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The aim of the work was to evaluate the risk of cultivation of cucumber pickling cultivars in Poland caused by unfavourable thermal conditions of soil. To achieve the goal of the work used starting data collected from 28 experimental stations of the Research Centre for Cultivar Testing (COBORU) and 47 meteorological stations of the Institute of Meteorology and Water Management (IMGW) in 1966–2005 were used. Curvilinear regression analysis was used to determine the relation between the total and marketable yield of cucumber and soil temperature at the depth of 5 cm in the period of sowing-the end of harvesting. Potential, at least of 5%, reduction in the total yield of cucumber occurred when average soil temperature at the depth of 5 cm in the period from sowing to the end of harvesting amounted to ≤17.9°C and of the marketable yield ≤17.3°C. The highest reduction in yield, occurring in south-west and south-east part of Poland. The reduction was from 15 up to over 18% in the case of the total yield and from 12 up to 15% in the case of the marketable yield. On average, it occurred respectively every 1.5–2 years and 2.5–3 years. Taking into account the data from the whole country area in 1966–2005, a considerable increase appeored by 0.2°C/10 years in soil temperature in the period from sowing to the end of harvesting. The highest increase by 0.4°C/10 years was recorded in southern and central Poland and in the western part of the Masurian Lakeland where a risk of cucumber cultivation caused by too low soil temperature will probably in the incoming years undergo the quickest reduction.
Celem pracy było poznanie wpływu opadów atmosferycznych w poszczególnych okresach agrofenologicznych ogórka, sprzyjających dobremu plonowaniu tej rośliny w okolicy Rzeszowa. Na podstawie analizy skupień wydzielono cztery, istotnie różniące się, grupy lat pod względem przebiegu warunków opadowych, determinujących różne wielkości plonu ogórka. Największym plonom ogórka sprzyjały opady nieco mniejsze od średnich wieloletnich, wynoszące 189 mm, w okresie od siewu do początku zbioru oraz większe od przeciętnych, wynoszące 361 mm, w okresie od siewu do końca zbioru, przy czym około 40 mm opadów przypadło na okres siew-koniec wschodów, 103 mm - koniec wschodów-początek kwitnienia, 11 mm - początek kwitnienia-początek zawiązywania owoców, 35 mm - początek zawiązywania owoców-początek zbioru i 172 mm - początek zbioru-koniec zbioru.
In the world of plants frost is a particularly dangerous phenomenon. Destructive effect of frost on plants is both direct and secondary. The amount of damage done by frost depends on its intensity, frequency, a season of its occurrence and a plant species. The aim of the work was to find spatial and temporal distribution of ground frost in Poland and to determine effect of minimum air temperature at the ground level on the dates of phenological phases and harvesting and duration of development stages and also on the quantity of cucumber yield of pickling cultivars at the turn of the 20th and 21st centuries. Source materials used in the present study were collected from 28 experimental stations of COBORU and from 51 meteorological stations of IMGW in the years 1966–2005. Ground frost was characterised, e.g., by means of average dates of last spring and first autumn frost, duration of the period without frost and also intensity and frequency of its occurrence and a linear trend. Effect of minimum air temperature at the ground level on the growth, development and crop productivity of cucumber was determined with the use of linear and curvilinear regression analysis and the linear trend of occurrence of last spring and first autumn frost and duration of the period without frost with the use of linear regression analysis. Ground frost poses high potential risk for field cultivation of cucumber in Poland not only because of the fact that it significantly determines the rate of growth, development and yield quantity of the plant but also because of its high spatial and temporal variability; the highest cultivation risk occurs in north-eastern Poland where significant shortening, year by year, of the period without frost was proved and where the highest frequency of frost occurrence both at the beginning and at the end of the cucumber growing season is recorded.
The aim of the work was to separate, by means of cluster analysis, sets of agrotechnical dates and phenological phases that are conducive to big and low yields of field cucumber of pickling cultivars and the evaluation of solar and thermal conditions accompanying these sets. On the basis of cluster analysis three, significantly different, groups of observations in relation to the course of growth and development, determining different volumes of cucumber yields in Poland, were isolated. Cluster 2 included observations which were characterised by high yields (amounting to 37.7 t·ha⁻¹ for the total yield and 20.1 t·ha⁻¹ for the marketable yield), and cluster 3 by low yields (respectively 27.6 and 15.6 t·ha⁻¹). The following calendar of agrotechnical dates and phenological phases was conducive to high yield of cucumber (cluster 2): sowing on 14th May, the end of emergence 27th May, the beginning of flowering 29th June, the beginning of fruit setting 4th July, the beginning of harvesting 13th July, the end of harvesting 24th August. The delay, in relation to the dates in cluster 2 (high yield), of the sowing date by 6 days, emergence by 16 days, flowering and fruit setting by 18 days, the beginning of harvesting by 19 days, and the end of harvesting by 22 days may contribute to a decrease in cucumber yields even by about 27% and 22%, respectively for the total yield and the marketable yield. Higher than average values of both sunshine duration and air temperature, which during the vegetation season amounted respectively to 7.9h and 17.5°C, were conducive to earlier agrotechnical and phenological dates, and, in consequence, high cucumber yields (cluster 2).
The goal of the present work was to find temporal and spatial distribution of agrotechnical dates and phenological phases and duration of development stages of pickling varieties of cucumber and also to determine influence of duration of development stages on the yield in the whole country and in its various regions. In Poland, in the years 1966–2005, both agrotechnical and phenological dates and development stages of cucumber were characterised by high temporal and spatial variability; with temporal variability being, on average, twice as high as spatial variability and oscillating between 2–3 and 7 weeks. All considered cucumber dates were characterised, year on year, by acceleration (from -0.07 day per 10 years in the case of sowing up to -6.4 days per 10 years in the case of the end of harvesting), and development stages by shortening (the whole growing season by -7.4 days per 10 years). Regression analysis describing relationship between yield and duration of cucumber development stages confirmed a negative influence of the period from sowing to the beginning of harvesting on the total yield and a positive influence of the period from the beginning of harvesting to the end of harvesting on the total and marketable yield. In Poland, potential reduction in the total yield of cucumber caused by assumed ten-day lengthening of duration of the period from sowing to the beginning of harvesting usually oscillated between 3 and 18% below the multi-annual average and caused by shortening of duration of the period from the beginning of harvesting to the end of harvesting between 9 and 18% in the case of the total yield and between 15 and 24% in the case of the marketable yield; the highest reduction occurred in the Sudetian Foothills, the Carpathian Foothills and in the north-east. Frequency of the occurrence of an excessively long period from sowing to the beginning of cucumber harvesting oscillated in Poland between 10 and 20%, and an excessively short period from the beginning of harvesting to the end of harvesting between 10 and 40%.
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