摘要:

Summary.Experiments with granular dichlobenil have been carried out under glasshouse conditions, in order to estimate the area of contamination near the surface and the leaching beneath by the toxicant from individual granules. Special techniques using a restricted range of granule size and ryegrass as indicator plant have been developed.The area of contamination produced by grouping several granules together or by granules containing different concentrations of toxicant, increased generally with, but not in proportion to, the amount of toxicant applied. The area of contamination and the depth of leaching were smaller in moist soil than in drier soil, due possibly to the transport and action of dichlobenil in the vapour state. When granules were placed on sub‐irrigated soil, the maximum area of contamination was reached after 6 days for 7.5% granules, and after 12 days for 15% and 25% granules; after 19 days, the area decreased markedly, especially in the case of 7.5% granules. Soil composition, especially organic matter content, affected strongly the area of contamination near the surface and the leaching beneath.The importance of uniform distribution of granules in field practice is stressed in conclusion.Migration dans le sol du dichlobénil appliqué sous forme de gran

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00872.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Summary.Seeds ofPolygonum lapathifoliumwere collected from eight localities during 1962. Plants of these populations were grown in the field and sampled at fortnightly intervals during June and July 1964. There were significant differences between populations in dry weight, leaf area index and nitrogen content at all samplings, and populations also differed in date of flowering and in certain morphological feature. Smooth curves were fitted to some of the growth data, and an account of the fitting procedure is given. For comparison, certain growth functions were calculated from the smooth curves as well as from the observed data. The populations differed in relative growth rate, net assimilation rate, relative nitrogen absorption rate and in certain other calculated functions, A number of growth attributes were significantly correlated with the latitude, longitude or length of the growing season of the locality of origin, and it is tentatively suggested that the populations represent climatic ecotypes.Études sur des espèces de mauvaises herbes du genre Polygonum L.II. Variations physiologiques dansP. lapathifolium

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00873.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Summary.Two experiments are described in which plants of Polygonum lapathifolium were grown with barley in small field plots and sprayed with 2‐(2‐4‐dichlorophenoxy)propionic acid (dichlorprop) at a range of dose rates. Counts of the number of living plants before spraying and at intervals after spraying enabled the progress of mortality to be followed and the final mortality to be calculated. Probit analysis showed that there were considerable differences in LD50among five populations from different localities of origin. In a second experiment, in which P. lapathifolium plants were sprayed at three stages of growth, there were large differences in LD50between two populations at all three stages of growth, but no consistent or regular trend in LD50with stage of growth.Etudes d'espèces de mauvaises herbes appartenant au genrePolygonumL. III. Variations de la sensibilité deP.lapathifoliumL.à l'acid2‐(2,4‐dichlorophénox

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00874.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Summary.It is practicable to use herbicides as an alternative to ploughing grass swards for the preparation of a seedbed for the sowing of cereals and kale. The yields of spring barley and kale following a glaass/clover sward killed with 10 lb/ac amitrole‐T were similar to those obtained following ploughing. Yields of tip to 40 cwt/ac of winter wheat were obtained following grass swards killed with amitrole‐T compared with up to 45 cwt/ac after ploughing.The ideal herbicide must kill all plants in a sward and have no residual toxicity to the subsequent crop. At 10 lb/ac, amitrole‐T killed most plants in the sword, but it was considered necessary to delay sowing for at least 3 weeks after spraying to minimize the danger of residual toxicity. Ploughing gave the lowest incidence of grasses persisting from the sward. Paraquat did not control clover andAgropyron repens, while broad‐leaved weeds were more common on the ploughed than on the sprayed land.There were differences in the amount of nitrogen mineralized in ploughed and In undisturbed soil, but these were insufficient to affect crop yields materially. When a lower yield followed herbicidal destruction of the sward, this was not accompanied by a reduced percentage nitrogen content.L'emploi des déherbants pour la rénovation de

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00875.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Summary.Paraquat dichloride was applied to maize, tomato and broad bean plants as droplets of an aqueous solution and analysed al intervals. It was shown to be degraded under some conditions, but the amount of degradation was least under conditions which would have been most favourable for metabolism of the chemical. The analytical results and results from cation‐exchange paper chromatography and thin layer chromatography showed that the degradation was caused by photochemical decomposition on the surface of the leaves of the plants, not by metabolism. The degradation was not observed in the dark, and only occurred to a significant extent in daylight in the summer.Two photochemical degradation products from methyl‐labelled paraquat‐14C dichloride, viz., 4‐carboxy‐l‐(methyl‐14C)‐pyridinium chloride and methylamine‐14C hydrochloride, were isolated from plants sprayed with the herbicide.Le devenir du paraquat dans le

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00876.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00877.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00878.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00879.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00880.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1966.tb00881.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY