scholarly journals Assessment and modeling of the generation and transport of water and solutes in representative watersheds of Navarre (Spain): toward an optimal and sustainable agrarian activity

2021 ◽  
Author(s):  
◽  
Iker Hernández García
Keyword(s):  
Overland Flow ◽  
Black Box ◽  
Controlling Factors ◽  
Special Focus ◽  
Agricultural Systems ◽  
Dissolved Solids ◽  
Winter Cereal ◽  
Dissolved Nitrogen ◽  
Connectivity Indices ◽  
Watershed Approach

The overarching aim of this thesis is to expand the knowledge base on the dynamics of total dissolved solids, with special focus on the most widespread nutrients in agricultural systems (N, and to a lesser extent P). To this end, (1) the exports of dissolved solids and their dynamics in a watershed network have been quantified, considering different agrosystems of the region of Navarre (Spain). Recognizing the influence of these compounds on different water bodies, and with the aim of shedding more light on the black box watershed approach in water quality, (2) the relatively recent concept of overland flow connectivity has been assessed through an Overland Flow Connectivity index. This index is based on broadly adopted overland flow connectivity indices, and implemented at two rainfed winter cereal watersheds (Latxaga and La Tejería). Regarding nutrients, and focusing on nitrate and phosphate dynamics, (3) these two watersheds have been characterized in terms of concentration and exports of nitrate and phosphate, for a range of temporal scales, with insights on the controlling factors of these processes. Finally, (4) the nutrient controlling factors previously identified have been quantified considering different possible scenarios. The AnnAGNPS model capacity has been evaluated for dissolved nitrogen exports at the two rainfed winter cereal watersheds.

scholarly journals Modified Richards’ Equation to Improve Estimates of Soil Moisture in Two-Layered Soils after Infiltration

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1174 ◽  
Author(s):  
Honglin Zhu ◽  
Tingxi Liu ◽  
Baolin Xue ◽  
Yinglan A. ◽  
Guoqiang Wang
Keyword(s):  
Soil Moisture ◽  
Overland Flow ◽  
Hydrological Cycle ◽  
Soil Depth ◽  
Controlling Factors ◽  
Moisture Distribution ◽  
Richards Equation ◽  
Infiltration Process ◽  
Soil Moisture Distribution

Soil moisture distribution plays a significant role in soil erosion, evapotranspiration, and overland flow. Infiltration is a main component of the hydrological cycle, and simulations of soil moisture can improve infiltration process modeling. Different environmental factors affect soil moisture distribution in different soil layers. Soil moisture distribution is influenced mainly by soil properties (e.g., porosity) in the upper layer (10 cm), but by gravity-related factors (e.g., slope) in the deeper layer (50 cm). Richards’ equation is a widely used infiltration equation in hydrological models, but its homogeneous assumptions simplify the pattern of soil moisture distribution, leading to overestimates. Here, we present a modified Richards’ equation to predict soil moisture distribution in different layers along vertical infiltration. Two formulae considering different controlling factors were used to estimate soil moisture distribution at a given time and depth. Data for factors including slope, soil depth, porosity, and hydraulic conductivity were obtained from the literature and in situ measurements and used as prior information. Simulations were compared between the modified and the original Richards’ equations and with measurements taken at different times and depths. Comparisons with soil moisture data measured in situ indicated that the modified Richards’ equation still had limitations in terms of reproducing soil moisture in different slope positions and rainfall periods. However, compared with the original Richards’ equation, the modified equation estimated soil moisture with spatial diversity in the infiltration process more accurately. The equation may benefit from further solutions that consider various controlling factors in layers. Our results show that the proposed modified Richards’ equation provides a more effective approach to predict soil moisture in the vertical infiltration process.

scholarly journals Sustainability Comparison Between Organic and Conventional Systems at Farm and Field Scale: A Case Study in Olive Production Systems in Apulia Region

