Distribution, salinity, kinetic and thermodynamic characteristics of urease activity in a vertisol profile

Soil Research ◽  
1985 ◽  
Vol 23 (1) ◽  
pp. 49 ◽  
Author(s):  
RC Dalal
Keyword(s):  
Urease Activity ◽  
Elevated Temperatures ◽  
Thermodynamic Characteristics ◽  
Organic Substrate ◽  
Natural Soil ◽  
Organic C ◽  
Glucose Addition ◽  
Top Soil ◽  
Soil Urease ◽  
Different Depths

The distribution, and the effects of temperature, moisture and organic C substrate on urease activity of a vertisol up to 120 cm depths were studied. The kinetic and thermodynamic characteristics of urease activity in the soil were also studied. Urease activity (measured at the natural soil pH) was found to be higher in soil at 20-60 cm than in the top soil (0-10 cm). It remained relatively constant for up to 900 days, when the soil was kept either field moist at 4�C or air-dried at 25�C. However, partial drying of the soil or rewetting of air-dried soil, especially at elevated temperatures (40�C), and glucose addition, affected substantially but differentially the urease activity of soil obtained from different depths. The distribution in soil urease activity assayed at an optimum pH (using tris-HCl buffer, pH 9.0) became relatively uniform at all depths. From the effect of different buffer pH's on soil urease and from kinetic and thermodynamic characteristics, it is suggested that lower urease activity in the top soil was primarily a consequence of suboptimal pH, resulting in greater configurational or steric hindrance in formation and/or breakdown of urea-urease complex in the soil. Differences in seasonal variation in temperature, moisture, organic substrate and microbial activity may also affect distribution and stability of urease at different depths.

Why copper and zinc are ineffective in reducing soil urease activity in New Zealand dairy-grazed pasture soils

Soil Research ◽  
2018 ◽  
Vol 56 (5) ◽  
pp. 491 ◽  
Author(s):  
Kamal P. Adhikari ◽  
Surinder Saggar ◽  
James A. Hanly ◽  
Danilo F. Guinto ◽  
Matthew D. Taylor
Keyword(s):  
New Zealand ◽  
Urease Activity ◽  
Clay Content ◽  
Exchange Capacity ◽  
Urea Hydrolysis ◽  
Organic C ◽  
Grazed Pasture ◽  
Soil Urease ◽  
The Impact ◽  
Cu And Zn

Micronutrients copper (Cu) and zinc (Zn) have the potential to inhibit soil urease activity (UA) and reduce ammonia (NH3) emissions over long duration (8–12 weeks) but have not been tested for reducing NH3 losses from cattle urine deposited in dairy-grazed pasture soils. The objective of this study was to assess the effectiveness and longevity of Cu and Zn in reducing soil UA, for the use of these metals to reduce NH3 emissions from deposited urine by grazing cattle. A series of experiments were conducted to (i) assess the relationship between inherent Cu and Zn status and soil UA of New Zealand dairy-grazed pasture soils, (ii) determine the impact of Cu and Zn addition to pasture soils on soil UA and (iii) investigate how soil organic carbon (C) and other C-related textural and mineralogical properties such as clay content and cation exchange capacity influence the effectiveness of added Cu and Zn in reducing urea hydrolysis. The results showed significant positive correlations of soil total C and total nitrogen (N) with soil UA. However, there were no significant negative correlations of soil UA with inherent Cu and Zn levels. Similarly, addition of Cu and Zn to soil did not significantly reduce soil UA. However, when Cu was added to two different soil supernatants there was a significant reduction in hydrolysis of urea applied at 120 and 600 mg urea-N kg–1 soil. Additions of Zn achieved negligible or small reductions in urea hydrolysis after 120 and 600 mg urea-N kg–1 soil applications to soil supernatants. This result suggests that Cu can inhibit soil UA and urea hydrolysis in soil supernatants with potentially low C, clay and cation exchangeable base contents. However, the interaction of bioavailable Cu with labile soil organic C and clay particles leads to its inactivation, resulting in ineffectiveness in organic C-rich pasture soils. Although most of the added Zn did not complex and remained bioavailable, the observed levels of bioavailable Zn had limited effect on soil UA.

