Volumetric Ring Method Research Articles

Evaluation of the root system of Vetiver grass (Chrysopogon zizanioides L. Roberty) using different sampling methods

BackgroundVetiver grass (Chrysopogon zizanioides L. Roberty) is one of the most studied and applied species in soil bioengineering techniques all over the world, but there are technical information related to its root system deserving a better comprehension provided by different methodologies’. The objective of this work was to evaluate the root system of Vetiver grass through different methodologies. The trench method evaluated 50 images in 10 × 10 cm squares in its vertical face. The volumetric ring method uses a metallic ring with a volume of 50 cm3 (diameter ≅ 4.6 cm and height ≅ 3.0 cm) to collect samples in the same trench’s vertical face. A hand auger hole method worked with soil samples and roots removed from the surface up to 0.50 m depth. The monolith method comprises a 0.50 m wide, 0.50 m long, and 1 m deep monolith. A spatial correlation between root volume and root area was observed in the kriging maps by the volumetric ring method.ResultsThe root area values for both the volumetric ring method and the hand auger hole method were similar, up to 0.10 to 0.20 m. On the analyzed variables, the root area showed the best correlation coefficient among the root methods, especially those that use the limited spatial distribution by its sampling collection, such as the volumetric ring method and the hand auger hole method (r = 0.526, p < 0.05).ConclusionsThe studied methods can be separated in different groups, such as those that provide more detailed information on the behavior and distribution of the root system, like trench and monolith methods and the methods that better describe the morphological characteristics of the features, like the volumetric ring method. Both require greater spatial coverage, and therefore have greater precision.

In-situ soil dry density estimation using actively heated fiber-optic FBG method

Soil dry density (ρd) is extremely important for soil compaction. It is challenging to monitor its in-situ spatial variation. This study presents a ρd estimation technique based on actively heated fiber-optic fiber Bragg grating (AHFO-FBG) method. The technique introduces two calculation methods, one is based on the thermal conductivity (λ-based method), the other is based on the temperature characteristic value (Tt-based method). Both λ and Tt have a clear response to the variation of ρd. For Tt-based method, an exponential Tt - ρd relationship is established and a numerical simulation calibration approach considering the thermal contact resistance of soil–sensor interface is proposed to obtain the Tt - ρd fitting parameters. Furthermore, an in-situ test was conducted to verify the effectiveness of the ρd estimation technique. Compared with the λ-based method, the Tt-based method has higher accuracy in the field test with a 4% error from the volumetric ring method.

DIGITAL IMAGE PROCESSING FOR EVALUATION OF PASPALUM MILLEGRANA SCHRAD ROOT SYSTEM1

ABSTRACT The characterization of the plant root system is of great importance for the understanding of its contribution to soil shear resistance, constituting an important tool for decision making in soil bioengineering works. The objective of this work was to evaluate the growth and distribution characteristics of the root system of Paspalum millegrana Schrad. grass in Entisol using Digital Imaging Processing (DIP). The data were obtained by opening a soil pit to expose the root system of Paspalum grass up to 1.70 m depth. The profile wall and volumetric ring methods were used to collect quantitative information of the root system. The SAFIRA software and the ArcMAP software belonging to the ArcGIS suite were used for image processing. The profile wall method showed that Paspalum grass has a large volume of roots in the first 0.40 m to 1.30 m soil depth. It was observed that the root length and volume of Paspalum grass reach depths beyond 1.70 m, which is important to increase soil resistance to erosion processes. The profile wall method when compared to the volumetric ring method proved to be more efficient to understand the behavior of the Paspalum grass root system since it enables an assessment of its spatial distribution with better detailing.

