摘要:

Summary:Chlortoluron hadàhalf‐tire in soil of 4–6 weeks. The only metabolite identified was monomethyl chlortoluron, half‐life 8 weeks. 3‐Chloro‐4‐methylphenylurea hadàsimilar half‐life but was not detected in soils treated with chlortoluron or monomethyl chlortoluron suggesting that 3‐chloro‐4‐methylaniline was formed directly from monomethyl chlortoluron. This aniline hadàhalf‐life of 1–2 days in soil, initial concentrations above 5 ppm yielding dimers and trimers predominantly C — N linked. Neither the aniline nor polymeric products were detected in chlortoluron treated soils, presumably because slow formation of the aniline was followed by rapid degradation

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01568.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:Echium plantagmeum is a widespread, persistent, and often dominant votunteer species in southern Australia. In pastures. it commonly grows with Trifolium subterraneion. This paper describes glasshouse studies investigating the effects of soil fertility. plant density. sward composition, defoliation frequency. and delayed estabilishment of t. subserraneum on the growth of E. pluntagineum and T. subterraneum when grown in pure swards and in mixtures.Generally. herbage production of swards was increased by the presence of E. plantagineum. the addition of nutrogen and phosphorus fertilizers, and increasing density, It was decreased by defoliation. E. pluntagineum plants generally produced more shoots and roots than did T. subterraneum. Both species responded. E. plantiagineum generally more than T. subterraneum. to added phosphorus and nitrogen fertilizers. Both species showed a non‐linear reduction in plant size as plant density of the sward was increased. especially during early growth. E. plantagineum was, however. more plastic in its response to density than T. subterraneum. Defoliation reduced the plant weight of both species. more for E. plantagineum than for T. subterraneum.In mixtures. there was little competition between the two species during early growth. when swards were defoliated and when both species established at the same time. T. subserraneum was, howerver. sometimes suppressed during later growth if swards were undefoliated. if soil fertility was high. and if E. plantaginteum established before t. subserraneum. Such competition appeared to be between shoots rather than between roots.In the field. E. plantagineum is likely to be fovoured in undergrazed situations, where soil fertility is high and when false or early seasonal breaks allow it to establish earlier than t. subterruneum. Its high productivity under a wide range of pasture situations ‐ especially in autumn and winter when pasture availability is ofter critically low and the fact that it is relatively nutritious and readily eated by stock suggest that it is a useful pasture spec

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01569.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:Trails with glyphosate spred onto the soil around profusely suckering apple cherry pear and plum trees so as to wet the suckers, were carried out at ballygagn. Are East malling Kent; Long ash tom, Bristol and Loughall N Ireland Trees were sprayed to simulate normal weed killing in winter when the suckers were dormant, in April when the sucker buds had recently burst and in june when the sucker were in full leaf no damage was cused to the parent trees in the year of treatment or the following year in any of the trails. No glyphosate residues (<1ppm) were found in the leavws of the parent apple tree at all soles sucker deths or damage was greater and apple trees. At all sites sucker death or damage was greatest and re grow the least with the full leaf spray. Damage was greater with the April than the January cpray Sucketrs of the different kinds of from varied in susceptibility ot glyphosate There was no damage ot the parent trees at long Ashton when suckers were sparyed to run off in July

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01570.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:The decline of a population ofA. fatuaestablished in September 1971, and not allowed to seed thereafter, was monitored in three successive barley crops Numbers of viable seeds in the son in June fell from 159 m2in 1972 to 1 m2in 1974 declining by 83° in the first, and by 96° in the second year. Seedling numbers fell from 138 m2in 1972 to 9 m2in 1974, declining by 32° in their first and by 89° in the second year. The slower decline of seedling numbers in the first year was attributed to loss of dormancy of seed reserves giving proportionally more seedlings in the second spring.Cultivations had no major influence on the pattern of seedling emergence in the spring, but they did affect population level. Where the stubble was cultivated immediately after seeding in September 1971, twice as many seedlings and three times as many seeds in the soil were present in 1972 compared with delayed autumn cultivations in 1971. From this greater reserve of seeds in the soil more seedlings arose in 1973 and in 1974. Time cultivation in the winter of 1971 resulted in slightly more seedlings in 1972 than did ploughing; this greater population declined more rapidly with line cultivation in 1973 and 1974. It is suggested that with no herbicidal control annual line cultivation will lead to a more rapid build up than ploughing: whereA. fatuais controlled, the decline should be more rapid with tne cultivation. Persistence ofA. fatuaas a weed in arable situations seems related more to survivors shedding seeds than to the persistence of seeds on the soil. Factors which may influence the persistence of seeds in the soil are discus

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01571.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:The detection and estimatinn of herbicidés uith ihe aid of Chtorelta: investigation of optimum conditions and iheir applicalion to the analysis of several herbicidesThe use of a uniform culture of Chlorella as yn inoculum at a given density under known conditions of temperature, light and nutrition in a gaseous mixture has allowed an improvement in the technique and given highly reproducible results. Tests with atrazine have shown that it can be detected at a dose or 0.012 ppm and estimated to an accuracy of 0.04 ppm. Other herbicides have been tested and their sensitivity was found to be in lhe following descending order: lerbutryne>lenacil = isoproturon>atrazine>chlortoluron>methabenzthiazuron = metoxuron

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01572.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:Emergence ofVeronica hederifoliaseedlings began in mid‐October and continued into spring; few appeared from June to September. Ripe seeds shed in June were dormant but wben buried in soil outdoors developed a capacity for germination initially at low temperatures (constant4 C; daily alternations of 4‐10° and 4‐1 5 C) and later at somewhat higher temperatures, with peak germination in September‐November. During winter, spring and early summer thc germination capacity declined, to increase again in late summer and early autumn. Cyclic physiological changes thus occur in seeds ofV,hederifoliapresent in the soil, with which lhe consistent seasonal periodicity of seedling emergence is associated.In dry storage ihe capacity for germination progressively increased, but alter 12 months there was a sharp decline in germination at 4° C. Few seeds germinated at 20° C, but moistening with GA 4/7; brought about complete germination at this t

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01573.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:Kinetics of chemical degradation of propyzamide (Kerb) in aquatic environments—influence of pH and trace elementsDegradation of propyzamide in aquatic environments has been studied with particular reference to pH and the presence of trace elements. The degradation is quicker in alkaime than in acid surroundings but this is appreciable only in acidic and strongly alkaline media. Iron and copper salts had little influence but, on the contrary, silver salts had a strong effect. The mechanism of this interaction is discusse

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01574.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Summary:The effects of lenacil, terbacil, chlorthiamid and 2,4,5‐T at 100 ppm on carbon dioxide evolution, oxygen uptake and nitrogen transformation in two soils have been investigated for several months in the laboratory. The herbicides had no effect on CO2output from either Boddington Barn soil (organic carbon content 1.6%, pH 6.1) or Triangle soil (organic carbon content 3.7%, pH 4.8) apart from 2,4,5‐T which reduced it sometimes. All the herbicides caused temporary reductions in O2. uptake, but in Triangle soil treated with 2,4,5‐T a significant reduction was observed during the second half of the incubation. 2,4,5‐T and to a lesser extent chlorthiamid, reduced nitrification in Triangle soil. All the herbicides slightly increased mineralization of nitrogen except 2,4,5‐T which had variable effects in Tria

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01575.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1978.tb01576.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY