scholarly journals Runoff Chemistry at a Mini-Catchment Watered with “Unpolluted Precipitation”

1982 ◽  
Vol 13 (2) ◽  
pp. 115-128 ◽  
Author(s):  
N. Christophersen ◽  
A.O. Stuanes ◽  
R.F. Wright
Keyword(s):  
Steady State ◽  
Chemical Composition ◽  
Acid Soils ◽  
Acidic Precipitation ◽  
Natural Conditions ◽  
Long Term Experiments ◽  
Southern Norway ◽  
Spring Snowmelt ◽  
Water Extractable

600 mm of artificial, “unpolluted” precipitation with a chemical composition of assumed preindustrial quality ([H+] = 9 μeql−1, [SO4] = 11 μeql−1) was sprayed on a “mini-catchment” (98 m2) over a period of 3½ weeks. The mini-catchment is a granitic bowl partially covered with shallow, acid soils. It is located in the Storgama area, Telemark county, southern Norway, an area which today receives acidic precipitation ([H+] = 54 μeql−1, [SO4] = 59 μeql−1). The treatment resulted in lowered values for [H+], [Al] and [SO4] in runoff within a week. Excluding the spring snowmelt, [H+] ≈ 50 μeql−1 (pH = 4.3) under natural conditions, whereas during the experiment [H+] levelled off at 30 μeql−1 (pH = 4.5). Correlation analysis suggests that SO4 and organic anions are related to the runoff acidity. The level of total organic carbon in runoff was, however, elevated compared to undisturbed conditions. Under the present natural conditions S04 is the most important anion. The amount of water-extractable sulfate in the soil is equivalent to about ½ of the present yearly input. The response in the sulfate output to a reduced input is difficult to predict because of processes which transform sulfur to and from various compounds in the soil and vegetation. Several years may be required before a new steady state is reached after a substantial decrease in input. Long-term experiments in which the catchment is shielded against natural precipitation are required to obtain more certain estimates of the response in runoff composition.

A geophysiologist's thoughts on geoengineering

2008 ◽  
Vol 366 (1882) ◽  
pp. 3883-3890 ◽  
Author(s):  
James Lovelock
Keyword(s):  
Steady State ◽  
Chemical Composition ◽  
Greenhouse Gases ◽  
Land Surface ◽  
Physiological System ◽  
Surface Chemical ◽  
Surface Chemical Composition ◽  
The Earth ◽  
Nineteenth Century Medicine

The Earth is now recognized as a self-regulating system that includes a reactive biosphere; the system maintains a long-term steady-state climate and surface chemical composition favourable for life. We are perturbing the steady state by changing the land surface from mainly forests to farm land and by adding greenhouse gases and aerosol pollutants to the air. We appear to have exceeded the natural capacity to counter our perturbation and consequently the system is changing to a new and as yet unknown but probably adverse state. I suggest here that we regard the Earth as a physiological system and consider amelioration techniques, geoengineering, as comparable to nineteenth century medicine.

ANALYSIS OF HYDROGEOLOGICAL CONDITIONS SUPPORTED BY A MATHEMATICAL MODELING AS THE BASIC STAGE OF INVESTMENT PROJECTS IN GEOTHERMY FIELD

2018 ◽  
Vol 471 ◽  
pp. 179-184
Author(s):  
Barbara TOMASZEWSKA ◽  
Marta DENDYS ◽  
Leszek PAJĄK
Keyword(s):  
Mathematical Modeling ◽  
Chemical Composition ◽  
Mathematical Modelling ◽  
Basic Information ◽  
Geothermal Systems ◽  
Natural Conditions ◽  
Investment Projects ◽  
Basic Stage ◽  
Physical Features

Geothermal groundwaters are deposits that must be categorised as a mining property. Their exploitation is possible with a mining concession and permission of use. Geothermal groundwaters in Poland are used in heating, balneotherapy and recreation purposes. Over the last years, investigations have been carried out to intensify the use of geothermal groundwaters. They can be used as new geothermal products, for example as a mineralised concentrate. Investment projects related to geothermal groundwaters should be prepared with care about safe and sustained exploitation in long-term perspective. Using of geothermal groundwaters is determined by technical and economical conditions. However, successful exploitation depends also on natural conditions e.g. water temperature, physical features, chemical composition and durability of parameters, and renewability of resources. Recognition of these elements give a basic information that nowadays can be integrated as mathematical models. The models are created to analyse and simulate the conditions of geothermal systems. It often happens before starting project operating activities. The paper presents examples of projects carried out over the recent years. They have been associated with the using and management of geothermal groundwaters and the key role has been played by mathematical modelling in the field of geothermy and hydrogeology.

