Improvements of physical properties of degraded shallow organic soils by admixing organic overlays and mineral sublayers

1991 ◽  
Vol 71 (1) ◽  
pp. 101-117 ◽  
Author(s):  
H. Dinel ◽  
S. P. Mathur ◽  
M. Lévesque
Keyword(s):  
Soil Structure ◽  
Crop Yields ◽  
Organic Amendments ◽  
Aggregate Size ◽  
Organic Soils ◽  
Structure Stability ◽  
Size Fractionation ◽  
Physical Conditions ◽  
Soil Media ◽  
The Stability

Twenty-five soil media representing 13 subsoils and organic overlays, and their mixtures, that had been used in pot culture fallow, or for growing root, leafy vegetable and grass crops, were studied to determine if the benefits of organic amendments to crop yields in optimally watered and fertilized soils were due to improvements in soil physical conditions. The soils were subjected to particle and aggregate size fractionation; and the stability of the aggregates was determined. The results suggested that admixing of residual organic overlays improved the structure of all mineral subsoils, except perhaps an alluvial sand. Aggregation and stability of aggregates > 2 mm were improved, thus leading to improved aeration, root proliferation and to increases in crop yields. In addition, grass crops were shown to be more effective than root and leafy crops for improvement of the structure of the various soils. Key words: Organic soils, soil aggregation, soil structure stability

Structure, Stability and Water Adsorption on Ultra-Thin TiO2 Supported on TiN

2019 ◽  
Author(s):  
Jose Julio Gutierrez Moreno ◽  
Marco Fronzi ◽  
Pierre Lovera ◽  
alan O'Riordan ◽  
Mike J Ford ◽  
...  
Keyword(s):  
Density Functional ◽  
Water Adsorption ◽  
Chemical Potential ◽  
Energy Gap ◽  
Molecular Water ◽  
Structure Stability ◽  
Ambient Conditions ◽  
Rutile Structure ◽  
The Stability ◽  
The One

<p></p><p>Interfacial metal-oxide systems with ultrathin oxide layers are of high interest for their use in catalysis. In this study, we present a density functional theory (DFT) investigation of the structure of ultrathin rutile layers (one and two TiO<sub>2</sub> layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti–O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti<sup>3+</sup> cations in TiO<sub>2.</sub> The structure of the one-layer oxide slab is strongly distorted at the interface, while the thicker TiO<sub>2</sub> layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly non-stoichiometric interfaces. Isolated water molecules dissociate when adsorbed at the TiO<sub>2</sub> layers. At higher coverages the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. Interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. A water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO<sub>1.75</sub>-TiN interface, where the Ti<sup>3+</sup> states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO<sub>2</sub>-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultrathin TiO<sub>2</sub> with potential application as photocatalytic water splitting devices.</p><p></p>

scholarly journals A short-term comparison of organic v. conventional agriculture in a silty loam soil using two organic amendments

2008 ◽  
Vol 146 (6) ◽  
pp. 677-687 ◽  
Author(s):  
J. F. HERENCIA ◽  
J. C. RUIZ ◽  
S. MELERO ◽  
P. A. GARCIA GALAVÍS ◽  
C. MAQUEDA
Keyword(s):  
Organic Farming ◽  
Crop Yields ◽  
Organic Amendments ◽  
Chemical Properties ◽  
Soil Nutrient ◽  
Short Term ◽  
Organic System ◽  
Conventional Agriculture ◽  
Silty Loam ◽  
Loam Soil

SUMMARYThe transition from conventional to organic farming is accompanied by changes in soil chemical properties and processes that could affect soil fertility. The organic system is very complex and the present work carries out a short-term comparison of the effects of organic and conventional agriculture on the chemical properties of a silty loam soil (Xerofluvent) located in the Guadalquivir River Valley, Seville, Spain, through a succession of five crop cycles over a 3-year period. Crop rotation and varieties were compared in a conventional system using inorganic fertilizer and two organic systems using either plant compost or manure. At the end of the study, organic farming management resulted in higher soil organic carbon (OC), N and available P, K, Fe and Zn. The available Mn and especially Cu values did not show significant differences. In general, treatment with manure resulted in more rapid increases in soil nutrient values than did plant compost, which had an effect on several crop cycles later. The present study demonstrated that the use of organic composts results in an increase in OC and the storage of nutrients, which can provide long-term fertility benefits. Nevertheless, at least 2–3 years of organic management are necessary, depending on compost characteristics, to observe significant differences. Average crop yields were 23% lower in organic crops. Nevertheless, only two crops showed statistically significant differences.

