scholarly journals Aggregation Index in Representative Soils of the Paraiba State

2021 ◽  
Vol 9 (7) ◽  
pp. 266-281
Author(s):  
Petrus Luiz de Luna Pequeno ◽  
Flávio Pereida de Oliveira ◽  
Viviane Barrozo da Silva ◽  
Antonio Carlos Duarte Ricciotti ◽  
Jairo André Schlindwein ◽  
...  
Keyword(s):  
Soil Aggregates ◽  
Weighted Average ◽  
Stability Index ◽  
Average Diameter ◽  
Soil Samples ◽  
Chemical Parameters ◽  
Aggregation Index ◽  
Soil Class ◽  
The Stability ◽  
Wet Sieving

The stability of soil aggregates is an important physical parameter as it mainly influences the flow of water and air in the soil. In this sence, the research aimed to determine the stability aggregates index in six representative soil classes in the Paraíba State-Brazil at different stages of pedological development. The soil classes analyzed is localized on the Microregions of the Curimataú Occidental (Ferrasol, Planosol, Leptosol, Arenosol) and Brejo Paraibano (Acrisol, Lixisol), on the Paraíba state, Brazil. At depths of 0-5 cm, 5-10 cm and 10-20 cm was collected three undeformed soil samples were collected per mini trench (one per depth), making a total of 15 samples per soil class and 90 total samples.  In each soil class was analysed: chemical parameters, granulometrics parameters, stability of agregates,  Weighted average diameter via wet sieving (DMPAu) and Weighted average diameter via dry sieving (DMPAs); agregate stability index (IEA). For the conditions that research was developed can conclude that: The IEA values tended to increase with clay contents in all soil classes; Among the less developed soils, the IEA values were better in the  Planosol soil, denoting that there is a probable relationship with the low contents of K, Na and Al; In the more developed soils, the high values of Na and Al may have contributed to the lower IEA in the PVd, while the lower values may have contributed to the higher IEA in Ferrasol and Lixisol soils.

scholarly journals Fast immersion to test the stability of aggregates in water: consequences for interpreting results from tropical soil classes

2019 ◽  
Vol 42 ◽  
pp. e42453
Author(s):  
Rodrigo Fonseca da Silva ◽  
Patriciani Estela Cipriano ◽  
Matias Siueia Junior ◽  
Geslin Mars ◽  
Moacir de Souza Dias Junior
Keyword(s):  
Soil Aggregates ◽  
Geometric Mean ◽  
Weighted Average ◽  
Aggregate Stability ◽  
Stability Index ◽  
Average Diameter ◽  
Tropical Soils ◽  
Organic Carbon Content ◽  
Pre Treatment ◽  
High Organic Carbon Content

Aggregates are the primary structural components of soil and have been used as an indicator of soil quality in conservation systems. The objective of this study was to analyse the effect of slow pre-wetting on the results of the aggregate stability test for different classes of tropical soils. Data were arranged in a 2 x 4 factorial design with three replications, in which the first factor comprised the two methods of pre-treatment on soil aggregates: without pre-wetting (WOPW), which considered the moisture of the aggregates in the field, and with pre-wetting (WPW), which considered the slow wetting of aggregates through capillarity on wet filter paper for 24h. The second factor consisted of four soil classes: Typic Dystrustept (Cambissolo Aplico distrófico in Embrapa), Typic Hapludult (Argissolo Amarelo distrófico), Rhodic Kandiudult (Nitossolo Vermelho distrófico), and Anionic Acrudox (Latossolo Vermelho distróferrico) and considered horizons A and B. The pre-wetting significantly increased the values of the weighted average diameter, geometric mean diameter and aggregate stability index. In soils with high organic carbon content, the practice of pre-moistening did not provide variation in aggregation.

