scholarly journals Renovation of Strawberries Grown on Plastic Mulch to Obtain Multiple Years of Harvest

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 800D-800
Author(s):  
Peter R. Probasco ◽  
Stephen A. Garrison ◽  
Joseph A. Fiola
Keyword(s):  
Fruit Size ◽  
First Year ◽  
Severe Winter ◽  
Plastic Mulch ◽  
Winter Conditions ◽  
Ice Accumulation ◽  
Winter Temperatures ◽  
Winter Severity

Chandler strawberries were planted on plastic mulch in September and renovated at various times after harvest during the next summer. Renovation treatments included mowing, thinning to three crowns/plant, and mowing plus thinning. These treatments were applied to 1-year-old and 2-year-old beds of `Chandler' strawberries. We conducted this study over two harvest seasons to compare winter conditions and the influence of polyester rowcovers. The second harvest season had severe winter temperatures (–5F), along with frequent ice accumulation. Marketable yields, culls, and fruit size were determined from each treatment. Yields varied with the time of treatment and with the degree of winter severity. Fruit size of renovated berries was smaller than first year berries, but still marketable. Polyester covers increased early yields.

An ecological study of the branchiobdellid commensals (Annelida-Branchiobdellidae) of some mid-western Ontario crayfish

1968 ◽  
Vol 46 (5) ◽  
pp. 835-843 ◽  
Author(s):  
John E. Bishop
Keyword(s):  
Host Specificity ◽  
Dominant Species ◽  
Ecological Study ◽  
Rabbit Serum ◽  
First Year ◽  
Serological Testing ◽  
Severe Winter ◽  
Orconectes Propinquus ◽  
Winter Conditions ◽  
Laurel Creek

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.

scholarly journals Mass mortality of invasive zebra and quagga mussels by desiccation during severe winter conditions

2014 ◽  
Vol 9 (3) ◽  
pp. 243-252 ◽  
Author(s):  
Rob Leuven ◽  
Frank Collas ◽  
K. Remon Koopman ◽  
Jon Matthews ◽  
Gerard van der Velde
Keyword(s):  
Mass Mortality ◽  
Severe Winter ◽  
Quagga Mussels ◽  
Winter Conditions

scholarly journals Ground-ice stable isotopes and cryostratigraphy reflect late Quaternary palaeoclimate in the Northeast Siberian Arctic (Oyogos Yar coast, Dmitry Laptev Strait)

2017 ◽  
Author(s):  
Thomas Opel ◽  
Sebastian Wetterich ◽  
Hanno Meyer ◽  
Alexander Yu. Dereviagin ◽  
Margret C. Fuchs ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Stable Isotope ◽  
Late Quaternary ◽  
Cold Winter ◽  
Winter Climate ◽  
Climate Conditions ◽  
Winter Conditions ◽  
Winter Temperatures ◽  
Siberian Arctic ◽  
Ice Wedge

Abstract. To reconstruct palaeoclimate and palaeonvironmental conditions in the Northeast Siberian Arctic, we studied late Quaternary permafrost deposits at the Oyogos Yar coast (Dmitry Laptev Strait). New infrared stimulated luminescence ages for distinctive floodplain deposits of the Kuchchugui Suite (112.5 ± 9.6 kyr) and thermokarst lake deposits of the Krest Yuryakh Suite (102.4 ± 9.7 kyr), respectively, provide new substantial geochronological data and shed light on the landscape history of the Dmitry Laptev Strait region during the Marine Isotope Stage (MIS) 5. Ground ice stable-isotope data are presented together with cryolithological information for eight cryostratigraphic units and are complemented by data from nearby Bol'shoy Lyakhovsky Island. Our combined record of ice-wedge stable isotopes as proxy for past winter climate conditions covers the last about 200 thousand years and is supplemented by texture-ice stable isotopes which contain annual climate conditions overprinted by freezing processes. Our ice wedge stable-water isotope data indicate substantial variations in Northeast Siberian Arctic winter climate conditions during the late Quaternary, in particular between Glacial and Interglacial but also over the last millennia to decades. Stable isotope values of Ice Complex ice wedges indicate cold to very cold winter temperatures about 200 kyr ago (MIS7), very cold winter conditions about 100 kyr ago (MIS5), very cold to moderate winter conditions between about 60 and 30 kyr ago, and extremely cold winter temperatures during the Last Glacial Maximum (MIS2). Much warmer winter conditions are reflected by extensive thermokarst development during the MIS5c and by Holocene ice-wedge stable-isotopes. Modern ice-wedge stable isotopes are most enriched and testify the recent winter warming in the Arctic. Hence, ice-wedge based reconstructions of changes in winter climate conditions add substantial information to those derived from paleoecological proxies stored in permafrost and allow for distinguishing between seasonal trends of past climate dynamics. Future progress in ice-wedge dating and an improved temporal resolution of ice-wedge derived climate information may help to fully explore the palaeoclimatic potential of ice wedges.