scholarly journals Effect of Organic Residues on Pesticide Behavior in Soils: A Review of Laboratory Research

Environments ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 32
Author(s):  
María J. Carpio ◽  
María J. Sánchez-Martín ◽  
M. Sonia Rodríguez-Cruz ◽  
Jesús M. Marín-Benito
Keyword(s):  
Crop Yields ◽  
Organic Matter Content ◽  
Organic Amendments ◽  
Matter Content ◽  
Laboratory Research ◽  
Laboratory Studies ◽  
Future Perspectives ◽  
Organic Residues ◽  
Multiple Factors ◽  
Adsorption Desorption

The management of large volumes of organic residues generated in different livestock, urban, agricultural and industrial activities is a topic of environmental and social interest. The high organic matter content of these residues means that their application as soil organic amendments in agriculture is considered one of the more sustainable options, as it could solve the problem of the accumulation of uncontrolled wastes while improving soil quality and avoiding its irreversible degradation. However, the behavior of pesticides applied to increase crop yields could be modified in the presence of these amendments in the soil. This review article addresses how the adsorption–desorption, dissipation and leaching of pesticides in soils is affected by different organic residues usually applied as organic amendments. Based on the results reported from laboratory studies, the influence on these processes has been evaluated of multiple factors related to organic residues (e.g., origin, nature, composition, rates, and incubation time of the amended soils), pesticides (e.g., with different use, structure, characteristics, and application method), and soils with different physicochemical properties. Future perspectives on this topic are also included for highlighting the need to extend these laboratory studies to field and modelling scale to better assess and predict pesticide fate in amended soil scenarios.

SOIL CONDITIONERS—THEIR EFFECT ON COARSE-TEXTURED SOILS, CROP YIELDS AND COMPOSITION

1957 ◽  
Vol 37 (2) ◽  
pp. 102-112
Author(s):  
R. M. Holmes ◽  
S. J. Toth
Keyword(s):  
Structural Changes ◽  
Crop Yields ◽  
Cultural Practices ◽  
Sandy Soils ◽  
Growing Season ◽  
Soil Aggregate ◽  
Crop Response ◽  
The Third ◽  
Soil Conditioners ◽  
The Stability

Crop response to soil structural changes caused by soil conditioner amendments was studied in several different sandy soils of New Jersey. The response varied with the crop and treatment. Those chemicals that were slightly hydrophobic were most effective and generally crop response was greatest on these treatments. Cations such as Na may be added in large amounts as part of some conditioners, and this may result in reduced uptake of other nutrients such as Mg. and K. Except for this effect, conditioners did not reduce nutrient uptake by plants. When elements such as Na and N are added in large amounts as part of some conditioners, there may be an increased uptake of these nutrients.Catalin and VAMA conditioners produced a dry surface mulch which appeared to reduce evaporation. Moisture reserves were, therefore, preserved through a drought and this resulted in increased growth of crops over those grown on other treatments. Cultural practices destroyed the stability of the conditioned aggregates, since in most cases the effect had largely disappeared by the third growing season. Chemicals which were effective in soil aggregate stabilization were also effective as anti-crustants when crusting was a problem.

scholarly journals Adaptasi Sanctification of Marriage Questionnaire: Versi Indonesia untuk Masyarakat Muslim

2021 ◽  
Vol 26 (1) ◽  
pp. 217-232
Author(s):  
Hepi Wahyuningsih ◽  
Dyna Rahayu Suci Pertiwi
Keyword(s):  
Factor Analysis ◽  
Confirmatory Factor Analysis ◽  
Construct Validity ◽  
Exploratory Factor Analysis ◽  
Factor Structure ◽  
Structure Stability ◽  
Validity And Reliability ◽  
Confirmatory Factor ◽  
The Stability ◽  
Composite Reliability

