scholarly journals Sampling plan for using a motorized penetrometer in soil compaction evaluation

2016 ◽  
Vol 20 (3) ◽  
pp. 250-255 ◽  
Author(s):  
Lindolfo Storck ◽  
Sarha G. K. Kobata ◽  
Betania Brum ◽  
André B. Soares ◽  
Alcir J. Modolo ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
Soil Compaction ◽  
Soil Depth ◽  
Penetration Resistance ◽  
Sampling Plan ◽  
Experimental Plot ◽  
The Mean ◽  
Depth Ranges ◽  
Resistance To Penetration

ABSTRACT This study aimed to estimate the size of blocks of observations of resistance to penetration, obtained by a motorized digital penetrometer, and the number of blocks with semi-amplitude of the confidence interval between 5 and 20% of the mean penetration resistance, for different soil depth ranges and cone diameters. Data were collected in two contrasting plots of a crop-livestock integration experiment, located in Abelardo Luz, SC, Brazil. Ten blocks were delimited and the resistance to penetration was determined in 20 points spaced by 20 cm, using a motorized digital soil penetrometer. To estimate the mean of resistance to penetration, 12 blocks of four points per experimental plot should be used for a semi-amplitude of the confidence interval equal to 10% of the mean (1 - p = 0.95). Twenty random points may be sampled to estimate mean of penetration resistance for a semiamplitude confidence interval of 10% of the man (1 - p = 0.95). The sample size for the layer of 0-10 cm is larger than in the deeper layers (0-20, 0-30 and 0-40 cm) and smaller for cones with larger diameter.

scholarly journals SPATIAL VARIABILITY OF SOIL PENETRATION RESISTANCE IN COFFEE GROWING

2018 ◽  
Vol 13 (3) ◽  
pp. 341
Author(s):  
Alan Delon Andrade ◽  
Rafael De Oliveira Faria ◽  
Diego José Carvalho Alonso ◽  
Gabriel Araújo e Silva Ferraz ◽  
Miguel Angel Diaz Herrera ◽  
...  
Keyword(s):  
Spatial Dependence ◽  
Soil Compaction ◽  
Soil Depth ◽  
Penetration Resistance ◽  
Spatial Behavior ◽  
Depth Range ◽  
Thematic Maps ◽  
Soil Penetration Resistance ◽  
Critical Zones ◽  
Depth Ranges

The intensive use of machines in agriculture tends to cause soil compaction, which can hamper the expansion of root system and the absorption of water and nutrients, thus affecting the crop development. In view of the above, the present study aimed to identify critical zones of soil compaction, through the spatial distribution of soil penetration resistance (SPR), having positions within the coffee rows and soil depth ranges as variables. The study was performed in a coffee plantation of 7.32 ha, belonging to the Bom Jardim Farm, located in the municipality of Bom Sucesso, MG, Brazil. The SPR was measured using a penetrometer in the depth range from 0 to 0.40 m, with discretization in four layers of 0.10 m. The data were interpreted based on geostatistics, in order to identify if there is spatial dependence of the SPR and generate thematic maps demonstrating the variable’s spatial behavior. It is concluded that there is spatial dependence of soil penetration resistance, being possible to use geostatistical tools to generate thematic maps based on classes of soil penetration resistance. The values of SPR in the tractor trail, for layers from 0.10 to 0.20 and from 0.20 to 0.30 m, were classified in the high SPR class and could cause damage to the crop.

scholarly journals The Probability That a Measurement Falls within a Range of Standard Deviations from an Estimate of the Mean

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Louis M. Houston
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
General Equation ◽  
Sample Sizes ◽  
The Mean ◽  
Standard Deviations ◽  
Intermediate Value ◽  
Theoretical Results

We derive a general equation for the probability that a measurement falls within a range of n standard deviations from an estimate of the mean. So, we provide a format that is compatible with a confidence interval centered about the mean that is naturally independent of the sample size. The equation is derived by interpolating theoretical results for extreme sample sizes. The intermediate value of the equation is confirmed with a computational test.

