Extraction and Colorimetric Determination of Urea in Soils

Douglas, L. A.; Bremner, J. M.

doi:10.2136/sssaj1970.03615995003400060015x

Cited by 254 publications

(76 citation statements)

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“…40 filter paper. Phenyl mercuric acetate, a urease inhibitor, was added to the solution to stop the significant hydrolysis of urea by soil urease that can occur during the extraction process (Douglas and Bremner 1970). A Technicon Autoanalyzer II Single-Channel Colorimeter was used to determine the concentrations of NO 3 --N + NO 2 --N and NH 4 + -N in the extract using the automated cadmium reduction method and the automated phenate colorimetric method respectively (Maynard and Kalra 1993).…”

Section: Soil Sampling and Analysesmentioning

confidence: 99%

“…Nitrate-N was determined by subtracting the NO 2 --N from the NO 3 --N + NO 2 --N value. The Technicon method used in the determination of urea-N is a modification of the carbamido-diacetyl reaction, as described by Douglas and Bremner (1970). Electrical conductivity (EC) and pH were measured using a 2:1 water to soil extract, an Orion conductivity meter and a Fisher Accumet pH meter (Hogg and Henry 1984;Hendershot et al 1993).…”

Section: (Ellis 2001)mentioning

confidence: 99%

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Efficiency of fall-banded urea for spring wheat production in Manitoba: Influence of application date, landscape position and fertilizer additives

Tiessen¹,

Flaten

Grant³

et al. 2005

Can. J. Soil. Sci.

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. 2005. Efficiency of fall-banded urea for spring wheat production in Manitoba: Influence of application date, landscape position and fertilizer additives. Can. J. Soil Sci. 85: 649-666. A 2-yr study was conducted to investigate the effects of application date, landscape position and a urease and nitrification inhibited formulation of urea on the efficiency of fall-banded N fertilizer under Manitoba conditions. To date, no studies have investigated how these factors interact to influence the efficiency of fall-banded N in western Canada. The effects of landscape position were apparent at three of the four sites, with significantly greater grain yields, straw yields and total recovery of N in the high landscape positions than in the low landscape positions. In the high landscape positions, there were no significant differences in crop response or recovered N among application dates in the fall and spring. However, in the low landscape positions, grain yields, grain yield increases and apparent recovered fertilizer N in the aboveground portion of the crop and in the soil (0-120 cm) were significantly greater for spring and late fall applications, when compared with early and mid-fall applications. At one site in the first year of the study, early fall-banded N with the urease and nitrification inhibitors produced greater increases in grain yield than early fall-banded N without the inhibitors in the low landscape positions. However, overall there was little agronomic benefit to the use of the additives, as there were few significant differences in crop yields or N uptake by the crop with the inhibitors than without, in either year or landscape position. The results demonstrate that selection of suitable timing for application of fertilizer N to optimize crop yields is much more critical for poorly drained areas within a field, or for poorly drained fields, than for better drained land.

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Section: Soil Sampling and Analysesmentioning

confidence: 99%

Section: (Ellis 2001)mentioning

confidence: 99%

Efficiency of fall-banded urea for spring wheat production in Manitoba: Influence of application date, landscape position and fertilizer additives

Tiessen¹,

Flaten

Grant³

et al. 2005

Can. J. Soil. Sci.

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“…Dans (Atlas et al 1978). These tests are usually designed to measure the effects of the pesticide on soil CO, production, the mineralization of common biopolymers, transformation of soil nitrogen and the activity of selected soil enzymes (Atlas et al 1978;Tu 1981 (Tabatabai and Bremner 1970); dehydrogenase (Casida et al 1964); acid phosphatase (Tabatabai and Bremner 1969); rhodanese (Tabatabai and Singh 1976); urease (Douglas and Bremner 1970 Twenty-five soil cores (0-3 cm) from both the control and treated fields were collected (immediatelv following application and 6 wk later) as described previously (Germida et al 1987 (Fig. 3).…”

mentioning

confidence: 99%

EFFECT OF Nosema locustae Canning (Microsporida) AND THREE CHEMICAL INSECTICIDES ON MICROBIAL ACTIVITY IN SOIL

Germida¹,

Onofriechuk²,

Ewen³

1987

Can. J. Soil. Sci.

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Nosema locustae Canning is a potential biological control agent for grasshoppers but some aspects of its environmental impact have not been investigated. This study assessed the impact of N. locustae and the chemical insecticides carbofuran, deltamethrin and dimethoate on microbial activity and nutrient cycling in soil. In a laboratory study, the insecticides were applied to a Haverhill loam at recommended field application rates and 10 times the field rates. There was no adverse effect from N. locustae or the chemical insecticides on any of the measured parameters. Analysis of field soils 6 wk after application of a mixture of N. locustae and dimethoate indicated this treatment had no adverse impact on microbial activity. Key words: Nosema locustae, carbofuran, deltamethrin, dimethoate, microbial activity

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“…Distilled water was added to bring the moisture content to 60% of WHC, and the samples were incubated at 27 °C for 3 weeks. The remaining urea in the soil was determined after 12 h, 24 h, 36 h, and 48 h using the method proposed by Douglas and Bremner (1970). The indophenol blue colorimetric method was used to assay the urease activity on day 14.…”

Section: Soil Incubation Experimentsmentioning

confidence: 99%

Maize Stover Biochar Accelerated Urea Hydrolysis and Short-term Nitrogen Turnover in Soil

Liu¹,

He²,

Lan³

et al. 2017

BioResources

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A soil incubation experiment was conducted to investigate the effect of biochar application (2% w/w) on urea hydrolysis and inorganic nitrogen accumulation. Fresh biochars were produced from maize stover that was pyrolyzed at 300 °C, 500 °C, and 700 °C. Then the matured biochars were obtained via a 50 days maturing process. Biochar prepared at 700 °C strongly accelerated the urea hydrolysis and increased soil pH. Fresh biochar, especially when pyrolyzed at low temperature, contained a relatively high concentration of labile carbon and 43% to 64% could be oxidized within 40 days of maturing incubation. The labile carbon in fresh biochars led to microbes thriving and resulted in an accelerated shortterm nitrogen (N) turnover, i.e., at an early stage of incubation, fresh biochar increased mineralization of soil organic N by 79 mg·kg −1 to 449 mg·kg −1 . However, a reduction of soil available N contents induced by microbial immobilization effect was observed at the end of incubation. The authors concluded that aged biochar was suitable for simultaneous soil amendment with urea rather than newly produced biochar. This is because aged biochar can avoid high soil available N accumulation; thus it can decrease the risk of inorganic N leaching loss.

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Extraction and Colorimetric Determination of Urea in Soils

Cited by 254 publications

References 0 publications

Efficiency of fall-banded urea for spring wheat production in Manitoba: Influence of application date, landscape position and fertilizer additives

Efficiency of fall-banded urea for spring wheat production in Manitoba: Influence of application date, landscape position and fertilizer additives

EFFECT OF Nosema locustae Canning (Microsporida) AND THREE CHEMICAL INSECTICIDES ON MICROBIAL ACTIVITY IN SOIL

Maize Stover Biochar Accelerated Urea Hydrolysis and Short-term Nitrogen Turnover in Soil

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