摘要:

SummaryStudies of the uptake and translocation of14C‐labelled 2, 4‐D, MCPA and aminotriazole inAgrostemma githagoL. andTussilago farfaraL. clarified the behaviour of the herbicides in both species.InA. githago, MCPA was more freely mobile than 2,4‐D after application to the leaf; it was distributed in the plant more rapidly and in greater quantity. Similarly, following root uptake MCPA was transported in the shoot in greater amounts than was 2,4‐D. There is a clear relationship between the susceptibility ofA. githagoto MCPA and the mobility of the herbicide in the plant.InT. farfara, 2,4‐D and aminotriazole applied to the leaves were equally well absorbed and relatively rapidly translocated. During the period up to 72 h the amounts of herbicide in the plant increased to similar levels; after that,14C activity in plants treated with 2,4‐D fell slightly whereas there was further accumulation of aminotriazole. Following uptake through the roots, translocation and accumulation in the leaves were considerably greater with aminotriazole than with 2,4‐D. The lack of accumulation of 2,4‐D could be a factor in the resistance ofT. farfarato this herbicidie.Recherches sur l'absorption et la migration d'herbicides marqués au14Cdans Agrostemma githago L. et Tus

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01003.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryStudies of the absorption and translocation of14C‐2,4‐D inChenopodium albumL.,Galinsoga parvifloraCav.,Datura stramoniumL. andGalium aparineL. in relation to their susceptibility gave the following results:InG aparine(resistant) there was little transport of 2,4‐D applied to the leaves, and a probable relationship between resistance and the immediate binding of the 2,4‐D in the treated leaf.D. stramonium(relatively resistant) transported 2,4‐D in considerable amounts alter uptake through the leaf, whileC. album(very susceptible) andG. parviflora(susceptible) were intermediate in respect of 2,4‐D translocation. No relationship between susceptibility of these four species and 2,4‐D uptake and translocation from the leaves could be established.After application to the root systems of the four species, 2,4‐D was taken up and translocated in the shoot to varying extents. InG. aparinemuch 2,4‐D was taken up and translocated. In contrast to leaf application, the herbicide was not immediately converted into a strongly‐held immobile form. InC. album, G. parvifloraandD. stramonium, however, no 2,4‐D was translocated in the shoot. There was thus no correlation between susceptibility and shoot transport of 2,4‐D in the four species studied.Distribution du2,4‐D marqué au14C dans des espèces de mauvaises herbes présent

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01004.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryIn a field trial, different doses of five herbicides applied in autumn and late winder were compared for the control of barley grass (Hordeum leporiumLink) in dryland Lucerne.Diuron at 1·1, 2·2, and 4·5 kg/ha and atrazine at 1·1 kg/ha were more effective in increasing Lucerne production than linuron at 4·5 kg/ha and various rates of dalapon and paraquat. Autumn application generally resulted in greater Lucerne production than late winter application. Most treatments reduced the amount of barley grass in the Lucerne. Diuron and atrazine also eliminated reduced the amount of barley grass in the Lucerne.Atrazine, diuron and linuron had a strong residual effect and reduced the density of subterranean clover and barley grass in the autumn following treat

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01005.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryTwo 5‐year trials were conducted in New South Wales on the control of broomrape (Orobanche minorSm.), a plant parasite of subterranean clover (Trifolium subterraneumL.) and skeleton weed (Chondrilla junceaL.). Applications of superphosphate to two soils of low phosphorus status stimulated clover growth, which caused a reduction in the number of skeleton weed plants and a decrease in the broomrape population. Similar but less effective control was obtained when subterranean clover pasture was sprayed with 2,4‐DB for skeleton weed control as soon as the clover seedlings had developed trifoliate leaves.In spring, sheep readily grazed the broomrape stems before flowering, causing death of the plants. Autumn application of super phosphate, coupled with grazing of the pasture by sheep, significantly reduced broomrape dens

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01006.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryGlasshouse studies showed that low doses of paraquat inhibited the germination ofLolium perenneL. broadcast directly onto the paraquat‐sprayed surfaces of a sphagnum and a peat soil, but that higher doses were necessary to produce phytotoxic symptoms on mineral soils, a compost and a loam. On all soils residual activity increased rapidly with increasing dose once the minimum phytotoxic dose was reached. On a sandy soil, residual activity increased almost linearly from the lowest to the highest dose applied.At 9·0, 4·5 and 2·24 kg/ha phytotoxicity on a compost was not affected by changes in the volume of application, but at 1·68 kg/ha and lower, reducing the volume from 562 1/ha to 281 and 112 1/ha resulted in increased phytotoxicity.Phytotoxic residues were eluted from paraquat‐treated compost surfaces by percolating de‐ionized water up soil columns but residual activity was not removed from the eluted surfaces. Surface irrigation of paraquat‐treated surfaces with water previously percolated through columns of untreated soil reduced residual acti

