Effect of soil type, exchangeable sodium percentage, water content, and organic amendments on urea hydrolysis in some tropical Indian soils

Wali, Pardeep; Kumar, Vinod; Singh, Jagdeep

doi:10.1071/sr01090

Cited by 20 publications

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“…These results may be due to a higher degree of urea hydrolysis at field capacity. Similar results were reported by Savant et al, (1985), Singh andSingh (1996), andWali et al, (2003) in which the rate of urea hydrolysis was determined to be higher at field capacity as compared to saturated conditions because regulated oxygen diffusion under field capacity conditions maximizes the urease activity in the soil.…”

Section: Resultssupporting

confidence: 89%

“…Leaching experiments in soil columns have demonstrated that urea moves through soil with irrigation water depending on the rate of water application (Antil et al, 1992). It has been found that the rate of urea hydrolysis was slow in saturated soils as compared to field capacity (Wali et al, 2003) and occurred at a higher rate at 40% versus 60% water-holding capacity (Sankhayan and Shukla, 1976). Information on the influence of crop residue additions and organic manures on urea hydrolysis in relation to applied water is limited.…”

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confidence: 97%

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Influence of Crop Residues and Organic Manures on the Hydrolysis of Urea in a Typic Haplustept

Mavi

Singh

2007

Arid Land Research and Management

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The emphasis on integrated use of organic amendments and fertilizers has made it imperative to study the effect of crop residues and organic manures on urea hydrolysis, which governs the release of N from urea fertilizer. Urea hydrolysis in soils is an enzymatic decomposition process facilitated by the extracellular enzyme urease. Our aim was to assess the influence of crop residues (rice straw, wheat straw) and organic manures (poultry manure, farm yard manure, cowpea, and sesbania) on urea hydrolysis by conducting a laboratory incubation experiment employing a Hasanpur silt loam soil (coarse loamy, mixed, hypothermic Typic Haplustept). The study was conducted at a constant temperature of 33 AE 1 C at two moisture levels (1:1 soil:water ratio and field capacity). The results showed that the rate of urea hydrolysis decreased with an increase in time of incubation (12 to 96 h), while the disappearance of urea N was associated with the corresponding increase in (NH 4 þ þ NO 3 À )-N content in soils treated with crop residues and organic manures. In the nonamended soil, the time required for the complete hydrolysis of the applied urea (200 mg urea N g À1 soil) was more than 96 h at both the moisture levels, whereas in amended soils, 60 to 72 h of incubation periods were required for urea hydrolysis. The rate of urea hydrolysis in the amended soil was of the following order: sesbania > cowpea > poultry manure > farmyard manure > rice straw and wheat straw, irrespective of the moisture regime. Urea hydrolysis followed first-order kinetics in all the treatments at both moisture levels. The rate constant value for urease activity was higher at field capacity, indicating that urea hydrolysis proceeded rapidly under the condition of field capacity rather than saturated conditions (1:1 soil:water ratio).

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Section: Resultssupporting

confidence: 89%

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confidence: 97%

Influence of Crop Residues and Organic Manures on the Hydrolysis of Urea in a Typic Haplustept

Mavi

Singh

2007

Arid Land Research and Management

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“…The hydrolysis of urea followed first order kinetics upto the first 24 h (see Figure 1). Kumar and Wagenet (1984) and Wali et al (2003) found that rate of urea hydrolysis in different soils followed first order kinetics and values of first order rate constant varied from 0.032 in Balsamand sand to 0.118 h 71 in Gulkani clay loam.…”

Section: Resultsmentioning

confidence: 98%

Effect of different factors on hydrolysis and nitrification of urea in soils

Kumar

Singh

2007

Archives of Agronomy and Soil Science

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We studied the effect of soil type, water content, salinity and sodicity on hydrolysis and nitrification of urea in laboratory at constant temperature (288C + 18C). Hydrolysis and nitrification of urea were studied separately in two experiments using six soils maintained at 70.03 MPa water content after addition of 150 mg urea-N kg 71 soil. In the second set of experiments, the urea hydrolysis and nitrification were studied in normal, saline (6 dS m 71 ) and sodic (30 ESP) soils each maintained at water matric potential of 70.03, 70.5 and 71.5 MPa. The nitrogen was applied at the rate of 150 mg N kg 71 soil in both the experiments. Soil and urea-N mixtures were incubated for 48 h for urea hydrolysis and up to 60 days for nitrification. The rate of urea hydrolysis in different soils followed the order: Uchani silty clay loam 4 Kaithal clay loam 4 Hisar loam 4 Kurukshetra clay loam 4 Sonepat loamy sand 4 Bawal loamy sand. The values of first-order rate constant (k) varied from 0.039 -0.069 h 71 . The rate of urea hydrolysis slowed down with the decrease in water content from 70.03 MPa to 71.5 MPa. The amount of urea hydrolyzed was higher in normal as compared to saline or sodic soil. At 71.5 MPa water content, 31.9 -37.6% of the added urea remained unhydrolyzed at 48 h in sodic and saline soils, respectively. The content of NO 3 À ÀN formation differed markedly among texturally different soils being highest in Kurukshetra clay loam and lowest in Bawal loamy sand. The NO 2 À ÀN appeared during 5 -30 d and most of the NO 2 À ÀN was detected between 10 and 20 d in different soils. Decreasing the water content from 70.03 to 71.5 MPa decreased the NO 3 À ÀN in normal, saline and sodic soils.

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“…Urea is readily hydrolyzed to ammonium carbonate by the enzyme urease. The rate of hydrolysis to ammonium and loss from volatilization in the form of ammonia depends on the timing of application, weather, soil temperature and pH and other factors (Khakural and Alva 1995;Wali et al 2003). These losses may exceed 20%, even 40% depending on pH ( Figure 2).…”

Section: Natural and Anthropogenic Enrichment Of Urea In Coastal Watersmentioning

confidence: 96%

Escalating Worldwide use of Urea – A Global Change Contributing to Coastal Eutrophication

et al. 2006

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While the global increase in the use of nitrogen-based fertilizers has been well recognized, another change in fertilizer usage has simultaneously occurred: a shift toward urea-based products. Worldwide use of urea has increased more than 100-fold in the past 4 decades and now constitutes >50% of global nitrogenous fertilizer usage. Global urea usage extends beyond agricultural applications; urea is also used extensively in animal feeds and in manufacturing processes. This change has occurred to satisfy the world's need for food and more efficient agriculture. Long thought to be retained in soils, new data are suggestive of significant overland transport of urea to sensitive coastal waters. Urea concentrations in coastal and estuarine waters can be substantially elevated and can represent a large fraction of the total dissolved organic nitrogen pool. Urea is used as a nitrogen substrate by many coastal phytoplankton and is increasingly found to be important in the nitrogenous nutrition of some harmful algal bloom (HAB) species. The global increase from 1970 to 2000 in documented incidences of paralytic shellfish poisoning, caused by several HAB species, is similar to the global increase in urea use over the same 3 decades. The trend toward global urea use is expected to continue, with the potential for increasing pollution of sensitive coastal waters around the world.

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Effect of soil type, exchangeable sodium percentage, water content, and organic amendments on urea hydrolysis in some tropical Indian soils

Cited by 20 publications

References 0 publications

Influence of Crop Residues and Organic Manures on the Hydrolysis of Urea in a Typic Haplustept

Influence of Crop Residues and Organic Manures on the Hydrolysis of Urea in a Typic Haplustept

Effect of different factors on hydrolysis and nitrification of urea in soils

Escalating Worldwide use of Urea – A Global Change Contributing to Coastal Eutrophication

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