The effect of burial in containers filled with naturally occurring soil and mine tailings on decomposition: a porcine pilot study.

Abstract: Lichens, being poikilohydric, have varying thallus water contents (WC) and show a complex interaction between net photosynthesis (NP) and WC. NP can be depressed at low WC (desiccation effects) and, in some species, also at high WC. In the latter case the depression is normally ascribed to increased CO2 diffusion resistances through water blockage. Recently, an earlier explanation, that the depression at high WC is due to recycling of CO2 from increased dark respiration processes (DR), has been given renewed prominence.The two explanations were distinguished by the concurrent use of gas exchange and chlorophyll fluorescence techniques to investigate NP: WC relationships in the lichens Peltigera leucophlebia (green algal) and P. neckeri (cyanobacterial). Both species had a distinct optimal WC for NP with depressed values at low and high WC. The maximal quantum yield for both CO2 fixation (initial slope of light response curves of NP) and photosystem II (fluorescence signals of dark‐adapted thalli) was depressed only at low WC and remained high at optimal and greater WC. In contrast, the relative electron transport rate (ETR, derived from fluorescence signals of thalli in the light) tracked NP and was depressed at low and high WC. The depression of both NP and ETR at high WC (not that at low WC) could be prevented by using elevated external CO2 concentrations. A single, linear relationship was found between all values of gross photosynthesis (NP + DR) and ETR regardless of external CO2 concentration or WC.Our results show that, for these lichens, the depression in NP at high WC is a real fall in photosynthetic rate of the photobionts and is not due to recycling of CO2. The removal of the depression in NP and ETR at high WC by using elevated external CO2 levels allows us to conclude that an additional CO2 diffusion resistance is present.

Bicarbonate concentration as affected by soil water content controls iron nutrition of peanut plants in a calcareous soil

The lithologic composition and bulk physical properties of sediments recovered by Kasten coring at 29 sites in the Cascadia Margin give insight into the processes of tectonic dewatering from the Pleistocene to the present. Shear strength and water content, in particular, reveal the degree to which tectonic influence has modified the sediments. The undeformed sediments of the abyssal plain have low shear strength and high water contents throughout the maximum cored depths of 3 m. In contrast, sediments at the base of the slope are characterized by extremely high shear strength and low water contents. Between these two end members, sediments from the deformation ridges on the continental margin show intermediate shear strength and water content values. There is a close relationship between the water content/porosity and the degree of sediment diagenesis. High water contents are restricted to silty to clayey intervals of minor consolidation, whereas low water contents appear in the cemented sandy to silty layers. Patterns of fluid migration in the near-surface section are inferred from these data and from pore water chemistry. Calculated rates of fluid expulsion at the seafloor are 2 × lO~4 L/m2/day (2.3 × I0 12 m3/m2/s). The results suggest that fluid expulsion is higher off central Oregon compared to the area off southern Washington. Based on the bulk mineralogical composition of the sediments examined and some grain-size analyses, I conclude that generation of the consolidated layers is closely related to the dewatering processes, a widespread phenomenon along the Cascadia Margin evidenced in vent fields.

Low-cost, accurate soil water sensors combined with wireless communication in an internet of things (IoT) framework can be harnessed to enhance the benefits of precision irrigation. However, the accuracy of low-cost sensors (e.g., based on resistivity or capacitance) can be affected by many factors, including salinity, temperature, and soil structure. Recent developments in wireless sensor networks offer new possibilities for field-scale monitoring of soil water content (SWC) at high spatiotemporal scales, but to install many sensors in the network, the cost of the sensors must be low, and the mechanism of operation needs to be robust, simple, and consume low energy for the technology to be practically relevant. This study evaluated the performance of a resistivity–capacitance-based wireless sensor (Sensoterra BV, 1018LE Amsterdam, Netherlands) under different salinity levels, temperature, and soil types in a laboratory. The sensors were evaluated in glass beads, Oso Flaco sand, Columbia loam, and Yolo clay loam soils. A nonlinear relationship was exhibited between the sensor measured resistance () and volumetric soil water content (θ). The – relationship differed by soil type and was affected by soil solution salinity. The sensor was extremely sensitive at higher water contents with high uncertainty, and insensitive at low soil water content accompanied by low uncertainty. The soil solution salinity effects on the – relationship were found to be reduced from sand to sandy loam to clay loam. In clay soils, surface electrical conductivity (ECs) of soil particles had a more dominant effect on sensor performance compared to the effect of solution electrical conductivity (ECw). The effect of temperature on sensor performance was minimal, but sensor-to-sensor variability was substantial. The relationship between bulk electrical conductivity (ECb) and volumetric soil water content was also characterized in this study. The results of this study reveal that if the sensor is properly calibrated, this low-cost wireless soil water sensor has the potential of improving soil water monitoring for precision irrigation and other applications at high spatiotemporal scales, due to the ease of integration into IoT frameworks.

