SHORT COMMUNICATION: Volatile losses of NH3 from surface-applied urea and urea ammonium nitrate with and without the urease inhibitors NBPT or ammonium thiosulphate

1996 ◽  
Vol 76 (3) ◽  
pp. 417-419 ◽  
Author(s):  
C. A. Grant ◽  
K. R. Brown ◽  
L. D. Bailey ◽  
S. Jia

Field microplot studies were conducted under zero-till conditions on a fine sandy loam (Orthic Black Chernozem) to determine the effect of the urease inhibitors N-(n-butyl) thiophosphoric triamide (NBPT) and ammonium thiosulphate (ATS) on volatile losses of NH3 from urea and urea ammonium nitrate (UAN). Two studies were conducted, one in late May and one in early August. Losses of NH3 were measured on days 1, 2, 4 and 7 after fertilizer application, using ammonia traps. Ammonia losses were higher in the second study due to the higher soil temperatures and lower soil moisture later in the growing season. Total NH3 losses increased in the order Control < UAN + NBPT = Urea + NBPT < UAN + ATS = UAN < Urea. Total loss of NH3 during the 7 d after fertilizer application was higher from urea than from UAN, particularly in the first study. Use of NBPT was effective in reducing NH3 volatilization from both UAN and urea during 7 d after fertilizer application while use of ATS had little influence on NH3 loss from UAN. The NBPT may delay losses by slowing the hydrolysis of urea, but volatilization may persist for a longer duration. The delay in urea hydrolysis could allow time for rainfall to carry the urea into the soil, thus reducing total volatilization losses from surface fertilizer application. Key words: N-(n-butyl) thiophosphoric triamide, zero tillage

1989 ◽  
Vol 69 (3) ◽  
pp. 551-565
Author(s):  
F. SELLES ◽  
A. J. LEYSHON ◽  
C. A. CAMPBELL

Prairie farmers are interested in applying nitrogen (N) in the fall or winter to reduce fertilizer costs and allow a better distribution of labor and machinery use. Two studies were conducted in southwestern Saskatchewan to determine the consequences of applying N in late fall. In the laboratory, fertilizer N barely penetrated into the snow at constant subzero temperatures, but under freeze-thaw conditions, urea and ammonium nitrate descended 27 cm in 3 d. In the field, ammonium nitrate and urea were applied to snow-covered and bare microplots of grass sod and cereal stubble (1981–1982) and grass sod only (1985–1986). Nitrogen from ammonium nitrate penetrated deeper into the snow than N from urea. Nitrogen recovery in April 1982 was 55–59% from ammonium nitrate and 39–51% from urea, but was near 100% for both sources on bare soil treatments in April 1986. More N was recovered when fertilizer was applied to bare than to snow-covered soil, especially during 1985–1986 when all the applied fertilizer was blown off the snow-covered plots. Mineral N generally declined from fall to spring in all treatments, probably because of denitrification and immobilization. In 1985–1986, a period of extremely low temperatures in late fall resulted in no movement or transformation of N until after early December. By late January, periods of above-zero soil temperatures resulted in substantial mineralization of soil organic N, in the fertilized plots. This apparent priming effect was attributed to perturbations in the organic matter and microbial biomass due to fertilizer application and freezing and thawing. Following this period there was a general decrease in mineral N towards spring, as observed in 1981–1982. Producers must consider the benefits of using labor and equipment more efficiently and of lower fertilizer cost in the fall against the risk of large potential N losses over winter. Key words: Urea, ammonium nitrate, N recovery, frozen soils, fertilizing in winter


2014 ◽  
Vol 94 (2) ◽  
pp. 329-335 ◽  
Author(s):  
C. A. Grant

Grant, C. A. 2014. Use of NBPT and ammonium thiosulphate as urease inhibitors with varying surface placement of urea and urea ammonium nitrate in production of hard red spring wheat under reduced tillage management. Can. J. Plant Sci. 94: 329–335. Field studies were conducted at two locations over 3 yr to evaluate the effect of surface placement of urea ammonium nitrate (UAN) and urea fertilizers, with and without the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) on straw and grain yield of hard red spring wheat (Triticum aestivum L.) grown under reduced tillage management. Ammonium thiosulphate (ATS) was also evaluated as a urease inhibitor with UAN. Surface sprayed applications of UAN were frequently less effective than dribble-banded UAN applications or broadcast or dribble-banded urea in increasing grain or straw yield of hard red spring wheat. Use of NBPT with the sprayed UAN increased its effectiveness, so that grain and straw yields were similar to those with urea or with surface dribble-banded UAN. Addition of NBPT to broadcast or banded urea did not increase straw or grain yield under the conditions of this study. While there was some indication that use of ATS with UAN may have had a limited effect on fertilizer efficiency, it did not increase final grain yield as compared with dribble-banded or spray UAN applied alone or with NBPT. If surface nitrogen (N) applications are used in reduced tillage systems, spray applications of UAN should be avoided in favour of dribble-band applications, or the use of urea. Alternately, NBPT may be effective in improving the efficacy of spray UAN.