THE EFFECTS OF TEMPERATURE ON THE OXYGEN CONSUMPTION, HEART RATE AND DEEP BODY TEMPERATURE DURING DIVING IN THE TUFTED DUCK AYTHYA FULIGULA

1992 ◽  
Vol 163 (1) ◽  
pp. 139-151 ◽  
Author(s):  
R. M. BEVAN ◽  
P. J. BUTLER
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Deep Body Temperature ◽  
Tufted Duck ◽  
Winter Conditions ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
The Mean ◽  
Maintain Body Temperature ◽  
Deep Body

Six tufted ducks were trained to dive for food at summer temperatures (air, 26°C, water, 23°C) and at winter temperatures (air, 5.8°C, water 7.4°C). The mean resting oxygen consumption (Voo2) a t winter temperatures (rwin) was 90% higher than that at summer temperatures (Tsum), but deep body temperatures (Tb) were not significantly different. Diving behaviour and mean oxygen consumption for dives of mean duration were similar at Twin and at Tsum, although the mean oxygen consumption for surface intervals of mean duration was 50% greater at Twin and Tb was significantly lower (1°C) at the end of a series of dives in winter than it was in summer. There appears to be an energy saving of 67 J per dive during winter conditions and this may, at least partially, be the result of the metabolic heat produced by the active muscles being used to maintain body temperature. While at rest under winter conditions, this would be achieved by shivering thermogenesis. Thus, the energetic costs of foraging in tufted ducks in winter are not as great as might be expected from the almost doubling of metabolic rate in resting birds.

Effects of Age, Burial, and Region on Germination and Viability of Halogeton Seed

Weed Science ◽  
1969 ◽  
Vol 17 (1) ◽  
pp. 63-65 ◽  
Author(s):  
W. C. Robocker ◽  
M. C. Williams ◽  
R. A. Evans ◽  
P. J. Torell
Keyword(s):  
Seed Germination ◽  
Soil Surface ◽  
First Year ◽  
Laboratory Conditions ◽  
Winter Conditions ◽  
Field Germination ◽  
Field And Laboratory Conditions ◽  
Halogeton Glomeratus

The longevity of brown and black forms of seed of halogeton (Halogeton glomeratus (M. Bieb.) C. A. Mey.), buried at four depths, was determined for a 10-year period in Nevada, Idaho, Utah, and Washington. The black form of seed had almost 100% field germination at all depths by the end of the first year and had completely germinated or was nonviable by the end of the second. Brown seed on the soil surface began field germination the first year at all locations and had germinated or become nonviable at the end of 6 years. Burial at 1, 3, and 6 inches delayed the peak of viability and tended to increase longevity of brown seed. Germination was less than 0.5% at the end of 10 years, and viability was near zero under both field and laboratory conditions. Seed germinated and lost viability most rapidly in Washington, the location where most favorable winter conditions for germination occurred.

scholarly journals Water use efficiency of different production techniques for zucchini

2019 ◽  
Vol 41 (1) ◽  
pp. 42604
Author(s):  
Anita Cristina Costa da Silva ◽  
Willian Fernandes de Almeida ◽  
Luiz Antonio Lima ◽  
Mayra Carolina De Oliveira ◽  
Alexandre Lasmar Guimarães
Keyword(s):  
Water Use Efficiency ◽  
Factorial Design ◽  
Water Use ◽  
Drip Irrigation ◽  
Drip Line ◽  
First Year ◽  
Line Position ◽  
Plastic Mulch ◽  
Use Efficiency ◽  
Subsurface Drip

 The effects of pulse drip, drip line position and soil mulch on water use efficiency in yields of zucchini cv. Clarinda were evaluated. The experiment was conducted in the experimental area of the Engineering Department of the Federal University of Lavras, Lavras, Minas Gerais State, Brazil, for two years. For the first year of the experiment, the experimental design was a randomized block design with a 2 x 2 x 2 factorial design (continuous and pulse drip irrigation, surface and subsurface dripping, with and without plastic mulch), with four replications. For the second year of the experiment, the design was completely randomized in a 2 x 2 x 2 factorial design with eight treatments and five replications. In relation to the position of the drip line, the subsurface drip line was installed at a 0.15-m depth, and the soil mulch was made with double-sided plastic (white/black). The results indicated that pulse drip irrigation did not affect the yield of zucchini and that soil mulch increased the yield and water use efficiency. In terms of the drip line position, the subsurface drip line increased the yield in the first year, but it had no effect on water use efficiency.

scholarly journals The Mass Balance of the Sea Ice of the Arctic Ocean

1973 ◽  
Vol 12 (65) ◽  
pp. 173-185 ◽  
Author(s):  
R. M. Koerner
Keyword(s):  
Arctic Ocean ◽  
Ablation Rate ◽  
The Arctic ◽  
First Year ◽  
The North ◽  
Ice Accumulation ◽  
The Pacific ◽  
The Arctic Ocean ◽  
Ridged Ice ◽  
Ice Production