Microbial and biochemical changes induced by rotation and tillage in a soil under barley production

1993 ◽  
Vol 73 (1) ◽  
pp. 39-50 ◽  
Author(s):  
D. A. Angers ◽  
N. Bissonnette ◽  
A. Légère ◽  
N. Samson
Keyword(s):  
Alkaline Phosphatase ◽  
Organic Matter ◽  
Microbial Biomass ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Soil Layer ◽  
Red Clover ◽  
Organic C ◽  
Top Soil ◽  
Total Organic C

Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase

Inhibition of soil urease activity and nitrification with some metallic cations

Soil Research ◽  
1986 ◽  
Vol 24 (4) ◽  
pp. 527 ◽  
Author(s):  
DS Yadav ◽  
V Kumar ◽  
M Singh
Keyword(s):  
Urease Activity ◽  
Nitrification Rate ◽  
Clay Loam ◽  
Inhibitory Effects ◽  
Soil Urease ◽  
Metallic Cations

Investigations to study the effects of 14 metallic cations on urease activity and nitrification rate in Hansi clay loam (Typic Ustochrepts) were undertaken at Haryana Agricultural University, Hissar, Haryana (India). The metallic cations inhibited soil urease activity, and the order of effectiveness varied when compared at 100, 500 and 1000 ppm. Increasing levels of metallic cations adversely affected the urease activity. Inhibitory effects of metallic cations at 1000 pprn decreased in order: Ag+ = Hg2+ > Cu2+ >Cd2+ > Co2+ >Ba2+ > Zn2+ > Ni2+ > Fe2+ > Cr3+ > Mn2+ > Sr2+ > Pb2+ > Al3+. Effects of Cr3+, Cu2+ and Hg2+ on nitrification were also tested. Above 80% of added N was nitrified at 21 days in the control (urea alone) and 100 ppm Cr3+ treatments, whereas addition of 500 and 1000 pprn cr2+ and 100, 500 and 1000 pprn Cu2+ delayed nitrification. A considerable amount of NH+4- remained unchanged in Hg2+ -treated soils after 28 days of incubation; these soils also contained more residual NO-2 than other treatments.

EFFECTS OF CATECHOL AND P-BENZOQUINONE ON THE HYDROLYSIS OF UREA AND ENERGY BARRIERS OF UREASE ACTIVITY IN SOILS

1984 ◽  
Vol 64 (1) ◽  
pp. 51-60 ◽  
Author(s):  
J. S. TOMAR ◽  
A. F. MacKENZIE
Keyword(s):  
Activation Energy ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Key Words ◽  
Urease Activity ◽  
Urea Hydrolysis ◽  
Urease Inhibitors ◽  
Soil Urease ◽  
Hydrolysis Of ◽  
Hydrolysis Of Urea

The effects of the urease inhibitors, catechol and p-benzoquinone, and temperature on the hydrolysis of urea in five soils were investigated in a laboratory study. Urea hydrolysis decreased significantly with the amount of inhibitors applied and increased significantly with each 5 °C increase in temperature from 5 to 25 °C. The effectiveness of inhibitors generally decreased with increases in temperature from 5 to 25 °C. The correlation of hydrolysis of urea with organic matter contents of the soils was highly significant (r = 0.67** to 0.86**). Both catechol and p-benzoquinone tended to increase the energies and entropies of activation of soil urease and the effect was enhanced with a decrease in soil organic matter. It is suggested that an increase in the activation energy of the soil urease as a result of inhibitor use was related to an increase in the effectiveness of the inhibitor. Key words: Urease inhibitors, urea hydrolysis, energy of activation

Relationships Between Soil Urease Activity and Other Soil Properties

1977 ◽  
Vol 41 (2) ◽  
pp. 350-352 ◽  
Author(s):  
M. I. Zantua ◽  
L. C. Dumenil ◽  
J. M. Bremner
Keyword(s):  
Soil Properties ◽  
Urease Activity ◽  
Soil Urease

Effect of Heavy Metals Cu, Cd, Pb and Zn on Enzyme Activity and Microbial Biomass Carbon in Brown Soil

2014 ◽  
Vol 1073-1076 ◽  
pp. 726-730 ◽  
Author(s):  
Lei Yu ◽  
Jie Min Cheng
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Enzyme Activity ◽  
Microbial Biomass ◽  
Catalase Activity ◽  
Urease Activity ◽  
Microbial Biomass Carbon ◽  
Biomass Carbon ◽  
Brown Soil ◽  
Soil Urease

To get more sensitive index for making scientific and objective judgment on heavy metal pollution in brown soil, the influence which heavy metals Cu, Cd, Pb and Zn exert on soil urease, catalase activity and microbial biomass carbon content were evaluated by means of laboratory simulation.Experiment results showed that urease activity firstly increased with the addition of Cu, Cd and Pb, then showed decline trends. But for Zn, the activity of urease was obviously decline with the increased Zn concentrations. Catalase activity firstly increased with the addition of Cu then showed decline trend. But for Cd, Pb and Zn, the activity of catalase obviously declined. Microbial biological carbon all showed decline trends with the addition of Cu, Cd, Pb and Zn.

Effect of methyl iodide fumigation on soil urease activity

2009 ◽  
Vol 17 (3) ◽  
pp. 616-618
Author(s):  
Yun ZHAO ◽  
Qiu-Xia WANG ◽  
Mei-Xia GUO ◽  
Zhao-Xin SONG ◽  
Ao-Cheng CAO
Keyword(s):  
Methyl Iodide ◽  
Urease Activity ◽  
Soil Urease
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