scholarly journals Modeling Mulch to Understand Agricultural Soil

Eos ◽  
2021 ◽  
Vol 102 ◽  
Author(s):  
Morgan Rehnberg
Keyword(s):  
Agricultural Soil ◽  
Surface Soil ◽  
Soil Conditions ◽  
New Model ◽  
Important Regulator ◽  
Shed Light

A new model helps shed light on residue mulch, an important regulator of surface soil conditions.

scholarly journals Interactive coupling of regional atmosphere with biosphere in the new generation regional climate system model REMO-iMOVE

2014 ◽  
Vol 7 (3) ◽  
pp. 1093-1114 ◽  
Author(s):  
C. Wilhelm ◽  
D. Rechid ◽  
D. Jacob
Keyword(s):  
Land Surface ◽  
Regional Climate ◽  
Regional Model ◽  
Horizontal Resolution ◽  
Soil Conditions ◽  
Data Sets ◽  
Vegetation Phenology ◽  
Land Surface Scheme ◽  
New Model ◽  
Surface Scheme

Abstract. The main objective of this study is the coupling of the regional climate model REMO with a new land surface scheme including dynamic vegetation phenology, and the evaluation of the new model version called REMO with interactive MOsaic-based VEgetation: REMO-iMOVE. First, we focus on the documentation of the technical aspects of the new model constituents and the coupling mechanism. The representation of vegetation in iMOVE is based on plant functional types (PFTs). Their geographical distribution is prescribed to the model which can be derived from different land surface data sets. Here, the PFT distribution is derived from the GLOBCOVER 2000 data set which is available on 1 km × 1 km horizontal resolution. Plant physiological processes like photosynthesis, respiration and transpiration are incorporated into the model. The vegetation modules are fully coupled to atmosphere and soil. In this way, plant physiological activity is directly driven by atmospheric and soil conditions at the model time step (two minutes to some seconds). In turn, the vegetation processes and properties influence the exchange of substances, energy and momentum between land and atmosphere. With the new coupled regional model system, dynamic feedbacks between vegetation, soil and atmosphere are represented at regional to local scale. In the evaluation part, we compare simulation results of REMO-iMOVE and of the reference version REMO2009 to multiple observation data sets of temperature, precipitation, latent heat flux, leaf area index and net primary production, in order to investigate the sensitivity of the regional model to the new land surface scheme and to evaluate the performance of both model versions. Simulations for the regional model domain Europe on a horizontal resolution of 0.44° had been carried out for the time period 1995–2005, forced with ECMWF ERA-Interim reanalyses data as lateral boundary conditions. REMO-iMOVE is able to simulate the European climate with the same quality as the parent model REMO2009. Differences in near-surface climate parameters can be restricted to some regions and are mainly related to the new representation of vegetation phenology. The seasonal and interannual variations in growth and senescence of vegetation are captured by the model. The net primary productivity lies in the range of observed values for most European regions. This study reveals the need for implementing vertical soil water dynamics in order to differentiate the access of plants to water due to different rooting depths. This gets especially important if the model will be used in dynamic vegetation studies.

scholarly journals Membrane-MEDYAN: Simulating Deformable Vesicles Containing Complex Cytoskeletal Networks

2021 ◽  
Author(s):  
Haoran Ni ◽  
Garegin A. Papoian
Keyword(s):  
Plasma Membrane ◽  
Leading Edge ◽  
Membrane Dynamics ◽  
New Model ◽  
Biological Matter ◽  
Membrane Cytoskeleton ◽  
Filament Bundles ◽  
Membrane Protrusions ◽  
Cytoskeletal Networks ◽  
Shed Light

