Bacteriostatic action of nitrification inhibitors

1982 ◽  
Vol 28 (10) ◽  
pp. 1093-1100 ◽  
Author(s):  
G. Alan Rodgers ◽  
John Ashworth
Keyword(s):  
Cross Sections ◽  
Laboratory Experiments ◽  
Culture Medium ◽  
Field Experiments ◽  
Nitrification Inhibitors ◽  
Bactericidal Action ◽  
Ethyl Xanthate ◽  
Bacteriostatic Action ◽  
Aqueous Urea ◽  
Potassium Ethyl Xanthate

Nitrification inhibitors were investigated in an attempt to establish whether such chemicals actually kill ammonium-oxidizing bacteria (bactericidal action) or whether bacteria remain viable but temporarily incapable of nitrification (bacteriostatic action). In laboratory experiments with nitrifying cultures, nitrification was completely inhibited, but numbers of ammonium-oxidizing bacteria were not significantly affected by a 48-h treatment with 2,6-dimethylbenzoquinone, dicyandiamide, or potassium ethyl xanthate applied at the rate of 100 mg inhibitor/L culture medium or by nitrapyrin at 10 mg/L. However, commercial formulations of etridiazole at 100 mg/L and nitrapyrin at 100 mg/L were apparently fatal to ammonium-oxidizing bacteria. In laboratory experiments with soil amended with nitrapyrin or etridiazole, both inhibitors were more bactericidal than in aqueous culture. Nitrification did not resume until 4 to 5 weeks after adding 0.5 mg inhibitor/kg soil and, especially with etridiazole, the population of ammonium oxidizers was drastically diminished and did not fully recover. However, in field experiments, nitrapyrin and etridiazole injected at 1.5 kg/ha with aqueous urea did not affect numbers of ammonium-oxidizing bacteria in cross-sections of the injected band of soil taken after injection in autumn or spring, although the inhibitors were present in concentrations that effectively inhibited nitrification.

Effects of several nitrification inhibitors, when injected with aqueous urea, on yields and nitrogen recoveries of ryegrass leys

1983 ◽  
Vol 101 (3) ◽  
pp. 637-656 ◽  
Author(s):  
G. A. Rodgers ◽  
F. V. Widdowson ◽  
A. Penny ◽  
M. V. Hewitt
Keyword(s):  
Carbon Disulphide ◽  
Nitrification Inhibitors ◽  
Ethyl Xanthate ◽  
Nitrate N ◽  
Aqueous Urea ◽  
Soil Temperatures ◽  
Better Than ◽  
Potassium Ethyl Xanthate

SUMMARYSeveral nitrification inhibitors were compared with nitrapyrin, which was taken as the standard, when injected with aqueous urea into ryegrass leys at Rothamsted during 1977–81 and at Liscombe Experimental Husbandry Farm, Dulverton, Somerset, during 1977–9. Injection was done in either autumn or winter or spring.All the inhibitors slowed down the rate of nitrate formation from the injected urea. Sodium trithioearbonate (STC) was less effective than nitrapyrin and potassium ethyl xanthate (KEtX) less effective than STC. A mixture of nitrapyrin and carbon disulphide was better than nitrapyrin alone, and a mixture of STO and KEtX was better than STC alone.At Rothamsted, injecting inhibitors in autumn or winter improved yields and N uptakes, probably because they prevented loss of nitrate N by leaching and perhaps by denitrification. STC, STC-KEtX mixture and etridiazole were as good as, and nitrapyrin–CS2 mixture better than, nitrapyrin alone. Injecting inhibitors in spring frequently decreased yields, perhaps because NH4:NO3 ratios were too large, and increased them only when more than 150 mm of rain fell afterwards.At Liscombe, where rainfall was higher, but soil temperatures were similar to those at Rothamsted, the benefits from using inhibitors in autumn were larger, but there were none from using them in spring.

