Review of recent developments in soil water simulation models

1996 ◽  
Vol 76 (3) ◽  
pp. 263-273 ◽  
Author(s):  
R. de Jong ◽  
A. Bootsma
Keyword(s):  
Soil Water ◽  
Spring Wheat ◽  
Arid Region ◽  
Management Practices ◽  
Simulation Models ◽  
Richards Equation ◽  
Water Model ◽  
Deterministic Models ◽  
Wide Range ◽  
Water Simulation

Soil water is of great importance to agricultural and hydrological systems, affecting crop yields, agricultural management practices and a wide range of physical and chemical processes in soils. Many models have been developed over the years to simulate soil water, ranging from simple water balance procedures to complex deterministic models. In this paper, some of the basic concepts, strengths, weaknesses and input requirements of soil water models are reviewed. Simple budget models which require only available water-holding capacity, based on the concepts of field capacity and wilting point, and monthly average values of precipitation and potential evapotranspiration (PET) are often adequate for climatic characterizations. However, detailed deterministic models are useful for investigating more complex processes such as solute movement, soil degradation and crop growth. These models are based on Richards’ equation, with an added term for root water extraction. They generally require daily or hourly meteorological data and detailed hydraulic conductivity and water potential functions for various soil layers.Meteorological data for input into models are widely available in Canada from a network of climate stations. However, the network density is sparse for those models which use the most accurate procedures for estimating PET, requiring parameters such as wind, solar radiation and/or humidity. Moreover, pedotransfer functions generally need to be used to estimate, from existing soil databases, the required soil inputs for sophisticated models.To demonstrate a practical application, a soil water model was used in conjunction with simple crop yield/water use relationships to characterize soil water regimes and crop production risks. The probability of obtaining break-even yields (PBEY) for continuous spring wheat was calculated and mapped for the Canadian prairie region. PBEY ranged from less than 20% in the most arid region of the prairies to between 60 and 100% in most humid areas. An estimate of PBEY based on modelled yields was in close agreement with that based on long-term measured yields in the sub-arid region. With increasing availability of integrated multi-process based models, this technique has potential for studying the effects of soil characteristics and crop management techniques on PBEY. Key words: Soil water, simulation models, review, spring wheat, break-even yield, Canadian prairies

Use of Soil Survey Data for Regional Soil Water Simulation Models

1985 ◽  
Vol 49 (5) ◽  
pp. 1238-1244 ◽  
Author(s):  
J. H. M. Wösten ◽  
J. Bouma ◽  
G. H. Stoffelsen
Keyword(s):  
Soil Water ◽  
Survey Data ◽  
Simulation Models ◽  
Soil Survey ◽  
Water Simulation

scholarly journals Soil properties impacting denitrifier community size, structure, and activity in New Zealand dairy-grazed pasture

2016 ◽  
Author(s):  
Neha Jha ◽  
Surinder Saggar ◽  
Donna Giltrap ◽  
Russ Tillman ◽  
Julie Deslippe
Keyword(s):  
New Zealand ◽  
Soil Water ◽  
Management Practices ◽  
Size Structure ◽  
Quantitative Polymerase Chain Reaction ◽  
Physicochemical Characteristics ◽  
Community Size ◽  
N2o Production ◽  
Wide Range ◽  
Structure And Activity

Abstract. Denitrification is an anaerobic respiration process that is the primary contributor of the nitrous oxide (N2O) production from grassland soils. Our objective was to gain insight to the relationships between denitrifier community size, structure, and activity for a range of pasture soils. We collected 10 dairy pasture soils with contrasting soil textures, drainage classes, management strategies (effluent irrigated or non-irrigated), and geographic locations in New Zealand, and measured their physicochemical characteristics. We measured denitrifier abundance by quantitative polymerase chain reaction (qPCR) and assessed community structure by terminal restriction fragment length polymorphism (T-RFLP) of the nitrite reductase (nirS, nirK) and N2O reductase (nosZ) genes. We quantified denitrifier enzyme activity (DEA) using acetylene inhibition technique. Differences in the physicochemical characteristics of the soils were driven mainly by soil mineralogy and the management practices of the farms. We found that nirS and nirK communities strongly structured along the gradients of soil water and phosphorus (P) contents. By contrast, the size and structure of the nosZ community was unrelated to any of the measured soil characteristics. In soils with high soil water content the richness and abundances of nirS, nirK and nosZ genes were significantly positively correlated with DEA. Our data suggest that soil moisture, microbial biomass, and fertility were the primary drivers of the structure and abundance of denitrifier communities across a wide range of geologic and geographical soil origins.

