CN Values Research Articles

Land-use changes in the periurban interface: Hydrologic consequences on a flatland-watershed scale

The aim of this work was to analyze the hydrologic effects on surface runoff and infiltration of changes in land use and land coverage. The periurban-flatland watershed of El Pescado Creek (Argentina) was the study site investigated. We used Geographic-Information-System techniques together with the curve-number method (CN) to estimate the surface runoff in five land-use scenarios having increasing levels of anthropic impact (years 1986, 1996, 2006, 2016, and 2026) considering two rainfalls and the antecedent-runoff conditions (ARC) defined by that methodology. We identified three hydrologic-soil Groups (B, C, and D) and five land uses (grassland, forest, urbanization, greenhouses, and poultry farms). Land use and land coverage change process increased CN values, and consequently the estimated surface runoff, especially in the upper watershed. Changes towards impervious (687 ha with greenhouses and poultry farms) or semi-impervious land coverage (800 ha with urbanizations) affected infiltration. The most contrasting results were related to the ARC I, II, and III weighted-average infiltration of the watershed that diminished from above 93.0%, down to 88.5% and finally to 50.4%, respectively (calculated with data from the 55.8-mm rainfall), and from 86.6%, to 58.3%, and to finally 28.8% (calculated with data from the 117.8 mm rainfall). Simulating a near-future land-use scenario (year 2026) enabled us to estimate the watershed pattern by adding new area containing semi-impervious and impervious land coverage. The estimated weighted-average infiltrations (ARC II) were 81.3% and 54.9%, for the above 55.8-mm and 117.8-mm rainfalls, respectively. Changes concerning infiltration might be disturbing the natural recharging process of aquifers, carrying out modifications in the hydrodynamics of the watershed, and also affecting water supply for human activities in the territory.

Socioeconomic - related inequalities in overweight and obesity: findings from the PERSIAN cohort study

BackgroundOverweight and obesity are major health concerns worldwide, with adverse health consequences during the life span. This study measured socioeconomic inequality in overweight and obesity among Iranian adults.MethodsData were extracted from 129,257 Iranian adults (aged 35 years and older) participated in the Prospective Epidemiologic Research Studies in IrAN (PERSIAN) in 14 provinces of Iran in 2014. Socioeconomic-related inequality in overweight and obesity was estimated using the Concentration Index (Cn). The Cn further decomposed to find factors explaining the variability within the Socioeconomic related inequality in overweight and obesity.ResultsOf the total number of participants, 1.98, 26.82, 40.76 and 30.43% had underweight, normal weight, overweight and obesity respectively. The age-and sex standardized prevalence of obesity was higher in females than males (39.85% vs 18.79%). People with high socioeconomic status (SES) had a 39 and 15% higher chance of being overweight and obese than low SES people, respectively. The positive value of Cn suggested a higher concentration of overweight (0.081, 95% confidence interval [CI]; 0.074–0.087) and obesity (0.027, 95% CI; 0.021–0.034) among groups with high SES. There was a wide variation in socioeconomic-related inequality in overweight and obesity rate across 14 provinces. The decomposition results suggested that SES factor itself explained 66.77 and 89.07% of the observed socioeconomic inequalities in overweight and obesity among Iranian adults respectively. Following SES, province of residence, physical activity, using hookah and smoking were the major contributors to the concentration of overweight and obesity among the rich.ConclusionsOverall, we found that overweight and obesity is concentrated among high SES people in the study population. . Accordingly, it seems that intersectional actions should be taken to control and prevent overweight and obesity among higher socioeconomic groups.

Statistical analysis of NRCS curve number (NRCS-CN) in arid basins based on historical data

CN method is a commonly used technique for estimation of direct runoff for flood mitigation studies. In Saudi Arabian (SA) arid basins, there is no analysis of NRCS-CN obtained from measured rainfall-runoff events. The research objectives are to find out the actual range of CN values in arid basins, the statistical distribution of CN, the confidence intervals of CNs, and the relation between the CN and initial abstraction factor, λ. Five basins with 19 sub-basins located in the southwest of Saudi Arabia were considered, and 161 rainfall-runoff events were analyzed during the period 1984–1987. The least squares method was used to obtain the optimum range of values for λ and CN based on three estimation methods. The rainfall and runoff exhibited log-normal distribution. The analysis showed that CN varied between 45 and 85 at λ = 0.2. The low CN values account for the transmission losses which is a typical phenomenon in arid regions. The initial abstraction ratio λ = 0.01 is found to be more representative to arid basins rather than λ = 0.2. The Beta distribution is the best to fit CN at both λ = 0.2 and 0.01. The confidence intervals are estimated and tabulated at different significant levels for flood risk assessment studies in arid basins.

Estimation of surface runoff using NRCS curve number in some areas in northwest coast, Egypt

The sustainable agricultural development in the northwest coast of Egypt suffers constantly from the effects of surface runoff. Moreover, there is an urgent need by decision makers to know the effects of runoff. So the aim of this work is to integrate remote sensing and field data and the natural resource conservation service curve number model (NRCS-CN).using geographic information systems (GIS) for spatial evaluation of surface runoff .CN approach to assessment the effect of patio-temporal variations of different soil types as well as potential climate change impact on surface runoff. DEM was used to describe the effects of slope variables on water retention and surface runoff volumes. In addition the results reflects that the magnitude of surface runoff is associated with CN values using NRCS-CN model . The average of water retention ranging between 2.5 to 3.9m the results illustrated that the highest value of runoff is distinguished around the urban area and its surrounding where it ranged between 138 - 199 mm. The results show an increase in the amount of surface runoff to 199 mm when rainfall increases 200 mm / year. The north of the area may be exposed to erosion hazards more than the south and a change in the soil quality may occur in addition to the environmental imbalance in the region.

Negative Selective Pressure Exerted By Maintenance Therapy Promotes the Extinction of Sub-Clones Carrying High-Risk Lesions in Multiple Myeloma

Negative Selective Pressure Exerted By Maintenance Therapy Promotes the Extinction of Sub-Clones Carrying High-Risk Lesions in Multiple Myeloma

Feasible Ranges of Runoff Curve Numbers for Korean Watersheds Based on the Interior Point Optimization Algorithm

Rainfall runoff is a complex phenomenon in nature. It differs from place to place due to different topographical features and rainfall patterns. The Natural Resources Conservation Service - Curve Number (NRCS-CN) is a well-adopted model to account for direct runoff volume from storm events. There are several studies on determining the initial abstraction and the CN from observed rainfall-runoff data; however, few studies demonstrate their statistical characteristics. The major aim of this study is to determine the feasible range and the confidence intervals of the CN. We examined 660 rainfall-runoff events collected from six medium sized watersheds in South Korea. The interior point optimization algorithm was adopted to ascertain the optimum value of CN and the initial abstraction coefficient (λ). The obtained results show that the CN value ranged from 45 to 90 and the average λ = 0.12 was best suited for Korean watersheds. The estimated confidence intervals were highly significant and strongly recommended for Korean watersheds.

Runoff Estimation of Watershed in Hemavathy Basin using GIS based SCS-CN Method

Estimation and quantification of catchment surface runoff an important hydrologic variable used in most of the water resources applications watershed development and management problems. In this study, rainfall-runoff relationship of Hemavathy river basin is determined using Soil Conservation Services-Curve Number (SCS-CN) method for runoff estimation for ungauged watersheds. The important parameters considered include land use/land cover, soil, vegetation, drainage, precipitation, contour, slope, daily rainfall data. From the 11year daily rainfall data daily runoff was estimated using SCS CN equation considering antecedent moisture conditions. Daily runoff depth in the watershed was then computed using SCS-CN equation was later converted to runoff volume. It was observed in runoff potential of the watershed about 41% of area having high CN value interprets in more runoff. The runoff thus calculated was compared with gauged flow at dam site observed that regression coefficient is almost same for both estimated and observed data and an increase of about 15% in inflow data as per project authorities in the catchment which may be due to regenerated water from irrigation and presences of perennial streams in the catchment even during non-monsoon months there is inflow observed.

