scholarly journals Sensitivity of fungi to urea, ammonium nitrate and their quimolar solution UAN

2008 ◽  
Vol 43 (No. 4) ◽  
pp. 157-164 ◽  
Author(s):  
K. Veverka ◽  
J. Štolcová ◽  
P. Růžek

The sensitivity of oomycota, saprophytic and pathogenic fungi to urea, ammonium nitrate and UAN (urea plus ammonium nitrate in equimolar solution) was studied in laboratory trials. The compounds were applied in agar in concentrations of 0.06, 0.19 and 0.6M. The most toxic was urea. Ammonium nitrate inhibited the growth of fungi only in higher concentrations. In contrast, the growth of <I>Gaeumannomyces graminis</I> was stimulated by even the highest concentration of 0.6M ammonium nitrate. The fungi most sensitive to urea and UAN were <I>Alternaria tenuissima, Botrytis cinerea, Cladosporium cladosporioides and Pseudocercosporella herpotrichoides</I>. No synergistic effect between the two compounds in UAN was found. Urea was toxic also to <I>Colletotrichum acutatum</I> which does not produce urease. Likewise, the urease inhibitor NBPT did not decrease the toxicity of urea to fungi; the urea degradation product ammonia should, therefore, not be assumed to be the only toxic agent. Application of urea in agricultural practice can decrease the population of a pathogen not only by the stimulation of antagonists, but also by the direct toxic effect. The tested concentrations of 0.06–0.6M correspond to 0.36–3.6% (w/w) solution of urea and to 0.64–6.4% UAN used in agricultural practice as a 75% water solution. If the dilution and metabolisation under natural conditions is taken into account, the concentration of urea 0.06M (0.36%) was too low to have an effect of practical importance on fungi. While after application of urea on plants or on plant debris its concentration is increasing due to water evaporation, the concentration of the extremely hygroscopic UAN is decreasing. Therefore, the control effect will depend more on the applied rate than on the concentration.

1991 ◽  
Vol 42 (5) ◽  
pp. 735 ◽  
Author(s):  
JF Angus ◽  
RA Fischer

Dryland wheat was fertilized with ammonium nitrate or liquid urea-ammonium nitrate at the time of sowing or about 3 months later (generally at the terminal-spikelet stage) on a well-drained site near Harden on the south-west slopes of New South Wales. The experiments continued from the second to the fifth year (1981-1984) of the cropping phase of a crop-pasture rotation. The maximum agronomic efficiencies for yield in the four consecutive years were 19, 4, 23 and 25 kg grain per kg of applied nitrogen (N). The three large responses were obtained in wetter than average seasons and the small response was obtained during drought. In the last three years of the study the yield response to nitrogen at the terminal-spikelet stage was found to be close to but slightly less than that for N applied at sowing. In those years the agronomic efficiencies for the late-applied N were 0, 22 and 22. The apparent recovery of fertilizer N in the above-ground parts of the crop at maturity was up to 70% of the fertilizer applied in the year of sowing, and, after the drought during which there was little uptake of fertilizer N, up to 62% by the subsequent crop. The fertilizer efficiencies in the non-drought years were higher than generally reported in south-eastern Australia, and indicate potential for profitable delayed application of N fertilizer to wheat. Grain-protein responses were variable from year to year and are discussed against a simple theoretical background of the amount of N applied and grain-yield response.


Weed Science ◽  
1992 ◽  
Vol 40 (1) ◽  
pp. 127-133 ◽  
Author(s):  
Karen A. Renner ◽  
Gary E. Powell

The response of ‘C-20’ navy bean and ‘Frankenmuth’ soft white winter wheat grown in rotation to clomazone, imazethapyr, bentazon, and acifluorfen was examined. Clomazone at 560 and 430 g ai ha−1plus 800 g ai ha−1pendimethalin and 2000 g ai ha−1chloramben visibly injured navy bean in 1 of 2 yr. However, navy bean seed moisture at harvest and yield was not reduced compared to the weed-free control. PPI and PRE treatments of 70 g ai ha−1imazethapyr did not injure navy bean or reduce yield. Imazethapyr applied POST at 70 g ha−1plus nonionic surfactant visibly injured navy bean. The addition of urea ammonium nitrate to imazethapyr enhanced visible injury and seed moisture compared to nonionic surfactant alone in 1 of 2 yr. However, seed yield was not reduced. Seed moisture at harvest was greater following treatment with 430 g ai ha−1acifluorfen plus nonionic surfactant or urea ammonium nitrate and 140 and 280 g ha−1acifluorfen plus 840 g ai ha−1bentazon in 1 of 2 yr compared to the weed-free control, but yield was not reduced. Wheat yield was reduced in 2 of 2 and 1 of 2 yr by 560 g ha−1and 430 g ha−1clomazone, respectively, plus pendimethalin plus chloramben compared to the weed-free control. Wheat yield was not reduced by imazethapyr, bentazon, or acifluorfen.


