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1.
Lydie-Stella Koutika Sonia Vanderhoeven Lydie Chapuis-Lardy Nicolas Dassonville Pierre Meerts 《Biology and Fertility of Soils》2007,44(2):331-341
Invasive exotic plants can modify soil organic matter (SOM) dynamics and other soil properties. We evaluated changes in particulate
organic matter (POM) and carbon (C) mineralisation in adjacent plots invaded by Solidago gigantea, Prunus serotina, Heracleum mantegazzianum and Fallopia japonica, and non-invaded control plots on different soils in Belgium. Litter decomposition of S. gigantea and P. serotina was compared to that of the native species Epilobium hirsutum, Betula pendula and Fagus sylvatica. Disregarding the differences in site characteristics (soil texture, parental material and plant species), we argued that
the invasion by S. gigantea and P. serotina enhance SOM dynamics by increasing C mineralisation in 2 out of 3 sites invaded by S. gigantea and in 1 out of 3 sites invaded by P. serotina; C in coarse POM (cPOM, 4,000–250 μm) and fine POM (fPOM, 250–50 μm) in 1 site invaded by S. gigantea and C content in total POM (tPOM, 4,000–50 μm) and the organo-mineral fraction (OMF, 0–50 μm) in 1 site invaded by P. serotina. H. mantegazzianum and F. japonica slowed down SOM dynamics by reducing C mineralisation in three out of four sites; C and nitrogen (N) of fPOM in the invaded
compared with the non-invaded plots at one site invaded by H. mantegazzianum. However, N content of cPOM (4,000–250 μm) was higher in the invaded sites by F. japonica compared with the non-invaded plots. Our results indicated that the effects of invasion by exotic plant species were not
species-specific but site-specific. 相似文献
2.
Moreau L Kim HJ Decker EA McClements DJ 《Journal of agricultural and food chemistry》2003,51(22):6612-6617
Oil-in-water emulsions containing droplets stabilized by beta-lactoglobulin (beta-Lg)-pectin membranes were produced using a two-stage process. A primary emulsion containing small droplets (d(32) approximately 0.3 microm) was prepared by homogenizing 10 wt % corn oil with 90 wt % aqueous solution (1 wt % beta-Lg, 5 mM imidazole/acetate buffer, pH 3.0) using a high-pressure valve homogenizer. The primary emulsion was then diluted with pectin solutions to produce secondary emulsions with a range of pectin concentrations (5 wt % corn oil, 0.45 wt % beta-Lg, 5 mM imidazole/acetate buffer, 0-0.22 wt % pectin, pH 3.0). The electrical charge on the droplets in the secondary emulsions decreased from +33 +/- 3 to -19 +/- 1 mV as the pectin concentration was increased from 0 to 0.22 wt %, which indicated that pectin adsorbed to the droplet surfaces. The mean particle diameter of the secondary emulsions was small (d(32) < 1 microm) at relatively low pectin concentrations (<0.04 wt %), but increased dramatically at higher pectin concentrations (e.g., d(32) approximately 13 microm at 0.1 wt % pectin), which was attributed to charge neutralization and bridging flocculation effects. Emulsions with relatively small mean particle diameters (d(32) approximately 1.2 microm at 0.1 wt % pectin) could be produced by disrupting flocs formed in secondary emulsions containing highly negatively charged droplets, for example, by sonication, blending, or homogenization. The particles in these emulsions probably consisted of small flocs containing a number of protein-coated droplets bound together by pectin molecules. These emulsions had good stability to further particle aggregation up to relatively high ionic strengths (< or =500 mM NaCl) and low pH (pH 3). The interfacial engineering technology used in this study could lead to the creation of food emulsions with improved physicochemical properties or stability. 相似文献
3.
Guermani-Nicolle Lydie Villaume Christian Bau Hwei-Ming Schwertz Annie Nicolas Jean-Pierre Mejean Luc 《Plant foods for human nutrition (Dordrecht, Netherlands)》2001,56(3):239-249
Numerous factors affect plasma cholesterol and, therefore, representpotential interferences with the specific effects of diet on lipid metabolism.After casein intake, serum cholesterol levels depend on many experimentalconditions in rats, such as the type of casein, the presence or absence ofcholesterol in the diet, the age and strain of rat, the diet composition, thenutritional status. The effect of fasting duration on selected parameters wasstudied in adult male Wistar rats fed a 20% casein and 1% cholesterol-based diet. No changes were observed in total serum, lipoproteins-B andHDL cholesterol and in triglyceride values after an 8 h-fast compared tonon-fasted animals. A significant decrease was induced in total andlipoproteins-B cholesterol with a 12 h-fast. A prolonged fast resulted ina significant decrease in these parameters and in triglycerides and inHDL-cholesterol levels.Fasted animals fed heated soybean meal instead of casein did not display amarked decrease in serum lipids. It appeared that the fasting effect wasmore marked in animals fed casein than in animals fed soybeans. Theseresults showed the importance of experimental conditions such as nutritional status ofanimals when blood samples are taken in studies of the hypocholesterolemiceffect of soy protein compared to casein. 相似文献
4.