Correlations of soybean yield with soil porosity and bulk density of an Oxisol

ABSTRACT The spatial variability of soil physical attributes is important to indicate management practices that best suit agricultural areas. This study aimed to analyze spatial correlations between soybean grain yield and soil mass-volume relationships, in order to select which attribute is correlated with yield, as well as to evaluate the spatial variability of soil attributes and yield components of this crop, in an Oxisol under no-tillage system. The soil attributes analyzed (0.0-0.10 m and 0.10-0.20 m) were the following ones: soil bulk density (paraffin-coated clod and volumetric ring methods), particle density (volumetric flask and modified volumetric flask methods) and total porosity. The soybean yield components were evaluated as it follows: grain yield, number of pods per plant, number of grains per pod, mass of 100 grains, grain mass per plant, plant population and plant height. The total soil porosity, calculated by the relations between the bulk density (volumetric ring method) and particle density (volumetric flask), in the 0.10-0.20 m layer, was the best indicator of soybean grain yield under no-tillage conditions.

Carbon Stocks and Soil Organic Matter Quality Under Different of Land Uses in the Maranhense Amazon

In the face of the traditional model of succession of native environments in pastures or agricultural areas, followed by superpastejo and the concern with emissions of greenhouse gases in the Brazilian Amazon region, this work aims to determine the influence of different land uses on carbon sequestration and soil organic matter changes in the municipality of Pindaré-Mirim, in state of Maranhão. This study evaluated different uses of the soil: native forest; secondary vegetation (capoeira); degraded pasture and CLFI (Crop-Livestock-Forest Integration) system. The deformed and undisturbed samples were collected at depths: 0.00-0.10, 0.10-0.20, 0.20-0.30, 0.30-0.40, 0.40-0.60, 0.60-0.80 and 0.80-1.00 m. Soil densities were determined by the volumetric ring method, the carbon stocks by the carbon content in the soil evaluating the dry combustion, and the accumulated carbon stocks were calculated in 1.00 m. The physical fractions of the organic matter were determined by means of the granulometric method. At depth 0.0-0.10 m, the soil density in the native forest (1.17 g cm-3) was lower than the average of degraded pasture (1.40 g cm-3). There was no difference in the carbon content between all the land uses up to 0.40 m depth. The accumulated carbon stocks up to 1.00 m ranged from 49.52 Mg ha-1 to 64.41 Mg ha-1 and were higher in the native forest compared to capoeira and the ICLF system. In relation to the accumulated carbon stock, the native forest and degraded pasture were the ones that obtained the highest levels, followed by the capoeira and the CLFI system.

STRUCTURING POTENTIAL OF COVER CROPS IN A CLAYEY OXISOL AND THEIR EFFECT ON CRAMBE GRAIN YIELD AND OIL CONTENT

This study aimed to assess the potential of twelve cover crops in improving the structural state of the soil evaluating soil bulk density and soil resistance to penetration and their effects on crambe grain yield and oil content. The experiment was conducted at the Experimental Center of Agricultural Engineering (NEEA), at the State University of West Parana (UNIOESTE) - Cascavel - Parana. The cover crops were named as treatments and consisted of twelve species, namely: Crotalaria juncea, Crotalaria spectabilis , Pigeon pea, Jack bean, Foxtail millet, Forage sorghum, Lablab beans, Guandu beans, Mucuna aterrimum , Mucuna Pruriens , Mucuna deeringiana , Mucuna aterrima , and a control treatment (fallow area). The experimental design used consisted of randomized blocks with four replications and plots measuring 5 x 5 m. When species were in full bloom in May 2010, they were managed by desiccation with non-selective herbicide and subsequent mowing in order to accelerate the decomposition rate of their roots. In August 2011 we performed the planting of crambe for further analysis of its grain and oil yield. In January 2012 soil samples were collected to evaluate soil bulk density by the volumetric ring method at depths of 0.0-0.1, 0.1-0.2 and 0.2-0.3 m. Soil resistance to penetration was determined using a penetrometer until 0.4 m deep. In order to determine crambe grain yield, crambe was collected in an area of 4 m 2 in the central part of each plot. In ordet tor determe seed oil content it was used the Soxhlet method. The statistical analyzes for soil variables (soil penetration density and resistance) and plant (grain yield and oil yield) consisted of analysis of variance (ANOVA), with a comparison test of mean values. It was also performed linear regression analyzes between data concerning to grain yield and oil yield, as well as grain yield and bulk density. The species Crotalaria spectabilis and Mucuna aterrima provided a significant reduction in soil bulk density when compared to the fallow area, showing higher structuring potential than other species after the first year of use. Considering the structural state of the soil prior to the experiment, with bulk density values lower than 1.2 Mg m -3 , there was no significant effect on soil structure by any of the coverage species used and there was also no beneficial effect on crambe grain yield and oil content.