2017 ◽  
Vol 9 (11) ◽  
pp. 17 ◽  
Author(s):  
H. Habibullah ◽  
Kelly A. Nelson ◽  
Peter P. Motavalli

Use of nitrification inhibitors (NI) in agricultural production systems is considered a risk management strategy for both agricultural and environmental considerations. It can be utilized when risk of reduced nitrogen (N) fertilizer use efficiency or yield, and risk of pollution from mineral N is high which can occur in poorly-drained soils that are vulnerable to waterlogging and runoff. Field research was conducted on corn (Zea mays L.) from 2012 to 2015 in Missouri, USA on a poorly-drained claypan soil. Treatments consisted of two application timings of urea ammonium nitrate (UAN) fertilizer solution [pre-emergence (PRE) and V3 growth stage], two application rates (143 and 168 kg N ha-1) in the presence or absence of nitrapyrin, and a non-treated control. UAN at 143 kg ha-1 with nitrapyrin at the V3 growth stage resulted in the highest yield (8.6 Mg ha-1). Similarly, pre-emergence application of UAN 168 kg ha-1 with nitrapyrin resulted in greater yields (7.7 Mg ha-1). UAN application rates and timings affected soil NO3-N and NH4-N concentrations more than the presence or absence of nitrapyrin during the growing season. A side-dress application of a lower rate of UAN with nitrapyrin at V3 was effective in poorly-drained soils when risk of N losses during the growing season due to unfavorable precipitation events and other environmental variables was high. A pre-emergence application of UAN with nitrapyrin was also effective and it may eliminate the need for split-application of N fertilizer later in the season thereby reducing the workload on growers during the growing season.


1986 ◽  
Vol 66 (4) ◽  
pp. 615-621 ◽  
Author(s):  
R. M. N. KUCEY

Urea, ammonium nitrate, and anhydrous ammonia were compared as sources of N for barley in southern Alberta in spring and fall, using broadcast and banded applications. No significant difference in effect was found among fertilizers when they were banded at a depth of 15 cm. When broadcast, the granular forms of N were not as effective as equivalent rates and forms added in a band. Spring-applied N was more effective than fall-applied N in three of the eight comparisons made. N uptake accounted for between 18 and 54% of the added N in the 2 yr of the experiment. Fertilizer additions had no effect on barley yield when water was limited over the growing season. Key words: Nitrogen, urea, ammonium nitrate, anhydrous ammonia, yield response


Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 161 ◽  
Author(s):  
Michael Thorstein Nikolajsen ◽  
Andreas Siegfried Pacholski ◽  
Sven Gjedde Sommer

Urea is the most used fertilizer nitrogen (N), and is often applied as urea ammonium nitrate (UAN), which may be an ammonia (NH3) emission source after application. This study examined whether the addition of urease inhibitors reduced NH3 emission, and, in combination with nitrification inhibitors, enhanced fertilizer N crop uptake. In three experiments, NH3 emission was measured from plots (100 m2) to which UAN was added with and without inhibitors. In March and May, the plots were covered with Triticum aestivum L., Sheriff (var), and in July, the soil was bare. The inhibitor mixed with urea was N-(n-butyl) thiophosphoric triamide (NBPT) and a mixture of NBPT and the new nitrification inhibitor DMPSA (3,4-Dimethylpyrazole succinic acid). Ammonia emissions were negligible from all plots after the first application of UAN due to the wet and cold weather while an average of 7% of applied UAN was emitted after application of UAN in April, where no significant effect of additives was observed. The harvest yield was low due to drought from May till August. Yield was highest when UAN was mixed with NBPT and lowest for untreated UAN. The highest emission from the bare plots was obtained from untreated UAN (17% of N), in contrast to 11% of N from the plots with added UAN + NBPT (not significant) and 7% from the plots with added UAN + NBPT + DMPSA (significantly different). Under the conditions of the current study, urease inhibitors reduce NH3 emissions in periods where the risk of emission is high, and the combination of urease and nitrification inhibitors increased yields.


