Search results for "soil water"
showing 10 items of 840 documents
The effects of land abandonment and long-term afforestation practices on the organic carbon stock and lignin content of Mediterranean humid mountain …
2019
Afforestation is an important strategy that can decrease atmospheric carbon by sequestering carbon in biomass and soil. In Spain, an active afforestation programme was adopted in the 1950s when the soil was severely eroded after widespread abandonment of arable land. The Araguás catchment (Central Spanish Pyrenees) is a good example of this programme because it was afforested with both Pinus sylvestris L. (PS) and Pinus nigra J.F.Arnold (PN). The soil organic carbon (SOC) stock and lignin content (based on the vanillyl, syringyl and cinnamyl contents) of these afforested soils were examined and compared to those of bare soil, secondary succession and meadow soils. Both the SOC stock and lig…
Transpiration/Evaporation Ratio in Prunus Fremontii and Marianna 2624 over a 4-Day Period of Drought
2017
Drought stress represents one of the major environmental limitations to crop production in a large portion of the Earth’s surface. Natural genetic resources are one of the most powerful weapons against environmental stress. In such contest, the behavior in terms of water loss of two species, P. fremontii (slower-growing) and Marianna 2624 (faster-growing), native to arid and humid regions respectively, was tested. Transpiration (T) and evapotranspiration (ET) rates and soil water content (SWC) were measured in the two species under controlled conditions. Evaporation rate from the soil surface was obtained by difference, and an average transpiration/evaporation ratio (T/E) was calculated to …
Implementing a cyber-physical system to monitor soil water status and environmental variables for irrigation scheduling
2018
The most advanced research on irrigation at farm scale, following the paradigm “more crop per drop”, has been aimed at the definition of strategies of precision irrigation, in order to optimize crop water productivity and to maximize the economic benefits without affecting environmental quality.Water saving management strategies, such as regulated deficit irrigation (RDI), can be effectively applied if supported by the real time control of soil/plant water status allowing the identification of appropriate irrigation scheduling parameters (irrigation timing and doses). This challenge can be achieved by integrating sensing technologies, internet of things and cloud computing supported with co…
Identifying the threshold of soil water content for the precise irrigation scheduling of a Citrus orchard under subsurface drip irrigation
2019
Proper irrigation scheduling requires the knowledge of the soil-plant-atmosphere system, including the relationships existing between its various components. During the last decade, the monitoring of soil water content (SWC) has been considered a standard way to determine when crops need to be irrigated. However, under drip irrigation systems in which laterals are laid on the soil surface or buried at a certain depth, the gradients of soil water content are rather high and therefore the threshold of SWC below which crop water stress occurs should account for the position of the sensors; the threshold, in fact, depends on the specific crop system, as well as on the relative position of the m…
Predicting the water retention characteristic of Sicilian soils by pedotransfer functions.
2008
Effects of Humic Substances and Soya Lecithin on the Aerobic Bioremediation of a Soil Historically Contaminated by Polycyclic Aromatic Hydrocarbons (…
2004
The high hydrophobicity of polycyclic aromatic hydrocarbons (PAHs) strongly reduces their bioavailability in aged contaminated soils, thus limiting their bioremediation. The biodegradation of PAHs in soils can be enhanced by employing surface-active agents. However, chemical surfactants are often recalcitrant and exert toxic effects in the amended soils. The effects of two biogenic materials as pollutant-mobilizing agents on the aerobic bioremediation of an aged-contaminated soil were investigated here. A soil historically contaminated by about 13 g kg(-1) of a large variety of PAHs, was amended with soya lecithin (SL) or humic substances (HS) at 1.5% w/w and incubated in aerobic solid-phas…
Ecological risk assessment of agricultural soils for the definition of soil screening values: A comparison between substance-based and matrix-based a…
2017
The Italian legislation on contaminated soils does not include the Ecological Risk Assessment (ERA) and this deficiency has important consequences for the sustainable management of agricultural soils. The present research compares the results of two ERA procedures applied to agriculture (i) one based on the “substance-based” approach and (ii) a second based on the “matrix-based” approach. In the former the soil screening values (SVs) for individual substances were derived according to institutional foreign guidelines. In the latter, the SVs characterizing the whole-matrix were derived originally by the authors by means of experimental activity.\ud \ud \ud The results indicate that the “matr…
A thermal inertia model for soil water content retrieval using thermal and multispectral images
2010
Soil moisture is difficult to quantify because of its high spatial variability. Consequently, great efforts have been undertaken by the research community to develop practical remote sensing approaches to estimate the spatial distribution of surface soil moisture over large areas and with high spatial detail. Many methodologies have been developed using remote sensing data acquiring information in different parts of the electromagnetic spectrum. Conventional field measurement techniques (including gravimetric and time-domain reflectometry) are point-based, involve on-site operators, are time expensive and, in any case, do not provide exhaustive information on the spatial distribution of soi…
Analyzing the role of soil water retention curve in slope stability for differently structured soils
2016
We analyzed the mechanical and hydrological effects of soil water retention curve (SWRC) models on the slope stability analyses of soils with unimodal and bimodal behavior. We used three different SWRC models, two bimodal models (Ross&Smettem and Dexter) vs. the traditional van Genuchten model, to evaluate the Factor of Safety (FS) of a simple designed hillslope, based on the Bishop approach for unsaturated soils. Two formulations for term were also considered. Results indicate that in cases of clayey soils, changes in FS obtained with different SWRC models especially at soil moisture values within the residual zone. In sandy soils the choice of formulations can be more important…
Life cycle environmental assessment of retaining walls in unsaturated soils
2022
Abstract Retaining structures above groundwater level support soils that are usually in a state of partial saturation and subject to the actions of atmospheric agents. The current design approach considers the possible extremes of soil conditions – either totally dry or totally saturated – but it neglects matric suction’s contribution to soil shear strength. This work aims to describe how unsaturated-soil mechanics of can positively influence the sustainability of retaining structures through a holistic, multidisciplinary, geotechnical, and environmental analysis. The geotechnical analysis allows to estimate the lateral earth pressure of a geostructure in both unsaturated and extreme soil c…