Calibration of methods for soil and diagnostic plant analysis in the Hungarian National Fertilization Long-term Trials. I. Comparison of soil P tests for agronomic purposes in the soils of long-term experiments

2011 ◽  
Vol 60 (2) ◽  
pp. 343-358
Author(s):  
Péter Csathó ◽  
Marianna Magyar ◽  
Erzsébet Osztoics ◽  
Katalin Debreczeni ◽  
Katalin Sárdi
Keyword(s):  
Plant Analysis ◽  
Soil P ◽  
Olsen P ◽  
Long Term Experiments ◽  
Soil P Tests

A szabadföldi trágyázási (tartam)kísérletek eredményeit talaj-, illetve diagnosztikai célú növényvizsgálatok segítségével tudjuk kiterjeszteni, általánosítani – figyelembe véve természetesen a kiterjesztés korlátait is. Célszerűnek láttuk ezen túl a talaj könnyen oldható tápelem-, közöttük P-tartalmát is meghatározni a hazánkban hivatalosan elfogadott AL- (ammónium-laktátos) módszer mellett az Európai Unióban és Észak-Amerikában alkalmazott P-tesztekkel is (CaCl2-, H2O-, Olsen-, Bray1-, LE-, Mehlich3- stb.) a hazai OMTK kísérletek talajmintáiban. A kísérleti helyek talajtulajdonságaiban megnyilvánuló jelentős különbségek lehetőséget adnak rá, hogy a talaj P-teszteket – és a növényi P-felvételt – jellegzetes hazai talajokon, sokszor szélsőséges talajparaméterek mellett vizsgáljuk. Az egyes P-szintek között a 28 év átlagában mintegy évi 50 kg P2O5·ha-1volt a különbség. A P0-szinten mért P-tartalmak jól jelezték az egyes kísérleti helyek talajának eltérő P-ellátottságát, illetve, közvetve, fizikai féleségében, pH és mészállapotában meglévő különbségeket. A P2-szinten – a hazai talajokra, P-igényes növényekre a hazai szabadföldi P-trágyázási tartamkísérleti adatbázisban talált összefüggésekre alapozott – új AL-P határértékek szerint csupán a bicsérdi csernozjom barna erdőtalajon nem javult a P-ellátottság legalább a „jó” szintig. Vizsgálataink megerősítették az AL-módszer függőségét a CaCO3-tartalomtól: a Mehlich3 módszerrel való összefüggésben a karbonátmentes és a karbonátos talajok csoportja erőteljesen elkülönült egymástól. Az AL-P korrekció elvégzése, azaz az AL-P értékeknek egy standard talajtulajdonság-sorra való konvertálása (KA: 36; pH(KCl): 6,8; CaCO3: 0,1%) látványosan csökkentette az AL-módszernek a talaj CaCO3-tartalmától való függőségét. Az AL-P és Olsen-P, valamint a korrigált AL-P és Olsen-P tartalmak összehasonlításában ugynakkor ugyanez az összefüggés nem volt állapítható, ami arra utal, hogy az Olsen módszer bizonyos fokig szintén pH- és mészállapot függő. Kísérleti eredményeink megerősítették a Sarkadi-féle AL-P korrekciós modell helytálló voltát. Fenti megállapításunkat ugyanakkor a növényi P-tartalmakkal való összefüggéseknek is igazolniuk kell. Szükséges tehát a talajvizsgálati eredményeknek a diagnosztikai célú növényvizsgálatokkal, valamint a terméseredményekkel való összevetése. A tartamkísérletek talajai lehetőséget nyújtanak a környezetvédelmi célú P-vizsgálatok értékelésére, a talaj P-feltöltöttsége környezeti kockázatának becslésére. Ezekkel a kérdésekkel a cikksorozat további részeiben kívánunk foglalkozni.

