Pertes d'azote par volatilisation ammoniacale après fertilisation en forêt de pin gris

1971 ◽  
Vol 1 (2) ◽  
pp. 69-79 ◽  
Author(s):  
D. Carrier ◽  
B. Bernier

In a field study, percentage of nitrogen lost as ammonia from a jack pine (Pinusbanksiana Lamb.) soil increased with increasing rates of urea application between 112 and 448 kg N/ha. After 7 days, losses amounted to 18–28% of a 224 kg urea-N/ha application, representing 60–87% of the total losses measured over a 6-week period. Maximum volatilization rates occurred between the third and the fifth day after fertilization, at which time urea hydrolysis was virtually complete. Negligible ammonia losses were measured in plots treated with ammonium sulfate, ammonium nitrate, and sulfur-coated urea. Applying superphosphate with urea markedly depressed ammonia volatilization, an effect which was enhanced by a joint application of K2SO4•MgSO4. Reduction of volatilization by artificial precipitation was significant and increased with increasing precipitation when the latter was applied soon after fertilization; decreases in volatilization were then related to the amount of residual urea subject to diffusion into the humus layer or to leaching towards the underlying soil horizons.

2013 ◽  
Vol 12 (1) ◽  
pp. CM-2013-0117-01-RS
Author(s):  
William Hunter Frame ◽  
Marcus M. Alley ◽  
Wade Thomason ◽  
Garnett Whitehurst ◽  
Brooks Whitehurst ◽  
...  

2016 ◽  
Vol 78 (6-12) ◽  
Author(s):  
Saima Kalsoom Babar ◽  
Mohd Khanif Yusop ◽  
Shakeel Ahmed Babar ◽  
Aijaz Ali Khooharo

Nitrogen (N) losses from agricultural fields are commonly observed particularly from urea. The rate of urea hydrolysis is accelerated as it remains in conventional form and about 70% of applied urea losses in different forms to atmosphere. Ammonia volatilization is persuasive loss among all the losses from urea. Therefore to minimize ammonia (NH3) volatilization the micronutrient coated urea is applied to enhance N-efficiency and its uptake. This study is an application of micronutrient coated urea with zinc (Zn) and copper (Cu) for two soil series of Malaysia. A laboratory experiment was designed according to the force draft technique for trapping the NH3 loss. The results have manifested that the rate of ammonia volatilization was 16% from uncoated urea and 8% from coated urea with micronutrients during the first two weeks of observations. After the six weeks of observations it was perceived that the ammonia losses for both soil series were gradually decreased with time. The mean comparison by using Tukey’s range test has shown the positive effect of micronutrient coated urea in comparison with the conventional urea. However the urea coated with the combination of both micronutrients Cu and Zn has shown significant difference in contrast to the coating urea with single micronutrient. The overall results revealed the efficacy of micronutrient coated urea on both of the soil series to maximize N-uptake and reduce NH3 volatilization.


2019 ◽  
Vol 8 (3) ◽  
pp. 23
Author(s):  
Maru Ali ◽  
Ahmed Osumanu Haruna ◽  
Nik Muhamad Abd Majid ◽  
Walter Charles Primus ◽  
Nathaniel Maikol ◽  
...  

Although urea use in agriculture is on the increase, increase in pH at soil microsite due to urea hydrolysis which causes ammonia emission can reduce N use efficiency. Among the interventions used to mitigate ammonia loss include urease inhibitors, clinoptilolite zeolite, coated urea, and biochar but with little attention to the use of soil water levels to control ammonia volatilization. The objective of this study was to determine the effects of soil water levels on ammonia volatilization from soils with and without chicken litter biochar. Dry soils with and without chicken litter biochar were subjected to 0%, 25% 50%, 75%, 100%, and 125% soil water. There was no urea hydrolysis in the soil without water. Chicken litter biochar as soil amendment effectively mitigated ammonia loss at 1% to 32% and 80% to 115% field capacity. However, urea used on soil only showed lower ammonia loss at 33% to 79% and 116% to 125% field capacity compared with the soils with chicken litter biochar. At 50% field capacity ammonia loss was high in soils with and without chicken litter biochar. Although chicken litter biochar is reputed for improving soil chemical properties, water levels in this present study affected soil chemical properties differently. Fifty percent field capacity, significantly reduced soil chemical properties. These findings suggest that timely application of urea at the right field capacity can mitigate ammonia emission. Therefore, whether soils are amended with or without chicken litter biochar, urea application should be avoided at 50% field capacity especially in irrigated crops.