AbstractThe plasma membrane defines the shape of the cell and plays an indispensable role in bridging intra- and extra-cellular environments. Mechanochemical interactions between plasma membrane and cytoskeleton are vital for cell biomechanics and mechanosensing. A computational model that comprehensively captures the complex, cell-scale cytoskeleton-membrane dynamics is still lacking. In this work, we introduce a triangulated membrane model that accounts for membrane’s elastic properties, as well as for membrane-filament steric interactions. The corresponding force-field was incorporated into the active biological matter simulation platform, MEDYAN (“Mechanochemical Dynamics of Active Networks”). Simulations using the new model shed light on how actin filament bundling affects generation of tubular membrane protrusions. In particular, we used membrane-MEDYAN simulations to investigate protrusion initiation and dynamics while varying geometries of filament bundles, membrane rigidities and local G-Actin concentrations. We found that bundles’ protrusion propensities sensitively depend on the synergy between bundle thickness and inclination angle at which the bundle approaches the membrane. The new model paves the way for simulations of biological systems involving intricate membrane-cytoskeleton interactions, such as occurring at the leading edge and the cortex, eventually helping to uncover the fundamental principles underlying the active matter organization in the vicinity of the membrane.

scholarly journals Simulation of Soil Compaction by a Tractor Passing

2021 ◽  
Vol 906 (1) ◽  
pp. 012105
Author(s):  
Pavla Bukovská ◽  
Patrik Burg ◽  
Vladimir Masán ◽  
Alice Cížková
Keyword(s):  
Cyclic Loading ◽  
Soil Compaction ◽  
Agricultural Soil ◽  
Elastic Behaviour ◽  
Soil Conditions ◽  
Vertical Deformation ◽  
Vertical Deflection ◽  
Loading Test ◽  
Final Level ◽  
Good Potential

Abstract Several methods for agricultural soil compaction evaluation are known. However, there is a lack of knowledge about a soil elasticity, which could be an important factor for final level of compaction. The paper deals with a possibility of evaluation of soil elasticity using automatic computerized oedometer. A simulation of tractor passing was performed as a part of research focused on the monitoring of soil conditions in vineyards. Cyclic loading test of five loading cycles (loading 300 kPa and un-loading 5 kPa) was performed and vertical deflection was observed, which changed in dependency on change of vertical stress. Course of vertical deformation indicates the ability of soil to relax when the load subsides. The paper presents pilot results, that show good potential of using oedometer for soil elasticity evaluating. Information on the elastic behaviour of soil will make it possible to design and apply means for improving soil elasticity and thus help to mitigate the effects of soil compaction.

Has tourism the resources and answers to a more inclusive society?

2020 ◽  
Vol 12 (6) ◽  
pp. 651-656 ◽  
Author(s):  
Jorge Costa
Keyword(s):  
Content Analysis ◽  
Design Methodology ◽  
Theme Issue ◽  
Content Type ◽  
New Model ◽  
Tourist Destinations ◽  
Universal Accessibility ◽  
Inclusive Approach ◽  
Inclusive Society ◽  
Shed Light

Purpose The purpose of this paper is to introduce the various papers in this issue and explain the pertinence of the strategic question. Design/methodology/approach A brief context for the strategic question is provided, as well as the issue alignment and a content analysis of the papers selected. Findings From the analysis of the papers selected for this theme issue, it becomes clear that destinations should reflect and work in a new model of tourism – more sustainable, innovative, responsible and supportive – adding value to the tourism ecosystem. Originality/value From various angles of analysis, the papers selected for this issue shed light on a relevant problem: the importance of tourist destinations in adopting a more inclusive approach. All tourist agents need to maintain their commitment to work together to promote universal accessibility and inclusiveness.

