Search results for " fisheries."
showing 10 items of 1015 documents
Herbicidal potential of aqueous extracts from Melia azedarach L., Artemisia arborescens L., Rhus coriaria L. and Lantana camara L.
2017
In the search for new strategies for weed management in agricultural systems, a great interest is to use the plant extracts to replace or integrate, chemical weed control. Two experiments were done to test the effects of plant water extracts from Chinaberry (Melia azedarach L.), Tree Wormwood (Artemisia arborescens (Vaill.) L.), Sicilian Sumac (Rhus coriaria L.) and Lantana (Lantana camara L.) on seed germination of Rocket (Eruca sativa Mill.), Rapeseed (Brassica napus L.), Bladderflower (Araujia sericifera Brot.) and Psyllium (Plantago psyllium L). The water extracts (pure and 50% mixtures) from the donor species were applied on seeds of recipient plants. In second experiment in pots, thes…
Relief and calcium from gypsum as key factors for net inorganic carbon accumulation in soils of a semiarid Mediterranean environment
2021
Abstract In semiarid environments, the total inorganic carbon (TIC) in soil may contribute to the total carbon (C) pool more than the total organic C pool (TOC), thus playing a key role in storing atmospheric CO2. However, due to the different origin pathways of soil carbonates, not all of the TIC pool can be accounted for CO2 sequestration. Indeed, the inorganic C can be accounted for a net sink of CO2 only when calcium (Ca2+) forming carbonates originate from non-carbonate minerals (atmogenic inorganic C, AIC). The aim of this study carried out in a gypsiferous area is to investigate the dissolution of Ca2+ that comes from gypsum (CaSO4·2H2O) in the formation of soil atmogenic carbonates …
The onset of the rainy season and farmers’ sowing strategy for pearl millet cultivation in Southwest Niger
2011
A multi-year (2004-2009) field survey of on-farm sowing practices in 10 villages located in south-west Niger close to Niamey, is analysed to investigate the relationships (i) between rainfall and the sowing date of pearl millet and the risk of sowing failure, (ii) between sowing and meteorological/agro-climatic onset dates, (iii) between sowing/onset dates, and simulated and observed yield/biomass at the end of the season. Even if some villages sow without any synchronous or anterior rainfall, most parcels (73% out of the 1551 available cases) are sown during and just after a 2-day wet spell receiving at least 10 mm. In fact, there is a strong correlation (r = 0.82-0.95 depending on onset d…
A prediction model for field drying of hay using a heat balance method
1993
Abstract A hay drying model with a multi-layer representation has been developed. This model, based on a heat balance method, was designed to compute hay drying dynamics in the field. It was implemented for hay spread over a field or in windrows. The necessary inputs are: (1) meteorological data (temperature, humidity, wind speed, solar and atmospheric radiation); (2) biological characteristics of the plant; (3) hay physical parameters (depth, leaf area index). The output provides time-dependent cumulative water losses and changes in water content and temperature in the different layers. The model was tested against data measured under experimental conditions with different kinds of grass (…
Assessing the suitability of American National Aeronautics and Space Administration (NASA) agro-climatology archive to predict daily meteorological v…
2017
Abstract For decades, the importance of evapotranspiration processes has been recognized in many disciplines, including hydrologic and drainage studies, irrigation systems design and management. In this research, the suitability of the Prediction Of Worldwide Energy Resource database published by the American National Aeronautics and Space Administration (POWER-NASA), to estimate daily meteorological variables and ET 0 was assessed in Sicily, Italy, for the period 2006–2014, based on ground data measured by a network of climate stations belonging to the regional Agro-meteorological Information Service (SIAS). After comparing the climate data (minimum, T min , maximum, T max , and average, T…
Sorption-Caused Attenuation and Delay of Water Vapor Signals in Eddy-Covariance Sampling Tubes and Filters
2014
AbstractAdsorption and desorption (together called sorption) processes in sampling tubes and filters of eddy-covariance stations cause attenuation and delay of water vapor signals, leading to an underestimation of water vapor fluxes by tens of percent. The aim of this work was (i) to quantify the effects on sorption in filters and tubes of humidity, flow rate, and dirtiness and (ii) to test a recently introduced sorption model that facilitates correction of fluxes. Laboratory measurements on the transport of water vapor pulses through tubes and filters were carried out, and eddy-covariance field measurements were also used.In the laboratory measurements, the effects of sorption processes we…
Disentangling the rhizosphere effect on nitrate reducers and denitrifiers: insight into the role of root exudates.
2008
International audience; To determine to which extent root-derived carbon contributes to the effects of plants on nitrate reducers and denitrifiers, four solutions containing different proportions of sugar, organic acids and amino acids mimicking maize root exudates were added daily to soil microcosms at a concentration of 150 μg C g−1 of soil. Water-amended soils were used as controls. After 1 month, the size and structure of the nitrate reducer and denitrifier communities were analysed using the narG and napA, and the nirK, nirS and nosZ genes as molecular markers respectively. Addition of artificial root exudates (ARE) did not strongly affect the structure or the density of nitrate reduce…
Shifts in size, genetic structure and activity of the soil denitrifier community by nematode grazing
2010
International audience; Bacterial-feeding nematodes represent an important driver of the soil microbial activity and diversity. This study aimed at characterizing the impact of nematode grazing on a model functional bacterial guild involved in N-cycling, the denitrifiers. Bacterial-feeding nematodes (Cephalobus pseudoparvus) were inoculated into soil microcosms whose indigenous nematofauna had previously been removed. The size, genetic structure and activity of the soil denitrifier community were characterized 15 and 45 days after nematodes inoculation using quantitative PCR of the nirK, nirS and nosZ denitrification genes, fingerprinting of the nirK and nirS genes and denitrification enzym…
Optimization of the Mix-Design System for the Sub-ballast Railroad
2017
Bituminous sub-ballast is an alternative solution to the unbound granular sub-ballast used in the railway track due to several benefits that it can provide. Indeed, it contributes to maintain the moisture content in the subgrade unchanged during all year. This decreases the subgrade deterioration process. Moreover, the presence of bituminous sub-ballast can also reduce vertical stiffness variations on the track; it can have a positive effect in the maintenance needs at transition sections (bridge-embankment) and in the attenuation of the vibrations induced by the rail traffic. Despite the importance of the presence of the bituminous sub-ballast to conceive the construction and/or rehabilita…
Changes in soil chemical properties as affected by pyrogenic organic matter amendment with different intensity and frequency
2017
Pyrogenic organic matter (PyOM) has long been used as a soil amendment to improve soil physicochemical properties. However, few studies simultaneously investigated both intensities and frequencies of PyOM addition on soil chemical properties of soil base cations, soil pH buffering capacity (pHBC), and plant available micronutrients. In the main food production area of lower Liaohe River Plain in Northeast China, a field manipulation of PyOM addition was initiated in 2013 to examine how the intensities (0, 1%, 3%, and 5% of 0–20 cm soil mass) and frequencies (3% of soil mass applied once versus yearly for 3 years) of PyOM amendment affected soil chemical properties. Higher intensity of PyOM …