STUDIES OF THE TOMATO IN RELATION TO ITS STORAGE: I. A SURVEY OF THE EFFECT OF MATURITY AND SEASON UPON THE RESPIRATION OF GREENHOUSE FRUITS AT 12.5 °C.

1938 ◽  
Vol 16c (2) ◽  
pp. 65-83 ◽  
Author(s):  
E. J. M. Walford
Keyword(s):  
Low Temperature ◽  
Respiration Rate ◽  
Stable State ◽  
Early Spring ◽  
Late Spring ◽  
Red Pigment ◽  
External Appearance ◽  
Late Autumn ◽  
Different Seasons

Tomatoes were grown in the greenhouse at different seasons of the year, individual fruits were picked at various stages of maturity and continuous records of their respiration obtained at 12.5 °C. It was found that the fruits of the late spring and summer went through the customary series of extensive changes in respiration rate as they ripened at the low temperature, and exhibited the lack of durability normal to this fruit. In contrast to this, the fruits of the late autumn, winter and early spring, if picked before the external appearance of red pigment, passed into a stable state in which ripening proceeded with but little change in respiration rate and with greatly enhanced duration of life at 12.5 °C.

Recovery of 15N-labelled fertilizers applied to bromegrass on a Thin Black Chernozem soil

1995 ◽  
Vol 75 (4) ◽  
pp. 539-542 ◽  
Author(s):  
S. S. Malhi ◽  
M. Nyborg ◽  
J. T. Harapiak
Keyword(s):  
Ammonium Nitrate ◽  
Early Spring ◽  
Late Spring ◽  
N Recovery ◽  
Chernozem Soil ◽  
Band Placement ◽  
Late Autumn ◽  
Time Of Application ◽  
Broadcast Application ◽  
Early Autumn

The availability of N fertilizers on established grass stands is a function of such processes as immobilization, gaseous loss, leaching and position of applied N. A field experiment was conducted on a Thin Black Chernozem soil at Crossfield, Alberta to determine the effect of source, time and method of application on the recovery of 15N-labelled fertilizers applied to smooth bromegrass (Bromus inermis Leyss.). The treatments included two sources of N [urea and ammonium nitrate (AN)], four application times (early autumn, late autumn, early spring and late spring) and two methods of placement (surface-broadcast and subsurface banding). In most cases the 15N recovery in soil did not differ much between urea and AN. However, when urea was surface-broadcast, there was, on average, 10.2% less 15N recovery in plants than AN. The N recovery for late spring > early spring > late autumn = early autumn. When urea was banded 4 cm deep into the soil, N recovery in plants increased significantly compared with its surface-broadcast application. However, this was not observed when the source of N was AN. Banding generally increased the amount of immobilized N present in the soil and N recovery. We concluded that the N recovery in plants and in plants plus soil was less for urea than for AN and was less with autumn broadcast N application than with spring broadcast application. Key words: Ammonium nitrate, band placement, bromegrass, recovery of N, surface-broadcast, time of application, urea

Ecology of lice on sheep. VII. Population dynamics of Damalinia ovis (Schrank)

1969 ◽  
Vol 17 (2) ◽  
pp. 179 ◽  
Author(s):  
MD Murray ◽  
G Gordon
Keyword(s):  
Population Dynamics ◽  
Matrix Model ◽  
Direct Relationship ◽  
Early Spring ◽  
Late Spring ◽  
Winter Period ◽  
Late Autumn ◽  
Early Autumn ◽  
Deterministic Matrix

The numbers of D. ovis decline in the spring, remain low during the summer, and increase during the winter. A density of two lice per square inch is necessary in the autumn if numbers are to increase during the winter to 200 per square inch, the density found on heavily infested sheep in the early spring. The time needed for this increase has been calculated using the deterministic matrix model ofpopulation increase described by Leslie (1945), and 4-5 months are required when there is only a small mortality. Thus, when the favourable winter period lasts only 3 months, the increase in louse numbers may be insufficient to sustain the losses which occur in late spring, summer, and early autumn. The factors responsible for these losses determine the density of the louse population at the commencement of winter. Should the winter period last c. 6 months there is usually a direct relationship between the number of lice on a sheep in the late autumn and in the following spring. However, should winter last 9 months it is suggested that other factors become increasingly significant, and determine the eventual size of the louse population.

