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.

scholarly journals Field Proximal Soil Sensor Fusion for Improving High-Resolution Soil Property Maps

Soil Systems ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 52
Author(s):  
Gustavo M. Vasques ◽  
Hugo M. Rodrigues ◽  
Maurício R. Coelho ◽  
Jesus F. M. Baca ◽  
Ricardo O. Dart ◽  
...  
Keyword(s):  
Soil Properties ◽  
Ordinary Kriging ◽  
Soil Property ◽  
Clay Content ◽  
Exchange Capacity ◽  
Organic C ◽  
Covariate Data ◽  
Independent Validation ◽  
Soil Sensors ◽  
Dense Grid

Mapping soil properties, using geostatistical methods in support of precision agriculture and related activities, requires a large number of samples. To reduce soil sampling and measurement time and cost, a combination of field proximal soil sensors was used to predict and map laboratory-measured soil properties in a 3.4-ha pasture field in southeastern Brazil. Sensor soil properties were measured in situ on a 10 × 10-m dense grid (377 samples) using apparent electrical conductivity meters, apparent magnetic susceptibility meter, gamma-ray spectrometer, water content reflectometer, cone penetrometer, and portable X-ray fluorescence spectrometer (pXRF). Soil samples were collected on a 20 × 20-m thin grid (105 samples) and analyzed in the laboratory for organic C, sum of bases, cation exchange capacity, clay content, soil volumetric moisture, and bulk density. Another 25 samples collected throughout the area were also analyzed for the same soil properties and used for independent validation of models and maps. To test whether the combination of sensors enhances soil property predictions, stepwise multiple linear regression (MLR) models of the laboratory soil properties were derived using individual sensor covariate data versus combined sensor data—except for the pXRF data, which were evaluated separately. Then, to test whether a denser grid sample boosted by sensor-based soil property predictions enhances soil property maps, ordinary kriging of the laboratory-measured soil properties from the thin grid was compared to ordinary kriging of the sensor-based predictions from the dense grid, and ordinary cokriging of the laboratory properties aided by sensor covariate data. The combination of multiple soil sensors improved the MLR predictions for all soil properties relative to single sensors. The pXRF data produced the best MLR predictions for organic C content, clay content, and bulk density, standing out as the best single sensor for soil property prediction, whereas the other sensors combined outperformed the pXRF sensor for the sum of bases, cation exchange capacity, and soil volumetric moisture, based on independent validation. Ordinary kriging of sensor-based predictions outperformed the other interpolation approaches for all soil properties, except organic C content, based on validation results. Thus, combining soil sensors, and using sensor-based soil property predictions to increase the sample size and spatial coverage, leads to more detailed and accurate soil property maps.

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

Structural vulnerability of New Zealand soils

Soil Research ◽  
1997 ◽  
Vol 35 (3) ◽  
pp. 461 ◽  
Author(s):  
A. E. Hewitt ◽  
T. G. Shepherd
Keyword(s):  
New Zealand ◽  
Management Practices ◽  
Clay Content ◽  
Vulnerability Index ◽  
Organic Carbon Content ◽  
Structural Vulnerability ◽  
Phosphate Retention ◽  
Mineral Soils ◽  
Physical Degradation ◽  
The Impact

Some New Zealand soils withstand intensive cultivation and support continuing high production and yet maintain essential soil physical qualities of infiltration, aggregation, and aeration. In other soils, essential soil qualities deteriorate rapidly under the impact of even moderately intensive management practices. Our objective was to estimate the inherent susceptibility of New Zealand soils to physical degradation by focusing on structural vulnerability. We took a deductive approach by reviewing the available information on the structural stability and physical degradation of New Zealand soils. We identified 4 soil attributes that are well represented in the national soils database and are most likely to control structural vulnerability: (i) stabilising short-range-order oxy-hydroxides of aluminium and iron as estimated by phosphate retention, (ii) total organic carbon content, (iii) clay content, and (iv) wetness. The 4 attributes were standardised and transformed and a simple structural vulnerability index (SV) was devised. We determined SV for all mineral soils in the national soils database. The results provide a ranking of soil groups according to their structural vulnerability. We concluded that the index may be used as a first approximation rating of the structural vulnerability of New Zealand soils to aid resource management.