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01007.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryThree rapid bioassays were tested on forty‐two herbicides having several different modes of action. A 50% or greater inhibition of growth was found at 1 ppm with thirty‐one herbicides in one or more of the bioassays. Of the remaining eleven herbicides, seven were detected at 10 ppm, two at 20 ppm and two at 30 ppm.The techniques used were aChlorellabioassay, a root bioassay with sorghum, oat and cucumber and a shoot bioassay with sorghum and oat. The duration of the bioassays was 1, 2 and 4 days respectively. As a general rule, theChlorellabioassay was especially sensitive to photosynthetic and respiratory inhibitors but not sensitive to herbicides with other modes of action, whereas the root and/or shoot bioassays were sensitive to most of the herbicides except the photosynthetic inhibitors. The use of the three bioassays simultaneously is suggested as a possible method for primary screening of herbici

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01008.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryThe effect of repeated annual applications over 7‐8 years of MCPA, triallate, simazine and linuron to field plots on the evolution of CO2and mineralization of nitrogen in soil samples incubated in the laboratory is described. The plots were either cropped and treated with standard doses, or uncropped and sprayed with doses 3‐4 times above the level used in agricultural practice. While the applications of MCPA and tri‐allate did not exert any inhibitory effects in soils from the uncropped plots those of simazine and linuron led to a lowering in CO2output in several instances and in mineral N on infrequent occasions. These effects are assumed to be the result of a difference in the content of easily‐degradable organic matter between the treated plots and the controls. A direct anti‐microbial action of the two herbicides is not very probable because in laboratory experiments with simazine up to 512 ppm the output of CO2and the mineralization of N was not affected while linuron at 500 ppm gave only a minor depression in CO2evolution. Effects on soil fertility are unknown but seem unlikely in view of the small extent and infrequency of the reductions observed. On the cropped plots the MCPA and tri‐allate treatment showed no effects. With linuron and simazine a significant lowering in respiration and mineralization of N occurred on single occasions only, during a 5

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01009.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryA spectrophotometric method was developed to detect bromoxynil in Regina heavy clay, and the breakdown under different temperature and moisture conditions was studied. At rates equivalent to 14 kg/ha, over 50% of the applied bromoxynil was degraded in 2 weeks at 25°C and at moisture levels in excess of the wilting point. Losses at 18°C were slightly slower. Little breakdown occurred in sterile soil, indicating that microbial degradation could be an important factor contributing to bromoxynil breakdown under field conditions.Paper and thin‐layer chromatographic techniques were used to isolate and identify soil degradation products. In addition to the parent compound small amounts of 3,5‐dibromo‐4‐hydroxybenzamide and 3,5‐dibromo‐4‐hydroxybenzoic aci

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01010.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryFruit harvested from gooseberry plots treated with up to 33·6 kg/ha of chlorthiamid and dichlobenil (applied at two dates) was examined for the presence of residues of 2,6‐dichlorobenzonitrile together with the possible metabolites, 2,6‐dichlorobenzamide and 2,6‐dichlorobenzoic acid. In addition the canned fruit was examined for taint. Residues of 2,6‐dichlorobenzonitrile resulting from the application of both herbicides at all rates were below 0·05 ppm. Residues of 2,6‐dichlorobenzamide ranged from 0·13 to 0·45 ppm with the greatest residues occurring in fruit from plots treated with the highest amounts of chlorthiamid in March. Fruit from some of the March applications of both herbicides contained residues of up to 0·16 ppm 2,6‐dichlorobenzoic acid. No taints were found in

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01011.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

SummaryNitrogen fertilizer in three forms, urea, sulphate of ammonia and calcium ammonium nitrate, was applied at three rates, 26, 52 and 104 kg N/ha, early (January) and late (May) during land preparation for three consecutive barley crops, to determine the effect of fertilization on wild oat populations.On the fertilized areas there was significantly greater germination of wild oats prior to sowing than on the unfertilized areas, with calcium ammonium nitrate and sulphate of ammonia tending to be more effective in stimulating germination than urea. Despite the destruction of these heavy populations of wild oat seedlings by cultivation prior to sowing, in‐crop infestations of the weed were still heavy. Late‐applied nitrogen by comparison with the early application tended to produce greater numbers of wild oat panicles in the crop, particularly at the lower fertilizer rates.The overall effect after three annual dressings of nitrogen was one of greatly increased wild oat seed reserves in the soil. These had increased five‐fold in no‐nitrogen plots, six‐fold in early‐fertilized plots and eight‐fold in late‐fertilized plots.It was concluded that annual dressings of nitrogen fertilizer on winter cereals in wild‐oat‐infested areas led to an increase in the population of the weed. Some suggestions are made as to why nitrogen fertilizer stimulated wild oats to germinate, and the overall results are discussed in the light of the agricultural situation o

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1971.tb01012.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY