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1.
M. Duru 《Journal of Agronomy and Crop Science》2008,194(5):401-412
For management purposes, models of lamina digestibility (DW) that are thermal time driven (Tsum) fail to account for plant nitrogen status (0 < Ni < 1) and defoliation intensity (residual sheath height: Sr). The objective of this paper was to enrich them using a functional processed-based model, which assumes that the decline in DW over time depends on the metabolic : structural tissue ratio and plant ageing. An experiment combining two N fertilizer rates and two defoliation regimes (differences in Sr) for two spring and two summer regrowth was done to analyse DW of laminae (youngest fully expanded) and tiller (whole green lamina) levels. For laminae, we show that both processes contribute to explain the decline in DW at a rate that depends on Ni but not on Sr. For tillers, consistent results were found justifying the use of a simple model: DW = f(+Ni; −Ni × Tsum; −Sr). Two different databases (from experiment and commercial farms) were used for validation: RMSD varied from 35 to 49 g kg−1. The process-based model strengthened the empirical model and improved the comprehensiveness of how management practices change DW. We used both models to create applications for reasoning yield in function of herbage mass in complement than in function of time. 相似文献
2.
Understanding the relationships between farmers' land‐use and management decisions, and plant diversity is a challenge. It requires characterization of plant diversity within and between fields and investigation of land‐use allocation to fields. To analyse how grassland functional composition [mean plant trait and functional diversity index (FD)] varies according to scale (field, land‐use type: cutting, grazing, farm), grasslands were characterized according to leaf dry‐matter content (leaf DM) and FD computed from leaf DM values. A leaf DM‐αFD framework was used to analyse how leaf DM‐based plant strategies were distributed at land‐use type and farm scales (βFD). The study was conducted on eight dairy and beef farms (169 grasslands) differing in their stocking rate. At field and land‐use type scales, leaf DM was significantly decreased and increased with N fertilizer rate and field elevation respectively. It was significantly higher for grazing than for cutting. At the farm scale, the main differences between farms resulted from differences in plant strategy distribution between land‐use types within a farm and among farms for a given land‐use type in relation to management intensity. Farms that contributed the most to αFD had the highest stocking rate, and those which had the most contrasting grasslands for management intensity had the highest βFD. Management practices need to be examined at a land‐use type scale for evaluating the within‐ and between‐field plant functional compositions. By contrast, the value of the analysis was reduced if data were collected and averaged at the farm scale. 相似文献
3.
Four cats were presented with respiratory signs and first-stage larvae of Aelurostrongylus abstrusus were found in faecal samples. Anthelmintic treatment was given to the infected cats and venous blood gases were analysed during the treatment period. Blood gas analysis suggested hypoventilation and respiratory acidosis in infected cats. Hypoventilation may be the result of airway obstruction by adults and larvae in respiratory bronchioles and the alveolar canals. The blood gas values had returned close to the physiological range by two months after treatment. Assessment of respiratory acidosis may aid development of additional treatment methods in cats infected with A. abstrusus. 相似文献
4.
A framework for managing rotationally grazed pastures for dairy cattle which enables the cows’ energy and protein requirements to be met while simultaneously limiting the amount of N excreted in order to reduce N losses is described. The first objective is achieved by ensuring that lamina mass and the N concentration of herbage do not limit herbage intake or feeding value. The second objective is achieved by limiting N fertilizer supply or increasing the interval between defoliations to reduce the N concentration of herbage. Lower and upper thresholds for the N concentration of herbage and lamina mass were estimated from published data. The method is illustrated using two vegetative regrowths (beginning and end of spring) in a cutting experiment with two fertilizer treatments, 0 or 120 kg N ha?1 (?N and +N), and early or late cutting. Decreasing N supply led to a reduction in grazing management flexibility, i.e. the defoliation interval ranges which were compatible with the required sward characteristics (minimum lamina mass and N concentration of lamina) for herbage intake and to meet the protein requirements of dairy cows. Aiming for the upper threshold N concentration of herbage increased the minimum interval between defoliations only for the +N treatments. Nevertheless, grazing management flexibility remained the highest for the +N treatments. 相似文献
5.
The effect of N and P fertilizer application and botanical composition on the leaf/stem ratio patterns in spring in Pyrenean meadows 总被引：2，自引：0，他引：2
The effect of botanical composition and nutrient availability on the relative allocation of biomass to stems and leaves in a permanent upland pasture in the central Pyrenees was assessed. Six short-term and medium-term fertilizer treatments (nitrogen and phosphorus) were applied to a meadow to create large differences in the proportions of the different species and a wide range of herbage nutrient status. The above-ground herbage dry-matter components (green leaves, sheaths and stems for grasses and dicotyledons, and senescent material) were measured for the first growth cycle.
The leaf mass depended mainly on the herbage N status, whereas the stem mass depended both on the botanical composition and on the herbage N and P status. During spring growth, the proportion of leaves in the above-ground dry matter decreased faster in plots that had the highest nutrient status or that were composed of species characteristic of nutrient-rich ( Festuca -poor) habitats. Application of fertilizer decreased the proportion of leaves both for grasses and dicotyledons, but to a larger extent for grasses. There was a single relationship between the proportion of leaves in the above-ground dry matter and the total mass of above-ground dry matter, irrespective of the sampling date, the botanical composition or the herbage nutrient status. This statistical relationship resulted from (i) a faster increase in stem mass than leaf mass for a given botanical composition when the herbage nutritional status increased, (ii) a greater stem mass when the sward was composed of species usually found in nutrient-rich habitats. 相似文献
The leaf mass depended mainly on the herbage N status, whereas the stem mass depended both on the botanical composition and on the herbage N and P status. During spring growth, the proportion of leaves in the above-ground dry matter decreased faster in plots that had the highest nutrient status or that were composed of species characteristic of nutrient-rich ( Festuca -poor) habitats. Application of fertilizer decreased the proportion of leaves both for grasses and dicotyledons, but to a larger extent for grasses. There was a single relationship between the proportion of leaves in the above-ground dry matter and the total mass of above-ground dry matter, irrespective of the sampling date, the botanical composition or the herbage nutrient status. This statistical relationship resulted from (i) a faster increase in stem mass than leaf mass for a given botanical composition when the herbage nutritional status increased, (ii) a greater stem mass when the sward was composed of species usually found in nutrient-rich habitats. 相似文献
6.
Arikan S Duru SY Gurkan M Agaoglu ZT Giger U 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2003,50(6):303-306
Blood typing of domestic cats has been performed in domestic and purebred cats in various parts of the world and is important in clinical practice in order to prevent neonatal isoerythrolysis (NI) and acute haemolytic transfusion reactions. Prevalence of blood types vary greatly between breeds of cats. Turkish Van and Angora cats are different breeds that originated in geographically distinct regions of Turkey. The present survey determined the frequency of blood types in these Turkish pedigreed cats in Turkey. Ethylenediaminetetraacetic-acid anti-coagulated blood of a total of 113 Turkish Van and Angora cats were examined for blood typing using a slide and tube agglutination assay. Of the 85 Van cats surveyed, 40% had type A, and 60% had type B blood. Of the 28 Turkish Angora cats, 53.6% had type A, and 46.4% had type B blood. No type AB cats were found between both breeds. There was no significant association between blood types and gender of both Angora and Van cats or eye colours of Van cats (P > 0.05). Although these are limited surveys, the overall prevalence of type B cats in these two breeds was very high compared with the results of previous studies worldwide. It appears likely that blood type incompatibilities responsible for feline NI and transfusion reactions are occurring in these breeds. The risk of transfusion incompatibility in Turkish Angora and Van cats was 46.4 and 60%, respectively. It is therefore strongly recommended to breeders and clinicians that blood typing be performed prior to breeding and transfusing cats. 相似文献
7.
?mür?BaysalEmail author Y.?Ziya?Gürsoy Hakan??rnek Ahmet?Duru 《European journal of plant pathology / European Foundation for Plant Pathology》2005,112(4):361-369
Bacterial canker is an economically important disease of tomato. Resistance induced by DL-β-Amino butyric acid against bacterial canker caused by Clavibacter michiganensis ssp. michiganensis in tomato plants was investigated. Different doses of DL-β-Amino butyric acid (250–1000 μg ml−1 doses) were tested on 3-week old plants inoculated with a 108 CFU ml−1 bacterial suspension, and disease development was evaluated after inoculation and treatment. Although in vitro growth of the bacteria was not affected by DL-β-Amino butyric acid treatment, foliage sprays of 500 μg ml−1 DL-β-Amino butyric acid significantly suppressed disease development up to 54% by day 14 after inoculation at the four different doses tested. Bacterial populations were reduced by 84% in BABA-treated plants compared to water-treated plants by day 4 after inoculation. Inoculated BABA-treated plants showed significantly higher phenylalanine ammonia-lyase activity, peroxidase activity, and H2O2 concentration than inoculated water-treated plants during day 1 after treatment. These findings suggest that the DL-β-Amino butyric acid treatment resulted in an increase of these enzymes and in H2O2 concentration in planta, and was associated with induction of resistance to bacterial canker. 相似文献
8.