FEATURES OF USING A GROUND LASER PROFILER TO ASSESS THE QUALITY OF SOIL CULTIVATION ON AGRICULTURAL SLOPE LANDSCAPES

2021 ◽  
pp. 16-23
Author(s):  
SERGEY A. VASILIEV ◽  
◽  
VIKTOR А. ALEKSEEV ◽  
MIKHAIL A. VASILIEV ◽  
ALEKSEI A. VASILIEV ◽  
...  
Keyword(s):  
Catchment Area ◽  
Soil Aggregates ◽  
Weighted Average ◽  
Software Tool ◽  
Average Diameter ◽  
Surface Slope ◽  
Cultivated Soil ◽  
Chuvash Republic ◽  
Equal Height

The authors analyze an extensive set of data for measuring the daily surface profi le of the cultivated soil to assess its agrotechnical parameters. The research was carried out on a small agricultural catchment area of the Orininsky rural settlement, which is located in the Morgaushy district of the Chuvash Republic. Three agricultural fi elds were selected, ranging from 25 ha to 53 ha. The studied areas were cultivated in various ways: plowing with harrowing, disking the soil and winter plowing. The profi les of the studied elementary sections were measured using a developed ground-based circular laser profi lometer. Data on the state of the profi le were used to determine the main agrotechnical parameters - clumping, cloddiness, surface slope, and deviation of the travel trajectory of a machine and tractor unit from the line of equal height. A software tool for processing and analyzing data received from sensors has been developed. The results established that the deviation of the projection of the greatest elevation line changes (measured by the slope) from the travel trajectory of a unit with an angle of 62, a slope of 6.5, and in a quantitative size distribution soil aggregates of 1…4 inches in diameter prevail. The weighted average diameter of the clods was 3.99 cm. The research results have determined the use of recommend methods for stating the agrotechnical parameters of the daylight surface to evaluate the cultivated soil in accordance with agrotechnical requirements.

scholarly journals Biomass Productivity of Different Winter Cover Crops and Their Effect on Soil Physical Properties

2020 ◽  
Vol 12 (10) ◽  
pp. 338
Author(s):  
Willian dos Reis ◽  
Monica C. Sustakowski ◽  
Edleusa P. Seidel ◽  
Maria do C. Lana ◽  
Renata F. Barabasz ◽  
...  
Keyword(s):  
Cover Crops ◽  
Dry Matter ◽  
Soil Aggregates ◽  
Geometric Mean ◽  
Weighted Average ◽  
Biomass Productivity ◽  
Total Porosity ◽  
Average Diameter ◽  
Soil Density ◽  
Common Vetch

The cultivation of cover crops is a vegetative practice considered an alternative for sustainable soil management, due to its beneficial action in different aspects of soil properties. Thus, the present work aimed to evaluate the effect of cultivation of different species of cover crops on soil density, porosity and diameter of soil aggregates. The experimental design was in randomized blocks, with four replications. The treatments consisted of four species of winter green manure: black oat, forage turnip, forage pea, and common vetch, a consortium of black oat + forage turnip and area kept fallow (control). The following evaluations were performed: dry matter production of cover crops, macroporosity, microporosity, total porosity, soil density, geometric mean diameter and weighted average diameter. The cultivation with forage turnip and the consortium of black oat + forage turnip presented higher dry matter productivity, decreased soil density, increased soil porosity, improved the distribution in relation to macropores and aggregate stability.

scholarly journals ORGANIC CARBON, NITROGEN AND THE STABILITY OF SOIL AGGREGATES IN AREAS CONVERTED FROM SUGAR CANE TO EUCALYPTUS IN THE STATE OF ALAGOAS

2018 ◽  
Vol 42 (4) ◽  
Author(s):  
Aldair de Souza Medeiros ◽  
Thamyris Suelle da Silva ◽  
Anderson Vitor Lins da Silva ◽  
Deni Rafaela Silva Barros ◽  
Stoécio Malta Ferreira Maia
Keyword(s):  
Bulk Density ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Conventional Tillage ◽  
Biological Properties ◽  
The State ◽  
Aggregation Index ◽  
Carbon And Nitrogen ◽  
Eucalyptus Forest ◽  
The Stability