Impression management and legitimacy strategies: The BP case

2013 ◽  
pp. 35-64 ◽  
Author(s):  
Giovanna Michelon
Keyword(s):  
Impression Management ◽  
Management Practices ◽  
Legitimacy Theory ◽  
British Petroleum ◽  
Wide Range ◽  
Management Techniques ◽  
Disclosure Tone ◽  
The Empirical Analysis ◽  
A Company ◽  
Texas City

The aim of this paper is to study if and how impression management varies during different phases of the legitimation process, in particular during the legitimacy building and legitimacy repairing phases (Suchman, 1995). We aim at understanding whether and how the disclosure tone adopted by a company in the two different moments is diverse and thus functional to the intrinsic objective of the each phase. The empirical analysis focuses on the case of British Petroleum Plc. We investigated the impression management practices undertaken by the company both during the preparation of the rebranding operation, i.e. a situation in which the company is trying to build legitimacy; and during the happenings of two legitimacy crises, like the explosion of the refinery in Texas City and the oil spill in the Gulf of Mexico. The evidence appears in line with the theoretical prediction of legitimacy theory. Results show that while the company tends to privilege image enhancement techniques during the legitimacy-building phase, it uses more obfuscation techniques when managing a legitimacy-repairing process. Moreover, the analysis suggests that the company makes more extensive use of impression management techniques in the disclosures addressed to shareholders, investors and other market operators than in the disclosures addressed to the wide range of other stakeholders.

Applying the Soil Water Assessment Tool to 5th Canadian Division Support Base Gagetown

2014 ◽  
Vol 49 (4) ◽  
pp. 372-385
Author(s):  
Shawn Burdett ◽  
Michael Hulley ◽  
Andy Smith
Keyword(s):  
Water Quality ◽  
Soil Water ◽  
Land Management ◽  
Management Practices ◽  
Assessment Tool ◽  
Anthropogenic Activities ◽  
Quality Model ◽  
Sediment Yields ◽  
Soil Water Assessment Tool ◽  
Water Assessment

A hydrologic and water quality model is sought to establish an approach to land management decisions for a Canadian Army training base. Training areas are subjected to high levels of persistent activity creating unique land cover and land-use disturbances. Deforestation, complex road networks, off-road manoeuvres, and vehicle stream crossings are among major anthropogenic activities observed to affect these landscapes. Expanding, preserving and improving the quality of these areas to host training activities for future generations is critical to maintain operational effectiveness. Inclusive to this objective is minimizing resultant environmental degradation, principally in the form of hydrologic fluctuations, excess erosion, and sedimentation of aquatic environments. Application of the Soil Water Assessment Tool (SWAT) was assessed for its ability to simulate hydrologic and water quality conditions observed in military landscapes at 5th Canadian Division Support Base (5 CDSB) Gagetown, New Brunswick. Despite some limitations, this model adequately simulated three partial years of daily watershed outflow (NSE = 0.47–0.79, R2 = 0.50–0.88) and adequately predicted suspended sediment yields during the observation periods (%d = 6–47%) for one highly disturbed sub-watershed in Gagetown. Further development of this model may help guide decisions to develop or decommission training areas, guide land management practices and prioritize select landscape mitigation efforts.

scholarly journals Fitness of Herbicide-Resistant Weeds: Current Knowledge and Implications for Management