In recent years, the damage caused by thrips has become a key factor impacting the winter and spring production of fruits and vegetables in Hainan Province, China. This study aimed to elucidate the effects of different pupation environments on pupal development and eclosion of chilli thrips (Scirtothrips dorsalis Hood) by analyzing pupal development and eclosion of chilli thrips in an indoor environment with simulated natural soils and water content. Soil type, soil water content, and temperature substantially affected the eclosion of chilli thrips during the pupal stage. Both a low soil water content of 1% and a high soil water content of 15% were not conducive to the pupation and eclosion of chilli thrips. Moreover, the results indicated an interaction between soil type and soil water and temperature and soil water content, affecting the eclosion of chilli thrips. Chilli thrips not only pupated in soil but also completed pupation and eclosion in other soil-less environments, such as tender mango leaves, stalks, plastic mulch, and weed fabric. This study suggests that in addition to adopting pest control measures that target the canopy layer of crops, appropriate measures such as increasing soil water content can also be implemented in the ground layer to enhance the overall effectiveness of pest control.

Potassium uptake of field crops may be restricted when the upper soil layer, which is usually high in available K, dries out or is compacted. To evaluate the factors involved, the effect of soil water content and bulk density on maize (Zea mays L.) root growth, soil solution K concentration, and K mobility in soil was studied. Plants were grown in soil‐filled pots where roots could penetrate the bottom into a K‐free nutrient solution underneath. The soil was adjusted to bulk densities of 1.2, 1.4, and 1.6 g cm‐3 and gravimetric water contents (ω) of 10.7 to 19.0% w/w (corresponding to pF of 4.2 to 3.0), with a low (0.2 mol m−3) and a high (1.5 mol m−3) soil solution K concentration (CLi). Plants were harvested 11 and 19 d after sowing and root length, shoot dry weight, and K content were determined. High bulk density reduced root growth up to the first harvest. Thereafter, relative root growth rate varied from 1.0 × 10−6 s−1 at low to 2.3 × 10−6 s−1 at high water content independent of soil strength. Potassium uptake decreased with decreasing soil water content, because both root length and K influx were reduced at low water content by about 50%. Increasing soil bulk density tended to increase K influx because the volumetric water content (θ) increased when the gravimetric water content (ω) was kept constant. Drying the soil increased CLi, but its influence on K uptake was counteracted by the decrease of both θ and the impedance factor for diffusion (f). Model calculations simulating K transport in soil and K uptake by roots agreed fairly well with observed data, except at high soil water content, low K application, and high bulk density. Under these conditions, measured influx was lower than the calculated influx. It is concluded that this was due to uneven root distribution in compacted soil, which led to interroot competition. At high CLi, K influx was almost unimpaired by low water content because, as model calculations showed, the reduced K mobility was compensated by an increase of the K concentration gradient towards the root.