Sampling for Confidence Interval Estimation of the Fiber Shape Factor

1980 ◽  
Vol 102 (4) ◽  
pp. 366-368
Author(s):  
C. B. Russell ◽  
R. L. Barker ◽  
D. W. Lyons
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
Uniform Distribution ◽  
Shape Factor ◽  
Interval Estimation ◽  
Sampling Plan ◽  
Cotton Fibers ◽  
Longitudinal View ◽  
Confidence Interval Estimation ◽  
Adequate Sample Size

A method is described for estimating the shape factor, the ratio of the maximum and minimum projected diameters, of a fiber from measurements made on a longitudinal view. The method assumes that the measured diameters have a uniform distribution, an assumption which seems justified for cotton fibers. An estimator of the shape factor is given; a confidence interval for the shape factor is derived; and a sampling plan together with formulae for determining an adequate sample size is presented.

scholarly journals Root system and resistance to penetration of Mombaça grass fertilized with nitrogen and irrigated

2016 ◽  
Vol 37 (5) ◽  
pp. 3243
Author(s):  
Tatiane Beloni ◽  
Vanessa Cristina Piotto ◽  
Gracielle Caroline Mari ◽  
Alyson Andrade Pinheiro ◽  
Cassio Antonio Tormena ◽  
...  
Keyword(s):  
Root System ◽  
Production Systems ◽  
Soil Depth ◽  
Penetration Resistance ◽  
Panicum Maximum ◽  
Stocking Rate ◽  
Root Characteristics ◽  
Grass Sward ◽  
Stocking Rates ◽  
Resistance To Penetration

High stocking rates in intensive pasture-based animal production systems may compromise the development of the forage roots due to increased resistance in the surface layer. This study tested the hypothesis that an increase in stocking rate resulting from different levels of nitrogen fertilization in irrigated Mombaça grass (Panicum maximum Jacq. cv. Mombaça) pasture under intermittent grazing could increase resistance to penetration and consequently the growth of the root system. A split-plot design with randomized blocks and subplots was used, including three replications and the following four treatments: 0, 200, 400 and 800 kg N ha?1 year. Evaluations performed in spring, summer and fall seasons were assigned as subplots. The highest values for area, diameter, length and percentage of root biomass (91.4%) were concentrated at the 0-10 cm soil depth, which is explained by the lower penetration resistance in this layer. Increased stocking rate resulting from increased levels of nitrogen in the Mombaça grass sward does not directly affect the penetration resistance of the soil or root characteristics. However, in the rainy season, higher nitrogen levels lead to increased resistance, as they provide higher cumulative stocking rates in this period.

scholarly journals Sample Sufficiency for Estimation of the Mean of Rye Traits at Flowering Stage

2018 ◽  
Vol 10 (3) ◽  
pp. 178
Author(s):  
Cirineu Tolfo Bandeira ◽  
Alberto Cargnelutti Filho ◽  
Fernanda Carini ◽  
Denison Esequiel Schabarum ◽  
Jéssica Andiara Kleinpaul ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
Mean Amplitude ◽  
Descriptive Statistics ◽  
Flowering Stage ◽  
Sowing Time ◽  
The Mean ◽  
Uniformity Trials

The objective of this study was to determine the sample size to estimate the traits mean in cultivars and sowing times, at flowering of rye culture. Ten uniformity trials were performed combining two cultivars in five sowing times. In the flowering of culture, in 100 plants of each uniformity trial, eleven traits were evaluated. The descriptive statistics was calculated and it was determined the sample size to estimate the mean in levels of precision (amplitude of the confidence interval of 95% for 5, 10, …, 35% of the mean) by resampling with replacement. The cob length presented the lowest variability among the eleven traits and, consequently, smaller sample size in both cultivars and five sowing time. There is variability in the sample size to estimate the mean among the traits, cultivars and sowing times. The measurement of 425, 276, 189 and 138 plants in cultivar BRS Progresso and 642, 413, 285 and 211 plants in cultivar Temprano, are enough to estimate the mean amplitude of the confidence interval of 95% maximum of 20, 25, 30 and 35%, respectively, for all the traits and sowing times.