Lydie Dufour Marie Gosme Jimmy Le Bec Christian Dupraz 《Journal of Agronomy and Crop Science》2020,206(5):640-649
In agroforestry systems, the canopy of maturing trees progressively reduces the radiation available for the crop. Tree management practices such as pollarding can be used to restore the crop light availability. We monitored durum wheat, barley and pea yields during three consecutive years in an alley-cropping agroforestry system with hybrid walnut trees in Southern France. Trees have been pruned regularly to 4 m since planting (in 1995), and a section of 50 trees was pollarded at 4 m height for the first time in 2013. We measured the yields and yields components in the two different tree management systems and in a sole crop control. The non-pollarded trees reduced significantly the incident light (around 80% of the global radiation left in average) and both wheat (68% of the control) and pea (69% of the control), but not barley mean yields. In pollards inter-row, the average incident light was 98% of the total radiation the first year and the wheat yield 89% of the control. But 3 years after pollarding, the incident light was 79% of the total radiation and the pea yield was only 67% of the control. Pollarding had a transient positive impact on crop yield; after 3 years, pollards were more competitive for light than control trees. Pollarding may also reduce the belowground trees competition, but slightly, as the crop vegetative growth occurs when the trees are leafless. 相似文献
5.
Container-grown Ligustrum ovalifolium L. plants were used to determine the influence of nutrient availability on the mobilisation of carbon (C), nitrogen (N) and phosphorus (P) during spring growth. During the spring of the second growing season, plants either received no fertiliser, or were fertilised early (starting 17 days after bud break) or late (starting 3 months after bud break). Nutrient composition of different plant tissues was determined at several times during the second growing season from bud break to the end of elongation. Time of fertilisation did not influence aerial dry weight until flowering was completed. Plants that received no fertiliser or were fertilised late had greater root dry weight than plants that received fertiliser early. Fertilised plants had a second flush of growth after flowering completed. Nitrogen and phosphorus mobilisation occurred from bud break to the end of elongation (3 months). Nutrient mobilisation was effective in each perennial organ: root, trunk, ligneous stems and old leaves. However, the role of old leaves as storage organ was minor compared to evergreen tree leaves. Carbon mobilisation only occurred on the 1st month following bud break, before elongation. C-starch accumulation was observed in unfertilised plants even when the C-starch quantities in early fertilised plants were very low at the end of elongation, mainly in roots. In spite of fertilisation supplies, N and P quantities did not increase after elongation in the early fertilised plants, probably in relation to C insufficiency in roots to sustain N and P absorption and assimilation. By contrast, in late fertilised plants, high C quantities in roots were mobilised for N and P uptake and assimilation, which allowed both second growth flush and storage of N and P in perennial organs. The mobilisation of nutrients before and during elongation revealed the nutritional autonomy of shrubs, which could allow fertiliser use efficiency to be increased and environmental impacts to be minimised by delaying spring fertilisation. Nevertheless, the shrub ability to valorise fertilisation supplies for sustaining growth or nutrient storage restoration required sufficient C-starch quantities in roots. The starch accumulated in roots before late nutrient supply can be used for these objectives. 相似文献
6.
To evaluate the soil‐fertility sustainability of the fallow systems, nutrient concentrations and NH4+‐N mineralization were determined in different soil and fallow types in the humid forest zone of southern Cameroon. Two experiments were conducted, the first comprised planted leguminous tree Calliandra calothyrsus, planted leguminous Pueraria phaseoloides, and regrowth mainly composed of Chromolaena odorata on the Typic Kandiudult. The second experiment made up of a fallow dominated by C. odorata, a fallow with C. odorata removed, and a P. phaseoloides fallow on the Rhodic Kandiudult, Typic Kandiudult, and Typic Kandiudox. In the first experiment, available P, Ca2+, K+ concentrations and effective CEC under C. calothyrsus were, respectively, 40%, 22%, 45%, and 15% lower when compared to P. phaseoloides but no differences were found between soils under P. phaseoloides and C. odorata. Mineralization of NH4+‐N was higher under C. calothyrsus than under C. odorata‐ and P. phaseoloides‐fallow types, indicating the impoverishment of organic material under the former. In the second experiment, the beneficial effect of P. phaseoloides was found in the Rhodic Kandiudult in the 0–10 cm layer throughout its low NH4+ release from mineralization. In the Typic Kandiudult, no differences in NH4+‐N mineralization were found between C. odorata and P. phaseoloides fallows. In the Typic Kandiudox, there was no difference in NH4+ mineralization between the three fallow types. According to the nutrient concentrations and NH4+ mineralization, the fertility sustainability of the different fallow types may be ranked as follow: P. phaseoloides ≥ C. odorata > C. calothyrsus > fallow without C. odorata. 相似文献
7.