Assessment of the Impacts of Land Use/Cover Change and Rainfall Change on Surface Runoff in China

Assessment of the impacts of land use/cover change (LUCC) and rainfall change on surface runoff depth can help provide an understanding of the temporal trend of variation of surface runoff and assist in urban construction planning. This study evaluated the impacts of LUCC and rainfall change on surface runoff depth by adopting the well-known Soil Conservation Service-Curve Number (SCS-CN) method and the widely used Long-Term Hydrologic Impact Assessment (L-THIA) model. National hydrologic soil group map of China was generated based on a conversion from soil texture classification system. The CN values were adjusted based on the land use/cover types and soil properties in China. The L-THIA model was configured by using the adjusted CN values and then applied nationally in China. Results show that nationwide rainfall changes and LUCC from 2005 to 2010 had little impact on the distribution of surface runoff, and the high values of runoff depth were mainly located in the middle and lower reaches of the Yangtze River. Nationally, the average annual runoff depths in 2005, 2010 and 2015 were 78 mm, 83 mm and 90 mm, respectively. For the 2015 land use data, rainfall change caused the variation of surface runoff depth ranging from −203 mm to 476 mm in different regions. LUCC from 2005 to 2015 did not cause obvious change of surface runoff depth, but expansion of developed land led to runoff depth increases ranging from 0 mm to 570 mm and 0 mm to 742 mm from 2005 to 2010 and 2010 to 2015, respectively. Potential solutions to urban land use change and surface runoff control were also analyzed.

Improvement in biomass, lipid production and biodiesel properties of a euryhaline Chlorella vulgaris NIOCCV on mixotrophic cultivation in wastewater from a fish processing plant

In this study, the changes in biomass productivity, wastewater treatment, lipid production and biodiesel properties from mixotrophic cultivation of Chlorella vulgaris NIOCCV in untreated wastewater from a fish processing plant over F/2 medium was reported. A significant 6-fold increase in biomass productivity (257.87 ± 1.27 mg·L−1·d−1) and 1.3-fold in lipid accumulation (48%) was recorded for C. vulgaris NIOCCV cultivated in wastewater enrichment of 15% (v/v) over F/2 medium. The biomass productivity was significantly higher in wastewater enrichment up to 50% (v/v) and salt concentration 5% (w/v) than in F/2 medium. The fatty acid methyl esters based theoretical calculation for biodiesel properties from the microalgal biomass cultivated in wastewater enriched medium were found superior to the same from the F/2 medium. The resultant biodiesel properties (CN value, oxidation stability, and kinematic viscosity) were in compliance to both the ASTM D6751 and EN 14214 fuel standards. The cultivation of C. vulgaris NIOCCV in wastewater resulted in significant decrease in nutrient levels is another advantage. Therefore, C. vulgaris NIOCCV can effectively be cultivated in untreated fish processing industry wastewater without addition of nutrients. Further, C. vulgaris NIOCCV can efficiently be utilized as bioresource for biodiesel production.

Development of lag time and time of concentration for a tropical complex catchment under the influence of long-term land use/land cover (LULC) changes

Lag time (tL) and time of concentration (Tc) are essential time parameters used in hydrological flood-flow design methods for estimating peak discharge and flood hydrograph shape. They form the basis of a number of hydrological models used among the scientists. Kelantan River basin, Malaysia, is a tropical catchment receiving heavy monsoon rainfall coupled with intense land use/land cover (LULC) changes making the area consistently flood prone thereby deteriorating water balance in the area. The most recent is that of December 2014 flood which lead to catastrophic loss of huge amount of properties worth millions of Malaysian ringgit. In view of this, the current research was conducted with the aim of developing (1) tL and Tc based on 1984, 2002, and 2013 LULC conditions; (2) a relationship between tL and tL parameters; and (3) a relationship between tL and Tc among different LULC conditions. Kelantan River basin was first delineated into four major catchments, viz., Galas, Pergau, Lebir, and Nenggiri, due to its large size (approximately 13,100 km2). Soil map and LULC change maps corresponding to 1984, 2002, and 2013 were used for the calculation of CN values while NRCS lag equation was used for the estimation of tL and Tc. The results showed that deforestation for logging activities and agricultural practices were the dominant LULC changes across the watershed. Low values of both tL and Tc were obtained across the catchment which are typical for a tropical monsoon catchment characterized with high runoff and short peak discharge. Results of tL and Tc in this study are not affected by LULC changes in the basin. Slope was observed to be highly correlated with tL. Correlation coefficient was used to determine the relationship between tL and tL factor, and hydraulic length and slope (L√S). The results showed high correlation in all the catchments from 1984 to 2013 except for Lebir catchment where a moderate correlation was observed. The findings of this study may be useful to water resource planners in controlling water loss for future planning.

Ionic radii of hydrated sodium cation from QTAIM.

