Search results for "Horizon"
showing 10 items of 600 documents
Advances in designing drip irrigation laterals
2018
It is known that using paired laterals, in which two distribution pipes extend in opposite directions from a common manifold, contribute to increasing water use efficiency (WUE). Recently, an analytical procedure to optimally design paired drip laterals on uniform slopes was proposed. More recently, this design procedure was simplified by deriving simple explicit relationships, as a function of 16 calibration constants, with relative errors that were less than 2%. In this paper, further simple design relationships are derived that require only 3 calibration constants, thus more readily obtainable results are produced and the influence of the flow rate and diameter exponents of resistance eq…
Economics of climate change : sensitivity analysis of social cost of carbon
2016
Social cost of carbon (SCC) is the key concept in the economics of climate change. It measures the economic cost of climate impacts. SCC has influence on how beneficial it is to prevent climate change: if the value of SCC increases, investments to low-carbon technology become more attractive and profitable. This paper examines the sensitivity of two important assumptions that affect to SCC: the choice of a discount rate and time horizon. Using the integrated assessment model, we calculate SCC estimates with multiple discount rates and various time horizon lengths. Our results show that discount rate and time horizon have great effect on SCC. For example, the SCC estimates are drastically re…
Entrevista para el diario ABC
1994
Entrevista a José Vidal-Beneyto realizada por Isabel San Sebastián para el diario "ABC". Se desconoce si finalmente fue publicada.
Municipal Thematical and Territorial Indicator Systems for Sustainable Socio-Ecological Coastal Governance
2017
Abstract . There are recognized in Latvia the lack of locally based coastal socio-ecological research knowledge and its interpretation into municipal safety and development planning from one side as well as also only land-side oriented and separate sectorial development interests based coastal municipalities’ governance/planning practice from other side. Coastal governance practice development problems solution at the local level are to be seen at both ends of governance cycle – coastal situation evaluation (e.g. science) and policy design and implementation . Overall objective is to create, apply/test and use applicable interface system for integrated coastal science transfer into integrat…
Manual packing and soil reuse effects on determination of saturated hydraulic conductivity of a loam soil
2022
Abstract Performing laboratory measurement of saturated hydraulic conductivity, Ks, of sieved soil is important for many scientific purposes such as testing theories and methods to determine Ks. A given soil mass can be used only once or it can be reused after a previous use. Little is known on the dependence of the Ks measurements on both the applied packing method and the reuse of the same soil mass. This lack of knowledge makes comparisons among different investigations more or less uncertain. Four packing methods were tested on an initially dry loam soil by measuring Ks with the simplified falling head (SFH) technique. The four methods differed by the used compacting procedure (dropping…
Soil profile dismantlement by land levelling and deep tillage damages soil functioning but not quality
2016
We investigated the effects of land levelling followed by deep tillage, thus inducing a drastic dismantlement of soil profile, on both soil functioning and quality by monitoring various bioindicators (microbial biomass and community structure, basal respiration, enzyme activities) expressed on either whole soil and TOC mass units, respectively. As expected, in disturbed soils all measured properties had much higher coefficients of variation (CVs), regardless of either whole soil or TOC mass basis, due to the induced spatial variability. The amount of total organic C in the first cubic meter of soil profile was of one order of magnitude greater in undisturbed soils compared to disturbed ones…
Relationships between earthworm communities and burrow numbers under different land use systems
2010
International audience; This study addresses the influence of three different land use systems (continuous maize, pasture/maize rotation, permanent pasture) on the relationships between earthworm populations and the number of earthworm burrows quantified in a soil profile. Quantified burrows were limited to those observable by the naked eye (i.e. >2 mm in diameter) and enumerated earthworms were limited to those which could have created the observable burrows (i.e. >0.3 g). The results were combined with data from the literature coming from different geographical regions. This study showed that earthworm abundance decreased with the increasing land management intensity (maize crop vs. pastu…
Fire effects on soil aggregation: A review
2011
Abstract Fire can affect soil properties depending on a number of factors including fire severity and soil type. Aggregate stability (AS) refers to soil structure resilience in response to external mechanical forces. Many authors consider soil aggregation to be a parameter reflecting soil health, as it depends on chemical, physical and biological factors. The response of AS to forest fires is complex, since it depends on how fire has affected other related properties such as organic matter content, soil microbiology, water repellency and soil mineralogy. Opinions differ concerning the effect of fire on AS. Some authors have observed a decrease in AS in soils affected by intense wildfire or …
Effect of soil management on its radioisotopic composition
2015
Radioactive isotopes, both natural and artificial, present in the environment may be convenient indicators that can be used to study a number of physical and chemical processes and transport of pollutants in the ecosystem.The main aim of the study was to evaluate the impact of the type of soil use on the radioisotopic composition in its surface layers. The radioisotopic compositions of surface soil samples collected in the area of a cement plant abandoned for over 20 years and in the area of the nearby allotments were examined and compared. Calculations were performed using methods designed to study compositional variables.The results confirmed a significant impact of usage on the radioisot…
Selenium and heavy metals content in some Mediterranean soils
2010
Abstract The study of metal contents in industrial, agricultural or/and polluted soils compared with natural or unpolluted soils is currently necessary to obtain reference values and to assess soil contamination. Nonetheless, very few works published appear in international journals on elements like Se, Li and Sr in Spanish soils. This study determines the total levels of Se, Li, Sr, As, Cd, Co, Cr, Cu, Ni, Pb, V, Zn, Fe, Mn and Ba in 14 natural (unpolluted) soils (Gypsisols, Leptosols, Arenosols and Acrisols), 14 agricultural soils (Anthrosols, Fluvisols and Luvisols), and 4 industrial–urban affected-surface soil horizons (Anthrosols and Fluvisols) of Eastern Spain. The geochemical baselin…