scholarly journals A Rapid Method for Determining Physical Properties of Undisturbed Substrate

HortScience ◽  
1992 ◽  
Vol 27 (12) ◽  
pp. 1279-1280 ◽  
Author(s):  
Carl E. Niedziela ◽  
Paul V. Nelson

A new tube method for determining physical properties in container substrates was compared to an existing system. While both offer the advantages of undisturbed substrate and measurement of properties without altering the geometry of the substrate in the container, the tube method is easier to conduct. Both methods proved equally effective for determining air-tilled porosity, container capacity, total porosity, bulk density, and particle density.

2001 ◽  
Vol 11 (1) ◽  
pp. 31-35 ◽  
Author(s):  
S.B. Wilson ◽  
P.J. Stoffella ◽  
D.A. Graetz

Growth of golden shrimp plant (Pachystachys lutea Nees.) transplants was evaluated in media containing 0%, 25%, 50%, 75%, or 100% compost derived from biosolids and yard trimmings. A commercial coir- or peat-based media was amended with compost. As compost composition in the peat or coir-based media increased from 0% to 100%, carbon/nitrogen ratios decreased; and media stability, nitrogen mobilization, pH, and electrical conductivity increased. Bulk density, particle density, air-filled porosity, container capacity, and total porosity increased as more compost was added to either peat- or coir-based media. Plants grown in media with high volumes of compost (75% or 100%) had less leaf area and lower shoot and root dry weight compared to the controls (no compost). Regardless of percentage of compost composition in either peat or coir-based media, all plants were considered marketable after 8 weeks.


2020 ◽  
Vol 16 (No. 1) ◽  
pp. 29-38
Author(s):  
Jan Vopravil ◽  
Pavel Formánek ◽  
Tomáš Khel

Soil properties can be influenced by long-term agricultural management practices as described in pedological literature. In this study, selected physical properties (particle density and bulk density, total porosity, maximum capillary water capacity, minimum air capacity, field capacity, permanent wilting point and available water capacity) of topsoils from different reference soil groups (Cambisols, Luvisols, Fluvisols, Chernozems and Phaeozems, Leptosols, Stagnosols and Gleysols) were sampled and analysed in the years 2016–2017. The topsoil samples were taken from points of so-called S (specific) soil pits to be sampled from the General Soil Survey of Agricultural Soils (GSSAS) which was accomplished in the years 1961–1970. In addition, some of the properties were also compared with those measured during the GSSAS. Recognising the properties, only the particle density, the maximum capillary water capacity, the permanent wilting point and the available water capacity of the topsoil of the individual soil groups were statistically significantly (P < 0.05) different. A comparison of the physical properties with those analysed after more than 40 years was performed, the bulk density increased and the total porosity decreased in the topsoil of the major part of the studied soil groups.


HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1093c-1093
Author(s):  
William C. Fonteno

The determination of air and water holding capacities of horticultural substrates has been plagued by errors in measurement. The amount of air and water held at container capacity is influenced by the substrate and container height. Container capacity can be established through specific measurement. Air space, the difference between total porosity and container capacity, is usually poorly determined because of errors in total porosity measurement. Most researchers calculate total porosity (St) from the formula: St = 1-(ρb/ρp), where ρb is the dry bulk density and ρp is the particle density. While bulk density is usually measured, particle density is not. Many times an average ρp of 2.65 Mg·m-3 for mineral soils is used. This sometimes creates large errors in calculating total porosity because the values of ρp for horticultural substrates range from 0.35 to 2.1 Mg·m-3. Total porosity can be measured with great accuracy at 0 kPa tension on a pressure plate apparatus, but is costly in equipment and time. Using a modified method of extraction and a new apparatus, using standard aluminum soil sampling cylinders, total porosity was measured with an 85% reduction in time end no decrease in accuracy.


2012 ◽  
Vol 30 (3) ◽  
pp. 113-117
Author(s):  
James E. Altland ◽  
Charles Krause

Alternatives to pine bark for nursery crop substrates have been proposed, including the use of straw materials such as switchgrass. While straw substrates can be developed with suitable physical properties measured immediately after mixing, little is known about how the physical properties of straw-based substrates change over time. The objective of this research was to measure the change in air space (AS), container capacity (CC), total porosity (TP), and bulk density (Db) over time of a switchgrass-based substrate compared to a pine bark substrate. Switchgrass and pine bark substrates were packed into 15 cm (6 in) tall aluminum cores and placed in a production greenhouse with or without a single hibiscus plant. Physical properties of the substrates were measured at the beginning of the experiment and 9 to 10 weeks later when the plants were nearly too large for their containers. Air space decreased over time, primarily as a function of root growth and shrinkage. Container capacity increased slightly across all treatments over time. Bulk density changed very little over time. The switchgrass substrate was more prone to shrinkage than the pine bark substrate, although vigorous hibiscus root growth reduced shrinkage in switchgrass substrates.