Variation in the low temperature growth and frost tolerance of natural genotypes of Trifolium repens L. from Britain and Norway

1984 ◽  
Vol 102 (1) ◽  
pp. 11-21 ◽  
Author(s):  
J. H. Ollerenshaw ◽  
R. Haycock
Keyword(s):  
Low Temperature ◽  
Trifolium Repens ◽  
Cold Hardiness ◽  
Frost Tolerance ◽  
Early Spring ◽  
Late Spring ◽  
Temperature Growth ◽  
Naturally Occurring ◽  
Trifolium Repens L ◽  
Upland Field

SummarySixty-two genotypes of Trifolium repens (white clover) collected from latitudes 52° to 68° N and five selected genotypes of the cultivar S.184 were screened for shoot growth at low temperature and short daylengths in a controlled environment cabinet and in the field, and subjected to cold hardiness treatments ranging from – 2·5 to – 14·0 °C.Considerable variation was discovered in several of the growth characteristics and in the frost tolerance of the genotypes. Genotypes exhibiting the highest rates of stolon extension were found in the more southerly latitudes. A high proportion of leaves produced during winter on the primary stolons of the selected cultivar plants subsequently died during the late spring at the upland field site, but several of the naturally occurring genotypes were able to retain more leaves per stolon in spring. Some genotypes appeared to maintain either short or long internodes throughout the spring in the field, whilst others produced relatively short internodes in early spring and long internodes later in the season, and vice versa. Only a small percentage of the genotypes possessed relatively long leaflets. A correlation was found between maximum leaflet length of the genotypes in early spring, and maximum leaflet length in late spring.No relationship was found between frost tolerance and the growth of plants at low temperature. Frost sensitive and tolerant genotypes were found throughout the latitudinal and altitudinal ranges studied. Exposure to prevailing winds and possibly snow cover at the site of origin appeared to be important factors associated with the frost tolerance of T. repens plants.

scholarly journals Do applications of systemic herbicides when green fruit are present prevent seed production or viability of Alliaria petiolata (garlic mustard)?

2021 ◽  
pp. 1-17
Author(s):  
Leo Roth ◽  
José Luiz C. S. Dias ◽  
Christopher Evans ◽  
Kevin Rohling ◽  
Mark Renz
Keyword(s):  
Seed Production ◽  
Seed Viability ◽  
Early Spring ◽  
Alliaria Petiolata ◽  
Late Spring ◽  
Garlic Mustard ◽  
Viable Seed ◽  
Application Timing ◽  
Control Seed ◽  
Second Year

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) postemergence to established, second-year A. petiolata populations at three locations when petals were dehiscing, and evaluated control, seed production and seed viability. Postemergence glyphosate applications at this timing provided 100% control of A. petiolata by 4 weeks after treatment at all locations whereas triclopyr efficacy was variable, providing 38-62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, we found a 71-99% reduction in number of viable seed produced plant-1 regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals were dehiscing is a viable alternative to cutting or hand-pulling at this timing as it substantially decreased viable A. petiolata seed production. Management Implications Postemergence glyphosate and triclopyr applications in the early spring to rosettes are standard treatments used to manage A. petiolata. However, weather and other priorities limit the window for management, forcing field practitioners to utilize more labor-intensive methods such as hand-pulling. It is not known how late in the development of A. petiolata these herbicides can be applied to prevent viable seed production. Since prevention of soil seedbank replenishment is a key management factor for effective long-term control of biennial invasive species, we hypothesized late spring foliar herbicide applications to second year A. petiolata plants when flower petals were dehiscing could be an effective management tool if seed production or viability is eliminated. Our study indicated that glyphosate applications at this timing provided 100% control of A. petiolata plants by 4 weeks after treatment at all locations, whereas triclopyr efficacy was inconsistent. Although both glyphosate and triclopyr decreased viable seed production to nearly zero at one of our three study locations, the same treatments produced significant amounts of viable seed at the other two locations. Our findings suggest late spring glyphosate and triclopyr applications should not be recommended over early spring applications to rosettes for A. petiolata management, as our late spring application timing did not prevent viable seed production, and may require multiple years of implementation to eradicate populations. Nonetheless, this application timing holds value in areas devoid of desirable understory vegetation compared to no management practices or mechanical management options including hand-pulling when fruit are present, as overall viable seed production was reduced to similar levels as these treatments.