Plants ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 469 ◽  
Author(s):  
Vila-Aiub
Keyword(s):  
Life History ◽  
Herbicide Resistance ◽  
Management Practices ◽  
Current Knowledge ◽  
Resistance Management ◽  
Fitness Cost ◽  
Plant Fitness ◽  
Resistance Mutations ◽  
Fitness Costs ◽  
Wide Range

Herbicide resistance is the ultimate evidence of the extraordinary capacity of weeds to evolve under stressful conditions. Despite the extraordinary plant fitness advantage endowed by herbicide resistance mutations in agroecosystems under herbicide selection, resistance mutations are predicted to exhibit an adaptation cost (i.e., fitness cost), relative to the susceptible wild-type, in herbicide untreated conditions. Fitness costs associated with herbicide resistance mutations are not universal and their expression depends on the particular mutation, genetic background, dominance of the fitness cost, and environmental conditions. The detrimental effects of herbicide resistance mutations on plant fitness may arise as a direct impact on fitness-related traits and/or coevolution with changes in other life history traits that ultimately may lead to fitness costs under particular ecological conditions. This brings the idea that a “lower adaptive value” of herbicide resistance mutations represents an opportunity for the design of resistance management practices that could minimize the evolution of herbicide resistance. It is evident that the challenge for weed management practices aiming to control, minimize, or even reverse the frequency of resistance mutations in the agricultural landscape is to “create” those agroecological conditions that could expose, exploit, and exacerbate those life history and/or fitness traits affecting the evolution of herbicide resistance mutations. Ideally, resistance management should implement a wide range of cultural practices leading to environmentally mediated fitness costs associated with herbicide resistance mutations.

scholarly journals High-Resolution Monitoring and Assessment of Evapotranspiration and Gross Primary Production Using Remote Sensing in a Typical Arid Region

Land ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 396
Author(s):  
Junxia Yan ◽  
Yanfei Ma ◽  
Dongyun Zhang ◽  
Zechen Li ◽  
Weike Zhang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Land Surface ◽  
Arid Region ◽  
Management Practices ◽  
Gross Primary Production ◽  
Irrigation District ◽  
Heihe River ◽  
Freshwater Resource ◽  
Oasis Area

Land surface evapotranspiration (ET) and gross primary productivity (GPP) are critical components in terrestrial ecosystems with water and carbon cycles. Large-scale, high-resolution, and accurately quantified ET and GPP values are important fundamental data for freshwater resource management and help in understanding terrestrial carbon and water cycles in an arid region. In this study, the revised surface energy balance system (SEBS) model and MOD17 GPP algorithm were used to estimate daily ET and GPP at 100 m resolution based on multi-source satellite remote sensing data to obtain surface biophysical parameters and meteorological forcing data as input variables for the model in the midstream oasis area of the Heihe River Basin (HRB) from 2010 to 2016. Then, we further calculated the ecosystem water-use efficiency (WUE). We validated the daily ET, GPP, and WUE from ground observations at a crop oasis station and conducted spatial intercomparisons of monthly and annual ET, GPP, and WUE at the irrigation district and cropland oasis scales. The site-level evaluation results show that ET and GPP had better performance than WUE at the daily time scale. Specifically, the deviations in the daily ET, GPP, and WUE data compared with ground observations were small, with a root mean square error (RMSE) and mean absolute percent error (MAPE) of 0.75 mm/day and 26.59%, 1.13 gC/m2 and 36.62%, and 0.50 gC/kgH2O and 39.83%, respectively. The regional annual ET, GPP, and WUE varied from 300 to 700 mm, 200 to 650 gC/m2, and 0.5 to 1.0 gC/kgH2O, respectively, over the entire irrigation oasis area. It was found that annual ET and GPP were greater than 550 mm and 500 gC/m2, and annual oasis cropland WUE had strong invariability and was maintained at approximately 0.85 gC/kgH2O. The spatial intercomparisons from 2010 to 2016 revealed that ET had similar spatial patterns to GPP due to tightly coupled carbon and water fluxes. However, the WUE spatiotemporal patterns were slightly different from both ET and GPP, particularly in the early and late growing seasons for the oasis area. Our results demonstrate that spatial full coverage and reasonably fine spatiotemporal variation and variability could significantly improve our understanding of water-saving irrigation strategies and oasis agricultural water management practices in the face of water shortage issues.