PHYSICAL ATTRIBUTES OF SOIL AFTER SWINE WASTEWATER APPLICATION AS COVER FERTILIZER ON MAIZE CROP AND BLACK OATS SEQUENCE

ABSTRACT The rate of swine wastewater application (SW) in agricultural production could result in the replacement of chemical fertilizers. However, SW destroys soil physical properties by decreasing pore bulk, which negatively affects both crop yield and development. In this context, this study aimed at monitoring the influence of swine wastewater as a cover fertilizer in maize and black oats in sequence on soil physical properties. Five application rates (0, 100, 200, 300 and 537 m3ha - 1 equivalent to 0, 11.2, 22.3, 33.5 and 60 kg ha-1 N, respectively, based on the average nitrogen concentration in SW) were tested with four replications each. In the studied area, soil porosity, density, and water content, before maize sowing and at the end of the cycles of maize and black oats, were determined by the volumetric ring method. Data were submitted for regression analyses. There was a reduction in the macroporosity and total porosity of the soil when the SW application rate, before maize cultivation, was higher. The introduction of black oats helped to improve the physical quality of the soil and reduced the compaction of the surface layer from 0 to 15 cm and 100 to 300 m3 ha-1 SW rates.

Efeito de diferentes sistemas de pastejo em atributos físicos do solo

In view of the importance of the interaction soil-climate-plant-animal to attain good yields in the system, the objective of this study is to evaluate changes in soil physical properties caused by grazing systems continuous and rotated. The systems were used: conventional (CC): Brachiaria brizantha cv. BRS Piatã, unfertilized annual replacement, managed under continuous stocking; fertilizer (AD): Brachiaria brizantha cv. BRS Piatã managed under rotational stocking system, with annual replacement fertilization with NPK at a ratio of 45-20-20 kg ha-1 year-1, and intercropping (IC): Consortium of Brachiaria brizantha cv. BRS Piatã and Stylosanthes Campo Grande, managed in a rotational system of stocking, fertilization receiving annual replacement with 00-20-20 NPK kg ha-1 year-1. To evaluate the effect of animal trampling on systems with rings were collected soil samples with undisturbed layers from 0.00 - 0.06 m, 0.06 - 0.12 m before and after grazing for the determination of soil density by the volumetric ring method, macroporosity and total porosity by the method of the tension table, were also collected samples deformed structure in the same layer for determining the organic matter content. The resistance to penetration was determined before and after grazing in the depths of 0.0 - 0.1, 0.1 - 0.2, 0.2 - 0.3 and 0.3 - 0.4 m, with the impact penetrometer. Animal stepping changed only the microporosity, the use of different cropping systems and grazing no differences in relation to organic matter content. The soils of the conventional grazing system were more tendency to soil compaction measured by penetration resistance of roots.

Representative elementary area for soil bulk density measurements of samples collected in volumetric rings by CT image analyses