Proximate Analysis of British Columbia Herring in Relation to Season and Condition Factor

1939 ◽  
Vol 4b (5) ◽  
pp. 478-490
Author(s):  
John Lawson Hart ◽  
Albert L. Tester ◽  
Desmond Beall ◽  
John P. Tully
Keyword(s):  
British Columbia ◽  
Oil Content ◽  
Condition Factor ◽  
Calorific Value ◽  
Proximate Analysis ◽  
Early Spring ◽  
Different Seasons ◽  
Spawning Time ◽  
Average Condition ◽  
The Individual

Analysis by standard methods of samples of Clupea pallasii from different seasons and localities in British Columbia showed the following ranges in composition: water, 64.2 to 80.2%; oil, 4.1 to 19.4%; protein, 10.1 to 16.8%; ash, 1.9 to 2.8%. Oil content is highest in summer, declines during the fall and winter, and falls to a minimum after spawning time in early spring. There is an accompanying decline in the weight of the fish. Herring are highly variable in calorific value (2.41 to 0.94 Calories per gram). Potential oil yields on reduction as high as 30 gallons per ton are indicated with a minimum of 7 gallons per ton. Average condition factors for samples were determined by averaging the individual condition factors obtained from [Formula: see text], when C is the condition factor, W is weight in grams, L is length in millimetres, and 3.26 is the exponent in the empirically fitted equation W = CLn. This condition factor was found to be positively correlated with oil content and to follow in general the same seasonal trend.

Fall and Spring Preplant Herbicide Applications Influence Spring Emergence of Glyphosate-Resistant Horseweed (Conyza canadensis)

2010 ◽  
Vol 24 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Vince M. Davis ◽  
Greg R. Kruger ◽  
Bryan G. Young ◽  
William G. Johnson
Keyword(s):  
Early Spring ◽  
Late Spring ◽  
Conyza Canadensis ◽  
No Till ◽  
Early Fall ◽  
Winter Annual ◽  
Winter Annual Weeds ◽  
Annual Weeds ◽  
Spring Emergence ◽  
Residual Control

Horseweed (Conyza canadensis) is a common weed in no-till crop production systems. It is problematic because of the frequent occurrence of biotypes resistant to glyphosate and acetolactate synthase (ALS)-inhibiting herbicides and its ability to complete its life cycle as a winter or summer annual weed. Tactics to control horseweed while controlling other winter annual weeds routinely fail; herbicide application timing and spring emergence patterns of horseweed may be responsible. The objectives of this experiment were to (1) determine the influence of fall and spring herbicides with and without soil residual horseweed activity on spring-emerging glyphosate-resistant (GR) horseweed density and (2) evaluate the efficacy and persistence of saflufenacil on GR horseweed. Field studies were conducted in southern Indiana and Illinois from fall 2006 to summer 2007 and repeated in 2007 to 2008. Six preplant herbicide treatments were applied at four application timings: early fall, late fall, early spring, and late spring. Horseweed plants were counted every 2 wk following the first spring application until the first week of July. Horseweed almost exclusively emerged in the spring at both locations. Spring horseweed emergence was higher when 2,4-D + glyphosate was fall-applied and controlled other winter annual weeds. With fall-applied 2,4-D + glyphosate, over 90% of the peak horseweed density was observed before April 25. In contrast, only 25% of the peak horseweed density was observed in the untreated check by April 25. Starting from the initiation of horseweed emergence in late March, chlorimuron + tribenuron applied early fall or early spring, and spring-applied saflufenacil at 100 g ai/ha provided greater than 90% horseweed control for 12 wk. Early spring–applied saflufenacil at 50 g ai/ha provided 8 wk of greater than 90% residual control, and early spring–applied simazine provided 6 wk of greater than 90% control. When applied in late spring, saflufenacil was the only herbicide treatment that reduced horseweed densities by greater than 90% compared to 2,4-D + glyphosate. We concluded from this research that fall applications of nonresidual herbicides can increase the rate and density of spring emerging horseweed. In addition, spring-applied saflufenacil provides no-till producers with a new preplant herbicide for foliar and residual control of glyphosate- and ALS-resistant horseweed.

