Seasonal slope movements in an old clay fill embankment dam

2013 ◽  
Vol 50 (5) ◽  
pp. 503-520 ◽  
Author(s):  
A.S. Lees ◽  
G.J. MacDonald ◽  
A. Sheerman-Chase ◽  
F. Schmidt
Keyword(s):  
Water Demand ◽  
Plastic Limit ◽  
Embankment Dam ◽  
Soil Moisture Deficit ◽  
Slope Movements ◽  
High Soil Moisture ◽  
Moisture Deficit ◽  
Downstream Slope ◽  
Lower Slope ◽  
Upper Slope

A curious phenomenon of significant summertime downslope movements, observed at other sites where trees grow on the lower slope of clay fill embankments, has been recorded during 10 years of downstream slope monitoring at Aldenham embankment dam, UK. The data from four monitored sections of the slope are described. At two locations, downslope movements were observed in high soil moisture deficit (SMD) conditions, where it appeared that high SMD and shrinkage caused by trees growing on the lower slope allowed the grassed upper slope with lower SMD to slip downwards under its own weight. This led to a seasonal, ratcheting accumulation of crest settlement — a type of mechanism that presents a continual serviceability problem to infrastructure embankments as well as dams. This mechanism was simulated in a qualitative way by finite difference analysis. At a third monitored section, a sparser distribution of lower water-demand trees, lower plasticity clay fill, and a moisture content close to or below the plastic limit appeared to result in insignificant slope movements. At a fourth low-height monitored section, a slow accumulation of downslope movements, as well as tension cracking, was observed.

Ozone and Soil Moisture Deficit Effects on Nitrogen Metabolism of Soybean 1

Crop Science ◽  
1987 ◽  
Vol 27 (6) ◽  
pp. 1177-1184 ◽  
Author(s):  
R. B. Flagler ◽  
R. P. Patterson ◽  
A. S. Heagle ◽  
W. W. Heck
Keyword(s):  
Soil Moisture ◽  
Nitrogen Metabolism ◽  
Soil Moisture Deficit ◽  
Moisture Deficit

Site-specific wild oat (Avena fatua L.) management

2012 ◽  
Vol 92 (5) ◽  
pp. 923-931 ◽  
Author(s):  
H. J. Beckie ◽  
S. Shirriff
Keyword(s):  
Specific Treatment ◽  
Triticum Aestivum L ◽  
Avena Fatua ◽  
Slope Position ◽  
Wild Oat ◽  
Herbicide Application ◽  
Brassica Napus L ◽  
Site Specific ◽  
Lower Slope ◽  
Upper Slope

Beckie, H. J. and Shirriff, S. 2012. Site-specific wild oat ( Avena fatua L.) management. Can. J. Plant Sci. 92: 923–931. Variation in soil properties, such as soil moisture, across a hummocky landscape may influence wild oat emergence and growth. To evaluate wild oat emergence, growth, and management according to landscape position, a study was conducted from 2006 to 2010 in a hummocky field in the semiarid Moist Mixed Grassland ecoregion of Saskatchewan. The hypothesis tested was that wild oat emergence and growth would be greater in lower than upper slope positions under normal or dry early growing season conditions. Three herbicide treatments were imposed on the same plots each year of a 2-yr canola (Brassica napus L.) – wheat (Triticum aestivum L.) sequence: (1) nontreated (weedy) control; (2) herbicide application to upper and lower slope positions (i.e., full or blanket application); and (3) herbicide application to lower slope position only. Slope position affected crop and weed densities before in-crop herbicide application in years with dry spring growing conditions. Site-specific wild oat herbicide application in hummocky fields in semiarid regions may be justified based on results of wild oat control averaged across slope position. In year 2 of the crop sequence (wheat), overall (i.e., lower and upper slope) wild oat control based on density, biomass, and dockage (i.e., seed return) was similar between site-specific and full herbicide treatment in 2 of 3 yr. Because economic thresholds have not been widely adopted by growers in managing wild oat, site-specific treatment in years when conditions warrant may be an appropriate compromise between no application and blanket herbicide application.

scholarly journals The United Kingdom Meteorological Office rainfall and evaporation calculation system: MORECS version 2.0-an overview

1997 ◽  
Vol 1 (2) ◽  
pp. 227-239 ◽  
Author(s):  
M. N. Hough ◽  
R. J. A. Jones
Keyword(s):  
Land Use ◽  
Climatic Conditions ◽  
Soil Moisture Deficit ◽  
Water Capacity ◽  
The United Kingdom ◽  
Moisture Deficit ◽  
Available Water Capacity ◽  
Version 2.0 ◽  
Calculation System ◽  
New System