The objective of this study was to define soil bulk density (ρs) representative elementary areas (REA) of samples collected in volumetric rings. A new analysis procedure was proposed to define representative area intervals (RAI). A sandy clay loam (Geric Ferralsol – GF) and two clayey (Eutric Nitosol – EN and Rhodic Ferralsol – RF) soils were analyzed. Six samples of each soil were used to determine the ρs employing the volumetric ring method (VR) and computed tomography (CT). Tomography images were obtained with a first generation system equipped with a 241Am gamma-ray source. Consecutive areas from 1.2 to 678.8mm2 were selected in the images, according to three different Schemes: concentric areas starting from the center (Scheme 1), the lower (Scheme 2) and the upper (Scheme 3) borders of the image. Two types of analyses were adopted to investigate the REA: considering CT (Analysis 1) and VR results (Analysis 2) as references. For the RAI, ρs results obtained via both methods were considered simultaneously (Analysis 3). The ρs REA from Analysis 1, according to Schemes 1, 2 and 3, were 432.0; 393.3 and 334.0mm2 (GF), 473.1; 457.4 and 393.3mm2 (RF) and 349.7; 457.4 and 334.0mm2 (EN), respectively. It was not possible to define REA using Analysis 2, however, ideal areas established from the RAI coincided with the REA found for GF, according to the three Schemes, and for EN, according to Schemes 1 and 2. These results confirm the reliability of the new type of analysis proposed.

Indicadores de qualidade física para Argissolos sob pastagens nas regiões leste e sul de Minas Gerais

This research has been conducted in Argissolo areas in the Eastern and Southern Regions of Minas Gerais with the aim of evaluating the physical quality of the topsoil of this area, basing the results on Water Retention Curves (WRC) and using the secondary native forest as a reference. A completely randomized experimental design has been used for this purpose, with 4 management systems (South Pastures of Minas Gerais, East Pastures of Minas Gerais under regular grazing pressure, East Pastures under High grazing pressure and Native Forest) in 3 repetitions, totalizing 12 samples. To obtain the WRC, the undisturbed samples were prepared and subjected to matric potentials of -2, -4, -6, -8 e -10 kPa for suction units and of -33, -100, -500 e -1500 kPa for Richards chambers. The soil density (SD) was determined by the volumetric ring method. The attributes indicating the physic quality of the soil were calculated using the WRC: micro and macro-porosity, total porosity, available water capacity, pore distribution size and S index. The soil under native forest showed better structural quality that soils managed with grazing. In the Eastern region of Minas Gerais, land use with grassland under strong pressure of grazing caused degradation of soil structure, evidenced by the physical quality indicators extracted from the WRC: S index and pore distribution size. The S index values were higher in managements Forest and South Pasture Minas Gerais, indicating better structural soil conditions in these environments.

Gamma-ray attenuation method as an efficient tool to investigate soil bulk density spatial variability

Abstract The spatial variability of soil bulk density ( ρ b ) was measured by using the volumetric ring method (VRM) and the gamma-ray attenuation method (GAM). Collimated radiation from 3.7 GBq of 241 Am was used to evaluate the soil mass attenuation coefficient and its bulk density. Circular lead collimators were adjusted and aligned between source ( D = 1, 2 and 3 mm) and detector ( D = 4.5 mm). Results of GAM for average ρ b provided good agreement with the corresponding values obtained gravimetrically. Variations in bulk density for different collimator dimensions can be attributed to multiple scattering after photons interaction with soil, mainly for 3 mm collimator size. The best result of ρ b by the nuclear technique was obtained when ρ b represents an average of the measurements for collimators of 1 and 2 mm. Another cause for the differences in ρ b by GAM and VRM is the heterogeneity of soil when the collimated beam can interact with stones or large air-filled holes or channels present in the sample. Therefore, the pattern of spatial variability obtained by VRM was confirmed by GAM for all collimator sizes. This result is a good indication that GAM can be used with success to analyze soil spatial variability.

Micro-morphological analysis of the effect of sampling by the volumetric ring method on soil structure