Denitrification and immobilisation in flood-irrigated alkaline grey clays as affected by nitrification inhibitors, wheat straw, and soil texture

Soil Research ◽  
2000 ◽  
Vol 38 (3) ◽  
pp. 633 ◽  
Author(s):  
I. J. Rochester ◽  
G. A. Constable
Keyword(s):  
Wheat Straw ◽  
Soil Texture ◽  
Laboratory Experiments ◽  
Field Experiments ◽  
Clay Content ◽  
Field Capacity ◽  
Nitrification Inhibitors ◽  
N Loss ◽  
Waterlogged Soil ◽  
Nitrate N

Published field studies have shown that etridiazole and other nitrification inhibitors may significantly improve N fertiliser recovery in alkaline grey clays. Laboratory experiments were conducted to examine the extent to which nitrification inhibitors could suppress denitrification directly in waterlogged soil, and determine whether this may contribute significantly to the conservation of N fertiliser in the field. Etridiazole reduced the loss of added nitrate-N from waterlogged soil in the short term (days) only. All other nitrification inhibitors failed to suppress N loss. Little nitrate-N was lost from soil maintained at field capacity, whereas 15–85% of applied nitrate was lost from soil that was waterlogged for 10 days. The addition of milled wheat straw encouraged both denitrification and biological N immobilisation to similar extents, although both processes were probably restricted by C availability. Where no straw was added, little N was immobilised and denitrification was halved. Soil texture (clay content) also had a profound influence on N fertiliser recovery (N loss). The laboratory experiments indicated that a component of the responses to etridiazole observed in published field experiments conducted on these soils could be attributed to direct suppression of denitrification by etridiazole.

Experiments on the Control of “Potato-Sickness” by the addition of Certain Chemicals to Soil infected with Heterodera schachtii.

1935 ◽  
Vol 13 (4) ◽  
pp. 191-200 ◽  
Author(s):  
Richard H. Hurst ◽  
Marjorie J. Triffitt
Keyword(s):  
Ferric Chloride ◽  
Ferric Oxide ◽  
Laboratory Experiments ◽  
Ferrous Sulphate ◽  
Heterodera Schachtii ◽  
Potato Root ◽  
Chemical Treatments ◽  
Ethyl Xanthate ◽  
Sufficient Concentration ◽  
Potassium Ethyl Xanthate

1. Laboratory experiments have shown that solutions of ferric chloride, ferrous sulphate and chinosol, in sufficient concentration, have a lethal action on the larvae of H. schachtii. The vapours given off by potassium ethyl xanthate were also found to be lethal.2. Each of these four chemicals was mixed with moist infected soil and the mixture left for a period. When the cysts were separated and placed in a solution of potato-root excretion, the numbers of larvae which hatched were reduced as a result of the chemical treatments, in the order: potassium ethyl xanthate, ferric chloride, chinosol, ferrous sulphate.3. When ferric oxide was placed in a solution of root excretion containing cysts, the commencement of hatching was delayed.4. Experiments on a very small field scale were carried out, the chemicals being applied chiefly to the rows in which potatoes were planted. The plants growing on the treated areas did not, in general, show marked symptoms of root-eelworm infection as did those on the control areas.5. The yields of potatoes from each row are tabulated. The highest yields were obtained following the treatment with ferric oxide.

Comparison of the effects of aqueous and of prilled urea, used alone or with urease or nitrification inhibitors, with those of ‘Nitro-Chalk’ on ryegrass leys

1984 ◽  
Vol 103 (3) ◽  
pp. 671-685 ◽  
Author(s):  
G. A. Rodgers ◽  
F. V. Widdowson ◽  
A. Penny ◽  
M. V. Hewitt
Keyword(s):  
Field Experiments ◽  
Urea Hydrolysis ◽  
Nitrification Inhibitors ◽  
Urease Inhibitors ◽  
Urease Inhibitor ◽  
Broadcast Application ◽  
Prilled Urea ◽  
Aqueous Urea