Abstract. The operational system known as MORECS which provides estimates of evaporation, soil moisture deficit and effective precipitation under British climatic conditions has been revised as version 2.0. An overview of the new system is described with emphasis on the new additions. The major changes from the older version (Thomson, Barrie and Ayles, 1981) include the introduction of the crop oil-seed rape, a revised treatment of soils and available water capacity and a land use data base which is representative of the 1990s.

scholarly journals Using Plant Temperature to Evaluate the Response of Stomatal Conductance to Soil Moisture Deficit

Forests ◽  
2015 ◽  
Vol 6 (12) ◽  
pp. 3748-3762 ◽  
Author(s):  
Ming-Han Yu ◽  
Guo-Dong Ding ◽  
Guang-Lei Gao ◽  
Yuan-Yuan Zhao ◽  
Lei Yan ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Soil Moisture Deficit ◽  
Moisture Deficit

Influence of tillage displaced soil on the productivity and yield components of barley in northwest Iran

2012 ◽  
Vol 92 (4) ◽  
pp. 665-672 ◽  
Author(s):  
Leila Nazmi ◽  
Hossein Asadi ◽  
Ruzanna Manukyan ◽  
Hamdollah Naderi
Keyword(s):  
Field Experiment ◽  
Yield Components ◽  
Slope Position ◽  
Soil Productivity ◽  
Slope Gradient ◽  
Position Effects ◽  
Northwest Iran ◽  
Lower Slope ◽  
Tillage Erosion ◽  
Upper Slope

Nazmi, L., Asadi, H., Manukyan, R. and Naderi, H. 2012. Influence of tillage displaced soil on the productivity and yield components of barley in northwest Iran. Can. J. Soil Sci. 92: 665–672. In hilly landforms subject to long-term cultivation, erosion has denuded the upper slope positions of topsoil, and accumulated topsoil in the lower slope positions. Slope gradient and position effects aggregation processes, which in turn impact soil productivity. A field experiment was conducted to assess the tillage-induced soil displacement and its effects on the soil properties and barley (Hordeum vulgare var. Sahand) biomass production for three different landscapes. The study was conducted on a hill slope seeded with barley (1.4–10.1° slope) located in the Mollaahmad watershed of the Ardabil province in northwestern Iran. For this purpose, soil samples were collected from four slope positions in a grassland as well as an agricultural field (dryland). A field experiment was conducted to evaluate the effects of slope gradient and position on barley growth and soil quality. Soil generally had lower organic carbon, available phosphorus, calcium carbonate equivalent, soil water content and mean weight diameter of soil aggregates in the farmland than the grassland, and in the upper slope positions than in the lower slopes. Significantly higher barley growth indices were associated with lower slope positions. Agronomic productivity of the soil was lowest for landscapes with the highest slope gradient. The relationships between tillage erosion and yield components were found to be significant. Spike weight and slope position had the largest contribution for the explanatory capacity of canonical variables (tillage erosion and yield components) estimated when compared with other parameters (slope gradient, dry matter, spike number, grain yield and 1000-grain weight). The findings in this study can be used as a tool to assist farmers, soil and water conservationists, and other policymakers in decision making regarding the use of lands.

The effect of ground water-level on the yield of some common crops on a fen peat soil

1958 ◽  
Vol 50 (3) ◽  
pp. 243-252 ◽  
Author(s):  
H. H. Nicholson ◽  
D. H. Firth
Keyword(s):  
Ground Water ◽  
Water Level ◽  
Peat Soil ◽  
Good Condition ◽  
High Water ◽  
Water Levels ◽  
Ground Water Level ◽  
Potential Evaporation ◽  
Soil Moisture Deficit ◽  
Moisture Deficit

An account is given of a field experiment in the control of ground water-level in a Fen peat soil, together with its results on the yields of crops in a six-course rotation.The seasonal variations in rainfall are presented in terms of potential evaporation and soil moisture deficit. The effect of the water-level on the moistness of the soil above it is indicated. Even in a wet summer, drying was perceptible within 18–20 in. of the ground water-level between successive falls of rain.The fluctuations of the ground water-levels are discussed. Those of the high water-levels were chiefly due to individual incidences of rain causing rises short in duration, but sufficient in the case of water-levels within 20 in. of the surface to cause total waterlogging and surface ponding. Those of the deep water-levels were most influenced by evaporation, with steady and persistent falls during any rain-free period.The deterioration of the physical condition of the soil over high water-levels is shown in the result of sieving tests. In 6 years the loss of tilth over waterlevels within 20 in. of the surface was very marked and was discernible over those as low as 30 in.The possibilities of effectively using high ground water-levels occasionally in soils in good condition are shown by the results with celery and potatoes.

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