This report investigates the effect of sampling by the volumetric ring method on pore size number and shape distributions. Soil porosity was analyzed using the micromorphological image analysis technique, which helped to explain soil structure changes near the border of samples collected in cylinders and provided detailed information about pore shape, number, and size distribution variations along the samples. Compaction due to sampling affects mainly large irregular and rounded pores of the soils utilized in this study. When evaluating inaccuracies in density measurements due to the compacted regions caused by the sampling device the average soil bulk density for each soil resulted in the ranges of 1.72 ± 0.05 g.cm −3 for Geric Ferralsol soil, 1.66 ± 0.03 g.cm −3 for Eutric Nitosol soil and 1.33 ± 0.05 g.cm −3 for Rhodic Ferralsol soil, respectively. When calculating the average soil bulk density over smaller regions, e.g. in the center of each sample (area of 17.14 mm 2 ) results reduced to 1.64 ± 0.05 g.cm −3 with Geric Ferralsol soil, 1.56 ± 0.03 g.cm −3 with Eutric Nitosol soil and 1.29 ± 0.10 g.cm −3 with Rhodic Ferralsol soil, respectively. These results clearly indicate the effect of sampling by the volumetric ring method. The use of image analysis was essential to explain compaction differences close to the border of the samples collected using cylinders (volumetric ring method) and provided detailed information about pore shape and size distribution variations within soil samples. The results are useful as indicators of the consequences of sampling on the quality of soil samples.

Soil bulk density evaluation by conventional and nuclear methods

Among the methods used to measure soil bulk density, the following have been prominent: paraffin sealed clod (PS), volumetric ring (VR), and the modern methods like gamma ray computed tomography (GCT) and the neutron/gamma surface gauge (SG). The objective of this work was to compare soil bulk density values obtained through these methods, with the aim of assisting researchers on the choice of the more appropriate method. For this, a 200-m spatial transect was chosen in an experimental area cultivated with coffee, belonging to ESALQ/USP, Piracicaba, SP, Brazil. The SG readings were first taken in the field and thereafter soil samples were collected at 8 different points, spaced at 25 m, for the other methods. The lowest values of soil bulk density were obtained for the SG method (average 1.468 g/cm3) and the highest for the PS (average 1.685 g/cm3), which was similar to the GCT method (average 1.684 g/cm3). The average soil bulk density for the VR method, which has been used in soil science as a standard method, was 1.544 g/cm3. The Tukey test indicates that the PS and GCT methods do not differ significantly (P &gt; 0.05). They do differ in comparison with VR and SG, which also do not differ among themselves.

Evaluation of bulk density of Albaqualf soil under different tillage systems using the volumetric ring and computerized tomography methods

The volumetric ring and the computerized tomography (CT) techniques were applied to study soil bulk density, in order to understand the compaction of an Albaqualf soil (Planosol) of the Rio Grande do Sul State, Southern Brazil (latitude 31°52′00″S and Longitude 52°21′24″W). Among six different tillage systems and crop rotations the greatest soil bulk density was measured for the continuous irrigated rice crop system and the lowest for the no-tillage treatment under rye grass straw. The CT method enabled the measurement of bulk density variations in the soil profile and indicated critical zones not observed by the volumetric ring method that measures only the mean sample soil bulk densities. A meaningful correlation between soil bulk densities measured by both methods was found, although the CT method presented more reliable results in comparison to the volumetric ring method. A 3% variation in bulk density was observed due to method intrinsic errors, probably also correlated to different samples sizes.

Sistemas de cultivo de arroz irrigado e a compactação de um Planossolo

Em 1993 foi avaliada a compactação de um Planossolo cultivado sob diferentes sistemas de manejo, medindo-se a densidade do solo, por meio do método do anel volumétrico, em três camadas de solo. Os tratamentos consistiram de seis sistemas de manejo, selecionados de um experimento conduzido na Embrapa-Centro de Pesquisa Agropecuária de Clima Temperado, desde 1985. Observaram-se, de maneira geral, valores altos de densidade do solo; na primeira camada de solo (0-10 cm) o sistema que apresentou o menor valor foi o cultivo de arroz em plantio direto sob a resteva do azevém e nos sistemas que envolvem maior mobilização do solo (arroz contínuo e rotação arroz-soja-milho) os valores de densidade do solo foram maiores em relação aos sistemas de preparo reduzido do solo (azevém x arroz plantio direto e soja x arroz plantio direto). Ocorreu maior compactação, em relação à primeira camada, na camada intermediária (1020 cm), em todos os sistemas de cultivo, exceto no sistema de rotação arroz-soja-milho, no qual não houve diferença de densidade entre as camadas de solo.