Darlington, William, Thurber, George,
Includes index. Book.
0000 - Gale Group | Sabin
V. F. Bruns, Lowell W. Rasmussen,
... years an important agent in the dissemination of weed seeds. Egginton and Robbins (7) found a total of 81 different species of weeds in 156 weed seed catches from three different ditches during 1918 and 1919 and determined that the number of weed seeds passing a given point on a ditch ... millions. Hope (11) analyzed a considerable number of weed seed catches from irrigation channels during 1924 and ... that 1,674,030 seeds of 13 different weed species which occurred on the surface and to ... 1925. Further computations illustrated that the flow of weed seeds would amount to a deposition of 170, ...
Tópico(s): Biological Control of Invasive Species
1953 - Cambridge University Press | Weeds
... Miller; August 09, 1869 to Rev J. A. Weeds; Mexico, New York.
1869 - Gale Group | SAS Part 1
... of the competition between barley and certain annual weeds which are dominant at Woburn, under conditions where ... the plants are limited, has been studied. The weeds involved are Spergula arvensis Linn. (spurrey) and Matricaria ... and where barley or each of the two weeds are grown by themselves, there is a tendency ... the yield of the crop or of the weeds to reach a maximum with a definite density ... a limit is reached with each of the weeds where extra nitrogen, added as manure, does not ... amount of weediness, with either of the two weeds studied, an increase in the density of barley ...
Tópico(s): Nematode management and characterization studies
1945 - Wiley | Annals of Applied Biology
Photograph by Peter Henry Emerson. Royal Photographic Society/NMeM/ Science & Society Picture Library. Photographer: Peter Henry Emerson.
0000 - Gale Group | NCCO Photography
Winifred E. Brenchley, Katherine Warington,
In view of the favourable reduction in the weed‐seed population on Broadbalk wheat field (Rothamsted Experimental ... year was adopted to maintain control over the weeds. Annual samples for determining the weed seeds were taken from plots receiving farmyard manure, ... obtained were grouped to show the reduction in weed‐seed population during fallow and the behaviour of ... sulphate of ammonia greatly influenced the production of weed seeds. With most species nitrogen induced heavier seed ... the first year after fallowing the crop and weeds alike were usually able to benefit by the ...
Tópico(s): Allelopathy and phytotoxic interactions
1945 - Wiley | Annals of Applied Biology
Includes indexes. Book.
0000 - Gale Group | Sabin
... The critical phase of biological control work against weeds is the selection of species that will not ... species for introduction into a country against a weed is one that is safe to introduce, irrespective ... never-ending struggle to rid his lands of weeds. In this age of chemistry, there are yet millions of acres of land on which weeds flourish and where they either do not yield ... for other reasons. With some of the worst weeds known where chemical, mechanical, or precautionary measures have ... work is not eradication, but the reduction of weed densities to levels largely noninjurious to man's ...
Tópico(s): Plant and animal studies
1957 - University of California, Agriculture and Natural Resources | Hilgardia
Book.
1829 - Gale Group | NCCO Corvey
Various submerged weeds form tangled masses of vegetation in shallow, clear-water ponds in the Southeast. It is difficult or impossible to fish in such weed-infested ponds, and the weeds protect the small fish from carnivorous species so ... stunted populations result. Hence, the control of submerged weeds is an important problem in pond management. Commercial ... at each application, broadcasting the fertilizer over the weed-infested portion of the pond; make the first ... and others at about monthly intervals until the weeds are covered with filamentous algae. The algae shade ...
Tópico(s): Water Quality Monitoring and Analysis
1942 - Wiley | Transactions of the American Fisheries Society
Photograph of a row of women working in field in the modern state of Jammu and Kashmir, probably near the capital of Srinagar. The photograph dates to ...
0000 - Gale Group | NCCO Photography
... alone and with sixteen plants of several different weed species for from 7 to 11 weeks. Two ... of nitrogen were included. The effects of different weeds on dry‐weight growth of the crop plants ... wheat it was significant in only one experiment. Weed effects generally were not significantly decreased by high ... high nitrogen, but usually only slightly affected by weeds; nitrogen deficiency seems not to have been the sole cause of the weed effects. In two experiments with wheat, although high ... increased the leaf nitrogen percentage of plants with weeds, it had little effect on their leaf dry ...
Tópico(s): Allelopathy and phytotoxic interactions
1963 - Wiley | Annals of Applied Biology
Photograph of a row of children working in a field, probably near Srinagar in the modern-day state of Jammu and Kashmir in India, taken by an unknown ...
0000 - Gale Group | NCCO Photography
Economic losses caused by weed competition in Manitoba grain crops were studied on 142 farm fields during a 3-year period, 1956 to 1958 inclusive. ... each pair of plots was kept free of weeds by hand pulling at weekly intervals. The species of weeds present and the relative numbers were recorded. As ... harvested for yield determinations.Twenty-eight species of weeds were found growing in the fields. Weed counts ranged from 0 in the cleanest field to 2,143 weeds per square yard in the weediest field, with ...
Tópico(s): Soil Carbon and Nitrogen Dynamics
1960 - Canadian Science Publishing | Canadian Journal of Plant Science
Book.
0000 - Gale Group | The Making of Modern World
... them I susceptible to damage or elimination by weed competition. Various methods of establishment such as sowing ... not been entirely successful. The increased use of weed-controlling chemicals has awakened considerable interest in the ... can be safely used to control broad-leaved weeds in legumes (2, 5, 6, 7, 9, 13, ... that can be safely used (2, 9, 13). Weed grasses are not controlled by 4-(2-DB) ... the broad-leaved canopy encourages the growth of weed grasses. Kerr3 showed that weed grasses are more injurious to birdsfoot trefoil than ...
Tópico(s): Allelopathy and phytotoxic interactions
1960 - Cambridge University Press | Weeds
Book.
1830 - Gale Group | NCCO Corvey
Harold D. Kerr, Dayton L. Klingman,
... seedling growth makes establishment difficult because competition from weeds or companion crop plants often eliminates the young ... winter. Mowing alone has not been adequate for weed control in birdsfoot trefoil plantings when weed grasses are present in the sward. Repeated mowings will control broadleaved weeds, but the growth of the seedling trefoil may ... retarded by such treatment. In addition, mowing releases weed grasses from broadleaved weed competition and allows the grasses to compete critically ...
Tópico(s): Plant pathogens and resistance mechanisms
1960 - Cambridge University Press | Weeds
... the the Royal Grecian Theatre. 'Score of drama Weeds and flowers of Erin'. Performed at the Royal ... Grecian Theatre. Score dated December 29, 1870. folios Weeds and Mowers of Erin. Musical Work.
0000 - Gale Group | NCCO British Theatre
... few agricultural leaders and farmers became interested in weeds as a problem before 1200 A.D. or even 1500 A.D. For many centuries, weed control was mostly incidental to tillage for seedbed ... devices and a few inorganic herbicides specifically for weed control. State weed laws directed at control of plant diseases were enacted during 1721 to 1766, but weed and seed laws involving weeds directly were not enacted until 100 to 200 ... later. Only a few extension-type publications on weeds were issued in the United States and Canada ...
Tópico(s): Biological Control of Invasive Species
1970 - Cambridge University Press | Weed Science