Search results for "riga"
showing 10 items of 700 documents
Farmers’ autonomous management or state regulation? The consolidation of local irrigation associations in Spain (nineteenth to twentieth centuries)
2019
AbstractThe collective management of irrigation is an essential factor in agrarian development, both present and past. However, the relationship of irrigation associations with the state remains underexplored, despite the increasingly important role played by water policies in the modern world. The present article examines this relationship in Spain over the last two centuries. Our results suggest that, first, the state played a decisive part in the emergence and evolution of irrigation associations, and this belies the assumption of the traditional origin of these institutions; second, that farmers, despite being subject to the regulatory framework, enjoyed substantial autonomy in the mana…
Not only peasants: the myth of continuity in the irrigation communities of Valencia, Spain, in the medieval and early modern periods
2017
AbstractThe Horta of Valencia is a large irrigated area managed by eight communities of landowners. Traditionally, it was considered that these communities were composed of peasants, that they were self-managed and self-governed, and that they had remained immutable over time. However, the historical evidence shows that this is not true for pre-modern times. This article examines a possible Islamic origin of these institutions, the rupture caused by the Christian conquest of Valencia in the thirteenth century, the structure of the communities, and the social diversity of their members within the framework of feudalism. We conclude that irrigation communities cannot be used as examples of in…
Former students of the Riga Polytechnicum and Riga Polytechnic Institute (1862–1919) – literary workers
2018
The authors of the article have gathered literary works of poets and writers – former students of Riga Polytechnicum (RP) and Riga Polytechnic institute (RPI), and have characterized them. Several Latvian and foreign literary workers have studied at the institute. Only six of them – Alfrēds Andersons, Jānis Bergs, Rihards Ērglis, Ernests Eferts, Jānis Miķelsons and Arvīds Valdmanis – received diplomas in engineering after graduating from Departments of Engineering, Commerce and Agriculture. A. Valdmanis has written course books and literary works. Latvian poet Jānis Poruks and Russian writer Mihail Prishvin (Михаил Михаилович Пришвин) have also studied at the institute, but just like few ot…
"Faire du chiffre" pour exister. Les gendarmes et les policiers au principe des statistiques judiciaires (1875-1914)
2007
International audience; Gendarmes et policiers sont au XIXe siècle, déjà, les principaux pourvoyeurs de la justice pénale. À ce titre, ils jouent un rôle fondamental dans la construction de la statistique judiciaire, compilée annuellement dans le Compte général de l'administration de la justice criminelle. Sous la Troisième République, la crise sécuritaire, expose les forces de l'ordre à de violentes critiques. Ces attaques s'appuient sur des statistiques criminelles en hausse qui accréditeraient l'impéritie des gendarmes et des policiers. Stigmatisés au nom de chiffres, gendarmes et policiers cherchent alors à retrouver une légitimité institutionnelle et une utilité sociale en présentant d…
Pesticide contamination in water and sediment of the aquatic systems of the Natural Park of the Albufera of Valencia (Spain) during the rice cultivat…
2021
The Natural Park of the Albufera (Valencia, Spain) is a Mediterranean wetland where rice cultivation dominates the agricultural activity. The purpose of this study was to offer broader information about the current state of the wetland assessing the contamination by pesticides in four aquatic habitats during the rice cultivation period in 2016. Liquid chromatography with tandem mass spectrometer (UHPLC-MS/MS) was used to determine the pesticides in water and sediment samples from the rice fields, Lake Albufera and irrigation and outlet channels. 21 pesticides were detected in our samples (seven already forbidden by European legislation). Higher values than 10000 ng L of accumulated pesticid…
Prospective use of collected fog water in the restoration of degraded burned areas under dry Mediterranean conditions
2009
Abstract A mountainous plot located in the interior of the Valencia region (east coast of the Iberian Peninsula) was identified for reforestation using the fog-water collection potential prevailing in the area. Fog data were obtained by means of an instrument ensemble consisting of a passive cylindrical fog-water collector, a rain gauge, a wind direction and velocity sensor and a temperature and humidity probe. Preliminary results gave rise to the additional deployment of a low-cost 18-m 2 flat-panel collector connected to three 1000-l tanks for larger scale fog-water collection and storage. The 2007 annual rate of fog water that could be derived from the instrument ensemble amounted to 3.3…
Short-term emissions of CO 2 and N 2 O in response to periodic flood irrigation with waste water in the Mezquital Valley of Mexico
2015
Irrigation with waste water adds labile carbon and nitrogen compounds to the soil, and when applied by flooding it rapidly changes the soil's atmosphere and redox potential. In the Mezquital Valley more than 90 000 ha is irrigated with waste water from Mexico City, and enhanced emissions of CO2 and N2O follow each flooding. We measured the emissions of these two gases from a field irrigated periodically with waste water and under three crops, namely alfalfa, rye-grass and maize, using static chambers for 21 months. We also measured emissions from a field growing rain-fed maize before and shortly after two rain events. The data from repeated measurements from the same chambers are correlated…
Crop and irrigation water management using high resolution remote sensing and agrohydrological models
2006
A combined agrohydrological and remote sensing approach, called SIMODIS (Simulation and Management of On‐Demand Irrigation Systems) (D’Urso, 2001), has been used in a Sicilian test area to simulate the operation of on‐demand irrigation system. In SIMODIS the spatial distribution of crop factor, Kc, is directly calculated from canopy variables r (albedo), LAI (Leaf Area Index) and hc (crop height) derived from satellite‐based canopy spectral reflectance. Coupling these canopy variables with a specific data set of soil properties, the SIMODIS procedure was setup to simulate, in a distributed way, the water balance and, therefore, the irrigation deliveries for a set of 136 grape fields. For th…
Assessing crop coefficients of sunflower and canola using two-source energy balance and thermal radiometry
2014
Abstract A new technique for the local adjustments in crop coefficients is presented. This is an alternative to conventional lysimeter measurements traditionally used for improved irrigation scheduling. The method is based on the combination of a two-source energy balance model and local measurements of radiometric temperatures. Two experimental campaigns were carried out on sunflower and canola in a cropland area located in Barrax, Albacete, in the summer of 2011 and spring of 2012, respectively. Radiometric temperatures of soil and canopy were collected, together with biophysical and meteorological variables. Combining all these data in a two-source energy balance model allowed separation…
Modeling of Water Distribution under Center Pivot Irrigation Technique
2021
AbstractAiming to quantify the impacts of the center pivot irrigation technique on soil moisture dynamics and to improve irrigation crop water needs, a mathematical model was developed to estimate ...