Canopy characteristics and tillering dynamics of Marandu palisade grass pastures in the rainy–dry transition season          下载免费PDF全文

S. S. Santana  L. F. Brito  M. V. Azenha  A. A. Oliveira  E. B. Malheiros  A. C. Ruggieri  R. A. Reis 《Grass and Forage Science》2017,72(2):261-270

The objective of this study was to evaluate the effect of pasture management during the rainy–dry transition season in Jaboticabal, Brazil, on the structural and tillering characteristics of Marandu palisade grass. The treatments were as follows: 15 cm sward height in the rainy season and ungrazed in the rainy–dry transition season (15/0); 25 cm sward height during the rainy season and fixed stocking rate of 2·5 AU ha^?1 during the rainy–dry transition season (25/2·5); and 35 cm sward height in the rainy season and fixed stocking rate of 2·5 AU ha^?1 in the rainy–dry transition season (35/2·5). There were more herbage mass, stem and dead herbage mass in treatments 25/2·5 and 35/2·5 than 15/0. Tiller appearance rate was greater in treatment 15/0 and tiller mortality rate was higher in treatment 35/2·5 compared to treatment 15/0. Tiller population stability index was 1 in treatment 15/0 and lower in treatment 35/2·5. Although treatment 15/0 showed favourable structural and tillering characteristics, it also has the lowest herbage mass. Treatment 25/2·5 can be regarded as an adequate management strategy for Marandu palisade grass, since it has similar herbage mass and better tillering characteristics than treatment 35/2·5.  相似文献   

Anaesthesia of hatchling green sea turtles (Chelonia mydas) with intramuscular ketamine-medetomidine-tramadol     

TF Scheelings  C Gatto  RD Reina 《Australian veterinary journal》2020,98(10):511-516

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Mongolian Tree Rings and 20th-Century Warming   总被引：3，自引：0，他引：3  

GC Jacoby  RD D'Arrigo  T Davaajamts 《Science (New York, N.Y.)》1996,273(5276):771-773

A 450-year tree-ring width chronology of Siberian pine (Pinus sibirica Du Tour) growing at timberline (2450 meters) in the Tarvagatay Mountains in west central Mongolia shows wide annual growth rings for the recent century. Ecological site observations and comparisons with instrumental temperature records indicate that the ring widths of these trees are sensitive to annual temperature variations. Low-frequency variations in the Tarvagatay tree-ring record are similar to those in a reconstruction of Arctic annual temperatures, which is based on 20 tree-ring width series from northern North America, Scandinavia, and western Russia. The results indicate that recent warming is unusual relative to temperatures of the past 450 years.  相似文献   

Rundschau     

Leib RD i. R. Dr Edmund 《Journal of pest science》1989,62(3):59-61

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Rundschau     

RD i. R. Dr. E. Leib 《Journal of pest science》1984,57(2):35-38

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Rundschau     

RD i. R. Dr. Edmund Leib 《Journal of pest science》1984,57(4):74-77

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Rundschau     

RD i. R. Dr. Edmund Leib 《Journal of pest science》1982,55(9):140-142

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Rundschau     

RD i. R. Dr. Edmund Leib 《Journal of pest science》1988,61(7):138-140

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Rundschau     

Edmund Leib  RD i. R. Dr. Edmund Leib 《Journal of pest science》1980,53(7):107-109

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Carbon uptake by secondary forests in Brazilian Amazonia   总被引：2，自引：0，他引：2  

Philip M. Fearnside  Walba Malheiros Guimares 《Forest Ecology and Management》1996,80(1-3):35-46

Estimating the contribution of deforestation to greenhouse gas emissions requires calculations of the uptake of carbon by the vegetation that replaces the forest, as well as the emissions from burning and decay of forest biomass and from altered emissions and uptakes by the soil. The role of regeneration in offsetting emissions from deforestation in the Brazilian Legal Amazon has sometimes been exaggerated. Unlike many other tropical areas, cattle pasture (rather than shifting cultivation) usually replaces forest in Brazilian Amazonia. Degraded cattle pastures regenerate secondary forests more slowly than do fallows in shifting cultivation systems, leading to lower uptake of carbon. The calculations presented here indicate that in 1990 the 410 × 10³ km² deforested landscape was taking up 29 × 10⁶ t of carbon (C) annually (0.7 t C ha⁻¹ year⁻¹). This does not include the emissions from clearing of secondary forests, which in 1990 released an estimated 27 × 10⁶ t C, almost completely offsetting the uptake from the landscape. Were the present land-use change processes to continue, carbon uptake would rise to 365 × 10⁶ t annually (0.9 t C ha⁻¹ year⁻¹) in 2090 in the 3.9 × 10⁶ km⁶ area that would have been deforested by that year. The 1990 rate of emissions from deforestation in the region greatly exceeded the uptake from regrowth of replacement vegetation.  相似文献