scholarly journals Estimating Soil Water Susceptibility to Salinization in the Mekong River Delta Using a Modified DRASTIC Model

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1636
Author(s):  
Thanh N. Le ◽  
Duy X. Tran ◽  
Thuong V. Tran ◽  
Sangay Gyeltshen ◽  
Tan V. Lam ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Water ◽  
Management Practices ◽  
Global Climate ◽  
Anthropogenic Activities ◽  
Rapid Development ◽  
Anthropogenic Factors ◽  
Drastic Model ◽  
River Catchment ◽  
Modified Drastic

Saltwater intrusion risk assessment is a foundational step for preventing and controlling salinization in coastal regions. The Vietnamese Mekong Delta (VMD) is highly affected by drought and salinization threats, especially severe under the impacts of global climate change and the rapid development of an upstream hydropower dam system. This study aimed to apply a modified DRASTIC model, which combines the generic DRASTIC model with hydrological and anthropogenic factors (i.e., river catchment and land use), to examine seawater intrusion vulnerability in the soil-water-bearing layer in the Ben Tre province, located in the VMD. One hundred and fifty hand-auger samples for total dissolved solids (TDS) measurements, one of the reflected salinity parameters, were used to validate the results obtained with both the DRASTIC and modified DRASTIC models. The spatial analysis tools in the ArcGIS software (i.e., Kriging and data classification tools) were used to interpolate, classify, and map the input factors and salinization susceptibility in the study area. The results show that the vulnerability index values obtained from the DRASTIC and modified DRASTIC models were 36–128 and 55–163, respectively. The vulnerable indices increased from inland districts to coastal areas. The Ba Tri and Binh Dai districts were recorded as having very high vulnerability to salinization, while the Chau Thanh and Cho Lach districts were at a low vulnerability level. From the comparative analysis of the two models, it is obvious that the modified DRASTIC model with the inclusion of a river or canal network and agricultural practices factors enables better performance than the generic DRASTIC model. This enhancement is explained by the significant impact of anthropogenic activities on the salinization of soil water content. This study’s results can be used as scientific implications for planners and decision-makers in river catchment and land-use management practices.

scholarly journals Environmental Drivers and Age Trends in Site Productivity for Oak in Southern Poland

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 209
Author(s):  
Luiza Tymińska-Czabańska ◽  
Jarosław Socha ◽  
Marek Maj ◽  
Dominika Cywicka ◽  
Xo Viet Hoang Duong
Keyword(s):  
Nitrogen Deposition ◽  
Management Practices ◽  
Additive Model ◽  
Climatic Conditions ◽  
Environmental Indicators ◽  
Environmental Drivers ◽  
Site Productivity ◽  
Site Factors ◽  
Wide Range ◽  
Si Model

Site productivity provides critical information for forest management practices and is a fundamental measure in forestry. It is determined using site index (SI) models, which are developed using two primary groups of methods, namely, phytocentric (plant-based) or geocentric (earth-based). Geocentric methods allow for direct site growth modelling, in which the SI is predicted using multiple environmental indicators. However, changes in non-static site factors—particularly nitrogen deposition and rising CO2 concentration—lead to an increase in site productivity, which may be visible as an age trend in the SI. In this study, we developed a geocentric SI model for oak. For the development of the SI model, we used data from 150 sample plots, representing a wide range of local topographic and site conditions. A generalized additive model was used to model site productivity. We found that the oak SI depended predominantly on physicochemical soil properties—mainly nitrogen, carbon, sand, and clay content. Additionally, the oak SI value was found to be slightly shaped by the topography, especially by altitude above sea level, and topographic position. We also detected a significant relationship between the SI and the age of oak stands, indicating the long-term increasing site productivity for oak, most likely caused by nitrogen deposition and changes in climatic conditions. The developed geocentric site productivity model for oak explained 77.2% of the SI variation.

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