This study aims to adapt the Sanctification of Marriage Questionnaire for Muslims inIndonesia. Adaptation of the Sanctification of Marriage Questionnaire is carried out throughthe stages: translation, providing evidence of construct validity and reliability. Evidence of construct validity was carried out by exploratory factor analysis followed by MGCFA (Multi-Group Confirmatory factor Analysis). In this study, we used a composite reliability. Subjects to reveal the factor structure of sanctification of marriage were 160 married individuals, while the subjects to test the stability of factor structure consisted of 102 husbands and 111 wives. The result of exploratory factor analysis shows that the construct of sanctification of marriage has three factors / dimensions, namely: belief, perceived sacred qualities and manifestation of God. The structure stability of sanctification of marriage was then empirically tested by MGCFA. The results of MGCFA showed that the three factors / dimensions of sanctification of marriage proved stable. The composite reliability coefficient of the Sanctification of Marriage Questionnaire was in a good category. Further research can be carried out to provide evidence of construct validity with predictive validity and concurrent validity of the Sanctification of Marriage Questionnaire. Limitations in this study are discussed further.Keywords: exploratory factor analysis, multi-group confirmatory factor analysis, muslim,sanctification of marriage, scale adaptation

scholarly journals IS THE CAPITAL STRUCTURE STABLE IN BRAZIL?

2019 ◽  
Vol 20 (4) ◽  
Author(s):  
PÂMELA A. TRISTÃO ◽  
IGOR B. SONZA
Keyword(s):  
Capital Structure ◽  
Statistical Significance ◽  
Graphical Analysis ◽  
Structure Stability ◽  
Publicly Traded ◽  
Publicly Traded Companies ◽  
Tax Benefits ◽  
The Stability ◽  
Second Period ◽  
The Capital Structure

ABSTRACT Purpose: This paper’s objective is to analyze whether the capital structure of Brazilian publicly traded companies remained stable over the last twenty years. Originality/value: The paper is focused on the Brazilian capital market, in which there is a lack in the literature about the study of the leverage behavior and its immaturity, where factors related to the companies and characteristics in contracting leverage alter the demand of credit. Design/methodology/approach: To achieve its objective, initially a graphical analysis of market and book debt evolution was carried out, and a GMM-Sys regression model through panel data was estimated to identify the stability of leverage along time. Findings: The results indicate a reduction of the market leverage with higher statistical significance after 2008, indicating, both in the graphic and the regression analysis, that the use of debt was unstable in the first period analyzed (1995-2007), behavior not observed during the second period (2008-2015) when analyzed market measures in which capital structure stability was prevalent, with considerable reduction of corporate leverage, otherwise, book measures of leverage would have shown a stability trend in leverage patterns. The principal determinants of the capital structure were the tax benefits (book debt) and the size (market debt), supporting trade-off theory.

Design and analysis of a new frame-foot wall-climbing robot

2021 ◽  
pp. 095440702110402
Author(s):  
Ping Huo ◽  
Yangyang Xu ◽  
Jiangtao Yu ◽  
Yazhou Wang
Keyword(s):  
Structure Design ◽  
Working Environment ◽  
Structure Stability ◽  
Foot Wall ◽  
Climbing Robot ◽  
3D Design ◽  
Motion Equations ◽  
Solution Models ◽  
New Type ◽  
The Stability

This paper designs and develops a new type of frame-foot wall-climbing robot structure. According to the bionic principle, a new parallel telescopic leg structure is proposed, and the 3D design of the overall structure of the wall-climbing robot is completed. Secondly, the kinematics analysis of the robot is carried out, and the forward and inverse solution models of the leg structure position are completed to verify the feasibility of the leg structure stability. Based on the polynomial motion equations, the robot motion planning and gait design are established, and the speed and acceleration change graphs of the leg structure slider are obtained, which avoids the rigid impact between the parts, and realizes the alternate adsorption and continuous movement of the robot legs, which the rationality of the legs structure design and the stability of the movement are verified. Through simulation and experimental results, it is shown that during the robot’s movement, the leg structure can adjust the step distance and step height according to obstacles, so as to achieve the expected obstacle crossing goal. The leg structure is adjusted according to the working environment to ensure that the fuselage and the working surface are always kept parallel to improve the stability of the overall structure.