ABSTRACT The conversion of areas cultivated with sugarcane into eucalyptus forests can promote improvements in the physical, chemical and biological properties of the soil. Within this context, the aim of this study was to evaluate the changes in the stocks and levels of carbon and nitrogen and soil-aggregate stability in an area of transition from sugarcane to eucalyptus in the State of Alagoas, Brazil. The study was carried out on a rural property, located in the district of Atalaia. The systems under evaluation consisted of four areas, one cultivated with sugarcane for approximately 20 years, taken as the reference area for the study, and three adjacent areas cultivated with eucalyptus forest, at 1, 3 and 6 years of age. Bulk density, the levels and stocks of carbon and nitrogen, and the soil aggregation index were all determined. The conversion of a sugarcane plantation under conventional tillage with straw burning into eucalyptus plantations promoted an increase in the levels and stocks of carbon and nitrogen in the soil; it also reduced bulk density and increased the water stability of aggregates. The results show that the conversion of sugarcane into eucalyptus in the Atlantic Forest region of Alagoas may be an alternative for promoting carbon sequestration and improving soil quality.

scholarly journals Aggregate stability by the "high energy moisture characteristic" method in an oxisol under differentiated management

2014 ◽  
Vol 38 (5) ◽  
pp. 1633-1642 ◽  
Author(s):  
Érika Andressa da Silva ◽  
Geraldo César de Oliveira ◽  
Bruno Montoani Silva ◽  
Carla Eloize Carducci ◽  
Junior Cesar Avanzi ◽  
...  
Keyword(s):  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Surface ◽  
Stability Index ◽  
Tropical Soils ◽  
High Energy ◽  
Stability Parameters ◽  
Aggregation State ◽  
Moisture Characteristic ◽  
The Stability

Studies testing the High Energy Moisture Characteristic (HEMC) technique in tropical soils are still incipient. By this method, the effects of different management systems can be evaluated. This study investigated the aggregation state of an Oxisol under coffee with Brachiaria between crop rows and surface-applied gypsum rates using HEMC. Soil in an experimental area in the Upper São Francisco region, Minas Gerais, was studied at depths of 0.05 and 0.20 m in coffee rows. The treatments consisted of 0, 7, and 28 Mg ha-1 of agricultural gypsum rates distributed on the soil surface of the coffee rows, between which Brachiaria was grown and periodically cut, and compared with a treatment without Brachiaria between coffee rows and no gypsum application. To determine the aggregation state using the HEMC method, soil aggregates were placed in a Büchner funnel (500 mL) and wetted using a peristaltic pump with a volumetric syringe. The wetting was applied increasingly at two pre-set speeds: slow (2 mm h-1) and fast (100 mm h-1). Once saturated, the aggregates were exposed to a gradually increasing tension by the displacement of a water column (varying from 0 to 30 cm) to obtain the moisture retention curve [M = f (Ψ) ], underlying the calculation of the stability parameters: modal suction, volume of drainable pores (VDP), stability index (slow and fast), VDP ratio, and stability ratio. The HEMC method conferred sensitivity in quantifying the aggregate stability parameters, and independent of whether gypsum was used, the soil managed with Brachiaria between the coffee rows, with regular cuts discharged in the crop row direction, exhibited a decreased susceptibility to disaggregation.

scholarly journals Performance and Stability of Different Monoecious Hemp Cultivars in a Multi-Environments Trial in North-Eastern Italy

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1424
Author(s):  
Claudio Ferfuia ◽  
Fabio Zuliani ◽  
Francesco Danuso ◽  
Barbara Piani ◽  
Costantino Cattivello ◽  
...  
Keyword(s):  
Seed Yield ◽  
Cannabis Sativa ◽  
Weighted Average ◽  
Stability Index ◽  
Grain Filling ◽  
Mediterranean Area ◽  
Environment Interaction ◽  
North Eastern ◽  
Grain Filling Period ◽  
The Stability

The seed yield in hemp (Cannabis sativa L.) is strongly influenced, besides by genotype, by environment and the genotype x environment interaction, so establishing the fitness and stability of hemp cultivars in multiple environments is necessary. The purpose of this study was to investigate the performance and degree of stability and variance of seed yield, the main related traits, and the correlation among the traits in five hemp monoecious cultivars cultivated in six different environments. The environments resulted from the combination of four locations, two years, and two delayed sowings in a Mediterranean area of north-eastern Italy, and the stability index of the weighted average of absolute scores (WAAS) was used in order to identify the most productive and stable genotypes on the basis of their deviation from the average performance across environments. In this studied area, early varieties, such as Fedora and Felina, proved to be the best performing and stable for seed yield and both increased their yield in correspondence to delayed sowing times, opening up the possibility of cultivating hemp as a second crop. Among the climate parameters, high temperatures during the early grain filling period led to a progressive decrease in seed yield. For a dual-purpose crop, a good compromise could be a late monoecious cultivar (like Futura, in the present experiment), which, if sown early, could certainly provide notable biomass production and acceptable seed yield.