2018 ◽  
Vol 110 (2) ◽  
pp. 444-454 ◽  
Author(s):  
A. L. Woodley ◽  
C. F. Drury ◽  
X. M. Yang ◽  
W. D. Reynolds ◽  
W. Calder ◽  
...  

2008 ◽  
Vol 61 ◽  
pp. 70-79 ◽  
Author(s):  
M. Walter ◽  
B. Braithwaite ◽  
B.J. Smith ◽  
G.I. Langford

Botrytis cinerea and Colletotrichum acutatum are important strawberry pathogens Nitrogen (N) application can increase yield but also susceptibility to pathogens Strawberry plants (Camarosa and Ventana) were grown in sand fertilised with base nutrients plus ammonium nitrate ammonium sulphate or calcium nitrate at low (40 ppm N) and high (140 ppm N) concentration Controls consisted of base nutrients only and water only Flower production fruit yield and berry size all increased with increasing Nconcentration but Nsource itself was not important Disease susceptibility was affected by both Nconcentration and Nsource At high Nconcentration C acutatum fruit lesions were largest in ammonium sulphate treatments > ammonium nitrate > calcium nitrate; Botryits cinerea lesions were largest in ammonium nitrate > ammonium sulphate > calcium nitrate Similar trends were observed for leaf susceptibility to the two pathogens These data suggest that calcium nitrate may be a suitable source of nitrogen helping growers to reduce disease risk


2021 ◽  
Vol 12 ◽  
Author(s):  
Jiawen Xiao ◽  
Xiaojun Guo ◽  
Xinlei Qiao ◽  
Xuechao Zhang ◽  
Xiaomeng Chen ◽  
...  

Bacillus subtilis Z-14 can inhibit phytopathogenic fungi, and is used as a biocontrol agent for wheat take-all disease. The present study used the soil-borne fungus Gaeumannomyces graminis var. tritici (Ggt), which causes wheat take-all disease, and the soil microbial community as indicators, and investigated the antifungal effects of fengycin and iturin A purified from strain Z-14 using high performance liquid chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, respectively. The results showed that fengycin destroyed the internal structure of Ggt cells by digesting the cytoplasm and organelles, forming vacuoles, and inducing hyphal shrinkage and distortion. Iturin A induced cell wall disappearance, membrane degeneration, intracellular material shrinkage, and hyphal fragmentation. A biocontrol test demonstrated a 100% control effect on wheat take-all when wheat seedlings were treated with fengycin at 100 μg/ml or iturin A at 500 μg/ml. Iturin A and fengycin both reduced the relative abundance of Aspergillus and Gibberella. At the genus level, iturin A reduced the relative abundance of Mortierella and Myrothecium, while fengycin reduced that of Fusarium. Only fengycin treatment for 7 days had a significant effect on soil bacterial diversity.


Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1179
Author(s):  
Darlena Caroline da Cruz Corrêa ◽  
Abmael da Silva Cardoso ◽  
Mariane Rodrigues Ferreira ◽  
Débora Siniscalchi ◽  
Pedro Henrique de Almeida Gonçalves ◽  
...  

The reduction in ammonia (NH3) losses from volatilization has significant implications in forage production. The objective of this study was to evaluate the impact of N fertilizers (urea, ammonium nitrate, and ammonium sulfate) and four doses (0, 90, 180 and 270 kg N ha−1) on N losses by NH3 volatilization, accumulation, and forage chemical composition of Urochloa brizantha cv Marandu. Two field experiments were conducted to measure NH3 losses using semi-open chambers. The forage accumulation and chemical composition were evaluated in the third experiment; the response variables included forage accumulation, crude protein (CP), and neutral detergent fiber (NDF). Compared to urea, ammonium nitrate and ammonium sulfate reduced NH3 losses by 84% and 87% and increased total forage accumulation by 14% and 23%, respectively. Forage accumulation rate and CP increased linearly with the N levels, while NDF contents decreased linearly with the N levels. In both experiments, NH3 losses and forage characteristics were different according to the rainfall pattern and temperature variations. Our results indicate that the use of nitric and ammoniacal fertilizers and the application of fertilizer in the rainy season constitute an efficient fertilizer management strategy to increase forage yield and decrease losses from volatilization of NH3.