The sodium cation is ubiquitous in aqueous chemistry and biological systems. Yet, in spite of numerous studies, the (average) distance between the sodium cation and its water ligands, and the corresponding ionic radii, are still controversial. Recent experimental values in solution are notably smaller than those from previous X-ray studies and ab initio molecular dynamics. Here we adopt a "bottom-up" approach of obtaining these distances from quantum chemistry calculations [full MP2 with the 6-31++G(d,p) and cc-pVTZ basis-sets] of gas-phase Na+(H2O)n clusters, as a function of the sodium coordination number (CN = 2-6). The bulk limit is obtained by the polarizable continuum model, which acts to increase the interatomic distances at small CN, but has a diminishing effect as the CN increases. This extends the CN dependence of the sodium-water distances from crystal structures (CN = 4-12) to lower CN values, revealing a switch between two power laws, having a small exponent at small CNs and a larger one at large CNs. We utilize Bader's theory of atoms in molecules to bisect the Na+-O distances into Na+ and water radii. Contrary to common wisdom, the water radius is not constant, decreasing even more than that of Na+ as the CN decreases. We also find that the electron density at the bond critical point increases exponentially as the sodium radius decreases.

Assessment of the Soil Conservation Service–Curve Number method performance in a tropical Oxisol watershed

The Soil Conservation Service–Curve Number (SCS-CN) method is a rainfall-runoff model intended to estimate direct surface runoff (DSR) from rainfall. This method is based on an empirical approach of the relationship between rainfall (P) and ground conditions (soils, management, and antecedent moisture content). SCS-CN method can be applied using published tables containing a CN value for each combination of soil hydrology, land use, and management, and the total five-day antecedent rainfall (P₅). However, its accuracy increases as observed rainfall-runoff events are used for calibration. The standard SCS-CN method assigns 0.2 to the initial abstraction coefficient (λ), which refers to the ratio between initial rainfall abstraction (I_a) and the potential maximum retention (S). In this study, λ was evaluated for a tropical watershed with predominance of Oxisols using 15 methodologies for CN characterization, based on CN values published by <i>National Engineering Handbook</i>, Section 4 (NEH-4) and also derived from 166 monitored rainfall-runoff events. Such methodologies include the use of λ equal to 0.2—standard approach, 0.02—average value obtained from the 166 events, and 0.05—a value that has been suggested in some studies. The results demonstrated that a fixed area-weighted CN representing the entire watershed gave poor accuracy even when antecedent runoff condition (ARC) was considered. In contrast, the methodology based on calibration to the observed hydrological events provided good results. Improvements in DSR estimates were found for most of the methodologies applied when λ was set equal to 0.05 and 0.02 instead of 0.2, except for the spatially distributed CN model (Heterogeneity Model), in which the use of λ = 0.2 implied improvement of DSR estimates.

Socioeconomic disparities in unhealthy weight: A need for health promotion among school-aged children.

INTRODUCTION:Overweight and obesity as a major public health issue can lead to adverse health consequences during the life span. This study aimed to measure socioeconomic inequality in unhealthy weight among school students in Kermanshah, west of Iran.METHODS:The cross-sectional study measured the socioeconomic-related inequalities in unhealthy weight among 1404 secondary school students aged 11–16 years in Kermanshah in 2018. Unhealthy weight is defined as body mass index of >25 kg/m2 in the study. Socioeconomic-related inequality in unhealthy weight was calculated using the concentration index (Cn). A logistic regression model was used to estimate the marginal effect of independent variables.RESULTS:The prevalence of unhealthy weight for the total sample was 0.13 (95% confidence interval [CI]: 0.11 –0.14). Of these, the prevalence of unhealthy weight for girls and boys was 0.11 (95% CI: 0.09–0.14) and 0.15 (95% CI: 0.12–0.18), respectively. The value of Cn for the total sample was 0.12 (95% CI: 0.03–0.2), which indicates a higher concentration of unhealthy weight among the high socioeconomic status (SES) students. Two factors of SES (49.11%) and gender (40.08%) had the largest contribution to socioeconomic inequality in unhealthy weight among the study students.CONCLUSIONS:Socioeconomic-related inequality in unhealthy weight was concentered among high-SES students in the study. Thus, public health policies need to be formulated to change sedentary lifestyles and unhealthy dietary patterns among students with higher SES.

