Irrigation of Lucerne under semi-arid conditions in Cyprus   总被引：1，自引：0，他引：1  

Chr. Metochis 《Irrigation Science》1980,1(4):247-252

Summary Three amounts of water –1.0, 0.8 and 0.6 of the irrigation requirement — were used to irrigate lucerne at two frequencies of application — once or twice during each growth cycle. Screened Class A pan evaporation, adjusted by monthly crop coefficients, proved a dependable guide for irrigation. Irrigating once per growth cycle was sufficient, and the highest yield was obtained when the full irrigation requirement was applied. The average annual dry matter yield for the three amounts of irrigation water — 1390, 1110 and 829 mm per year — was 20 285, 16 353 and 12 952 kg ha^–1 respectively, i. e., yield decreased linearly with decreasing amount of water applied. As the water used was saline — with an electrical conductivity of 3 mmhos/cm^–1 — the main root zone became gradually salinized with the drier treatments, while with the wettest treatment salts accumulated below 80 cm depth. Yields were drastically reduced during the hot summer months, even when adequate water was available in the soil profile. This combined with the high irrigation requirement resulted in very low efficiency of irrigation during summer.  相似文献   

Ecological effects of climate fluctuations   总被引：3，自引：0，他引：3  

Stenseth NC  Mysterud A  Ottersen G  Hurrell JW  Chan KS  Lima M 《Science (New York, N.Y.)》2002,297(5585):1292-1296

Climate influences a variety of ecological processes. These effects operate through local weather parameters such as temperature, wind, rain, snow, and ocean currents, as well as interactions among these. In the temperate zone, local variations in weather are often coupled over large geographic areas through the transient behavior of atmospheric planetary-scale waves. These variations drive temporally and spatially averaged exchanges of heat, momentum, and water vapor that ultimately determine growth, recruitment, and migration patterns. Recently, there have been several studies of the impact of large-scale climatic forcing on ecological systems. We review how two of the best-known climate phenomena-the North Atlantic Oscillation and the El Ni?o-Southern Oscillation-affect ecological patterns and processes in both marine and terrestrial systems.  相似文献   

Untersuchungen auf Salmonellen bei Amphibien und Reptilien aus der östlichen Türkei     

H.-H. Wuthe  Chr. Schubert  R. Rohde 《Zoonoses and public health》1973,20(4):318-320

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Nonnenfalterkontrolle auf biologischer Grundlage     

Chr Hofmann 《Forstwissenschaftliches Centralblatt》1937,59(17):549-551

Ohne Zusammenfassung  相似文献   

Farbtafel Atlas der Krankheiten und Sch?dlinge an landwirtschaftlichen Kulturpflanzen     

Gram E.  P. Bovien und Chr Stapel 《Journal of pest science》1971,44(10):158

Ohne Zusammenfassung  相似文献   

Ein Vergleich der Effizienz von verschiedenen Clusterformen in forstlichen Großrauminventuren     

Chr Kleinn 《European Journal of Forest Research》1996,115(1):378-390

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Field assessment of partial resistance to powdery mildew in spring barley     

J. Chr. Nørgaard Knudsen  H. H. Dalsgaard  J. Helms 《Euphytica》1986,35(1):233-243

Summary Partial resistance to powdery mildew in spring barley was evaluated in three plot types: large isolation plots, in 1.4 m² plots in chessboard design with guard plots of spring wheat and in single rows. Percentage leaf area covered by powdery mildew was scored four to six times during the season and partial resistance was characterized by the area under the disease progress curve. Varietal differences were revealed in al three plot designs, differences between the most resistant and susceptible genotypes being of a factor five. Differences between varieties decreased with decreasing plot size. The relationship between single scores of amount of powdery mildew on the upper four leaves and the area under the disease progress curve was high in all plot designs during the first two to three weeks after heading, allowing selection for the trait by one or two scorings. Differential ranking of varieties between different plot designs was observed, and is assumed to be due to increasing plot interference with reduced plot size and reduced distance between plots. A reliable selection for partial resistance could be made in large isolation plots and in 1.4 m² plots, but hardly in single rows.  相似文献   

Predictive thresholds for plague in Kazakhstan     

Davis S  Begon M  De Bruyn L  Ageyev VS  Klassovskiy NL  Pole SB  Viljugrein H  Stenseth NC  Leirs H 《Science (New York, N.Y.)》2004,304(5671):736-738

In Kazakhstan and elsewhere in central Asia, the bacterium Yersinia pestis circulates in natural populations of gerbils, which are the source of human cases of bubonic plague. Our analysis of field data collected between 1955 and 1996 shows that plague invades, fades out, and reinvades in response to fluctuations in the abundance of its main reservoir host, the great gerbil (Rhombomys opimus). This is a rare empirical example of the two types of abundance thresholds for infectious disease-invasion and persistence- operating in a single wildlife population. We parameterized predictive models that should reduce the costs of plague surveillance in central Asia and thereby encourage its continuance.  相似文献   

Isolation of Treponemas from the colon of pigs with clinical dysentery]     

V Chrástová  M Hornich 《Veterinární medicína》1979,24(1):13-20

Optimal culture conditions in artificial nutritive media were determined for a defined avirulent strain of Treponema hyodysenteriae and for four field strains of treponemas in pigs with clinical dysentery. The treponemas were isolated with the use of milliporous filters with pores of 0.3 micrometer in diameter, which were located on the surface of blood agar. No significant difference in the influence of equine, bovine or sheep blood on the growth of treponemas was determined. The commercial amount of glucose in the used media, 2.0 to 2.5 g per 1,000 ml, was quite sufficient for the growth of the treponemas and it was not necessary to increase the amount. After reaching the optimal rate of growth the oxidoreduction potential was diminished by adding cystein or cystein hydrochloride and placing the Petri dishes with the media, prior to inoculation, into an anaerobic medium filled with hydrogen. The suitable composition of the culture atmosphere created in a special anaerostat comprised 0.4 to 1.0% carbon dioxide and the rest being hydrogen. Treponemas grew on the blood agar in zones with very slight hemolysis without forming separated colonies.  相似文献   

Immune Responsiveness in Cattle Fatally Affected by Bovine Virus Diarrhea-Mucosal Disease1     

F. Steck  S. Lazary  H. Fey  A. Wandeler  Chr. Huggler  G. Oppliger  H. Baumberger  R. Kaderli  J. Martig 《Zoonoses and public health》1980,27(6):429-445

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