2021 ◽  
Author(s):  
Martin Zanutel ◽  
Sarah Garré ◽  
Charles Bielders

<p>In the context of global soil degradation, biochar is being promoted as a potential solution to improve soil quality, besides its carbon sequestration potential. Burying biochar in soils is known to effect soil physical quality in the short-term (<5 years), and the intensity of these effects depends on soil texture. However, the long-term effects of biochar remain largely unknown yet and are important to quantify given biochar’s persistency in soils. The objective of this study was therefore to assess the long-term effect of biochar on soil physical properties as a function of soil texture and biochar concentration.  For this purpose, soil physical properties (particle density, bulk density, porosity, water retention and hydraulic conductivity curves) were measured in the topsoil of three fields with former kiln sites containing charcoal more than 150 years old in Wallonia (southern Belgium).  The fields had a silt loam, loam and sandy loam texture.  Samples were collected along 3 transects in each field, from the center of the kiln sites outwards. </p><p>Particle density and bulk density slightly decreased as a function of charcoal content. Because particle density and bulk density were affected to a similar extent by charcoal content, total porosity was not affected by the presence of century-old charcoal. Regarding the soil water retention curve, charcoal affected mostly water content in the mesopore range. This effect was strongest for the sandy loam. On the other hand, the presence of century-old charcoal increased significantly the hydraulic conductivity at pF between 1.5 and 2 for the silt loam, while no effect of charcoal was observed for the loamy soil.  The study highlights a limited effect of century-old charcoal on the pore size distribution (at constant porosity) and on the resulting soil physical properties for the range of soils and charcoal concentrations investigated here.  Further research may be needed to confirm the observed trends over a wider range of soil types. </p>


2011 ◽  
Vol 6 (No. 2) ◽  
pp. 73-82 ◽  
Author(s):  
S.E. Obalum ◽  
J.C. Nwite ◽  
J. Oppong ◽  
C.A. Igwe ◽  
T. Wakatsuki

One peculiar feature of the inland valleys abundant in West Africa is their site-specific hydrology, underlain mainly by the prevailing landforms and topography. Development and management of these land resources under the increasingly popular sawah (a system of bunded, puddled and levelled rice field with facilities for irrigation and drainage) technology is a promising opportunity for enhancing rice (Oryza sativa L.) production in the region. Information on the variations in selected soil physical properties as influenced by the prevailing landforms may serve as a useful guide in site selection. This is of practical importance since majority of the inland valleys are potentially unsuitable for sawah development and most farmers in the region are of low technical level. Three landforms (river levee, elevated area and depressed area) were identified within a sawah field located in an inland valley at Ahafo Ano South District of Ghana. Each of these landforms was topsoil-sampled along on identified gradient (top, mid and bottom slope positions). Parameters determined included particle size distribution, bulk density, total porosity and field moisture content. The soil is predominantly clayey. There were no variations in the particle size distribution among the slope positions in the river levee. Overall, the river levee had lower silt content than the elevated and the depressed landforms. The bulk density, total porosity, and gravimetric moisture content indicated relative improvements only in the depressed area in the order, bottom &gt; mid &gt; top slope. Irrespective of slope position, the three landforms differed in these parameters in the order, depressed &gt; river levee &gt; elevated. The sand fraction impacted negatively on the silt fraction and bulk density of the soil, both of which controlled the soil moisture status. Despite the fairly low silt content of the soil, the silt fraction strongly influenced the gravimetric moisture content (R<sup>2</sup> = 0.80). So too did the soil bulk density on the gravimetric moisture content (R<sup>2</sup> = 0.90). It is concluded that: (1) since the landforms more prominently influenced the measured parameters than the slope positions, the former should take pre-eminence over the latter in soil suitability judgment; (2) with respect to moisture retention, variations in silt fraction and bulk density of this and other clayey inland-valley soils should be used as guide in site selection for sawah development.


2008 ◽  
Vol 32 (4) ◽  
pp. 1437-1446 ◽  
Author(s):  
Milton da Veiga ◽  
Dalvan José Reinert ◽  
José Miguel Reichert ◽  
Douglas Rodrigo Kaiser

