Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 173 for “"soil surface"”.
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Numerically Simulated Soil Surface Degradation (Erosion, Hydraulics)
Accelerated soil erosion is a serious problem because it destroys the land were it occurs and the resulting sediment pollutes the waters where it is carried and deposited. Experimental studies have led to the development of empirical equations describing soil erosion. Mathematical representations …
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Surface conditions effect on energy exchange at the soil surface
… were conducted to determine the effect of soil surface properties on physical processes occurring at or near the soil surface. Study one examined tillage effects on soil thermal properties and heat flux. Study two examined surface roughness effects on soil reflectance, net radiation, and …
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Multiple scattering of microwaves from soil surface and vegetation canopies
… parameters. This attempts to both improve soil moisture and vegetation attenuation and scattering parameter retrievals under moderate to dense canopy covers and capture the full microwave vegetation signature. The model is developed using a ray tracing method of first-order interactions …
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Classification of soil surface texture using high-resolution RGB images captured under uncontrolled field conditions
Understanding the properties of soil and its impact on the environment and farming practices requires accurately classifying its texture. Accurate soil texture classification can optimize soil nutrient levels and improve land management. This study proposes a framework that uses images captured …
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Effect of geochemical processes and environment on the spatial pattern of selenium in soil, surface water, and groundwater at the Hovland Ranch, central South Dakota
… as that may relate to selenium geochemistry in soil and water system at the Hovland Ranch, Haakon County, South Dakota. Representative samples were collected from soil, water, and soil moisture in the field. Preparation of samples and chemical analysis were done in the Water Quality Laboratory, …
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Rodent Mediated Seed Dispersal of Joshua tree (Yucca brevifolia)
… ground squirrels, and seeds and fruits on the soil surface were quickly removed by animals. Rodents given seeds labeled with scandium - 46 cached them between 0.1 cm and 4.1 cm deep. Seedling emergence was most common for seeds planted between 1 cm and 3 cm in the field, and at 1 cm in a growth …
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Behaviour of buried pipes adjacent to ground voids under dynamic loading
… the world. Therefore, there is a need for new soil improvement techniques such as geosynthetic materials installation to protect these pipes from damage. This study used large-scale laboratory tests to study the behaviour of buried pipes. A total of 22 large-scale tests were performed to study …
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Double-Cropped Soybean Response to Various Wheat Stubble Managements
… for double-cropped glyphosate-resistant soybean, soil moisture retention and soil surface shading, monitor weed response characteristics, and to perform a simple economic analysis comparing the four WSM treatments. Soybean plant height, lowest pod height, and soil surface shading were greater in …
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Out of the darkness and into the light : the quest for fluorescence-based soil tracers
… tracers to monitor the redistribution of soil at high temporal and spatial resolutions. Soil redistribution happens on a second by second basis with individual particles moving millimetres at a time. There are few, if any, existing tracing methods which permit the monitoring of soil …
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The effects of selected corn-soybean tillage systems on rill cross-sectional geometry and soil erosion for two Illinois soils
… geometry under different tillage, crop and soil conditions and to relate variations in rill geometric properties to measured sediment discharge and to soil erosion and sediment transport predicted by various models. In the experimental phase of this study, simulated rainfall and additional …
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Simulation of pesticide availability and transfer into overland flow
… which affect the availability and transfer of soil applied pesticides to runoff water on the soil surface were investigated. This research was composed of three major components: field investigation of pesticide transport as a function of pesticide formulation and application technique, …
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Harvesting effects on the hydrology of wet pine flats
… causes extensive rutting and churning of the soil surface and may alter the subsurface flow of soil water. An operational-scale experiment was established in 20-year-old loblolly pine (Pinus taeda) plantations to determine the hydrologic response of wet pine flats to wet- and dry-weather …
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A data-driven approach to bucket-filling control for autonomous excavators
… for autonomous excavators. Interactions between soil and an excavator bucket are highly complex and nonlinear, making traditional physical modeling difficult to use for real-time control. Here, we propose a data-driven method, exploiting data obtained from laboratory tests. We use the data to …
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Distribution of phosphorus in sandy soils of coastal fynbos
The levels of soil phosphorus (both total and plant available) were investigated at the Pella intensive study site and were found to be low. Resin extractable phosphorus fluctuated seasonally, peaking at the soil surface during summer and declining to a minimum in the winter months. Rates of …
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Forage Production and Nutritive Value in a Temperate Appalachian Silvopasture
… of yield and nutritive value characteristics. Soil surface temperature, forage canopy temperature, soil moisture, and photosynthetically active radiation were measured to determine forage responses to field treatments as functions of resource allocation. Tree density had the greatest effect on …
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Live Oak (<em>Quercus virginiana</em>) Recruitment and Seedling Survivorship in a Southern Maritime Forest
… hundred fifty acorns were directly sown on the soil surface and 150 acorns were buried at a depth of 6 cm. Acorns were also planted in the lab to produce seedlings that would be used for transplantation. At 6 months of age, seedlings grown in the lab were transplanted (n=50) among seedlings that …
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Long-term Effects of Fertilization on Phosphorus Biogeochemical Pools in Forest Soils
… (N) and phosphorus (P) availability in the soil environment. While the absolute quantities of P in forests soils may be large, the concentration of inorganic P in the soil solution is typically very small (< 0.01 mg L²-1). A onetime application of just 56 kg P ha²-1 can substantially …
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Toprak yüzey pürüzlülüğünün ölçülmesinde uzaktan algılamanın kullanımı
… zincir yöntemi ile karşılaştırılmıştır. Soil surface roughness is directly related to the erosion power of the climate, but also plays an important role in determining the tendency of soil to erosion. Chain method is one of the most commonly used methods for measuring surface roughness. …
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No-Till Vegetable Production at the Cal Poly Organic Farm
Tillage and subsequent bare soil have been linked to erosion, nutrient leaching, reduced biological diversity, loss of organic matter, and release of CO2 into the atmosphere (Brady and Weil, 2004). The usefulness of an organic no-till system for transplanted vegetables was explored over two growing …
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SLOPE AND EXPOSURE EFFECTS ON RANGE SITE INTERPRETATIONS (ARIZONA).
… for subsample sites. Environmental, complete soil descriptions, and vegetational composition data were taken. All data were analyzed using analyses of variance, ordination programs, and regression analyses to determine climate, soils, and vegetational relationships among exposures. The …
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