2013 ◽  
Vol 2 (4) ◽  
pp. 19
Author(s):  
Jenny Calabrese ◽  
Cesare Pacini ◽  
Concetta Vazzana ◽  
Mariana Nikolla
Keyword(s):  
Sustainability Assessment ◽  
Production Systems ◽  
Special Focus ◽  
Agricultural Systems ◽  
Gross Margin ◽  
Accounting Systems ◽  
Accounting Information System ◽  
Natural Systems ◽  
Conventional Systems

Dependence of conventional agricultural systems on chemical fertilizers and pesticidesmakes agricultural systems less stable and important drift polluters influencing to theregional and global sustainability. This problem made human being think about thealternative systems: agricultural systems that mimic natural systems and are friendly to theenvironment; those have higher economical efficiency concerning production level andcosts. The objective of the present study was sustainability assessment and comparison oforganic and conventional system with special focus environmental and economicalperformance. The case study consisted of two organic and conventional olive producingfarms in the South of Italy. The method used for sustainability assessment wasEnvironmental Accounting Information System (EAIS) that integrates togetherenvironmental (soil organic matter, soil erosion, genetic and landscape biodiversity,EPRIP, etc ) and economical indicators (gross margin). Data used for assessment ofEAIS indicators values were mainly collected from: farm economic-accounting systems,interviews, farm maps, area public organizations, bibliographical sources, farm nutrientaccounting systems, observations and field assessments and chemical soil analyses. Theindicator values measured into two farms were compared to theoretical or referenceindicator values. Based on indicator assessment it was concluded that organic olivegrowing farm had better performance than conventional farm.

The Dramatic Theatre in The Netherlands

2002 ◽  
Vol 27 (2) ◽  
pp. 192-200
Author(s):  
Wil Hildebrand
Keyword(s):  
The Netherlands ◽  
Detailed Examination ◽  
Black Box ◽  
Special Focus

An analysis of the main companies, groups and practitioners producing text-based theatre in the Netherlands in the last few years provides a backdrop for a more detailed examination of the work of writer/director Gerardjan Rijnders. Further, special focus is given to the work of the greatest theatre innovator of the last two decades, Jan Joris Lamers, and two young theatre collectives are presented as representative of a broader movement of playwrights, actors and directors, who perform in smaller black-box theatres.

Savanna on the Nile

2021 ◽  
pp. 926-953
Author(s):  
Dorian Q. Fuller ◽  
Leilani Lucas
Keyword(s):  
Agricultural Systems ◽  
Late Neolithic ◽  
Winter Cereal ◽  
Cultivation System ◽  
Economic Changes ◽  
Near Eastern ◽  
The North ◽  
Winter Crop ◽  
Sub Saharan ◽  
Cereal Cultivation

This paper provides an overview of changing agricultural systems from the Neolithic to the Post-Meroitic Period in the greater Nubian region. There remain major gaps in the archaeobotanical evidence, and larger samples collected by systematic sieving and flotation are few and far between. Gaps in our knowledge include the initial establishment of the summer, sub-Saharan cereal cultivation system, but other important trends are much clearer, such as the arrival of the classic Egyptian winter cereal cultivation system of Near Eastern origin in the Late Neolithic at least in Lower Nubia; the latter of which complemented established pastoral traditions providing for the emergent political economy. The northward spread of the summer savannah crop system during the first few centuries ce formed the basis for subsequent intensification through the adoption of the cattle-powered saqia. Diversification and intensification through an integration of the summer and winter crop systems along with the development of a cash crop industry facilitated the development of Meroitic state. These processes also may have played an important role in economic changes in the Late Meroitic to Post-Meroitic transition, including the devolution of the Meroitic state. In addition to representing a long-term frontier of overlapping agricultural systems, Nubia was a frontier in cooking traditions, a crossroads between a world of bread in the North and one of liquid preparations, porridges, and beers in the South.