scholarly journals Interactive Effects of Biochar and Sewage Sludge on Bioavailability and Plant Uptake of Cu, Fe, and Zn, and Spinach (Spinacia oleracea L.) Yields under Wastewater Irrigation

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1901
Author(s):  
Ugele Majaule ◽  
Oagile Dikinya ◽  
Bruno Glaser
Keyword(s):  
Sewage Sludge ◽  
Crop Yields ◽  
Spinacia Oleracea ◽  
Block Design ◽  
Organic Amendments ◽  
High Rate ◽  
Interactive Effects ◽  
Yield Response ◽  
Yield Increase ◽  
Spinacia Oleracea L

Biochar can influence bioavailability of micronutrients and crop yields in sewage sludge-treated soils, but the mechanisms of its effects remain poorly understood. Therefore, this field experiment was conducted on a Luvisol and Cambisol to investigate the bioavailability and uptake of some micronutrients and spinach (Spinacia oleracea L.) yields grown in soil amended with biochar and sewage sludge. Ten treatments arranged in randomized complete block design with three levels of biochar (0, 2.5, 5 t/ha) and sewage sludge (0, 6, 12 t/ha) and combinations thereof were applied. High rate of sole sewage sludge, and its combination with biochar significantly (p < 0.05) increased yield on the Luvisol. On the Cambisol, only marginal yield increase resulted from high rates of sole organic amendments and chemical fertilizer, while co-applications decreased yields. Co-amendments generally increased bioavailability of micronutrients relative to sole amendments in the order Fe > Cu = Zn, with greater increase on the Cambisol, but uptake of micronutrients decreased with co-application rates of amendments. Contents of micronutrients in plant leaves were within the normal range, except for a combination of highest dosage of co-amendments on the Cambisol (Fe; 560 mg/kg), which resulted in leaf necrosis and 7% yield depression. The results showed greater yield response of spinach to co-application of amendments on the Luvisol.

Amending soil with sludge, manure, humic acid, orthophosphate and phytic acid: effects on aggregate stability

Soil Research ◽  
2014 ◽  
Vol 52 (4) ◽  
pp. 317 ◽  
Author(s):  
A. I. Mamedov ◽  
B. Bar-Yosef ◽  
I. Levkovich ◽  
R. Rosenberg ◽  
A. Silber ◽  
...  
Keyword(s):  
Humic Acid ◽  
Phytic Acid ◽  
Structural Stability ◽  
Organic Amendments ◽  
Aggregate Stability ◽  
Loamy Sand ◽  
Soil Aggregate Stability ◽  
Before And After ◽  
Soil Structural Stability ◽  
The Stability

Recycling of organic wastes via their incorporation in cultivated lands is known to alter soil structural stability. Aggregate stability tests are commonly used to express quantitatively the susceptibility of soil structural stability to deformation. The objective of this study was to investigate the effects of biosolids addition, namely composted manure (MC) and activated sludge (AS), and spiking of the soils with orthophosphate (OP), phytic acid (PA) or humic acid (HA), on soil aggregate stability of semi-arid loamy sand, loam and clay soils before and after subjecting the soils to six rain storms (each 30 mm rain with a break of 3–4 days). Aggregate stability was determined from water-retention curves at high matric potential. The effects of the applied amendments on pre- and post-rain aggregate stability were inconsistent and soil-dependent. For the pre-rain state, all of the tested amendments improved aggregate stability relative to the control. For the post-rain condition, aggregate stability was lower in the MC, OP and PA treatments and higher in the AS and HA treatments than in the control. The coarse-textured loam and loamy sand soils were more affected by the soil amendments than the clay soil. For the pre-rain state, addition of organic matter significantly improved macro-porosity and hence the stability of apparent macro-aggregate (>250 μm). Our results indicate a possible advantage for separation of aggregates into macro- and micro-aggregates for more precise evaluation and understanding of the effects organic amendments might have on aggregate stability.

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