scholarly journals Characteristics of Soils Developing from Gabbro, Phyllite and Chert Parent Rock in Karangsambung District

2019 ◽  
Vol 4 (3) ◽  
pp. 131
Author(s):  
Ratna Taher ◽  
Makruf Nurudin ◽  
Eko Hanudin
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Particle Density ◽  
Chemical Properties ◽  
Clay Content ◽  
Exchange Capacity ◽  
Parent Rock ◽  
Soil Morphology ◽  
Total N ◽  
Organic C

Understanding the nature of the soil is very important to know the potential and the proper management of the soil. This study aimed to determine the differences in morphological, physical, and chemical properties of the soils developing from gabbro, phylitte and chert parent materials. The soil profile was made to represent each parent rock of gabbro, phyllite and chert located on the upper and middle slopes with pine-dominated vegetation and mixed gardens. Observation in the field is a professional description to observe soil morphology. Soil samples were taken at each horizon to analyze soil physical properties (bulk density, particle density, and texture), soil chemical properties (pH, exchanged cations, cation exchange capacity, available P, organic C, and total N). Texture analysis results showed that clay content of the soil developing from parent rock of Gabro 1 is the highest, followed by the soil clay content from  Chert 1, Phyllite 1, Chert 2, Phyllite 2, and Gabbro 2, respectively. The order of soil acidity level (pH) is Gabbro 2 > Gabbro 1> Chert 1 ~ Chert 2 > Phyllite 1 ~ Phyllite 2. Meanwhile, the order of the cation exchange capacity is Gabbro 1> Gabbro 2> Phyllite 1> Chert 1> Phyllite 2> Chert 2, and the order of the base saturation is Chert 2> Gabbro 2> Chert 1> Phyllite 2 > Phyllite1> Gabbro 1.

Fertiliser contaminants in New Zealand grazed pasture with special reference to cadmium and fluorine — a review

Soil Research ◽  
2003 ◽  
Vol 41 (3) ◽  
pp. 501 ◽  
Author(s):  
P. Loganathan ◽  
M. J. Hedley ◽  
N. D. Grace ◽  
J. Lee ◽  
S. J. Cronin ◽  
...  
Keyword(s):  
New Zealand ◽  
Future Research ◽  
Soil Ingestion ◽  
Cd Accumulation ◽  
Grazed Pasture ◽  
Economic Production ◽  
Liver And Kidney ◽  
Potential Risks ◽  
Fertiliser Use ◽  
The Impact

Phosphorus (P) fertilisers are an essential input for the economic production of legume-based pastures in New Zealand (NZ) and Australia, but they often contain some unwanted elements that can contaminate the soil, thereby creating potential risks to the health of grazing animal, food quality, and soil quality. Fluorine (F) and cadmium (Cd) are considered to be the elements of most concern. Incidences of F toxicity (from direct ingestion of fertiliser), and accumulation of Cd in offal products above the maximum permissible concentration (MPC) set by the food authorities, have been reported in NZ. Similarly, Cd concentrations in some food grains may exceed the newly proposed MPCs by the Australian and New Zealand Food Authority. Cadmium and F continue to accumulate in the topsoils of NZ and Australian pastures as a result of P fertiliser use. The mobility of both these elements in soils is low and is similar to that of P. Risk of ground water contamination from F and Cd applied to most NZ pastures is low. The plant uptake of these elements, especially F, is also low in most pastoral soils. Cadmium accumulates mainly in liver and kidney of grazing animals mostly through herbage ingestion, whereas F accumulates mainly in the bones of these animals, mostly through soil ingestion. Soil ingestion is highest during the wetter winter months and at high stocking rates. Models have been developed to assess the impact of fertiliser use on the potential risks associated with F and Cd accumulation in soils. Measures to control F and Cd accumulation in soils, plants, and grazing animals are presented and future research needs are identified.

scholarly journals Soil urease inhibition by various plant extracts

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0258568
Author(s):  
Muhammad Ajmal Rana ◽  
Rashid Mahmood ◽  
Sajid Ali
Keyword(s):  
Plant Extracts ◽  
Urease Activity ◽  
Urea Hydrolysis ◽  
Melia Azedarach ◽  
Base Line ◽  
Urease Inhibition ◽  
Jack Bean Urease ◽  
Plant Materials ◽  
Jack Bean ◽  
Soil Urease