2018 ◽  
Vol 64 (No. 1) ◽  
pp. 26-31 ◽  
Author(s):  
Holečková Zlata ◽  
Kulhánek Martin ◽  
Hakl Josef ◽  
Balík Jiří

The aim of this research is to estimate the influence of a bioeffector (BE) application on dry matter yield and nutrient content (P, K, Ca, Mg, S) in maize (Zea mays L.). Between 2014 and 2016, a field experiment with silage maize as a testing plant was realized on sandy loam Cambisol. The application of Pseudomonas sp. in combination with phosphorus (rock phosphate (RP) or triple superphosphate (TSP)) and nitrogen fertilizers (ammonium nitrate with urea, ammonium nitrate with limestone, calcium nitrate or ammonium sulfate with a nitrification inhibitor) and with different application strategies was studied. The effects of a bioeffector application on the increase of dry matter yields were not confirmed. An important influence on the BE application and its activity was probably those of soil and site conditions and competition of the researched microorganisms with other present microorganisms. Higher yields of dry matter were shown in treatments where P fertilizers were applied. There was almost no difference between the application of RP and TSP. This could be caused by the fact that the soil had a slightly acidic pH value. In this case, the RP showed similar results to the TSP. The application of bioeffector significantly increased Mg, K and S contents in maize above-ground biomass. An increase of the Ca content was almost significant and a tendency towards a higher average content of phosphorus was also recorded.


Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 87-93 ◽  
Author(s):  
David T. Patterson ◽  
Robert L. Musser ◽  
Elizabeth P. Flint ◽  
Robert E. Eplee

Ethylene-stimulated germination of witchweed [Striga luteaLour. =S. asiatica(L.) O. Ktze.] seed first occurred after 13, 10, 6, 3, and 2 days of conditioning in moist sand at day/night temperatures of 20/14, 23/17, 26/20, 29/23, and 32/26 C, respectively. Maximum germination percentages in these regimes were 0.5, 3, 20, 24, and 37%, respectively. No germination occurred at 17/11 C. Witchweed seed survived in sand frozen for 7 weeks at −7 or −15 C and subsequently germinated in response to ethylene or in the presence of corn (Zea maysL., ‘DeKalb B73 × Mo.17H′) roots. The parasites emerged from the soil and flowered when maintained at 29/23 C after the termination of the freezing treatments. In other experiments, witchweed parasitized corn and/or sorghum [Sorghum bicolor(L.) Moench ‘DeKalb E-59+′] root systems in a sandy loam under 26/17, 26/20, 29/20, 32/23, and 32/26 C day/night regimes. Witchweed emerged from the soil with 26/20, 29/20, 32/23, and 32/26 C and flowered with 26/20, 32/23, and 32/26 C day/night regimes. Underground development and subsequent emergence of the parasites were substantially reduced with day/night temperatures below 29/20 C. Winter soil temperatures and growing season soil and air temperatures are unlikely to limit the spread of witchweed into important corn- and sorghum-producing areas of the United States.


1977 ◽  
Vol 89 (3) ◽  
pp. 767-768 ◽  
Author(s):  
E. A. Garwood ◽  
K. C. Tyson

When high rates of fertilizer N are applied to grass in an area of low rainfall, considerable amounts may be lost to drainage in the subsequent winter if the N is not fully utilized owing to dry soil conditions during the growing season (Garwood & Tyson, 1973). The data now presented were obtained from the lysimeters described in that paper. The soil is a sandy loam, overlying chalk. The swards of perennial ryegrass (Lolium perenne cv. S. 23) were cut four times each year. Two rates of N were applied as ammonium nitrate (Nitrana), 250 kg (LN) and 500 kg N/ha per year (HN). Two-fifths of this N were applied in March and one-fifth after each of the first three cuts.


Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 709 ◽  
Author(s):  
David F. Lambert ◽  
John E. Sherwood ◽  
Paul S. Francis

Although the dominant methods for the determination of urea in clinical applications incorporate selective enzymatic hydrolysis of urea, the determination of urea in soil extracts is complicated by the presence of urease inhibitors. The spectrophotometric determination of urea with an acidic solution diacetyl monoxime and semicarbazide is a viable option but traditional manual procedures are time-consuming. New variations on these procedures, based on microplates or flow-injection analysis methodologies, allow a far greater number of samples to be analysed with high precision and sensitivity.


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.


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