The objective was to establish a model of vegetative regrowth of plant matter in a stand of cocksfoot and tall fescue according to their nitrogen status. For three years (1989–1991), at the end of each spring, we studied regrowths in relation to differing supplies of nitrogen (120 kg/ha or low supply or nil). The herbage nitrogen status (IN) was estimated from the nitrogen concentration in the herbage and the above ground dry matter. The accumulated above ground dry matter was related to the amount of photosynthetic active radiation intercepted (PARi). The two parameters of the model, PARi (resulting from incident radiation and LAI) and the radiation use efficiency (RUE) depended on the herbage nitrogen status. For LAI, the parameters a, b, c of the model (LAI = a + b*T + c*T*IN) were not significantly different for the two species, (T = accumulated daily temperatures from the beginning of regrowth). On the other hand, RUE was about 15% higher for tall fescue in relation to a higher net photosynthesis activity. For other regrowths than those used for model calibration, measured above ground biomasses and LAI data were in good agreement with simulated data. 相似文献
9.
Pablo Cruz Fernando Luis F. De Quadros Jean Pierre Theau Adriana Frizzo Claire Jouany Michel Duru Paulo Cesar F. Carvalho 《Strength and Conditioning Journal》2010,63(3):350-358
Plant functional types (PFT) have been used to describe the response of native vegetation to environmental factors (i.e., fertility) and to livestock disturbance, but rarely under conditions of continuous grazing. In this work we investigate whether the long-term response of grassland communities submitted to a gradient of continuous grazing pressure can be described with such an approach. After 15 yr of differentiation of the grazing pressure applied to native grasslands we measured leaf dry-matter content (LDMC) and specific leaf area (SLA) of Poaceae populations of the communities. A grazing pressure gradient was created by levels of daily forage allowance: 4, 8, 12, and 16 kg of dry matter per day per 100 kg of animal live weight, monitored monthly. PFTs were defined by numerical analysis, where an algorithm finds the optimal trait subset based on the agreement between matrices of species × traits, paddocks × grass biomass, and environmental variables (levels of forage allowance and soil characteristics). The results show that it is possible to describe a gradient of grazing pressure by means of LDMC and/or SLA measured only on the Poacea contributing at least 80% of the total Poaceae biomass. Four PFTs were differentiated by these leaf traits. PFTs having low LDMC and high SLA are characteristic of high intensity of use and are made up largely of stoloniferous C4 species typical of rapid resource capture strategies. Conversely, PFTs characterized by high LDMC and low SLA include species that are representative of low grazing pressure. Variations in the aggregate value of traits are due to changes in the species proportions and not to leaf-size adaptation as hypothesized. We conclude than in the absence of a gradient of fertility, plants with strategies of resource capture tend to be more represented under high grazing pressures. This situation results in a loss of functional diversity, but in particular a reduction in forage availability, which is incompatible with high animal production. 相似文献
10.
N. Rossignol D. Andueza P. Carrère P. Cruz M. Duru J.‐L. Fiorelli A. Michaud S. Plantureux E. Pottier R. Baumont 《Grass and Forage Science》2014,69(3):534-548
To assess the whole‐sward maturity, which is a primary concern for grassland managers, we studied three forage grass species with contrasting phenology over a range of climatic conditions among sites. We considered two main issues: (i) How is grass population maturity related to population phenology, and is this relation affected by environmental factors? and (ii) Is the sum of temperatures a good index to describe phenological development under contrasting climates? To explore the role of temperature accumulation in species population development, we described the phenological development of populations of three grass species along latitudinal and altitudinal gradients at eight locations across France. We used a numerical index of tiller development to quantify sward morphological structure and discriminate phenological peak from average maturity. We report that phenological development rates were similar among sites for each species, but required fewer growing degree days to start at higher latitudes and altitudes. However, we found that population maturity and phenological peak differed significantly due to among‐site variability in vegetative tiller percentage in whole‐population biomass. Our results underlined the importance of considering tiller distribution among phenological stages, especially tiller development synchrony, together with phenology to assess sward maturity in semi‐natural permanent grasslands. 相似文献