scholarly journals Aggregation of subtropical soil under liming: a study using laser diffraction

2010 ◽  
Vol 34 (3) ◽  
pp. 725-734 ◽  
Author(s):  
Edson Campanhola Bortoluzzi ◽  
Cristiano Poleto ◽  
Álvaro José Baginski ◽  
Vanderlei Rodrigues da Silva
Keyword(s):  
Traditional Method ◽  
Soil Aggregates ◽  
Aggregate Stability ◽  
Soil Surface ◽  
Stability Index ◽  
Laser Diffraction ◽  
Soil Aggregation ◽  
Subtropical Soil ◽  
Dispersion Agent ◽  
The Stability

Laser diffraction (LD) provides detailed analysis of particle size distribution. Its application to testing the stability of soil aggregates can assist studies on the aggregation of soils with contrasting electrochemical properties. The objectives of the present work were: (a) to propose a protocol for using LD to study soil aggregation, (b) to study the aggregation of an Acrisol under the influence of different doses and forms of lime. Samples were collected in 2005 from a Brazilian Acrisol that in 1994 had received 0.0; 2.0; 8.5 and 17.0 Mg ha-1 of lime, left on the soil surface or incorporated. Aggregates from 4.76 to 8.00 mm diameters were studied using the traditional method proposed by Kemper & Chepil (1965), with wet sieving, while aggregates from 1.00 to 2.00 mm were studied using a CILAS® laser diffractometer that distinguishes particles ranging from 0.04 to 2,500.00 μm. LD readings were made after six consecutive pre-treatments, using agitation times, a chemical dispersion agent and ultrasound. Mean Weighted Diameter (MWD) and the Aggregate Stability Index (ASI) calculated, using the traditional method does not discriminate the treatments. However, LD is able to produce detailed data on soil aggregation, resulting in indexes of stability of aggregates that are linearly related to the doses of lime applied (MWD: R² = 0.986 and ASI: R² = 0.876). It may be concluded that electrochemical changes in the Brazilian Acrisol resulting from incorporated lime affect the stability of aggregates, increasing stability with increased doses of lime.

Characteristics and Stability of Soil Aggregates in Tea Plantation

2011 ◽  
Vol 343-344 ◽  
pp. 968-974
Author(s):  
Zi Cheng Zheng ◽  
Ting Xuan Li ◽  
Shu Qin He
Keyword(s):  
Soil Aggregates ◽  
Geometric Mean ◽  
Aggregate Stability ◽  
Stability Index ◽  
Soil Aggregate ◽  
Tea Plantation ◽  
Soil Aggregate Stability ◽  
Mean Weight Diameter ◽  
Eucalyptus Plantations ◽  
Wet Sieving

Soil aggregate stability as a key indicator of soil structure and erodibility to evaluate soil stability, is a product of interactions between soil environment, management practices, and land use patterns. The objective of this study was to analyze the distribution characteristics, characteristics of fractal features and stability of soil aggregates in tea plantations and eucalyptus plantations of Western Sichuan in China. The dry- and water-stable aggregate size distributions were determined by dry sieving and wet sieving methods. The results showed that soil structural properties in tea and eucalyptus plantations were similar. With increase in depth of soil layer, the aggregate stability of tea plantation soil became stronger. Comparative analysis of dry and wet sieving results showed that most of the aggregates in tea plantation soil were unstable. The soil aggregates >5mm and 0.5-0.25mm in size had higher stability, while those 2-1mm in size had lower stability. For tea plantation soil, the correlation coefficients between aggregate stability index and mean weight diameter, geometric mean diameter, fractal dimension were bigger under wet sieving than those under dry sieving. The results showed that aggregate stability index, mean weight diameter, geometric mean diameter, fractal dimension of water-stable aggregates could characterize soil aggregate stability in tea plantation ideally.

