Cover crops can increase ammonia volatilization and reduce the efficacy of urease inhibitors

Stephanie B Kulesza ◽  
Alex L. Woodley ◽  
Kayleigh Heather ◽  
Grace Kilroy
2016 ◽  
Vol 40 (2) ◽  
pp. 133-144 ◽  
Eduardo Lopes Cancellier ◽  
Douglas Ramos Guelfi Silva ◽  
Valdemar Faquin ◽  
Bruno de Almeida Gonçalves ◽  
Leandro Lopes Cancellier ◽  

ABSTRACT High nitrogen losses by ammonia volatilization are expected when urea is used as the source of N. The use of controlled-release urea and urease inhibitors are possible strategies to reduce such losses and increase nitrogen use efficiency. This study aimed to evaluate nitrogen losses by ammonia volatilization from stabilized, slow and controlled release urea and its absorption by maize grown under no-till in an improved Cerrado soil. Four N sources were used: conventional urea, urea + N-(n-butyl) thiophosphoric triamide (NBPT), urea + Cu and B and urea coated by sulfur + polymers. These N sources were surface applied along the rows using three N doses of 100, 150 and 200 kg ha-1. No N was added to the control. Data were collected regarding N losses by volatilization, the N contents accumulated in the stubble and grains, and the yields of the stubble and grains. Stabilized urea and slow release urea were efficient for postponing the ammonia volatilization peaks. The urease inhibitors postponed the peaks for up to two days, reducing the accumulated volatilization by 18% when compared with common urea. Polymer sulfur coated urea resulted in a 37% reduction in ammonia volatilization. Increasing the N application rate to 200 kg ha-1 resulted in 16% greater yields and 37% greater N accumulation in the plants relative to the control. However, the stabilized and slow-release urea did not improve the N accumulation or yield. Consequently, the nitrogen use efficiency of maize was not improved relative to the use of conventional urea.

2018 ◽  
Vol 20 (3) ◽  
pp. 1-11
Nutifafa Adotey ◽  
Manoch Kongchum ◽  
Jifeng Li ◽  
Garnett Whitehurst ◽  
Eric Sucre ◽  

Iara Magalhães Barberena ◽  
Marcelo Curitiba Espindula ◽  
Larissa Fatarelli Bento de Araújo ◽  
Alaerto Luiz Marcolan

Abstract: The objective of this work was to evaluate urease inhibitors for the reduction of ammonia volatilization in Amazonian soils. The work was carried out on a clayey yellow Oxisol, a clayey red Oxisol, and on a light silty Ultisol. Each experiment was conducted in split plots, using standard urea, urea + a benzimidazole-type urease inhibitor (BZI1), urea + a benzoylthiourea-type urease inhibitor (RTB68), urea + N-(n-butyl) triamide thiophosphate (NBPT), or a fertilizer-free control. Volatilized ammonia was collected at 48, 96, 144, 192, 240, 288, 336, and 384 hours after fertilization. Ammonia volatilization reached a maximum at 144 hours in the urea, urea + benzimidazole, and urea + benzoylthiourea treatments. A peak level was reached at 192 and 288 hours in the urea + N-(n-butyl) triamide thiophosphate treatment. In yellow Oxisols, benzimidazole and benzoylthiourea reduced the ammonia losses by 22 and 10%, respectively, in soils without urease inhibitors. However, neither of these agents significantly reduced ammonia volatilization at the rate determined for standard urea in red Oxisols or Ultisols. N-(n-butyl) triamide thiophosphate is the most efficient urease inhibitor for the soils of southwestern Amazonia.

2017 ◽  
Vol 52 (3) ◽  
pp. 194-204 ◽  
Ioná Rech ◽  
José Carlos Polidoro ◽  
Paulo Sérgio Pavinato

Abstract: The objective of this work was to develop urea-based fertilizers with internal incorporation of urease inhibitors and other additives in the granule. The effects of the incorporation of NBPT, copper (Cu+2), boric acid (H3BO3), elemental sulphur (Sº), and a clay mineral from the zeolite group in powder urea - with ten different combinations of these additives - were evaluated as to N losses by volatilization and leaching. The losses in laboratory-developed formulations were compared with those of commercial fertilizers coated with the same additives (Super N, FH Nitro Mais, and FH Nitro Gold). The evaluations were made in greenhouse conditions, using a Ultisol accommodated in PVC columns. Nitrate and ammonium leaching was evaluated in the solution percolated through the soil columns. Ammonia volatilization was measured with a semi-open static chamber. The incorporation of urease inhibitors (NBPT, H3BO3, and Cu+2) into the urea granules was efficient to reduce N volatilization. Ammonia volatilization in the laboratory-developed ureas was lower than in commercial fertilizers coated with the same additives, while ammonium sulfate losses by leaching were similar. The addition of zeolite does not reduce N volatilization. Mineral N leaching in the soil profile is not affected by urease inhibitors.

2009 ◽  
Vol 33 (6) ◽  
pp. 1685-1694 ◽  
Hamilton Seron Pereira ◽  
Anabelisa Ferreira Leão ◽  
Adriana Verginassi ◽  
Marco Aurélio Carbone Carneiro

The aim of this study was to evaluate the N losses due to volatilization at different rates of common urea, polymer coated urea and urease inhibitor-treated urea in the out-of-season corn, using semi-open static collectors. The treatments consisted of N levels on side-dressing fertilization with urea in different treatments: (a) control (without N), (b) urea 40 kg ha-1 N, (c) urea 80 kg ha-1 N, (d) polymer coated urea 40 kg ha-1 N, (e) polymer coated urea 80 kg ha-1 N and (f) urea with the urease inhibitor (UI) N 80 kg ha-1 N. The results showed that the treatments with polymer coated urea and with urease inhibitor-treated urea reduced the volatilization of N around 50 % compared to common urea, either in the first and the second N side-dressing fertilizations. Thus, they demonstrate that the polymer coat and the urease inhibitors were effective in reducing the volatilization of urea N applied in coverage, which resulted in higher productivity. There was also increasing urease activity in the treatments with application of common urea.

2018 ◽  
Vol 102 (4) ◽  
pp. 16-19
Tai McClellan Maaz ◽  
Cliff Snyder

Stabilized N sources are N fertilizers treated with urease inhibitors, nitrification inhibitors, or a combination of both. They can comprise “right source” in many situations in which 4R Nutrient Stewardship is implemented. Several meta-analyses demonstrate that nitrification inhibitors with and without urease inhibitors consistently reduce N2O emissions. Nitrification inhibitors are effective at decreasing NO3- leaching but can increase ammonia volatilization, while urease inhibitors are effective at preventing volatilization losses.

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