Soil tillage promotes changes in soil structure. The magnitude of the changes varies with the nature of the soil, tillage system and soil water content and decreases over time after tillage. The objective of this study was to evaluate short-term (one year period) and long-term (nine year period) effects of soil tillage and nutrient sources on some physical properties of a very clayey Hapludox. Five tillage systems were evaluated: no-till (NT), chisel plow + one secondary disking (CP), primary + two (secondary) diskings (CT), CT with burning of crop residues (CTb), and CT with removal of crop residues from the field (CTr), in combination with five nutrient sources: control without nutrient application (C); mineral fertilizers, according to technical recommendations for each crop (MF); 5 Mg ha-1 yr-1 of poultry litter (wetmatter) (PL); 60 m³ ha-1 yr-1 of cattle slurry (CS) and; 40 m³ ha-1 yr-1 of swine slurry (SS). Bulk density (BD), total porosity (TP), and parameters related to the water retention curve (macroporosity, mesoporosity and microporosity) were determined after nine years and at five sampling dates during the tenth year of the experiment. Soil physical properties were tillage and time-dependent. Tilled treatments increased total porosity and macroporosity, and reduced bulk density in the surface layer (0.00-0.05 m), but this effect decreased over time after tillage operations due to natural soil reconsolidation, since no external stress was applied in this period. Changes in pore size distribution were more pronounced in larger and medium pore diameter classes. The bulk density was greatest in intermediate layers in all tillage treatments (0.05-0.10 and 0.12-0.17 m) and decreased down to the deepest layer (0.27-0.32 m), indicating a more compacted layer around 0.05-0.20 m. Nutrient sources did not significantly affect soil physical and hydraulic properties studied.


2004 ◽  
Vol 61 (4) ◽  
pp. 446-450 ◽  
Author(s):  
Carolina Fernandes ◽  
José Eduardo Corá

Change on substrate bulk density during the growing period may negatively affect other substrate physical properties and, consequently, plant growth. The objectives of this research were 1) to characterize physical properties of two horticultural substrates (S1 and S2), 2) to evaluate the effect of different bulk densities values of those substrates on their air/water relationship, and 3) to develop mathematical functions to estimate the air/water relationship by increasing substrates bulk density value. First, the distribution of particles size, the bulk density, and the water release curve of the substrates were determined. Then, substrates were packed with three different bulk density values, i.e. 10% (D1), 20% (D2) and 30% (D3), higher than the bulk density (D) determined in the characterization phase. The water release curves were determined for each bulk density value of both substrates. The effect of increasing substrate bulk density in the total porosity (TP), aeration space (AS), available water (AW), easily available water (EAW), buffering water (BW), and in the remaining water (RW) was evaluated using simple linear regression and polynomial analysis. The particles size distribution and the water release curves were significantly different for the two substrates. Increasing the bulk density value decreased TP and AS, and increased BW and RW. The highest values of AW and EAW were observed for D1. Regression equations obtained can be used to choose the more appropriate air/water relationship for each growing condition.


Author(s):  
Ryszard Oleszczuk ◽  
Milena Truba

Abstract The analysis of some physical properties of drained peat-moorsh soil layers. The paper presents the results of measurements of some physical properties for 14 drained fen peat-moorsh layers (degree of decomposition, bulk density, particle density, porosity and saturated moisture content). The soil samples were taken from north- -east, central and east part of Poland. These areas were drained in order to use as a grassland and meadows. The article presents obtained data of selected physical properties from several drained peatlands in Poland and shows the comparison of established results with relevant data published in literature.


2020 ◽  
pp. 1-10
Author(s):  
Iroegbu, Chidinma S ◽  
Asawalam, Damian O ◽  
O. A. Dada ◽  
J. E. Orji

Aim: To determine the effect of different rates of sawdust (SD) and poultry manure (PM) applied on some soil physical properties of acid sandy Ultisol, and some growth parameters and yield of cocoyam. Study Design: 2 x 5 factorial arrangement in a randomized complete block design replicated three times.  Place and Duration of Study: The experiment was conducted in Eastern farm of Michael Okpara University of Agriculture, Umudike during 2014 and 2015 planting seasons. Methodology: The treatments comprised of two manure sources at five levels each: sawdust (0, 2, 10, 15 and 20t/ha) and poultry manure (0, 2, 4, 6 and 8t/ha). The treatments were assigned randomly to the plots and incorporated into the soil two weeks before planting. Data were collected on plant height, number of leaves, leaf area, corms, cormels and total yield. Soil samples were collected with core samplers for physical properties such as Soil Bulk density and Total Porosity. All the data collected were subjected to ANOVA for factorial experiment in RCBD at 5% probability level. Results: The result showed that the interactions of poultry manure and sawdust significantly (p<0.05) improved soil bulk density and total porosity with the lowest value obtained with 0t/ha SD + 8t/ha PM in both 2014 and 2015. The result showed that the interactions of poultry manure and sawdust significantly (p<0.05) increased the leaf area with the highest value obtained with 20t/ha SD + 8t/ha PM in both 2014 and 2015. Also, only the increasing rates of treatment applied significantly (p<0.05) increased the number of leaves, plant height, leaf area and cocoyam yield with the highest value obtained with 20t/ha SD + 8t/ha PM. Also, the various rates of treatment application significantly (p<0.05) increased the cocoyam yield (weight of corms and cormels) with the highest value obtained with 20t/ha SD + 8t/ha PM. Conclusion: Improvement in growth and yield of cocoyam resulted from the improved nutrient status of the soil as a result of the amendments applied.


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