AbstractFrom data taken on the British Trans-Arctic Expedition it is calculated that 9% of the Arctic Ocean surface between the North Pole and Spitsbergen was hummocked or ridged ice, 17% was unridged ice less than a year old, 73% was unridged old ice and 0.6% was ice-free. The mode of 250 thickness measurements taken through level areas of old floes along the entire traverse lies between 2.25 and 2.75 m. The mean end-of-winter thickness of the ice is calculated to be 4.6 m in the Pacific Gyral and 3.9 m in the Trans-Polar Drift Stream. From measurements of the percentage coverage and thickness of the various ice forms, it is calculated that the total annual ice accumulation in the Arctic Ocean is equivalent to a continuous layer of ice 1.1 m thick. 47% of this accumulation occurs in ice-free areas and under ice less than 1 year old. 20% of the total ice production is either directly or indirectly related to ridging or hummocking. An ice-ablation rate of 500 kg m−2 measured on a level area of a multi-year floe is compared with the rate on deformed and ponded ice. Greatest melting occurs on new hummocks and least on old smooth hummocks. The annual balance of ice older than 1 year but younger than multi-year ice is calculated from a knowledge of ice-drift patterns and the percentage coverage of first-year ice. The same calculations give a mean-maximum drift period of 5 years for ice in the Trans-Polar Drift Stream and 16 years in the Pacific Gyral. It is calculated that for the period February 1968 to May 1969 the annual ice export was 5 580 km3.

Method for Incubating Leaf Tissue to Study Decomposition in Streams

1978 ◽  
Vol 35 (2) ◽  
pp. 247-248 ◽  
Author(s):  
D. C. Eidt ◽  
J. H. Meating
Keyword(s):  
Leaf Tissue ◽  
Severe Winter ◽  
Winter Conditions ◽  
Leaf Packs ◽  
Mesh Bags ◽  
Black Plastic

Discs of leaf tissue in mesh bags were incubated inside black plastic tubes secured to the stream bottom. The method minimizes losses of samples due to severe winter conditions and is easier to use than leaf packs or decomposition boxes.

scholarly journals Winter Conditions Correlate with Phytophthora alni Subspecies Distribution in Southern Sweden

2015 ◽  
Vol 105 (9) ◽  
pp. 1191-1197 ◽  
Author(s):  
Miguel A. Redondo ◽  
Johanna Boberg ◽  
Christer H. B. Olsson ◽  
Jonàs Oliva
Keyword(s):  
Laboratory Experiments ◽  
Alnus Glutinosa ◽  
Climatic Conditions ◽  
Southern Sweden ◽  
Black Alder ◽  
Forest Pathogen ◽  
Winter Conditions ◽  
Winter Temperatures ◽  
Major River ◽  
Highly Correlated

During the last century, the number of forest pathogen invasions has increased substantially. Environmental variables can play a crucial role in determining the establishment of invasive species. The objective of the present work was to determine the correlation between winter climatic conditions and distribution of two subspecies of the invasive forest pathogen Phytophthora alni: P. alni subspp. alni and uniformis killing black alder (Alnus glutinosa) in southern Sweden. It is known from laboratory experiments that P. alni subsp. alni is more pathogenic than P. alni subsp. uniformis, and that P. alni subsp. alni is sensitive to low temperatures and long frost periods. By studying the distribution of these two subspecies at the northern limit of the host species, we could investigate whether winter conditions can affect the geographical distribution of P. alni subsp. alni spreading northward. Sixteen major river systems of southern Sweden were systematically surveyed and isolations were performed from active cankers. The distribution of the two studied subspecies was highly correlated with winter temperature and duration of periods with heavy frost. While P. alni subsp. uniformis covered the whole range of temperatures of the host, P. alni subsp. alni was recovered in areas subjected to milder winter temperatures and shorter frost periods. Our observations suggest that winter conditions can play an important role in limiting P. alni subsp. alni establishment in cold locations, thus affecting the distribution of the different subspecies of P. alni in boreal regions.

The crayfish Orconectes virilis: survival in a region with severe winter conditions

1968 ◽  
Vol 46 (2) ◽  
pp. 207-211 ◽  
Author(s):  
D. E. Aiken
Keyword(s):  
Physiological Response ◽  
River System ◽  
Small Degree ◽  
Winter Survival ◽  
Severe Winter ◽  
Orconectes Virilis ◽  
Gonadal Maturation ◽  
Seasonal Movement ◽  
Winter Conditions ◽  
Observed Behavior

An attempt was made to determine whether Orconectes virilis from a shallow river system in eastcentral Alberta has evolved a behavioral or physiological response which allows it to survive under the severe winter conditions of this region. From observations and experiments in the field and laboratory it was concluded that O. virilis cannot withstand even a small degree of freezing, and does not actively burrow into mud to escape the danger of freezing. The only observed behavior contributing to winter survival is a seasonal movement of mature animals to deeper water, and this is apparently associated more with gonadal maturation than with winter survival. The results from these experiments indicate that immature animals suffer a higher winter kill than do mature animals, and that winter survival of the species in any region is dependent upon the presence of habitat in which there is some water which does not freeze to the substratum at any time during the year.

Sign in / Sign up

Export Citation Format

Share Document