Cooperative domains in lipid membranes

Phase transitions of multibilayer structures of hydrated L-α-dipalmitoyl- and L-α-dimyristoylphosphatidylcholine (DPPC and DMPC) were studied by differential scanning calorimetry. For the main phase transition, thermodynamic parameters (temperature, enthalpy, half-width and cooperative domain size, CN) were determined in a broad range of scanning rates x, from 0.1 to 40.0 K min−1. Marked dependence on scanning rate was obtained for CN, while for other parameters it was much weaker. A hyperbolic dependence CN (x) = c + b/(x + a) was established (a, b, c are constants). The lowering of the scanning rate causes an abrupt CN increase at x → 0, which is one of the reasons of the large scatter (by 1–2 orders) in the literature data on CN values. Based on the data obtained, a criterion is proposed for the choice of optimum scanning rate that would minimize the error in CN determination. It is argued that reliable CN values can be obtained if the measured peak half-width is much larger than the corresponding experimental error for the given system.

A New Baseline Subtraction Method for Di-hadron Correlations in High-multiplicity Small System Collisions

Azimuthal anisotropy in high-multiplicity small system collisions is often quantified by the harmonic modulations cn = ‹cos (nΔφ)› in di-hadron azimuthal correlations, with a non-flow baseline subtraction using correlation functions in low-multiplicity events. We present mathematical evaluations for three different baseline subtraction methods; i) the template fit method, ii) the reference fit method, and iii) the c1 scaling method. We describe conceptual differences among the three methods. These methods are compared and examined using a toy Monte Carlo model with various realistic cn values implemented in high-multiplicity events. Our results show the reference fit method is more stable than the template fit method because the reference fit does not estimate the flow yield. On the other hand, the template fit method can evaluate the flow effect reasonably, for the case where the flow does not contain c1 factor.

New Derivation Method of Region Specific Curve Number for Urban Runoff Prediction at Melana Watershed in Johor, Malaysia

The Soil Conservation Services (SCS) rainfall-runoff model has been incorporated into many types of software and adopted by Malaysian government agencies for design use. However, hydrologists argue the accuracy of the predicted runoff results from this model in recent decades. Malaysia does not have a regional specific curve numbers available for the use in rainfall-runoff modelling, and therefore SCS-CN practitioner has no option but to adopt its guideline and handbook values which are specific to US region. Unlike the conventional SCS-CN technique, the proposed calibration methodology in this paper discarded the use of CN as input to the SCS model, rearranged the model equation and derived statistically significant CN value(s) of a specific region through rainfall-runoff events directly through the use of inferential statistics. The SCS rainfall-runoff framework can now be calibrated quickly to address urban runoff prediction challenge under rapid land use and land cover or climate changes with the proposed methodology. Between July and October of 2004, the derived λ was 0.0005 while λ = 0.20 was found to be statistically insignificant at alpha = 0.01 level at Melana watershed in Johor, Malaysia. Optimum CN of 90.45 was derived to represent the rainfall-runoff characteristic of Melana watershed. Runoff prediction error was reduced by 90% and achieved the Nash-Sutcliffe (NS) index of 0.86. The new method can provide CN adjustment guidelines for SCS practitioners and any software which incorporated the model to predict urban runoff.

Application of cubic spline in soil erosion modeling from Narmada Watersheds, India

Soil erosion by water is ubiquitous, exhibits spatio-temporal variability, and is fundamental to determining sediment yield which is key to proper watershed management. In this study, we propose a relationship between the curve number and sediment yield index (SYI) using cubic splines. Using field data from four watersheds, the relation between observed and computed SYI is found to have a coefficient of determination (R2) value from 0.63 to 0.88 suggesting that such a relation can be used to determine SYI from the available CN value. It is found that cubic splines perform satisfactorily with Nash-Sutcliff efficiency ranging from 60.18 to 64.01%, absolute prediction error from 1.35 to 5.56%, integral square error from 1.21 to 5.82%, coefficient of correlation from 79.32 to 93.78%, and degree of agreement from 0.87 to 0.99%.

