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EN
The experiments with Trifolium repens in pure sowing were established on black soil and peat-muck soil. Fertilization in the experiments equated to a dose of 44 kg ha⁻¹ P, 66 kg ha⁻¹ K, 90 kg ha⁻¹ N on mineral soil and 45 kg ha⁻¹ N. In two harvest years (1998-1999) productivity of eleven white clover cultivars: 'Alice' , 'Anda', 'Armena' , 'Arta', "Astra', 'Dara', 'Rema', 'Romena', 'Riesling', 'Riwendel' and 'Santa' was assessed. The plants were cut three times a year. In the study period average yields of white clover cultivars were high. Weather conditions in 1998 were more beneficial for growth and productivity of Trifolium repens than during the next vegetative period. Yielding of white clover in pure sowing depended on the year of clover utilisation and the type of soil and also interaction between soil and clover cultivar. Greater productivity of this species was noted in the first harvest year. Large and medium-leaved cultivars - 'Alice' , 'Anda', 'Armena', 'Arta' and 'Dara' - yielded higher on the light mineral soil than on the peatmuck soil. Habitat conditions did not differentiate the productivity of small-leaved clover cultivars 'Riesling' and 'Riewendel' and caused only minimal changes in the productivity of some medium-leaved cultivars, e.g. 'Rema' and 'Romena'. Such maintenance of mentioned cultivars seems to be indicative of their higher water requirements.
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EN
Cyanogenic glucosides, linamarin and lotaustralin occurring in white clover, are the secondary metabolites which during enzymatic cleavage or hydrolysis release cyanide, acetone and metylethylketon. These compounds may cause chronic or acute poisoning in animals. Thus, from a nutritional point of view the cyanogens are recognised as antinutritive factors. In the present review, recent literature data on the occurrence of cyanogens and the enzymes hydrolysing them in plants as weil as biochemical polymorphism of cyanogenesis in white clover are presented. Some problems of the costs and benefits of cyanogen synthesis in plant and their possible ecological function have also been discussed. Since cyanogens are recognised by many authors as a compounds protecting plants against herbivores, some aspects of their influence on animal are summarised. It was thought until recently that Polish varieties of white clover contain trace amounts of cyanogenic glucosides. Our recent studies showed, however, that some varieties recommended in 1993 contain high amounts of these compounds and that this concentration may drastically change during the growing season. The presented data clearly show that at least some of these varieties should not be recommended to be used as pasture sward components.
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EN
Seed yield components of white clover varieties /Alda, Astra, Owen, Radzikowska/ represented by 10 clones were Investigated in 2-year cycles of field experiments. Differentiation of clones within particular varieties with regard to weight and number of seed per head and 1000 seed weight was determined on the basis of Wricke's ecovalence coefficients. Also the share of genetic and environmental variance in the total variability of the traits under study was determined. It has been found that breeding work contributed to differentiation of yield components and ecovalence coefficients of the varieties tested and their representative clones. A lack of negative correlation between yield structure traits and ecovalence coefficients proved the possibility of improvement of the white clover seed yield stability.
RU
В двух циклах двухлетних полевых огятов исследовали компоненты урожая сеиян у 4 сортов клевера белого /Альда, Астра, Овен, Радзиковска/ представленных 10 клонани. Дифференциацию клонов в пределах сорта в отношении веса и числа сеиян в головке и веса 1000 сеиян оценивали на основании коэффициентов эковалентности Врикке. Определяли также участие генетической и средовой изменчивости в общей изменчивости исследуемых признаков. Установлено, что дифференциация компонентов урожая и коэффициентов эковалентности исследуемых сортов и представляющих их клонов произошла в результате селекционных работ. Отсутствие отрицательной корреляции между признаками структуры урожая и коэффициентами эковалентности указывает на возможность улучшения стабильности урожая семян клевера белого.