The survey of wild birds for West Nile virus in Poland

2011 ◽  
Vol 14 (4) ◽  
pp. 573-577 ◽  
Author(s):  
J. Niczyporuk ◽  
E. Samorek-Salamonowicz ◽  
W. Kozdruń ◽  
Z. Mizak
Keyword(s):  
West Nile Virus ◽  
Genetic Material ◽  
Early Spring ◽  
Wild Birds ◽  
Rt Pcr ◽  
West Nile ◽  
Late Autumn ◽  
The Brain

The survey of wild birds for West Nile virus in PolandTwo thousand one hundred and forty birds belonging to 39 different species from different locations in Poland were examined. The study has taken place from the early spring till late autumn 2007-2010 when the activity of the mosquitoes was the highest. The brain samples were taken from the birds and whole cellular RNA was isolated, then the RT-PCR and NRT-PCR were performed to detect the presence of West Nile virus (WNV). The obtained results were confirmed by the commercial WNV Kit. No genetic material of WNV was found in the examined samples.

scholarly journals Study on the Geological Condition Analysis and Grade Division of High Altitude and Cold Stope Slope

2021 ◽  
Vol 13 (22) ◽  
pp. 12464
Author(s):  
Ruichong Zhang ◽  
Shiwei Wu ◽  
Chenyu Xie ◽  
Qingfa Chen
Keyword(s):  
Low Temperature ◽  
High Altitude ◽  
Stable State ◽  
Geological Condition ◽  
Rock Layer ◽  
Eastern Slope ◽  
Geological Conditions ◽  
Grade Ii ◽  
Grade Division ◽  
Grade Iii

Analysis of the geological conditions of high-altitude and low-temperature stope slopes and the study of grade division are the basis for the evaluation of slope stability. Based on the engineering background of the eastern slope of the Preparatory iron mine in Hejing County, Xinjiang, we comprehensively analyse and summarize the factors that affect the geological conditions of high-altitude and cold slopes and finally determine nine geological conditions that affect the index parameters. Based on a back-propagation (BP) neural network algorithm, we establish an applicable network model to analyse the geological conditions of slopes in cold areas. The model is applied to the eastern slope to analyse and classify the geological conditions of the high-altitude and low-temperature slopes. The research results show that the skarn rock layer in the eastern slope is in a stable state and not prone to landslides, and its corresponding geological condition is Grade I; meanwhile, the monzonite porphyry rock layer is in a relatively stable state, with a potential for landslides and a corresponding geological condition Grade II. The marble rock layer is in a generally stable state, there is the possibility of landslide accidents, and the corresponding geological condition level is Grade III. The limestone rock layer is in an unstable state and prone to landslide accidents, it has a corresponding geology condition Grade IV. Therefore, the eastern slope can be divided into different geological condition regions: Zone I, Zone II, Zone III, and Zone IV, and the corresponding geological condition levels for these are Grade I, Grade II, Grade III, and Grade IV. These results may provide a basis for the stability evaluation of high altitudes and cold slopes.

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