The thermal properties including volumetric heat capacity, thermal conductivity, thermal diffusivity, and diurnal and annual damping depths of 10 representative soil series of Korea were calculated using some measurable soil parameters based on the Taxonomical Classification of Korean Soils. The heat capacity of soils demonstrated a linear function of water content and ranged from 0.2 to <TEX>$0.8cal\;cm^{-3}^{\circ}C^{-1}$</TEX> for dry and saturated medium-textured soil, respectively. A small increase in water content of the dry soils caused a sharp increase in thermal conductivity. Upon further increases in water content, the conductivity increased ever more gradually and reached to a maximum value at saturation. The transition from low to high thermal conductivity occurred at low water content in the soils with coarse texture, and at high water content in the other textures. Thermal conductivity ranged between <TEX>$0.37{\times}10^{-3}cal\;cm^{-1}s^{-1}^{\circ}C^{-1}$</TEX> for dry (medium-textured) soil and <TEX>$4.01{\times}10^{-3}cal\;cm^{-1}s^{-1}^{\circ}C^{-1}$</TEX> for saturated (medium/coarse-textured) soil. The thermal diffusivity initially increased rapidly with small increases in water content of the soils, and then decreased upon further increases in the soil-water content. Even in an extreme soil with the highest diffusivity value (<TEX>$1.1{\times}10^{-2}cm^2s^{-1}$</TEX>), the daily temperature variation did not penetrate below 70 cm soil depth and the yearly variation not below 13.4 m as four times of damping depths.

The viscosity of a series of six synthetic dacitic liquids, containing up to 5.04 wt% dissolved water, was measured above the glass transition range by parallel-plate viscometry. The temperature of the 1011 Pa s isokom decreases from 1065 K for the anhydrous liquid, to 864 K and 680 K for water contents of 0.97 and 5.04 wt% H2O. Including additional measurements at high temperatures by concentric-cylinder and falling-sphere viscometry, the viscosity (η) can be expressed as a function of temperature and water content w according to: $$\log _{10} {\text{ }}\eta = - 4.43{\text{ }} + {\text{ }}{{\left( {7618.3 - 17.25{\text{ }}\log _{10} {\text{ }}\left[ {w{\text{ }} + {\text{ }}0.26} \right]} \right)} \mathord{\left/ {\vphantom {{\left( {7618.3 - 17.25{\text{ }}\log _{10} {\text{ }}\left[ {w{\text{ }} + {\text{ }}0.26} \right]} \right)} {\left( {T - \left\{ {406.1 - 292.6{\text{ }}\log _{10} {\text{ }}\left[ {w{\text{ }} + {\text{ }}0.26} \right]} \right\}} \right)}}} \right. \kern-\nulldelimiterspace} {\left( {T - \left\{ {406.1 - 292.6{\text{ }}\log _{10} {\text{ }}\left[ {w{\text{ }} + {\text{ }}0.26} \right]} \right\}} \right)}}$$ where η is in Pa s, T is temperature in K, and w is in weight percent. Within the conditions of measurement, this parameterization reproduces the 76 viscosity data with a root-mean square deviation (RMSD) of 0.16 log units in viscosity, or 7.8 K in temperature. The measurements show that water decreases the viscosity of the dacitic liquids more than for andesitic liquids, but less than for rhyolites. At low temperatures and high water contents, andesitic liquids are more viscous than the dacitic liquids, which are in turn more viscous than rhyolitic liquids, reversing the trend seen for high temperatures and low water contents. This suggests that the relative viscosity of different melts depends on temperature and water content as much as on bulk melt composition and structure. At magmatic temperatures, rhyolites are orders of magnitude more viscous than dacites, which are slightly more viscous than andesites. During degassing, all three liquids undergo a rapid viscosity increase at low water contents, and both dacitic and andesitic liquids will degas more efficiently than rhyolitic liquids. During cooling and differentiation, changing melt chemistry, decreasing temperature and increasing crystal content all lead to increases in the viscosity of magma (melt plus crystals). Under closed system conditions, where melt water content can increase during crystallization, viscosity increases may be small. Conversely, viscosity increases are very abrupt during ascent and degassing-induced crystallization.