scholarly journals Stability and moment bounds under utility-maximising service allocations: Finite and infinite networks

2020 ◽  
Vol 52 (2) ◽  
pp. 463-490
Author(s):  
Seva Shneer ◽  
Alexander Stolyar
Keyword(s):  
Steady State ◽  
Wide Class ◽  
Continuous Time ◽  
Service Rate ◽  
Fluid Limit ◽  
Natural Conditions ◽  
Infinite Systems ◽  
Moment Bounds ◽  
Infinite Networks ◽  
State Moment

AbstractWe study networks of interacting queues governed by utility-maximising service-rate allocations in both discrete and continuous time. For finite networks we establish stability and some steady-state moment bounds under natural conditions and rather weak assumptions on utility functions. These results are obtained using direct applications of Lyapunov–Foster-type criteria, and apply to a wide class of systems, including those for which fluid-limit-based approaches are not applicable. We then establish stability and some steady-state moment bounds for two classes of infinite networks, with single-hop and multi-hop message routes. These results are proved by considering the infinite systems as limits of their truncated finite versions. The uniform moment bounds for the finite networks play a key role in these limit transitions.

scholarly journals Can Long-Term Experiments Predict Real Field N and P Balance and System Sustainability? Results from Maize, Winter Wheat, and Soybean Trials Using Mineral and Organic Fertilisers

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1472
Author(s):  
Ilaria Piccoli ◽  
Felice Sartori ◽  
Riccardo Polese ◽  
Maurizio Borin ◽  
Antonio Berti
Keyword(s):  
Winter Wheat ◽  
Nutrient Balance ◽  
Environmental Indicators ◽  
Nutrient Loss ◽  
Real Field ◽  
Short Term ◽  
Organic Fertiliser ◽  
Long Term Experiments ◽  
P Balance

Agri-environmental indicators such as nutrient balance may play a key role in soil and water quality monitoring, although short-term experiments might be unable to capture the sustainability of cropping systems. Therefore, the objectives of this study are: (i) to evaluate the reliability of long-term experimental N and P balance estimates to predict real field (RF) (i.e., short-term transitory) conditions; and (ii) to compare the sustainability of short- and long-term experiments. The LTE-based predictions showed that crops are generally over-fertilised in RF conditions, particularly maize. Nutrient balance predictions based on the LTE data tended to be more optimistic than those observed under RF conditions, which are often characterised by lower outputs; in particular, 13, 44, and 47% lower yields were observed for winter wheat, maize, and soybean, respectively, under organic management. The graphical evaluation of N and P use efficiency demonstrated the benefit of adopting crop rotation practices and the risk of nutrient loss when liquid organic fertiliser was applied on a long-term basis. In conclusion, LTE predictions may depend upon specific RF conditions, representing potential N and P use efficiencies that, in RF, may be reduced by crop yield-limiting factors and the specific implemented crop sequence.

Monitoring the Chemical Composition of Air in Case of Interplanetary and Long-Term Space Flights: Problems, Approaches, and Solutions

2019 ◽  
Vol 13 (4) ◽  
pp. 685-713
Author(s):  
Sh. Sh. Nabiev ◽  
G. Yu. Grigor’ev ◽  
A. S. Lagutin ◽  
L. A. Palkina ◽  
A. A. Vasil’ev ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Space Flights

scholarly journals Long-term repopulating hematopoietic stem cells and “side population” in human steady state peripheral blood

2013 ◽  
Vol 11 (1) ◽  
pp. 625-633 ◽  
Author(s):  
Philippe Brunet de la Grange ◽  
Marija Vlaski ◽  
Pascale Duchez ◽  
Jean Chevaleyre ◽  
Veronique Lapostolle ◽  
...  
Keyword(s):  
Stem Cells ◽  
Steady State ◽  
Hematopoietic Stem Cells ◽  
Peripheral Blood ◽  
Side Population ◽  
Hematopoietic Stem
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