Tourism – ten possible solutions for a more inclusive society

2020 ◽  
Vol 12 (6) ◽  
pp. 775-779
Author(s):  
Jorge Costa ◽  
Mónica Montenegro ◽  
João Gomes
Keyword(s):  
Design Methodology ◽  
Theme Issue ◽  
Content Type ◽  
New Model ◽  
Tourist Destinations ◽  
Universal Accessibility ◽  
Inclusive Approach ◽  
Main Ideas ◽  
Inclusive Society ◽  
Shed Light

Purpose The purpose of this paper is to critically review the contributions made by the writing team for this theme issue and to present the main ideas, lines of action and implications for a model of inclusive tourism. Design/methodology/approach A content analysis of the papers selected for this issue was performed so as to identify the most relevant contributions made by the authors. Findings From the analysis of the papers in this theme issue, it is clear that destinations need to reflect on and work towards a new model of tourism – more sustainable, innovative, responsible and supportive – adding value to the tourism ecosystem. Originality/value The papers in this theme issue shed light on the importance for tourist destinations of adopting a more inclusive approach. All tourist actors need to maintain their commitment to work together to promote universal accessibility and inclusiveness and this can be characterized via a new model of positive tourism.

Drying of surface soil decreased Lupinus angustifolius root length and manganese uptake in a split-root experiment

1998 ◽  
Vol 49 (7) ◽  
pp. 1119 ◽  
Author(s):  
W. L. Crabtree ◽  
A. D. Robson ◽  
G. S. P. Ritchie
Keyword(s):  
Root Length ◽  
Surface Soil ◽  
Field Capacity ◽  
Lupinus Angustifolius ◽  
Soil Conditions ◽  
Soil Drying ◽  
Split Root ◽  
Manganese Uptake ◽  
Soil Wetting ◽  
Wilting Point

In a glasshouse, a split-root experiment was used to determine the ability oflupins (Lupinus angustifolius L.) to take up manganese(Mn) from dry soil either when young or at mid-flowering of the primarybranches. Three soil-watering regimes (maintained at field capacity,maintained below wilting point, and alternating from field capacity to wellbelow wilting point) were imposed after taproots had grown through topsoil andinto a nutrient solution below. Four sequential harvests (11, 22, 37, and 49days after sowing) were taken to determine the effect of soil drying on lupingrowth, Mn uptake, and soil-extractable Mn.Soil drying early in the lupin plant's life stopped the growth of lateralroots in the soil and slowed the growth of roots grown in subsoil solution andthe growth of lupin tops. Soil drying decreased uptake of Mn in the tops to13% of that under continuous wet soil conditions. Of the 13%,most (11%) was taken up while the soil was drying. Soil re-wettingenabled the plants to resume uptake of Mn and soil re-drying (just beforeanthesis) decreased the Mn concentration in the lupin stems to 4·8µg/g, whereas stems of lupins grown in the wet and dry soilscontained 10·3 and 3·3 µg/g, respectively. Easilyreducible and plant-available soil Mn were not affected by soil wetting anddrying treatments.This study confirms that the uptake of Mn by lupin may be severely restrictedby drying of surface soil at both the beginning and the end of the lupinplant's life. The decrease in root length rather than the chemical form of Mn restricted Mn uptake.

Characteristics of sediment loads in Ontario streams

1988 ◽  
Vol 15 (6) ◽  
pp. 1067-1079 ◽  
Author(s):  
W. T. Dickinson ◽  
D. R. Green
Keyword(s):  
Suspended Sediment ◽  
Extreme Events ◽  
Surface Soil ◽  
Extreme Values ◽  
Seasonal Pattern ◽  
Soil Conditions ◽  
Rill Erosion ◽  
Spring Period ◽  
Annual Peak ◽  
Sediment Loads

This study has involved a literature review and data analysis regarding suspended stream sediments in southern Ontario, highlighting knowledge and identifying gaps with reference to stream loadings, seasonal and areal variability, extreme events, sources of sediments, and sediment and water quality. The quantity of sediment transported in Ontario streams is generally not of major proportion or of major significance. Daily loads follow a distinctive seasonal pattern, the bulk being transported during the spring period; and sediment transport in the province is an event-oriented process, a large percentage of the load moving in a small percentage of time. Extreme events transport a significant portion of the total suspended load, but so also do annual peak events. The bulk of the load emanates from sheet and rill erosion in cropland areas, and areal variability in loads can be related to land use and surface soil conditions. Suspended sediment has been documented to be both a pollutant carrier or source of contamination and a sink or trap for pollutants such as phosphorus, organic compounds, pesticides, and heavy metals. Key words: suspended sediment, loads, temporal patterns, areal variability, extreme values, sources.