scholarly journals COMPARACION DEL PROMEDIO Y LA MEDIANA COMO ESTIMADORES DE LA MEDIA PARA MUESTRAS NORMALES DEPENDIENDO DEL TAMAÑO DE MUESTRA

2017 ◽  
Vol 23 (2) ◽  
pp. 33
Author(s):  
José W. Camero Jiménez ◽  
Jahaziel G. Ponce Sánchez
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
Normal Distribution ◽  
Confidence Intervals ◽  
Hypothesis Tests ◽  
Sample Mean ◽  
Palabras Clave ◽  
The Mean ◽  
The Difference

Actualmente los métodos para estimar la media son los basados en el intervalo de confianza del promedio o media muestral. Este trabajo pretende ayudar a escoger el estimador (promedio o mediana) a usar dependiendo del tamaño de muestra. Para esto se han generado, vía simulación en excel, muestras con distribución normal y sus intervalos de confianza para ambos estimadores, y mediante pruebas de hipótesis para la diferencia de proporciones se demostrará que método es mejor dependiendo del tamaño de muestra. Palabras clave.-Tamaño de muestra, Intervalo de confianza, Promedio, Mediana. ABSTRACTCurrently the methods for estimating the mean are those based on the confidence interval of the average or sample mean. This paper aims to help you choose the estimator (average or median) to use depending on the sample size. For this we have generated, via simulation in EXCEL, samples with normal distribution and confidence intervals for both estimators, and by hypothesis tests for the difference of proportions show that method is better depending on the sample size. Keywords.-Sampling size, Confidence interval, Average, Median.

scholarly journals Type A evaluation of measurement uncertainty when the sample size is not predetermined

ACTA IMEKO ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 30
Author(s):  
Robin Willink
Keyword(s):  
Confidence Interval ◽  
Measurement Uncertainty ◽  
Sample Size ◽  
Bayesian Approach ◽  
Unbiased Estimate ◽  
Type A ◽  
Standard Uncertainty ◽  
Level Of Confidence ◽  
The Mean

The archetypal procedure in Type A evaluation of measurement uncertainty involves making <em>n</em> observations of the same quantity, taking the sample figure <em>s</em>² to be an unbiased estimate of the underlying variance and quoting the figure <em>s</em> / sqrt(<em>n</em>) as the relevant standard uncertainty. Although this procedure is theoretically valid when the sample size <em>n</em> is fixed, it is not necessarily valid when <em>n</em> is chosen in response to the growing dataset. In fact, when the experimenter makes observations until a certain level of uncertainty in the mean is reached, the bias in the estimation of the variance can be as much as -45 %. Likewise, the usual nominal 95 % confidence interval can have a level of confidence as low as 88 %. This issue is discussed and techniques are suggested so that Type A evaluation of uncertainty becomes as accurate as is implied. The 'objective Bayesian' approach to this issue is discussed and an associated unacceptable phenomenon is identified.

Confidence Interval Construction by Stein's Method: A Practical and Economical Approach to Sample Size Determination

1989 ◽  
Vol 26 (2) ◽  
pp. 237-240 ◽  
Author(s):  
Raphael Gillett
Keyword(s):  
Confidence Interval ◽  
Sample Size ◽  
Sample Size Determination ◽  
Size Determination ◽  
Correction Factors ◽  
Mean And Variance ◽  
The Mean ◽  
Sound Theoretical Basis ◽  
Straightforward Approach ◽  
Economical Choice

A two-stage method of confidence interval construction developed by Stein is a practical and straightforward approach to sample size determination when one wants to estimate the mean of a normal distribution of unknown mean and variance. The technique has several advantages over the modified version of current informal practice proposed by Shiffler and Adams in a recent JMR article: (1) the need for correction factors is eliminated, (2) the precision of the confidence interval is fixed rather than uncertain and the desired level of confidence is guaranteed, irrespective of the unknown population variance, and (3) a sound theoretical basis is provided for making an economical choice of sample size.