EN
The studies were carried out on the plant material taken from the first and the second regrowths in the second harvest year of Trifolium repens. Fertilization in experiment equated to a dose of 90 kg ha⁻¹ N, 44 kg ha⁻¹ P and 66 kg ha⁻¹ K. Three cultivars of white clover: 'Rema', 'Rawo' and 'Alice' were chosen for chemical analyses. Clover plants were divided on leaflets, petioles and heads with peduncles. The content of N was determined by the Kjeldahl method, P colorimetrically, K, Ca, Mg and Na by spectrophotometry of atomic absorption. There was confirmed that the content of nutrient in Trifolium repens was varied in dependence on white clover cultivar, a part of plant and canopy structure in the following plant regrowths. 'Rema' cultivar accumulated more N, P and K while 'Rawo' cultivar more Ca and Mg. Leaflets of white clover were conspicuous by N and Ca content. Its petioles contained more K, Mg and Na and heads with peduncles were abundant in P. Higher concentration of the main macroelements in the plants of spring regrowth and abundance of Ca, Mg and Na in dry matter of summer plant regrowth were the consequence of changes in canopy structure during vegetative period.
PL
W pracy przedstawiono wartość pokarmową pasz z użytków zielonych w warunkach ekstensywnych i zrównoważonych form gospodarowania. Ograniczenia wynikające z potrzeb pokarmowych zwierząt wysokopro- dukcyjnych, powodują wykorzystanie mniej intensywnych systemów gospodarowania na łąkach i pastwiskach, w żywieniu zwierząt o niższym potencjale produkcyjnym, na przykład bydła mięsnego. W proekologicznych formach produkcji pasz na użytkach zielonych, większego znaczenia nabierają gatunki roślin drugorzędnych, wzbogacające bioróźnorodność runi i jej wartość pokarmową. Podkreślono wzrastające znaczenie roślin motylkowatych, zwłaszcza koniczyny białej, poprawiającej wartość paszy i równocześnie wiążącej azot atmosferyczny. Zdaniem autorów, w pełni ekologiczne, ekstensywne gospodarowanie na użytkach zielonych, jest trudne do przeprowadzenia, tak ze względów żywieniowych jak i ekonomicznych. Większą rolę mogą natomiast odgrywać systemy zrównoważone, które w przyszłości, winny być traktowane na równi z intensywnymi formami produkcji i wykorzystania pasz z łąk i pastwisk.
EN
The study presents nutritive values of feeds from grasslands in extensive conditions and sustainable forms of management. Restrictions resulting from high nutritional requirements of high - yielding animals encourage the use of less intensive management systems on meadows and pastures in feeding of animals with lower production potential, for example, by beef cattle. In pro-ecological forms of fodder production on grasslands, the secondary plant species increasing sward biodiversity and its nutritive value begin to increase in importance. The increasing importance of leguminous plans, especially of white clover, which can improve the feed value and, simultaneously, fix atmospheric nitrogen was emphasized. In authors' opinion, it would be difficult to introduce a fully ecological, extensive management system on grasslands, for both, nutritional and economic reasons. However, it is possible to implement sustainable systems which in future should be treated on equal footing with intensive systems of production and utilization of feeds from meadows and pastures.
EN
In years 1993-1995 experiments were carried out on the behaviour of four cultivars of white clover (Trifolium repens) in a multi-specific sward of production pastures for dairy cows at Brody. In 1993, directly after the first cutting the, white clover seedlings of the following cultivars: Anda, Armena, Roma and Romena were introducted into the sward of paddock situated on half bog and gray brown podzolic soils. During the vegetative season such features as: length of stolons, number and area of leaves were studied. The response of the examined cultivars to the applied conditions varied. Armena and Romena developed well and can be considered as valuable cultivars. The former one, in particular, seems promising and very suitable for permanent pastures for cattle. It is worth nothing that white clover did very well in conditions of sward with domination of meadow bluegrass (Poa pratensis). On the other hand, growth and development of white clover was negatively affected by the presence of quack grass (Elymus repens) and dandelion (Taraxacum officinale).
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