The effective relative dielectric constant ɛe, r and the effective conductivity σe have each been determined as a function of frequency in the range 1–3000 MHz at volumetric water contents of up to approximately 0.74 for clays, 0.83 for a peat and 0.56 for a silt.At frequencies above about 25 MHz (depending on soil type), ɛe, rincreases with water content for all samples. However, at lower frequencies, ɛe, ronly increases with water content as long as the wet density also increases, which is the case for water contents up to a critical value lying between 0.35 and 0.48. At higher water contents, ɛe, rand the wet density decrease with increasing water content. Consequently, curves of ɛe, rversus frequency for two wet samples with different water contents, at least one of them higher than the critical value, are seen to cross at about 25 MHz. Below the critical value the curve of the sample with the lower water content is below the other curve at all freqencies applied. At a given frequency, σe has a maximum as a function of water content. This is tentatively explained by assuming that σe is the sum of pore water conductivity (increasing with water content until all salts in the soil are dissolved into the water and then decreasing) and surface water conductivity (increasing with wet density and therefore increasing with water content up to the critical value and then decreasing).At frequencies higher than 1000 MHz, ɛe, rdepends only weakly on salinity (which is represented by the measured conductivity). It shows an increasing dependence if the frequency is decreased towards 1 MHz.The highest values of ɛe, rand σe, measured in this work, occur for a sample of wet, nearly saturated silt originating from a location below sea‐level near to the Dead Sea, Israel: ɛe, rdecreases continuously from a value of about 104 at 3 MHz to about 102 at 200 MHz, while σe rises from about 4 S/m to 5 S/m at these respective frequencies. The dependence of the wavelength on the loss‐tangent is strong and the wavelength is considerably smaller than it would be in a dielectric. This is the only sample for which σe increases with water content, even if the latter is above its critical value. Therefore it is assumed that the pore water conductivity is greater than the surface water conductivity if the volumetric water content is lower than 0.564, the maximum value applied. The measurements give evidence for the presence of a relaxation at about 3 MHz for all samples examined.

&amp;lt;div&amp;gt; &amp;lt;p&amp;gt;This study investigates whether and how vegetation cover affects the spatial heterogeneity and vertical penetration of water through the Upper Critical Zone (UCZ). We assessed rainfall, throughfall and soil water contents on a 1&amp;amp;#8208;ha temperate mixed beech forest plot in Germany. Throughfall and soil water content in two depths (7.5 cm and 27.5 cm) were measured on an event basis during the 2015 - 2016 growing season in independent high&amp;amp;#8208;resolution stratified random designs. We calculated the increase of soil water content (&amp;amp;#916;&amp;amp;#952;) due to the rainfall by the difference between measurements at the beginning (pre-event) and the maximum soil water content after the end of rainfall event (post-event). Since throughfall and soil water content cannot be assessed at the same location, we used kriging to derive the throughfall values at the locations where soil water content was measured. We explore the spatial variation and temporal stability of throughfall and soil water content and evaluate the effects of throughfall, soil properties (field capacity and air capacity), and vegetation parameters (next tree distance) on soil water content variability.&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;Throughfall patterns were related to canopy density although correlation length decreased with increasing event size. Temporal stability was high, leading to persistently high and lower input locations across rainfall events.&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;A linear mixed effect model analysis confirmed that the soil water content increase due to precipitation depended on throughfall patterns, in that more water was stored in the soil where throughfall was enhanced. This was especially the case in large events and in both investigated soil depths. However, we also identified additional factors that enhanced or decreased water storage in the soil, and probably indicate fast drainage and runoff components. Locations with low topsoil water content tended to store less of the available water, indicating the role of preferential flow. In contrast in subsoil, locations with high water content, and probably poor drainage, stored less water, indicating lateral flow. Also, distance to the next tree and air capacity modified soil water storage.&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;Spatial soil water content patterns shortly before a rainfall event (pre-event conditions) seem to be a key factor in soil water content increase, and also explained much of soil water content shortly after the rainfall event. Pre-event soil water content was mostly driven by random local effects, probably microtopography and root water uptake, which were not quantified in this study. The remaining spatial variation was explained by air capacity in both soil layers, indicating the role of macroporosity.&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;Our findings show at the same time systematic patterns of times and locations where the soil capacity to store water is reduced and water probably conducted quickly to greater depth. Not only soil moisture patterns but also deeper percolation may depend on small scale spatial heterogeneity of canopy input patterns.&amp;lt;/p&amp;gt; &amp;lt;/div&amp;gt;

