. Maillacheruvu ◽  
Melissa Hoerber
Keyword(s):  
Water Content ◽  
Empirical Models ◽  
Soil Types ◽  
Data Sets ◽  
Regression Equations ◽  
Compression Index ◽  
Empirical Formulas ◽  
Wide Range ◽  
Compression Data ◽  
Water Contents

This paper proposes a new method to evaluate the reliability of published empirical formulas in terms of accuracy and applicability to different soil types. Different empirical models are proposed to properly approximate the compression index for a wide range of water contents and soil types. They were developed using a unique technique and a substantial number of published regression equations and compression data. Familiar empirical equations were examined for their reliability in predicting the compression index of clay for any water content. A comparison was made between available and newly-proposed empirical formulas using combined regression data sets compiled independently by several authors. The newly proposed empirical compression index equations are applicable to a wide range of clay soils, and in validating other published relationships. The degree of scatter and variations in the computed compression index values are minimized for any water content.

A New Approach to Measure Soil Shrinkage Curve

2018 ◽  
Vol 42 (1) ◽  
pp. 20150237 ◽  
Author(s):  
Lin Li ◽  
Xiong Zhang
Keyword(s):  
New Approach ◽  
Shrinkage Curve ◽  
Soil Shrinkage

Using a selective fast turn-around bioassay for population density determination of Heterodera schachtii

Nematology ◽  
2013 ◽  
Vol 15 (7) ◽  
pp. 809-819 ◽  
Author(s):  
Annabell Meinecke ◽  
Andreas Hermann ◽  
Andreas Westphal
Keyword(s):  
Sugar Beet ◽  
Globodera Pallida ◽  
Heterodera Schachtii ◽  
Soil Types ◽  
Meloidogyne Hapla ◽  
Cyst Nematodes ◽  
Soil Extraction ◽  
Easy Method ◽  
Wide Range ◽  
Field Samples

In Central Europe, Heterodera schachtii is kept below threshold levels by cover-cropping with resistant crucifers and crop rotation with non-hosts. Determining population densities of H. schachtii in soil is critical when implementing resistant and tolerant sugar beet cultivars in integrated pest management (IPM) programmes. Soil extraction of the cysts followed by egg counts or extraction of the second-stage juveniles (J2) facilitated by the chemical stimulant acetox can be unsatisfactory in mixed field populations of cyst nematodes. In contrast to H. schachtii, nematodes typically present in sugar beet soils, e.g., Globodera pallida, G. rostochiensis, H. avenae, H. filipjevi, Meloidogyne hapla, M. incognita and Pratylenchus penetrans, rarely penetrated radish roots. In this bioassay, equivalents of 50 g of soil dry weight were adjusted to 10-20% moisture, seeded with Raphanus sativus cv. Saxa 3, and incubated at a day-night (16:8 h) cycle of 28/23°C for 4 days before J2 in radish roots were enumerated. In different soil types, penetration by H. schachtii reflected the inoculation levels. When inoculated with mixes of H. schachtii with H. avenae or H. filipjevi, counts of H. schachtii were similar to those in soils with H. schachtii only. When comparing three methods in three soils spiked with H. schachtii cysts, the bioassay and the extraction method were lightly impacted by the soil texture but results of the acetox method varied with texture. When implemented for field samples from Franconia, the radish bioassay and the acetox method provided results related to cyst and egg extraction data. The radish bioassay provided a quick and easy method for quantifying H. schachtii in the presence of other nematode species in a wide range of soil types. Including this assay in IPM programmes may serve as an alternative to standard methods and will improve the decision making in sustainable production systems.

Sand type influences the energetics of nest escape in Brisbane river turtle hatchlings

2018 ◽  
Vol 66 (1) ◽  
pp. 27 ◽  
Author(s):  
Mohd Uzair Rusli ◽  
David T. Booth
Keyword(s):  
Fine Sand ◽  
Coarse Sand ◽  
Soil Types ◽  
Energetic Cost ◽  
Energy Reserves ◽  
Freshwater Turtles ◽  
Cohort Size ◽  
Substrate Type ◽  
Wide Range ◽  
Influence Of Substrate

Freshwater turtles can construct their nest in a wide range of soil types, and because different soil types have different physical characteristics such as particle size distribution and compactness, soil type presumably affects digging performance and the energetics of nest escape of turtle hatchlings. Previous studies have reported how cohort size affects the energetic cost of nest escape in turtle hatchlings, but no studies have reported the influence of substrate type on the energetic cost of nest escape. The time taken and the energy required by the same number of hatchlings to dig through two different sand types were quantified by open-flow respirometry. Brisbane river turtle hatchlings digging through fine sand escaped faster and spent less energy than hatchlings digging through coarse sand, and a larger cohort size provided a clear energetic advantage while digging in both sand types. Across all group sizes, hatchlings digging through fine sand spent 33.8% less energy compared with hatchlings digging through coarse sand. We conclude that hatchlings emerging from nests constructed in fine sand have an energetic advantage over hatchlings emerging from nests constructed in course sand because they would have greater energy reserves upon reaching the nest’s surface.

Soil and plant relationships with cattle production on a property scale in the monsoonal tallgrass tropics.

1988 ◽  
Vol 10 (1) ◽  
pp. 18 ◽  
Author(s):  
TH McCosker ◽  
PK O'Rourke ◽  
AR Eggington ◽  
FW Doyle
Keyword(s):  
Pregnancy Rate ◽  
Average Daily Gain ◽  
Previous History ◽  
Grazing Pressure ◽  
Soil Types ◽  
Cattle Production ◽  
Protein Nitrogen ◽  
Themeda Triandra ◽  
Wide Range ◽  
Native Pastures

Extreme variability in cattle production between replicate paddocks in a large supplementation experiment on Mount Bundey Station in the Danvin pastoral district of the Northern Territory, led to a search for reasons for the differences. Soil type, land unit and pasture parameters were related to cattle production parameters. Pregnancy rates of lactating heifers were positively related to yields of Themeda triandra, Sorghum plumosum, Eriachne burkittii and Eragrostis spp., the fist three of which declined in yield following heavy grazing pressure. Quantity of pasture was more closely correlated with animal production than was quality due to the wide range in yields and narrow range in quality attributes. Pregnancy rate in lactating heifers was more sensitive to yield of pasture species than was lactating cow pregnancy rate, breeder mortality, calf weight per breeder mated or steer average daily gain. Heifers consumed less supplement relative to their requirements than mature cows and steers and their response was not confounded by previous history. These factors probably account for their greater sensitivity to pasture variations. Pregnancy rate of cows was positively related to the proportion of lowland soil types and negatively to proportion of lithosol (hills). An equation incorporating the percentages of these soils, explained 63%. 42% and 39% of the variation in lactating cow pregnancy rate in 1982, 1983 and 1984 respectively. Variation in pregnancy rate among paddocks was therefore largely attributed to variation in the proportions of "upland" and "lowland" soil types. Sensitivity to grazing pressure of species within the native pasture was indicated by localized damage to T. triandra and S. plumosum and a large reduction in yield of Sintrans after five years of continuous grazing with access to non-protein nitrogen supplements at one breeder to 14ha. Native pastures in the Adelaide River area would not sustain this stocking rate. 18

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