Uptake of soil mineral nitrogen by Acacia mangium and Eucalyptus urophylla × grandis: No difference in N form preference 
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下载免费PDF全文 Daniel Epron Lydie‐Stella Koutika Sogni Viviane Tchichelle Jean‐Pierre Bouillet Louis Mareschal 《植物养料与土壤学杂志》2016,179(6):726-732
The introduction of N2‐fixing tree species in fast growing tree plantations is a sustainable management option aiming to reduce the risk of nitrogen (N) deficiency due to a large and frequent exportation of nutrients at harvest. Differences in soil mineral N preferences between Eucalyptus urophylla × grandis and Acacia mangium may, in addition to facilitation related to atmospheric N2 fixation, contribute to the success of mixed‐species plantations of the two species on nutrient‐poor soils of the coastal Congolese plains. We tested whether these two species differ in their preference for nitrate or ammonium by supplying either ammonium or nitrate enriched in 15N to six‐month‐old potted trees growing in an open‐air nursery. Although the uptake of nitrate tended to be higher than that of ammonium by both species, the difference was not significant and there was no significant difference between the species regarding their preferred form of soil mineral N. Despite much lower N contents in foliage, stems, and roots of eucalypt compared to acacia, the specific rates of N uptake were up to three times higher for eucalypt than acacia, which suggests that atmospheric N2 was the major source of N in the six‐month‐old acacias. We conclude that N2 fixation rather than complementarity for soil mineral nitrogen alleviates the competition between species in successful mixed eucalypt and acacia plantations. 相似文献
8.
Trees at low density and cereals may be combined in silvoarable agroforestry systems: tree rows and their companion vegetation introduce an heterogeneity in the cropped field that may modify the dynamics of insects crop pests and their predators. This hypothesis was tested in tree-wheat systems by monitoring aphids and their predators for two years in southern France, in two fields in 2006 and one in 2007. Tree row vegetation diversity was either suppressed by weeding or stimulated by seeding flowering species that could attract adult predators of aphids. The dynamics of aphids and predators were recorded by tiller sampling and yellow trap monitoring. Between 3500 and 5000 aphids were collected from each studied field. Surprisingly, no differences could be evidenced on the dynamics of both aphids and their predators between agroforestry and monocropping plots, nor between weeded and flowered plots. The heterogeneity induced by the tree row in the cropped field was probably not strong enough to alter the populations dynamics. A high landscape diversity in the area due to nearby forest patches and fallows may have blurred the impact of the tree lines. Different results may be expected in areas with lower biodiversity like cereal monocropping zones. 相似文献
9.
Pierre Casadebaig Lydie GuilioniJérémie Lecoeur Angélique ChristopheLuc Champolivier Philippe Debaeke 《Agricultural and Forest Meteorology》2011,151(2):163-178
Yield improvement certainly depends on breeding new genotypes, but also on identifying the best genotype for a given location and crop management system. Hence we need to quickly evaluate the performance of each new variety in different cropping systems and environmental conditions.Our objective was to develop a model (SUNFLO) which can help to improve genotypic assessment in the sunflower crop. The present work aimed at identifying, quantifying and modelling the phenotypic variability of crop performance in response to the main abiotic stresses occurring in the field (light, temperature, water, nitrogen) but also in the expression of genotypic variability.We therefore include just enough genetic information to enable the model to be used with new genotypes. Each genotype was thus defined by chosen phenotypic traits which were transcribed into a set of 12 genotype-specific parameters.The model's performance was evaluated in both specific field experiments and generic multi-environment trials (MET). The first evaluation assessed model robustness: no variables had a large prediction error, indicating that the final output error results more from poor prediction for all variables than from error compensation. An ANOVA on the simulated MET dataset showed that although the model simulates less variability than in reality (60%), there was genotype-environment interaction and the ranking of the ANOVA factors was identical in both observed and simulated networks. The model's accuracy was sufficient to discriminate between genotypes from different breeding periods, but was similar to the difference in performance between actual genotypes (∼0.2 t ha−1).To improve the understanding of crop physiology and crop-environment interactions, this kind of model shows weaknesses, especially when dealing with environmental stress integration or biomass allocation. On the other hand, SUNFLO seems sufficiently robust to estimate the influence on yield of breeding traits or to explore new management practices. 相似文献
10.