Development and assessment of rules to parameterise the ACRU model for design flood estimation

Design flood estimation (DFE) is essential in the planning and design of hydraulic structures. In South Africa, outdated methods are widely applied for DFE. In this paper the potential of a continuous simulation modelling (CSM) approach to DFE in South Africa, using the daily time-step ACRU agrohydrological model, is investigated. The paper focuses on the links and similarities between the SCS-SA and ACRU models and the subsequent preliminary investigations that were undertaken to account for and incorporate the land cover classes, including land management practices and hydrological condition, of the SCS-SA model into the ACRU CSM approach. The approach to this study was to investigate how design volumes simulated by the SCS-SA model for various land management practices or conditions could be simulated by the ACRU model. Since peak discharge estimation in both models is directly dependent on simulated volumes, this preliminary study focused only on design runoff volumes, with subsequent investigations on peak discharge required in future research. In the absence of observed data, design runoff volumes and changes in design runoff volumes, as simulated by the SCS-SA model, were used as a substitute for observed data, i.e., as a reference, to achieve similar design runoff volumes and changes in design volumes in the ACRU model. This was achieved by adjusting relevant input parameters in the ACRU model to represent the change in management practice or hydrological condition, as represented in the SCS-SA model. Following a sensitivity analysis of relevant ACRU parameters, calibration of 2 selected parameters against SCS-SA CN values for selected land cover classes was performed. A strong linear relationship (R2 = 0.94) between these ACRU parameters and SCS-SA CNs for selected land cover classes was found and consequently specific rules and equations were developed to represent SCS-SA land cover classes in ACRU. Recommendations are made to further validate and verify the approach and to further the development of a CSM system for DFE in South Africa.

Flood Hazard Management in Public Mountain Recreation Areas vs. Ungauged Fluvial Basins. Case Study of the Caldera de Taburiente National Park, Canary Islands (Spain)

Las Angustias River is an ungauged stream in the Caldera de Taburiente National Park (Spain), where frequent intense flash-flood events occur. The aim of this research is to analyze the flood hazard at the Playa de Taburiente. Based on the limited information available (short time-series of daily precipitation), a statistical frequency analysis of 24 h rainfall was completed and the precipitation results were transformed into surface runoff. To determine if the model underestimates the flows that are generated in the basin, the dendro-geomorphological information available was used to calibrate results. The results of the HMS model were significantly lower. At this point, both the rainfall data and the rainfall-runoff model were re-analyzed to maximize the rainfall intensity values and the runoff generated (increasing the CN value for the basin). For the 1997 flood event, a 1250 m3·s−1 flood minimizes the RMSE for the disturbed tree sample; this flow value also clearly exceeds any peak flow derived from the rainfall-runoff analysis. It is only when rainfall intensity and surface runoff are maximized that the peak flows obtained approximate those associated with dendro-geomorphological data. The results highlight the difficulties of flood hazard management in ungauged torrential basins in mountain recreational areas (such as National Parks). Thus, in the absence of flow records, when considering the maximum rainfall intensity scenario may be a useful and effective tool for flood risk management.

Process-based modelling of NH&amp;lt;sub&amp;gt;3&amp;lt;/sub&amp;gt; exchange with grazed grasslands

Abstract. In this study the GAG model, a process-based ammonia (NH3) emission model for urine patches, was extended and applied for the field scale. The new model (GAG_field) was tested over two modelling periods, for which micrometeorological NH3 flux data were available. Acknowledging uncertainties in the measurements, the model was able to simulate the main features of the observed fluxes. The temporal evolution of the simulated NH3 exchange flux was found to be dominated by NH3 emission from the urine patches, offset by simultaneous NH3 deposition to areas of the field not affected by urine. The simulations show how NH3 fluxes over a grazed field in a given day can be affected by urine patches deposited several days earlier, linked to the interaction of volatilization processes with soil pH dynamics. Sensitivity analysis showed that GAG_field was more sensitive to soil buffering capacity (β), field capacity (θfc) and permanent wilting point (θpwp) than the patch-scale model. The reason for these different sensitivities is dual. Firstly, the difference originates from the different scales. Secondly, the difference can be explained by the different initial soil pH and physical properties, which determine the maximum volume of urine that can be stored in the NH3 source layer. It was found that in the case of urine patches with a higher initial soil pH and higher initial soil water content, the sensitivity of NH3 exchange to β was stronger. Also, in the case of a higher initial soil water content, NH3 exchange was more sensitive to the changes in θfc and θpwp. The sensitivity analysis showed that the nitrogen content of urine (cN) is associated with high uncertainty in the simulated fluxes. However, model experiments based on cN values randomized from an estimated statistical distribution indicated that this uncertainty is considerably smaller in practice. Finally, GAG_field was tested with a constant soil pH of 7.5. The variation of NH3 fluxes simulated in this way showed a good agreement with those from the simulations with the original approach, accounting for a dynamically changing soil pH. These results suggest a way for model simplification when GAG_field is applied later at regional scale.