Potential Dissipation of Atrazine in the Soil Unsaturated Zone: a Comparative Study in Four European Countries     

Salah Issa  Martin Wood  Luc Pussemier  Vincent Vanderheyden  Catherine Douka  Spyros Vizantinopoulos  Zoltan Gyori  Maria Borbely  Janos Katai 《Pest management science》1997,50(2):99-103

A European-wide project has been undertaken to establish the potential for dissipation of atrazine in the soil subsurface environment. Samples were obtained, avoiding contamination, in four countries (Belgium, Greece, Hungary and UK) and laboratory studies carried out. In order to make comparisons between results from each laboratory, a ring experiment was carried out using common methodology for sampling, extraction and analytical techniques. Subsurface materials from each country were distributed to the other countries. Atrazine dissipation was determined in each country for all materials under the same laboratory conditions. The results of this comparative study showed generally good agreement between all laboratories. Significant potential microbiological dissipation was detected in certain samples. Where differences occurred between laboratories this was attributed to small, spatially heterogeneous microbial populations in the subsurface materials. © 1997 SCI.  相似文献   

Evaluating physiological traits to complement empirical selection for wheat in warm environments   总被引：4，自引：1，他引：3  

M.P. Reynolds  R.P. Singh  A. Ibrahim  O.A.A. Ageeb  A. Larqué-Saavedra  J.S. Quick 《Euphytica》1998,100(1-3):85-94

The response of spring wheat to heat stress has been determined in several hot wheat growing environments worldwide on different types of germplasm. Physiological data has been collected to identify potential traits to assist in the empirical breeding for heat tolerance. Initial studies focused on 10 established varieties to determine genetic diversity for heat tolerance, identify association between heat tolerance and traits measured, and evaluate genotype by environment interaction (G x E). Yields from over 40 hot environments were analysed for G x E, and relative humidity (RH) was identified as the major factor determining relative genotype ranking. Further analysis focused on 16 environments: those with low RH and relatively high yields, i.e., over 2.5 t ha^-1. For these environments, mean yield of lines correlated with a number of physiological traits measured in Mexico, including canopy temperature depression (CTD), membrane thermostability, leaf conductance and photosynthetic rate at heading, chlorophyll content during grainfilling, leaf internal CO₂ concentration, and dark respiration. Morphological traits were measured in all environments and the following showed associations with yield: above ground biomass at maturity, days from emergence to anthesis and to maturity, grain number m^-2, and ground cover estimated visually after heading. Subsequent studies focused on breeding material, namely recombinant inbred lines derived from crosses between parents of contrasting heat tolerance, and 60 advanced breeding lines selected for performance under heat stress. The genetic basis for association between heat tolerance and CTD was established by demonstrating a correlation between the two traits in RILs (recombinant inbred lines). Data from RILs, as well as from the 60 advanced lines grown at several international locations, indicated CTD to be a powerful and robust selection criterion for heat tolerance. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Repellence of Myzus persicae (Sulzer): evidence of two modes of action of volatiles from selected living aromatic plants     

Tarek Dardouri  Hlne Gautier  Refka Ben Issa  Guy Costagliola  Laurent Gomez 《Pest management science》2019,75(6):1571-1584

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Effect of Bay (Laurus nobilis L.) Essential Oil on Surimi Gels Nutritionally Enhanced with Salmon and Flaxseed Oils     

Ugochukwu Anyanwu  Fatimah Alakhrash  Seyed Vali Hosseini  Salam A. Ibrahim 《Journal Of Aquatic Food Product Technology》2017,26(4):431-446

Bay essential oil (BEO) at 0.5 and 1 g/100 g was added to surimi gels fortified with omega (ω)-3 rich oils. Although the fortification resulted in increased (P < 0.05) susceptibility of surimi to lipid oxidation, 0.5 g/100 g BEO significantly reduced TBARS (P < 0.05). Addition of ω-3 rich oil or BEO improved the texture. Color values of the surimi seafood were improved particularly when BEO was added. Sensory properties, water activity, and pH values were generally within the acceptable range. These results suggest that the incorporation of BEO may allow food manufacturers to nutritionally enhance surimi seafood with beneficial ω-3 rich oils.  相似文献   

Degradation of atrazine and isoproturon in the unsaturated zone: a study from Southern England     