Author(s):  
D. V. Syshchykov ◽  
I. V. Agurova ◽  
O. V. Syshchykova

As a result of the carried out studies of biological activity of edaphotopes of anthropogenic transformed ecosystems, it was found that the largest number of microorganisms and streptomycetes it was characteristic for common chernozem. For the soil horizons of primitive undeveloped fragmented soils, was recorded the lowest percentage of the microorganisms number (on average 4-5% relative to the control). The number of streptomycetes in both intrazonal and soils of anthropogenic transformed soils and zonal soils varies in horizons. However, we have noted that in intrazonal and anthropogenic transformed soils streptomycetes are in most cases concentrated in underlying soil horizons. Our studies on micromycetes have found that this group of microscopic fungi accounts for up to 50% of the total number of microbiocenosis, with the smallest number recorded in the genetic horizons of primitive undeveloped soils on sandstone. Cellulose-destroying microorganisms in the soil microbocenosis of monitoring sites are least represented.


1981 ◽  
Vol 11 (2) ◽  
pp. 414-422
Author(s):  
C. Camiré ◽  
B. Bernier

Six nitrogen fertilizers (urea, sulfur-coated urea, urea-formaldehyde, ammonium nitrate, ammonium sulfate, and ammonium nitrate) were individually applied, either in fall or in spring, at a rate of 224 kg N/ha and compared for nitrogen retention in the different horizons of a podzol under jack pine. Despite its susceptibility to nitrogen losses through ammonia volatilization, urea was by far, among readily available nitrogen fertilizers, the one whose nitrogen is best retained in soil surface horizons. Retention varied with weather conditions that prevailed immediately after fertilizer application. With the other fertilizers used, nitrogen retention followed this order: ammonium sulfate > ammonium nitrate > calcium nitrate. After four seasons, about 50% of the nitrogen applied as sulfur-coated urea and urea-formaldehyde was still found in its original form. Ammonium sulfate is next to urea among the recommended nitrogen sources for similar jack pine sites, considering that fertilizers with nitrate are prone to leaching and the sulfur-coated urea and urea-formaldehyde used presented problems of nitrogen availability.


1988 ◽  
Vol 39 (3) ◽  
pp. 351 ◽  
Author(s):  
ACF Trevitt ◽  
JR Freney ◽  
JR Simpson ◽  
WA Muirhead

The effects of differences in size of microplot and type of enclosure on the floodwater parameters determining ammonia volatilization were studied. The results show that the use of enclosures can retard urea hydrolysis, suppress the maximum daytime pH values (an effect which is cumulative over a number of days), and significantly reduce the potential for ammonia volatilization. These effects are the consequence of lowered light (and heat) penetration in the enclosed area due to shading of the floodwater by the enclosure walls. The magnitude of these effects varies with plot size and shape, and the material used for construction of the plot wall. A preliminary analysis suggests that, if errors due to shading are acceptable when 90% or more of the incident solar radiation always penetrates to the enclosed floodwater, then square plots with opaque walls must be at least 1.2 m along a side and cylindrical plots must be at least 1.2 m in diameter when wall height is 0.1 m above the floodwater.


1974 ◽  
Vol 4 (3) ◽  
pp. 381-398 ◽  
Author(s):  
G. F. Weetman ◽  
D. Algar

The response of a 40-year-old even-aged jack pine (Pinusbanksiana Lamb.) stand to nitrogen fertilization was studied in four experiments.Smothering of the ericaceous ground vegetation layer with straw led to increased tree growth rates and improved N uptake. The application of calcium nitrate, ammonium nitrate, and urea at 112 and 448 kg N/ha was followed by analysis of the composition of extractable humus N, together with foliar and increment analyses. After a 3-year response period, there was evidence for the superiority of the ammonium nitrate form of N fertilizer over urea. The applications of urea appear to have been associated with possible N volatilization losses, and also inadequate urease activity in the thin dry humus layer which led to delayed N uptake by the trees. Calcium nitrate, although not an efficient fertilizer, was associated with appreciable growth responses, even though increased foliar and extractable humus N concentrations were not maintained.An optimum nutrition experiment utilizing repeated fertilization indicated that sustained foliar nutrient regimes can be maintained.The study indicated that growth increases were associated with increased unit needle weights as well as increased foliar N concentrations. A graphical technique which analyzes treatment responses, unit needle weight, and nutrient concentration, was used to screen response data, without waiting the customary 5-year period for stem increment response.


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