Search results for "gri"
showing 10 items of 10209 documents
Analysing the effect of land use and vegetation cover on soil infiltration in three contrasting environments in northeast Spain
2017
Este estudio presenta el análisis conjunto de la información obtenida a partir de 195 ensayos de infiltración en el campo, que fueron realizados mediante dispositivos de doble anillo. Los experimentos se realizaron en 20 situaciones contrastadas de usos del suelo, los cuales se encuentran distribuidos en tres contextos geográficos (costa NE de Cataluña, monte bajo del sector central del valle del Ebro y montaña media de la vertiente Sur del Pirineo central). El objetivo de esta investigación es determinar los factores más importantes que explican la variabilidad de la infiltración: uso del suelo, tipo de cubierta vegetal, características del suelo y del substrato rocoso, humedad del suelo y…
Tillage Impacts on Initial Soil Erosion in Wheat and Sainfoin Fields under Simulated Extreme Rainfall Treatments
2021
The main aim of this research was to determine the potential effects of different tillage systems (TT: traditional tillage and RT: reduced tillage) on runoff and erosion at two different locations (Kahramanmaras and Tarsus, Southern Turkey) under (i) fallow, (ii) wheat (Triticumaestivum L.), and (iii) sainfoin (Onobrychissativa L.) crops. Rainfall simulations with intensity of 120 mm h&minus
Anthropogenic lead distribution in soils under arable land and permanent grassland estimated by Pb isotopic compositions
2008
International audience; The role of land use on fate of metals in soils is poorly understood. In this work, we studied the incorporation of lead in two neighboring soils with comparable pedogenesis but under long-term different agricultural management. Distributions of anthropogenic Pb were assessed from concentrations and isotopic compositions determined on bulk horizon samples, systematical 5–10 cm increment samples, and on 24-h EDTA extracts. Minor amounts of anthropogenic lead were detected until 1-m depth under permanent grassland, linked to high earthworm activity. In arable land, exogenous Pb predominantly accumulated at depths <60 cm. Although the proximity between the two sites ens…
Blood flow in the internal jugular veins during the spaceflight - Is it actually bidirectional?
2020
Recently intriguing results of the research performed on astronauts of the International Space Station have been published. Unexpectedly, in some crew members a stagnant and bidirectional flow in the internal jugular vein was found, and in one of the astronauts this vein seemed to be totally thrombosed. If it actually were the case that in the settings of weightlessness there is a substantial risk of jugular vein thrombosis, any long-term human space missions would be extremely dangerous. Yet, we interpret these findings differently. In our opinion, what has been explained as bidirectional flow, actually represented the flow separation, and what has been described as occluded vein was rathe…
High spatio- temporal resolution land surface temperature mission - a copernicus candidate mission in support of agricultural monitoring
2018
International audience; Evolution in the Copernicus Space Component (CSC) is foreseen in the mid-2020s to meet priority Copernicus user needs not addressed by the existing infrastructure, and/or to reinforce services by monitoring capability in the thematic domains of CO 2 , polar, and agriculture/forestry. This evolution will be synergetic with the enhanced continuity of services for the next generation of CSC. The “High Spatio-Temporal Resolution Land Surface Temperature Monitoring (LSTM) Mission”, identified as one of the CSC Expansion High Priority Candidate Missions (HPCM), currently undergoes an ESA preparatory phase (phase A/B1) study to establish mission feasibility. The LSTM missio…
Half a century of forest cover change along the Latvian-Russian border captured by object-based image analysis of Corona and Landsat TM/OLI data
2020
Abstract After 1991, major events, such as the collapse of socialism and the transition to market economies, caused land use change across the former USSR and affected forests in particular. However, major land use changes may have occurred already during Soviet rule, but those are largely unknown and difficult to map for large areas because 30-m Landsat data is not available prior to the 1980s. Our goal was to analyze the rates and determinants of forest cover change from 1967 to 2015 along the Latvian-Russian border, and to develop an object-based image analysis approach to compare forest cover based on declassified Corona spy satellite images from 1967 with that derived from Landsat 5 TM…
Humusica 2, article 19: Techno humus systems and global change - Conservation agriculture and 4/1000 proposal
2018
International audience; Philosophy can overlap pedology. It is not casual that life begins and finishes in the soil. We separated the concepts of Humipedon, Copedon and Lithopedon. Some sections were dedicated to the founders of the movement for a new type of agriculture (agroecology). They simply proclaim to accompany the process of natural evolution instead of spending a lot of energy in hunting competitor organisms with pesticides or boosting the soil with mineral fertilisation and tillage. The core of the article is built on a biological concept of the soil and shows researches supporting this view. After pointing to the soil structure and illustrating its natural genesis, explaining wh…
Optimizing Gaussian Process Regression for Image Time Series Gap-Filling and Crop Monitoring
2020
Image processing entered the era of artificial intelligence, and machine learning algorithms emerged as attractive alternatives for time series data processing. Satellite image time series processing enables crop phenology monitoring, such as the calculation of start and end of season. Among the promising algorithms, Gaussian process regression (GPR) proved to be a competitive time series gap-filling algorithm with the advantage of, as developed within a Bayesian framework, providing associated uncertainty estimates. Nevertheless, the processing of time series images becomes computationally inefficient in its standard per-pixel usage, mainly for GPR training rather than the fitting step. To…
Laboratory evaluation of falling-head infiltration for saturated soil hydraulic conductivity determination
2020
Falling-head one-dimensional infiltration procedures, such as the simplified falling-head (SFH) technique, yield estimates of saturated soil hydraulic conductivity, Ks, with parsimonious and rapid experiments. Factors that can influence determination of Ks by the SFH technique were tested in the laboratory on three repacked soils differing by particle diameter ranges (0-2000, 0- 105 and 105-2000 mm, respectively). Using the theoretically calculated depth of ponding on the infiltration surface, D, instead of the measured one had a small impact on the Ks calculations (means differing by a factor of 1.1-1.2, depending on the soil). For the finest soil, Ks decreased by 3.1 times as D increased …
Effects of climate change and land use intensification on regional biological soil crust cover and composition in southern Africa
2022
Biological soil crusts (biocrusts) form a regular and relevant feature in drylands, as they stabilize the soil, fix nutrients, and influence water cycling. However, biocrust forming organisms have been shown to be dramatically vulnerable to climate and land use change occurring in these regions. In this study, we used Normalized Difference Vegetation Index (NDVI) data of biocrust-dominated pixels (NDVIbiocrust) obtained from hyperspectral and LANDSAT-7 data to analyse biocrust development over time and to forecast future NDVIbiocrust development under different climate change and livestock density scenarios in southern Africa. We validated these results by analysing the occurrence and compo…