A FORECAST OF PRODUCTIVE LONGEVITY OF HOLSTEIN COWS BY INDIRECT SIGNS

2020 ◽  
Author(s):  
З.С. САНОВА
Keyword(s):  
Correlation Coefficient ◽  
Aging Process ◽  
Direct Relationship ◽  
Stability Index ◽  
Age At First Calving ◽  
Group I ◽  
Predicted Values ◽  
The Stability ◽  
Relationship Of ◽  
The Relationship

В статье представлены материалы о взаимосвязи продолжительности продуктивного использования коров с характеристикой устойчивости к деградации, с возрастом отела и удоем. В исследованной, разнородной по происхождению, группе животных для прогноза продуктивного периода коров, обусловленного устойчивостью к деградации и возрастом первого отела, пригодно уравнение регрессии, аргументами в котором являются индекс устойчивости, возраст первого отела в первой и второй степенях. Коэффициент корреляции межу предсказанными значениями продуктивного периода и его фактическими величинами в I группе составляет 0,502, во II - 0,604. При этом крайние варианты прогнозируются со статистическими ошибками 5 мес при оценке индекса устойчивости по 2 лактациям и 4,1 мес по 3, а средние варианты, соответственно, 1,6 и 1,51 мес. Индекс устойчивости к процессу старения является важной характеристикой биологических особенностей коров, определяющий их продуктивное долголетие. Его оценка по первым 2 и 3 лактациям имеет прямолинейную связь с продуктивным периодом (r=0,4109 и r=0,5270), соответственно. Зависимость продуктивного периода от возраста первого отела криволинейная — с увеличением возраста первого отела сокращается срок продуктивного использования, при возрасте первого отела более 1400 дней срок продуктивного использования колеблется от 1,33 до 1,41 лактации. Коэффициент корреляции между этими характеристиками коров составляет - 0,2164 в I и - 0,2620 во II группах. The article presents materials about the relationship of the duration of productive use of cows with the characteristic of resistance to degradation, with the age of calving and milk yield. In the studied group of animals, which is heterogeneous in origin, the regression equation is suitable for predicting the productive period of cows due to resistance to degradation and the age of the first calving, the arguments of which are the stability index, the age of the first calving in the first and second degrees. The correlation coefficient between the predicted values of the productive period and its actual values in group I is 0.502, in group II - 0.604. At the same time, the extreme variants are predicted with statistical errors of 5 months when evaluating the stability index for 2 lactations and 4.1 months for 3, and the average variants, respectively, are 1.6 and 1.51 months. The index of resistance to the aging process is an important characteristic of the biological characteristics of cows, which determines their productive longevity. Its estimate for the first 2 and 3 lactations has a direct relationship with the productive period (r=0.4109 and r=0.5270), respectively. The dependence of the productive period age at first calving curvilinear with increasing age at first calving reduces the time to productive use, while age at first calving of more than 1400 days, the period of productive use ranges from 1.33 to 1.41 lactation. The correlation coefficient between these characteristics of cows is-0.2164 in I and-0.2620 in II groups.

scholarly journals On the optimal control of coronavirus (2019-nCov) mathematical model; a numerical approach

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
N. H. Sweilam ◽  
S. M. Al-Mekhlafi ◽  
A. O. Albalawi ◽  
D. Baleanu
Keyword(s):  
Mathematical Model ◽  
Optimal Control ◽  
Weighted Average ◽  
Necessary Optimality Conditions ◽  
Numerical Approach ◽  
Population Number ◽  
Infected People ◽  
The Stability ◽  
Novel Coronavirus ◽  
Theoretical Results

Abstract In this paper, a novel coronavirus (2019-nCov) mathematical model with modified parameters is presented. This model consists of six nonlinear fractional order differential equations. Optimal control of the suggested model is the main objective of this work. Two control variables are presented in this model to minimize the population number of infected and asymptotically infected people. Necessary optimality conditions are derived. The Grünwald–Letnikov nonstandard weighted average finite difference method is constructed for simulating the proposed optimal control system. The stability of the proposed method is proved. In order to validate the theoretical results, numerical simulations and comparative studies are given.

Sign in / Sign up

Export Citation Format

Share Document