This paper presents the water and chlorine content estimates on the bottom of the Martian crater Gale obtained by processing the data of active neutron sensing with the DAN experiment onboard theNASA “Curiosity”Mars rover at 412 spots along the 11-kilometer track. For 78% of the examined spots the water distribution in depth is found to be homogeneous with a mean content of 2.1±0.5% by mass (here and elsewhere variations correspond to the mean square deviations). For 22% of the examined spots the data require a two-layer model of water distribution down to the sensitivity limit of about 60 сm. The mean water content in upper layer of these spots is about 2−3% by mass, which is close to the content for spots with the homogeneous water distribution. In 8% of the examined spots the water content in the bottom layer at a depth of 27 ± 18 сm increases to 5.6 ± 2.7%. In 14% of the examined spots the water content in the bottom layer at a depth of 14 ± 7 сm decreases to 1.2 ± 0.5%. For interpretation of these results we conclude that the Gale crater has areas both with high and low water content, which correspond to distinct sedimentary layers from different past epochs, when sedimentation process took place underwater and in air correspondingly.

Field study on performance of jet grouting in low water content clay

This study was carried out to determine the carbon (C) allocation of tree components following water stress in radiata pine (Pinus radiata) seedlings. The seedlings were exposed to various water contents (low, moderate and high soil water content) for 30 days and labelled with 14CO2 gas for six hours on the 31st day. Biomass in all seedling components (foliage, stems and roots) was significantly higher in the moderate soil water content treatment than in the low soil water content treatment, while seedling biomass did not significantly differ between the moderate soil water and high soil water content treatments. The shoot/root ratio of seedlings decreased when soil water content decreased. The C concentrations of radiata pine seedlings were not affected by the soil water content, whereas the soil water stress-induced difference in the C allocation of seedlings was attributed to differences in seedling biomass. The translocation of pulse-labelled 14C from the foliage to the roots was enhanced by low soil water content. The distribution of 14C was highest in foliage, followed by roots, stems and soil. The results indicate that soil water content was one of the primary factors influencing biomass allocation in the early growth of radiata pine seedlings.

The formation of deep gullies (called ‘dongas’ locally) in rangeland in KwaZulu‐Natal Province in South Africa is a natural phenomenon. These U‐shaped, very wide gullies have considerable lateral expansion due to the episodic collapse of sidewalls.The dongas have developed in duplex soils such as Luvisols and Lixisols formed on Permian sedimentary rocks or unconsolidated Quaternary colluvium. This study combined morphological, mineralogical and chemical characterization with measurements of grain‐size content, structural stability and the complete shrinkage curve to detect changes in soil properties of the different horizons located in the gully banks.The different soil horizons present clear and sharp differences in physical and mineralogical properties. The topsoil with complete grass cover is very resistant to soil detachment. However, the leached E horizon and the BC horizon have low structural stability. The soil profile down to and including the Bt horizon contains exclusively illite in the clay fraction, while the BC colluvial layer and the C horizon (mudstone) contain expandable interstratified illite–smectite. The Bt horizon has a high water content at saturation and high shrinkage, while the BC and C horizons have a high residual shrinkage and a very low water content at saturation.Because this type of gully expansion is not significantly linked to slope value or the stream power index (SPI) at the gully head, to land‐use change, high rainfall intensities or the threshold of concentrated runoff being exceeded at the gully head, other causes were investigated. It was concluded that the heterogeneity between horizons with different mineralogical properties and structural stabilities, soil types and parent material, anisotropic water‐saturation and shrink‐swell properties are of major importance. This heterogeneity between different soil horizon morphologies and their physical properties can explain why the relationship between the critical slope and the drainage area for gully initiation showed a threshold for gullying much lower than that found elsewhere. © 2020 John Wiley &amp; Sons, Ltd.

Vulnerability of Bavarian silty loam soil to compaction under heavy wheel traffic: impacts of tillage method and soil water content