Tillage-induced differences in the growth and distribution of wheat-roots

1992 ◽  
Vol 43 (1) ◽  
pp. 19 ◽  
Author(s):  
KY Chan ◽  
JA Mead
Keyword(s):  
Root Growth ◽  
Root Length ◽  
Root Distribution ◽  
Shoot Growth ◽  
Surface Soil ◽  
Root Length Density ◽  
Soil Layer ◽  
Soil Conditions ◽  
The Poor ◽  
Direct Drilling

Root growth and distribution of wheat under different tillage practices was studied in a 4-year-old tillage experimental site at Cowra, N.S.W. Tillage affected root density as well as distribution. Up to 98 days after sowing, root length density was lower (P < 0.05) in the 0.05-0.10 m layer of the direct-drilled soil than the conventionally cultivated soil. Poor root growth found in direct-drilled soils, which was significantly related to the poor shoot growth, was not caused by soil physical conditions, viz. higher bulk density and soil strength. Rather, biological factors were involved because fumigation completely eliminated the poor shoot growth and significantly increased root length density of the direct drilled soils. Compared to a compaction treatment, roots grown under direct drilling, in addition to having lower density, also had impaired function. Under conventional cultivation, significantly lower root length density was found in the surface soil layer (0-0.05 m) and maximum root length density was found in the 0-05-0.10 m layer. Fumigation did not change the root distribution pattern. This tillage-induced difference in root distribution reflected less favourable surface soil conditions as a result of cultivation, e.g. seedbed slumping, compared to the soil under direct drilling.

Blade loosening creates a deeper and near-stable rooting zone that raises the productivity of a structurally unstable texture contrast soil

Soil Research ◽  
2017 ◽  
Vol 55 (2) ◽  
pp. 101 ◽  
Author(s):  
G. J. Hamilton ◽  
J. Sheppard ◽  
R. Bowey ◽  
P. Fisher
Keyword(s):  
Moisture Content ◽  
Root Growth ◽  
Grain Yield ◽  
Surface Soil ◽  
Root Zone ◽  
Soil Disturbance ◽  
Soil Conditions ◽  
Gross Margin ◽  
Rooting Zone ◽  
Texture Contrast

Improving the workability and raising the productivity of structurally weak and/or dispersive texture contrast soils has been the objective of many research projects. These have used applications of gypsum, with and without ripping the top 300–400mm depth of soil, and responses have been moderate and short lived. The approach taken in the present study was to ameliorate the soil by a combination of subtle soil disturbance to a depth of approximately 300mm using a specially designed blade loosener, with controlled traffic and no-tillage crop establishment practices. The aim was to use the roots of the stimulated plant growth to stabilise a loosened and deepened root zone. Comparative conditions in the 0–500mm depth of soil in blade-loosened and normal seedbeds were monitored over three very different growing seasons (2001, 2002 and 2003) using chemical analyses, bulk density (BD), penetration resistance (PR) and soil moisture content measurements. Productivity was monitored by dry matter and grain yield, and profitability by gross margin analyses. Structural stability of the rooting zone soil, or the lack of it, was shown to be a consequence of how the seasonal dynamics of the profile moisture content affected the probability of waterlogged surface soil conditions. In the normal seedbed (control) the surface soil quickly reconsolidated (BD ≥1500kgm–3), and subsoil BD (BD ≈ 1800kgm–3), PR (≥1.8MPa) and percentage saturation (≥95%) remained at levels restrictive of root growth. Conversely, the same properties in the surface and subsoil of the blade-loosened seedbed remained at levels conducive to unrestricted root growth (BD ≤1400kgm–3, PR ≤1.1MPa, saturation ≤70%). The blade-loosened treatment was substantially more productive (average grain yield increase 35%; P<0.05) and profitable (average gross margin increase 56%).

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