Urea is the most popular and widely used nitrogenous fertilizer. High soil urease activity rapidly hydrolyses applied urea to ammonia which contributes to soil nitrogen (N) losses and reduces N use efficiency of crop plants. The ammonia losses can be minimized by the inhibition of soil urease activity which has been explored using various potential chemical inhibitors. However, the soil urease activity inhibition potential of plant extracts is rarely explored to date. In the present study, extracts of 35 plant materials were taken and evaluated against jack bean urease. Eleven extracts, showing >50% jack bean urease inhibition, were selected and further investigated in 13 soils collected from various districts of Punjab, Pakistan. Interestingly, except Capsicum annum, Melia azedarach, Citrus reticulata and Quercus infectoria, the plant extracts showed urease inhibition activities in soils, the extent of which was lower as compared to that observed in jack bean urease though. Maximum urea hydrolysis inhibition (70%) was noted with Vachellia nilotica which was 40% more than that of hydroquinone (50%) followed by that of Eucalyptus camaldulensis (24%). The extracts of V. nilotica and E. camaldulensis were coated on urea and applied to soil in the next step. At 21st day, 239% and 116% more urea-N was recovered from soil treated with V. nilotica and E. camaldulensis extracts coated urea, respectively, as compared to uncoated urea. Conclusively, these results indicated that the coating of V. nilotica and E. camaldulensis extracts on urea prills prolonged urea persistence in soil owing to minimum urea hydrolysis, probably, the extracts of V. nilotica and E. camaldulensis showed their urease inhibition potential. The results of this study provide a base line for the identification of new soil urease inhibitor compounds from plant materials in future.

scholarly journals Mapping soil slaking index and assessing the impact of management in a mixed agricultural landscape

SOIL ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 33-46
Author(s):  
Edward J. Jones ◽  
Patrick Filippi ◽  
Rémi Wittig ◽  
Mario Fajardo ◽  
Vanessa Pino ◽  
...  
Keyword(s):  
Management Practices ◽  
Agricultural Landscape ◽  
Aggregate Stability ◽  
Clay Content ◽  
Smartphone Application ◽  
Soil Aggregate ◽  
Relative Increase ◽  
Exchange Capacity ◽  
Soil Aggregate Stability ◽  
The Impact

Abstract. Soil aggregate stability is a useful indicator of soil physical health and can be used to monitor condition through time. A novel method of quantifying soil aggregate stability, based on the relative increase in the footprint area of aggregates as they disintegrate when immersed in water, has been developed and can be performed using a smartphone application – SLAKES. In this study the SLAKES application was used to obtain slaking index (SI) values of topsoil samples (0 to 10 cm) at 158 sites to assess aggregate stability in a mixed agricultural landscape. A large range in SI values of 0 to 7.3 was observed. Soil properties and land use were found to be correlated with observed SI values. Soils with clay content >25 % and cation exchange capacity (CEC) : clay ratio >0.5 had the highest observed SI values. Variation in SI for these soils was driven by organic carbon (OC) content which fit a segmented exponential decay function. An OC threshold of 1.1 % was observed, below which the most extreme SI values were observed. Soils under dryland and irrigated cropping had lower OC content and higher observed SI values compared to soils under perennial cover. These results suggest that farm managers can mitigate the effects of extreme slaking by implementing management practices to increase OC content, such as minimum tillage or cover cropping. A regression-kriging method utilising a Cubist model with a suite of spatial covariates was used to map SI across the study area. Accurate predictions were produced with leave-one-out cross-validation, giving a Lin's concordance correlation coefficient (LCCC) of 0.85 and a root-mean-square error (RMSE) of 1.1. Similar validation metrics were observed in an independent test set of samples consisting of 50 observations (LCCC = 0.82; RMSE = 1.1). The potential impact of implementing management practices that promote soil OC sequestration on SI values in the study area was explored by simulating how a 0.5 and 1.0 % increase in OC would impact SI values at observation points and then mapping this across the study area. Overall, the maps produced in this study have the potential to guide management decisions by identifying areas that currently experience extreme slaking and highlighting areas that are expected to have a significant reduction in slaking by increasing OC content.

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.

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