Salah Issa  Martin Wood 《Pest management science》1999,55(5):539-545

The potential for degradation of atrazine or isoproturon in the unsaturated zone of two boreholes was studied under laboratory conditions. Intact and uncontaminated samples were obtained from regular depths of 0–16.45 m and 0–9 m using a percussion coring technique. The results showed that the deep unsaturated zone contained micro-organisms capable of degrading atrazine or isoproturon. The rate of degradation was much faster in surface soil than in most unsaturated materials of both boreholes. The amount of atrazine remaining six months after incubation also varied between the two boreholes. A relatively small amount of atrazine was lost from sterilised samples, suggesting a significant role for microbial degradation. The addition of nutrient and energy sources into materials of low degradation capacity did not enhance the degradation of atrazine. Degradation rate was more related to the presence of a competent microbial population rather than to the presence of indigenous organic matter. However, the competent micro-organisms are more likely to be present when the organic matter content is high. The type and activity of these micro-organisms and their physical environment may have considerable influence on atrazine degradation and are likely to be responsible for much of the variation in the rate of degradation observed at different depths. © 1999 Society of Chemical Industry  相似文献   

Spatial analysis of soil surface hydraulic properties: Is infiltration method dependent?     

Ibrahim Mubarak  Rafael Angulo-Jaramillo  Jean Claude Mailhol  Mohammadreza Khaledian  Michel Vauclin 《Agricultural Water Management》2010,97(10):1517-150

The management of irrigated agricultural fields requires reliable information about soil hydraulic properties and their spatio-temporal variability. The spatial variability of saturated hydraulic conductivity, K_s and the alpha-parameter α_vG-2007 of the van Genuchten equation was reviewed on an agricultural loamy soil after a 17-year period of repeated conventional agricultural practices for tillage and planting. The Beerkan infiltration method and its algorithm BEST were used to characterize the soil through the van Genuchten and Brooks and Corey equations. Forty field measurements were made at each node of a 6 m × 7.5 m grid. The soil hydraulic properties and their spatial structure were compared to those recorded in 1990 on the same field soil, through the exponential form of the soil hydraulic conductivity given by the Gardner equation, using the Guelph Pressure Infiltrometer technique. No significant differences in the results obtained in 1990 and 2007 were observed for either particle-size distribution or dry bulk density. The mean value of α_vG-2007 was found to be identical to that of α_G-1990, while that of K_s-2007 was significantly smaller than that of K_s-1990. In contrast to the Gardner equation, the van Genuchten/Brooks and Corey expression was found to be more representative of a well-graded particle-size distribution of a loamy soil. The geostatistical analysis showed the two parameters, K_s and α_vG-2007, were autocorrelated up to about 30 and 21 m, respectively, as well as spatially positively correlated within a range of 30 m. Despite the difference in the mean values of K_s between the two studies, the spatial structures were similar to those found in the 1990 experiment except for the covariance sign. The similarity in autocorrelation ranges indicate that the spatial analysis of soil hydraulic properties is independent of the infiltration methods (i.e., measurement of an infiltration flux) used in the two studies, while the difference in the covariance sign may be linked to the use of two different techniques of soil hydraulic parameterization. The covariance values found in the 2007 campaign indicates a positive relationship between the two parameters, K_s and α_vG-2007. The spatial correlations of soil hydraulic parameters appear to be temporally stabilized, at least within the agro-pedo-climatic context of the study. This may be attributed to the soil textural properties which remain constant in time and to the structural properties which are constantly renewed by the cyclic agricultural practices. However, further experiments are needed to strengthen this result.  相似文献   

Determination of appropriate age and stocking density of vundu larvae, Heterobranchus longifilis (Valenciennes 1840), at the weaning time     

Ibrahim Imorou Toko  Emile D Fiogbé  & Patrick Kestemont 《Aquaculture Research》2008,39(1):24-32

Two experiments were conducted in order to determine the appropriate age and stocking density of vundu catfish Heterobranchus longifilis at the weaning time. In the first experiment, five triplicate groups of 100 larvae (initial mean weight=3.4 mg) per aquaria were stocked from first feeding [day 3 post‐hatch (p.h.)] to day 30 p.h., and then weaned, on days 3 (W3), 5 (W5), 8 (W8) and 14 (W14), and an unweaned group (An). Significant differences were observed in growth, survival, cannibalism, coefficient of weight variation and body composition among larvae weaned at different ages and the control group. The later the larvae were weaned, the better were the growth performances [final mean weight: from 65.1 to 201.1 mg and specific growth rate (SGR): from 11.0 to 15.2% day^?1] and the survival (from 36.5% to 74.3%). The experiment with stocking densities of 5, 10, 25 and 50 larvae L^?1 showed that increasing the stocking density decreased growth performances and weight variation but improved the survival rate of larvae. The best growth performances (SGR=13.4 and 11.4% day^?1) with the lowest survival rates (70.3% and 77.3%) were observed in larvae stocked at densities of 5 and 10 larvae L^?1 respectively.  相似文献