Wildfire as a Catalyst for Hydrologic and Geomorphic Change

2019 ◽  
Author(s):  
Francis K. Rengers
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Overland Flow ◽  
Special Focus ◽  
Soil Erodibility ◽  
Erosion Rates ◽  
Current State ◽  
Order Of Magnitude ◽  
Fundamental Research ◽  
Recurrence Intervals

Wildfire has been a constant presence on the Earth since at least the Silurian period, and is a landscape-scale catalyst that results in a step-change perturbation for hydrologic systems, which ripples across burned terrain, shaping the geomorphic legacy of watersheds. Specifically, wildfire alters two key landscape properties: (1) overland flow, and (2) soil erodibility. Overland flow and soil erodibility have both been seen to increase after wildfires, resulting in order-of-magnitude increases in erosion rates during rainstorms with relatively frequent recurrence intervals. On short timescales, wildfire increases erosion and leads to natural hazards that are costly and threatening to society. Over longer timescales, wildfire-induced erosion can account for the majority of total denudation in certain settings with long-term implications for landscape evolution. There is a special focus on debris flows in this document because they are the most destructive geomorphic processes observed to follow wildfires after high severity burns. To date, research on post-wildfire debris flows has focused on: the provenance of sediment moved in debris flows, the hydrologic and soil properties required to produce debris flows, and debris flow initiation mechanisms. Herein we highlight the relevant research articles showing the current state of progress in debris flow research as well as pointing to the fundamental research on post-wildfire hydrology and erosion necessary for understanding how water and sediment behave after wildfires.

scholarly journals The Influence of Soil Compaction on Runoff Formation. A Case Study Focusing on Skid Trails at Forested Andosol Sites

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 204 ◽  
Author(s):  
Julian J. Zemke ◽  
Michel Enderling ◽  
Alexander Klein ◽  
Marc Skubski
Keyword(s):  
Bulk Density ◽  
Soil Compaction ◽  
Heavy Rainfall ◽  
Overland Flow ◽  
Initial Conditions ◽  
Special Focus ◽  
Runoff Generation ◽  
Rainfall Events ◽  
Runoff Formation ◽  
Heavy Rainfall Events

This study discusses the influence of soil compaction on runoff generation with a special focus on forested Andosol sites. Because of their typical soil physical characteristics (low bulk density, high pore volumes) and the existent land use, these areas are expected to show low to no measurable overland flow during heavy rainfall events. However, due to heavy machinery traffic in the course of forestry actions and pumice excavations, skid trails have been established. Here, a distinct shift of soil dry bulk density (DBD) was observable, using a detailed soil mapping and data interpolation in order to generate in-depth DBD-cross profiles. Additionally, infiltration measurements and rainfall simulations (I = 45 mm·h−1, t = 30 min) were conducted to evaluate effects of observed soil compaction on infiltration rates and overland flow formation. Results show that soil compaction was increased by 21% on average in skid trail wheel ruts. As a consequence, observed runoff was 8.5-times higher on skid trails, while saturated hydraulic conductivity was diminished by 36%. These findings show, that soil compaction leads to a higher possibility of runoff formation during heavy rainfall events, especially at sites which showed initial conditions with presumably low tendencies of runoff formation.

scholarly journals Dissolved Nitrogen and Phosphorus Dynamics in the Lower Portion of the Paraiba do Sul River, Campos dos Goytacazes, RJ, Brazil

2001 ◽  
Vol 44 (4) ◽  
pp. 365-371 ◽  
Author(s):  
Mônica Aparecida Leite Silva ◽  
Claudia Ferreira Calasans ◽  
Alvaro Ramon Coelho Ovalle ◽  
Carlos Eduardo Rezende
Keyword(s):  
Dissolved Oxygen ◽  
Temporal Dynamics ◽  
Agricultural Practices ◽  
Controlling Factors ◽  
Phosphorus Compounds ◽  
Lower Reach ◽  
Wet Season ◽  
Nitrogen And Phosphorus ◽  
Dissolved Nitrogen ◽  
Paraíba Do Sul River