scholarly journals Resistance of soil to penetration as a parameter indicator of subsolation in crop areas of sugar cane

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aline Barbosa Arruda ◽  
Rodrigo Fernandes de Souza ◽  
Gustavo Henrique Mendes Brito ◽  
Jadson Belém de Moura ◽  
Manoel Henrique Reis de Oliveira ◽  
...  
Keyword(s):  
Soil Compaction ◽  
Diagnostic Method ◽  
Penetration Resistance ◽  
Soil Resistance ◽  
Agricultural Machinery ◽  
Compacted Soil ◽  
Soil Preparation ◽  
Critical Resistance ◽  
Resistance Value ◽  
Resistance To Penetration

AbstractSugarcane is a very important economic crop that relies heavily on agricultural machinery, which contributes to soil compaction and a consequent decline in productivity. Subsoiling operation reduces the problems caused by compression; however, it is necessary to know its location and intensity. Accordingly, the aim of this work is to present a compression diagnostic method based on soil resistance to penetration as the parameter that indicates need for intervention in the subsoil. Measurements of penetration resistance was carried out in areas of sugarcane, located in the municipalities of Goianésia, Barro Alto and Santa Isabel, in the Brazilian state of Goiás. The Falker penetrometer (PLG 1020) was used, adjusted to a maximum depth of 40 cm and adopted as a critical resistance value of 4.0 MPa. The data were interpolated using kriging and adjusted in AutoCAD 2013 (Autodesk). The methodology proved effective in areas of compacted soil, and the surface layer had less resistance. The reduction in soil preparation was 96.54% and when considering the topographic adjustments, the reduction was 74.07%, showing the viability and importance of the diagnosis to show the proper management.

scholarly journals Onchocerciasis control in Ghana (1974–2016)

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nana-Kwadwo Biritwum ◽  
Dziedzom K. de Souza ◽  
Odame Asiedu ◽  
Benjamin Marfo ◽  
Uche Veronica Amazigo ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Vector Control ◽  
Control Strategy ◽  
Financial Support ◽  
Control Programme ◽  
Ivermectin Treatment ◽  
Mobile Community ◽  
The Mean ◽  
The Impact ◽  
Onchocerciasis Control

Abstract Background The control of onchocerciasis in Ghana started in 1974 under the auspices of the Onchocerciasis Control Programme (OCP). Between 1974 and 2002, a combination of approaches including vector control, mobile community ivermectin treatment, and community-directed treatment with ivermectin (CDTI) were employed. From 1997, CDTI became the main control strategy employed by the Ghana OCP (GOCP). This review was undertaken to assess the impact of the control interventions on onchocerciasis in Ghana between 1974 and 2016, since which time the focus has changed from control to elimination. Methods In this paper, we review programme data from 1974 to 2016 to assess the impact of control activities on prevalence indicators of onchocerciasis. This review includes an evaluation of CDTI implementation, microfilaria (Mf) prevalence assessments and rapid epidemiological mapping of onchocerciasis results. Results This review indicates that the control of onchocerciasis in Ghana has been very successful, with a significant decrease in the prevalence of infection from 69.13% [95% confidence interval) CI 60.24–78.01] in 1975 to 0.72% (95% CI 0.19–1.26) in 2015. Similarly, the mean community Mf load decreased from 14.48 MF/skin snip in 1975 to 0.07 MF/skin snip (95% CI 0.00–0.19) in 2015. Between 1997 and 2016, the therapeutic coverage increased from 58.50 to 83.80%, with nearly 100 million ivermectin tablets distributed. Conclusions Despite the significant reduction in the prevalence of onchocerciasis in Ghana, there are still communities with MF prevalence above 1%. As the focus of the GOCP has changed from the control of onchocerciasis to its elimination, both guidance and financial support are required to ensure that the latter goal is met.

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