SummaryField experiments on ryegrass leys at Rothamsted in 1981, 1982 and 1983 examined the eifects of injected aqueous urea and of broadcast prilled urea applied alone or with one of several nitrification or urease inhibitors, on yields and N, K, Ca and Mg uptakes. Aqueous urea, prilled urea or ‘Nitro-Chalk’ were applied as single 375 kg N/ha dressings, and prilled urea or ‘Nitro-Chalk’ as three 125 kg N/ha dressings. The nitrification inhibitors etridiazole or nitrapyrin were injected with aqueous urea, but dicyandiamide (DCD) was broadcast with prilled urea. Neither the urease inhibitor hydroquinone nor the nitrification inhibitors slowed the rate of urea hydrolysis. Neither hydroquinone nor DCD diminished volatilization losses of ammonia from broadcast urea which ranged from 8 to 25 kg N/ha; they were less than 4 kg N/ha from injected urea or broadcast ‘Nitro-Chalk’. Nitrapyrin, etridiazole and DCD effectively inhibited nitrification. DCD, and to a lesser extent hydroquinone, increased yields and nitrogen uptakes from a single broadcast application of prilled urea given either in winter or in spring. However, these yields were still smaller than those given by injected urea or by divided dressings of urea, whether or not an inhibitor was used. The inhibitors did not increase yields with divided broadcast dressings of urea, which were slightly smaller than those with equivalent dressings of ‘Nitro-Chalk’. Inhibitors did not consistently increase yield when injected with aqueous urea. Inhibitors applied with injected or broadcast urea slightly increased K uptakes, and slightly decreased Ca and Mg uptakes.

Concentration of Impurities during Melting of Snow Made from Secondary Sewage Effluent

1986 ◽  
Vol 18 (2) ◽  
pp. 151-156 ◽  
Author(s):  
R. Zapf-Gilje ◽  
S. O. Russell ◽  
D. S. Mavinic
Keyword(s):  
Potassium Chloride ◽  
Chloride Solution ◽  
Laboratory Experiments ◽  
Field Experiments ◽  
Low Cost ◽  
Sewage Effluent ◽  
Potassium Chloride Solution ◽  
Laboratory Results ◽  
Solution Field ◽  
Concentration Of Impurities

When snow is made from sewage effluent, the impurities become concentrated in the early melt leaving the later runoff relatively pure. This could provide a low cost method of separating nutrients from secondary sewage effluent. Laboratory experiments showed that the degree of concentration was largely independent of the number of melt freeze cycles or initial concentration of impurity in the snow. The first 20% of melt removed with it 65% of the phosphorus and 90% of the nitrogen from snow made from sewage effluent; and over 90% of potassium chloride from snow made from potassium chloride solution. Field experiments with a salt solution confirmed the laboratory results.

Nitrones and Oxaziridines. XXXVI. Synthesis of Cyclic Thiohydroxamic Acids

1988 ◽  
Vol 41 (1) ◽  
pp. 37 ◽  
Author(s):  
DS Black ◽  
KL Ooi
Keyword(s):  
Hydroxamic Acids ◽  
Demethylating Agent ◽  
Ethyl Xanthate ◽  
Cyclic Hydroxamic Acids ◽  
Trimethylsilyl Iodide ◽  
Potassium Ethyl Xanthate

2-Cyano-1-pyrroline 1-oxides (1) could not be converted directly into the related cyclic thiohydroxamic acids (8). Potassium ethyl xanthate transformed nitrones (1) into the imidates (2). The cyclic hydroxamic acids (4) can be converted into the thiohydroxamic acids (8) via the methoxypyrrolidinones (5) and the methoxypyrrolidine thiones (6), making use of sodium p- tolylmercaptide as the demethylating agent. Reaction of methoxy thiones (6) with trimethylsilyl iodide led to the formation of the 2-methylthio-1-pyrroline 1-oxides (7).

scholarly journals Interactions Between Chill-Hours and Degree-Days Affect Carpogenic Germination in Monilinia vaccinii-corymbosi

2001 ◽  
Vol 91 (1) ◽  
pp. 77-83 ◽  
Author(s):  
H. Scherm ◽  
A. T. Savelle ◽  
P. L. Pusey
Keyword(s):  
Laboratory Experiments ◽  
Field Experiments ◽  
Degree Days ◽  
Carpogenic Germination ◽  
Conditioning Period ◽  
Low Degree ◽  
Heating Degree Days ◽  
Relationship Of ◽  
High Degree ◽  
The Relationship

The relationship of cumulative chill-hours (hours with a mean temperature <7.2°C) and heating degree-days (base 7.2°C) to carpogenic germination of pseudosclerotia of Monilinia vaccinii-corymbosi, which causes mummy berry disease of blueberry, was investigated. In two laboratory experiments, pseudosclerotia collected from rabbiteye blueberry in Georgia were conditioned at 5 to 6°C for 26 to 1,378 h prior to placement in conditions favorable for germination and apothecium development. The number of chill-hours accumulated during the conditioning period affected the subsequent proportion of pseudosclerotia that germinated and produced apothecia, with the greatest incidence of carpogenic germination occurring after intermediate levels of chilling (≈700 chill-hours). The minimum chilling requirement for germination and apothecium production was considerably lower than that reported previously for pseudo-sclerotia from highbush blueberry in northern production regions. The rate of carpogenic germination was strongly affected by interactions between the accumulation of chill-hours and degree-days during the conditioning and germination periods; pseudosclerotia exposed to prolonged chilling periods, once transferred to suitable conditions, germinated and produced apothecia more rapidly (after fewer degree-days had accumulated) than those exposed to shorter chilling periods. Thus, pseudosclerotia of M. vaccinii-corymbosi are adapted to germinate carpogenically following cold winters (high chill-hours, low degree-days) as well as warm winters (low chill-hours, high degree-days). Results were validated in a combined field-laboratory experiment in which pseudosclerotia that had received various levels of natural chilling were allowed to germinate in controlled conditions in the laboratory, and in two field experiments in which pseudosclerotia were exposed to natural chilling and germination conditions. A simple model describing the timing of apothecium emergence in relation to cumulative chill-hours and degree-days was developed based on the experiments. The model should be useful for better timing of field scouting programs for apothecia to aid in management of primary infection by M. vaccinii-corymbosi.

scholarly journals STUDIES ON THE ANTIBACTERIAL ACTION OF THE SULFONAMIDE DRUGS

1942 ◽  
Vol 75 (4) ◽  
pp. 383-394 ◽  
Author(s):  
W. Barry Wood ◽  
Robert Austrian
Keyword(s):  
Bacterial Growth ◽  
Culture Medium ◽  
Organic Dyes ◽  
Synthetic Medium ◽  
Antibacterial Properties ◽  
Antagonistic Action ◽  
Bacteriostatic Action ◽  
Great Excess ◽  
Related Drug

1. In cultures of Staphylococus aureus in a synthetic medium nicotinamide and cozymase were shown to block the bacteriostatic action of chemically unrelated sulfonamide drugs as well as the chemically related compound sulfapyridine. The antibacterial properties of organic dyes totally unrelated to the sulfonamide compounds (methylene blue and thionine) were also nullified by the addition of cozymase to the culture medium. 2. The antagonistic action of the pyridine-containing coenzyme, cozymase, was found, by quantitative study, to be no greater against sulfapyridine than against other structurally dissimilar sulfonamide compounds. 3. The antidrug effects of nicotinamide and cozymase in staphylococcus cultures were observed to be directly proportional to their ability to stimulate the growth of the organism in the synthetic medium. When tested in cultures of B. coli in which they failed to accelerate bacterial growth, these same substances failed to influence the bacteriostatic action of the sulfonamide drugs. 4. The in vitro action of the coenzyme, cocarboxylase, as measured in the Warburg respirometer, was shown to be unaffected by the chemically related drug, sulfathiazole, even when the latter was present in great excess. The above observations fail to support the theory that sulfapyridine, sulfathiazole, and sulfadiazine prevent bacterial growth by interfering with the functioning of the chemically related coenzymes, cozymase, and cocarboxylase. The mode of action of sulfanilamide and its more common derivatives is discussed in the light of these observations, and a tentative theory is offered to explain the differences in bacteriostatic potency exhibited by the various sulfonamide compounds.

scholarly journals Inhibition and Stimulation of Nitrification by Potassium Ethyl Xanthate

Microbiology ◽  
1987 ◽  
Vol 133 (11) ◽  
pp. 3237-3245
Author(s):  
S. E. Underhill ◽  
J. I. Prosser
Keyword(s):  
Ethyl Xanthate ◽  
Stimulation Of ◽  
Potassium Ethyl Xanthate
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