Soil Science Commons^™

Daytime Versus Nighttime Sprinkler Irrigation Of Two Urban Crops In A Semi-Arid Climate At High-Elevation, Samikshya Pyakurel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Nighttime irrigation scheduling is a longstanding water conservation approach to reduce evaporative losses in Utah's semi-arid, urban landscapes. However, residential demand now exceeds system capacity, and the efficiency of the practice has come under question. Therefore, the objectives of this study include: 1) quantify whether a water savings exists between day and night irrigation with a water balance and energy balance approach, and 2) analyze microclimate and crop quality effects to determine any changes to evaporative demand or plant stress by irrigation timing. In 2019, we established 12 field plots in North Logan, UT (41.77° N, -111.81° W, 1380 m …

The Optical Trapezoid Model: A Novel Approach To Remote Sensing Of Soil Moisture Applied To Sentinel-2 And Landsat-8 Observations, Morteza Sadeghi, Ebrahim Babaeian, Markus Tuller, Scott B. Jones

Plants, Soils, and Climate Faculty Publications

The “trapezoid” or “triangle” model constitutes the most popular approach to remote sensing (RS) of surface soil moisture based on coupled thermal (i.e., land surface temperature) and optical RS observations. The model, hereinafter referred to as Thermal-Optical TRAapezoid Model (TOTRAM), is based on interpretation of the pixel distribution within the land surface temperature - vegetation index (LST-VI) space. TOTRAM suffers from two inherent limitations. It is not applicable to satellites that do not provide thermal data (e.g., Sentinel-2) and it requires parameterization for each individual observation date. To overcome these restrictions we propose a novel OPtical TRApezoid Model (OPTRAM), which …

Experimental Evidence For Drought Induced Alternative Stable States Of Soil Moisture, David A. Robinson, Scott B. Jones, Inma Lebron, Sabine Reinsch, Maria T. Dominguez, Andrew R. Smith, Davey L. Jones, Miles R. Marshall, Bridget A. Emmett

Plants, Soils, and Climate Faculty Publications

Ecosystems may exhibit alternative stable states (ASS) in response to environmental change. Modelling and observational data broadly support the theory of ASS, however evidence from manipulation experiments supporting this theory is limited. Here, we provide long-term manipulation and observation data supporting the existence of drought induced alternative stable soil moisture states (irreversible soil wetting) in upland Atlantic heath, dominated by Calluna vulgaris (L.) Hull. Manipulated repeated moderate summer drought, and intense natural summer drought both lowered resilience resulting in shifts in soil moisture dynamics. The repeated moderate summer drought decreased winter soil moisture retention by ∼10%. However, intense summer drought, …

Temperature Dependence Of Soil-Moisture Potential, Jacob Willem Kijne

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Teachers have noticed that children draw only those objects which they know by name. Doubtless the adult has a similar tendency, exemplified by the researcher, to limit his observations or to relate them to that which can be expressed in the terminology of an existing or newly developed theory. In this thesis the data obtained from studies of the temperature and pressure dependence of the relative vapor pressure over moist soil samples are analyzed by a thermodynamic approach. Not all of the results can be explained completely by means of this tool. Natural systems, such as a moist soil, are …

Horizontal Movement Of Moisture In Soil, D. W. L. Read

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The movement of water in soils is of great importance to all of us but especially to agriculturalists. If it were not for this movement plants would not be able to survive in soil. If the moisture moves too freely in the soil insufficient water can be stored to supply plants during dry periods. The movement of water through soil may remove plant nutrients or accumulate salts in soil horizons.

The flow of water in soil has been studied extensively for many years. Water movement can occur in either saturated or unsaturated soil. Darcy's law can be used with a …

Bulletin No. 139 - The Movement Of Soluble Salts With The Soil Moisture, F. S. Harris

UAES Bulletins

In irrigated districts, where excessive quantities of water are used, there is usually an accumulation of alkali salts in the soils of the lower lands. These salts are probably dissolved from the soils through which the percolating waters pass and are carried along until the water comes to the surface and is evaporated, when the salts are deposited as a crust at the surface. Many of the most fertile soils of the arid regions have been ruined by the bringing to the surface of soluble salts in such large quantities that the growth of crops is prohibited. The rapidity with …