The Paraíba do Sul river lower reach was monitored monthly between August 1995 and July 1996. This study was aimed at evaluating the temporal dynamics of dissolved nitrogen and phosphorus and its main controlling factors. Minimum and maximum observed values were as follows: N-NO2- - 0.08/0.51; N-NO3- - 21/57; N-NH4+ - 1.4/6.7; DON - 4.9/86.0; DIN -24.5/60.9; P-PO4(3-) - 0.43/1.66; DOP - 0.05/0.92; pH - 6.2/7.8; Dissolved Oxygen - 6.4/10.1; Conductivity - 48/74; Temperature - 20.5/31.1 (Nutrients - µM; Dissolved Oxygen - mg/l; Conductivity - µS/cm; Temperature - °C). Discharge presented a characteristic seasonal variation, showing a peak in January. Increasing P-PO4(3-), DOP, N-NH4+ and N-NO2- concentrations with increasing discharges could be associated to the partial flooding of inumerous fluvial islands and floodplains and to the agricultural practices of sugar cane crops that during the wet season could transfer nitrogen and phosphorus compounds to the fluvial channel.

scholarly journals Tillage and Liquid Dairy Manure Effects on Overland Flow Nitrogen and Phosphorus Loss Potential in an Upper Midwest Corn Silage-Winter Triticale Cropping System

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1775
Author(s):  
Jessica F. Sherman ◽  
Eric O. Young ◽  
Jason Cavadini
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Overland Flow ◽  
Dairy Manure ◽  
Nutrient Loss ◽  
Upper Midwest ◽  
Manure Application ◽  
Total N ◽  
Winter Cereal ◽  
Cereal Grain

Dairy manure is an important crop nutrient source in Wisconsin and other parts of the upper Midwest but can contribute to nitrogen (N) and phosphorus (P) losses in overland flow/surface runoff. Winter cereal grain cover crops can help reduce erosion and nutrient transport in corn systems. However, few studies have compared tillage impacts on nutrient loss in live cover crop systems. The objective of this study was to evaluate vertical (VT) and chisel tillage (CT) effects on overland flow nutrient and sediment loss potential after spring-applied liquid manure. A surface application treatment (i.e., broadcast) and a no manure control were also included for comparison. After corn (Zea mays L.) planting into a live triticale (Triticale hexaploide L.) cover crop, four artificial rainfall-overland flow events were generated (42 mm h−1 for 30 min) on replicated field-scale plots in central Wisconsin. Mean total P, total N, and suspended solids loads were consistently lower for VT at 2 days post-manure application (with 97 to 99% lower losses than broadcast, respectively). Dissolved reactive P and ammonium-N concentrations for both CT and VT were significantly lower three weeks after manure application compared to broadcast. Results suggest that VT reduced soil/residue disturbance while incorporating manure sufficiently to reduce sediment, N, and P transport potential under simulated high overland flow conditions.

scholarly journals Flow analysis with WaSiM-ETH – model parameter sensitivity at different scales

2006 ◽  
Vol 9 ◽  
pp. 73-77 ◽  
Author(s):  
J. Cullmann ◽  
V. Mishra ◽  
R. Peters
Keyword(s):  
Water Balance ◽  
Overland Flow ◽  
Flow Analysis ◽  
Flood Forecasting ◽  
Special Focus ◽  
Time Step ◽  
Space Resolution ◽  
Process Dynamics ◽  
Time Calculation ◽  
Daily Time Step

Abstract. WaSiM-ETH (Gurtz et al., 2001), a widely used water balance simulation model, is tested for its suitability to serve for flow analysis in the context of rainfall runoff modelling and flood forecasting. In this paper, special focus is on the resolution of the process domain in space as well as in time. We try to couple model runs with different calculation time steps in order to reduce the effort arising from calculating the whole flow hydrograph at the hourly time step. We aim at modelling on the daily time step for water balance purposes, switching to the hourly time step whenever high-resolution information is necessary (flood forecasting). WaSiM-ETH is used at different grid resolutions, thus we try to become clear about being able to transfer the model in spatial resolution. We further use two different approaches for the overland flow time calculation within the sub-basins of the test watershed to gain insights about the process dynamics portrayed by the model. Our findings indicate that the model is very sensitive to time and space resolution and cannot be transferred across scales without recalibration.

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