PEDIATRICS ◽  
1959 ◽  
Vol 24 (1) ◽  
pp. 73-73

Aside from the great theoretic interest, the experiments described in this paper have considerable practical importance in providing a means of studying the efficacy of treatments designed to prevent kernicterus. A comprehensive study of a strain of rats (the Gunn strain) which have a hereditary deficiency of the enzyme required to conjugate bilirubin, and thus develope jaundice due to increased concentration of unconjugated bilirubin in the blood and tissues. The rats developed kernicterus which was apparently identical with that seen in human beings and is the only example of kernicterus in animals that fulfills rigid criteria outlined by the authors. Extensive data on the natural history of the bilirubinemia and development of kernicterus in the rats, as determined by chemical and pathologic techniques, are provided. Bilirubin itself is incriminated as the toxic agent producing the characteristic changes in the brain in kernicterus. Sulfonamides were found to augment the toxic effects of bilirubin, apparently because of competition between bilirubin and sulfonamides for binding sites on serum albumin. Neither infection nor hypoxia appeared to aggravate the effects of bilirubin. Administration of sodium glucuronate to jaundiced rats was followed by a decrease in bilirubin in the serum which at times exceeded 50%. This was not accompanied by any postponement of the onset of signs of damage to the central nervous system and did not prevent development of kernicterus. It appeared that the decrease in bilirubin in the serum may have resulted from an increased transferral to tissues rather than elimination through renal excretion. On the basis of the knowledge of this strain of rats, it should be possible to explore the usefulness of proposed therapeutic regimens in the experimental animal without jeopardizing the course of human infants who might be successfully treated with exchange transfusion pending the discovery of a more satisfactory therapy.


Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 469-475 ◽  
Author(s):  
W. Mack Thompson ◽  
Scott J. Nissen ◽  
Robert A. Masters

Laboratory experiments were conducted to identify adjuvants that improve absorption of imazethapyr, 2,4-D amine, and picloram by leafy spurge. Adjuvants (0.25% v/v) included crop oil concentrate (COC), methylated seed oil (MSO), nonionic surfactant (NIS), organosilicones (Silwet L-77®, Sylgard® 309, Silwet® 408), 3:1 mixtures of acetylinic diol ethoxylates (ADE40, ADE65, ADE85) with Silwet L-77, ammonium sulfate (2.5 kg ha−1), and 28% urea ammonium nitrate (UAN, 2.5% v/v). Adjuvants were combined with14C-herbicide and commercially formulated herbicide product. Leaves were harvested 2 DAT, rinsed with 10% aqueous methanol to remove surface deposits of herbicide, and dipped in 9:1 hexane:acetone to solubilize cuticular waxes. Imazethapyr absorption increased by 38 to 68% when UAN was combined with COC, NIS, or MSO. Total absorption of imazethapyr plus COC, MSO, or NIS exceeded 86% 2 DAT when UAN was added. Urea ammonium nitrate reduced the amount of imazethapyr associated with the cuticular wax by 2.0%. Imazethapyr absorption was similar on both the abaxial and adaxial leaf surface when UAN was not added; however, 12% more imazethapyr was absorbed from the abaxial leaf surface than from the adaxial leaf surface when UAN was combined with Sylgard 309. Uptake of 2,4-D ranged from 54 to 78% and was greatest with Silwet 408 and 3:1 mixture of ADE40: Silwet L-77. Picloram absorption ranged from 3 to 19%. Buffering picloram treatment solutions to pH 7 and including 2.5 kg ha-1ammonium sulfate increased picloram absorption to 37%.


2016 ◽  
Vol 30 (3) ◽  
pp. 2474-2477 ◽  
Author(s):  
Alon Grinberg Dana ◽  
Bar Mosevitzky ◽  
Gal Tvil ◽  
Michael Epstein ◽  
Gennady E. Shter ◽  
...  

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