moisture conditions
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2022 ◽  
Vol 14 (2) ◽  
pp. 404
Author(s):  
Yaqing Gou ◽  
Casey M. Ryan ◽  
Johannes Reiche

Soil moisture effects limit radar-based aboveground biomass carbon (AGBC) prediction accuracy as well as lead to stripes between adjacent paths in regional mosaics due to varying soil moisture conditions on different acquisition dates. In this study, we utilised the semi-empirical water cloud model (WCM) to account for backscattering from soil moisture in AGBC retrieval from L-band radar imagery in central Mozambique, where woodland ecosystems dominate. Cross-validation results suggest that (1) the standard WCM effectively accounts for soil moisture effects, especially for areas with AGBC ≤ 20 tC/ha, and (2) the standard WCM significantly improved the quality of regional AGBC mosaics by reducing the stripes between adjacent paths caused by the difference in soil moisture conditions between different acquisition dates. By applying the standard WCM, the difference in mean predicted AGBC for the tested path with the largest soil moisture difference was reduced by 18.6%. The WCM is a valuable tool for AGBC mapping by reducing prediction uncertainties and striping effects in regional mosaics, especially in low-biomass areas including African woodlands and other woodland and savanna regions. It is repeatable for recent L-band data including ALOS-2 PALSAR-2, and upcoming SAOCOM and NISAR data.


Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 221
Author(s):  
Muhammad Asyraf Mohd Amnan ◽  
Wan Mohd Aizat ◽  
Fiqri Dizar Khaidizar ◽  
Boon Chin Tan

Drought is one of the significant threats to the agricultural sector. However, there is limited knowledge on plant response to drought stress and post-drought recovery. Pandanus amaryllifolius, a moderate drought-tolerant plant, is well-known for its ability to survive in low-level soil moisture conditions. Understanding the molecular regulation of drought stress signaling in this plant could help guide the rational design of crop plants to counter this environmental challenge. This study aimed to determine the morpho-physiological, biochemical, and protein changes of P. amaryllifolius in response to drought stress and during recovery. Drought significantly reduced the leaf relative water content and chlorophyll content of P. amaryllifolius. In contrast, relative electrolyte leakage, proline and malondialdehyde contents, and the activities of antioxidant enzymes in the drought-treated and recovered samples were relatively higher than the well-watered sample. The protein changes between drought-stressed, well-watered, and recovered plants were evaluated using tandem mass tags (TMT)-based quantitative proteomics. Of the 1415 differentially abundant proteins, 74 were significantly altered. The majority of proteins differing between them were related to carbon metabolism, photosynthesis, stress response, and antioxidant activity. This is the first study that reports the protein changes in response to drought stress in Pandanus. The data generated provide an insight into the drought-responsive mechanisms in P. amaryllifolius.


PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262203
Author(s):  
Michał Beczek ◽  
Magdalena Ryżak ◽  
Rafał Mazur ◽  
Agata Sochan ◽  
Cezary Polakowski ◽  
...  

Soil splash is the first step in the process of water erosion, where impacting raindrops cause the detachment and transport of soil material. One of the factors that strongly influences the magnitude of soil splash is the incline of the surface (slope). The aim of this study was to investigate the effect of the slope on the course of the splash phenomenon caused by single-drop impact (one drop impact per soil sample), with respect to the mass and proportions of the ejected material, taking into account its division into solid and liquid phases i.e. soil and water. The investigation was carried out using three types of soil with different textures, in moistened (pressure head corresponding to -1.0 kPa) and air-dry (-1500 kPa) conditions. The soil samples were on three angles of slope, being 5°, 15°, and 30°, respectively. After a single-drop impact with a diameter of 4.2 mm, the ejected material was collected using a splash cup. The following quantities of splashed material were measured: the total mass, the mass of the solid phase, and the mass of the liquid phase. Additionally, the distribution and proportions (soil/water) of the splashed material were analysed in both the upslope and downslope directions. It was found that: (i) the change of slope had a variable influence on the measured quantities for different soils; (ii) in the case of moistened samples, the measured values were mainly influenced by the texture, while in the dry samples, by the angle of the slope; (iii) with the increase of slope, the splashed material was mostly ejected in the downslope direction (irrespective of moisture conditions); (iv) in the moistened samples, the ejected material consisted mostly of water, while in the dry samples it was soil—this occurred for material ejected both upslope and downslope. The obtained results are important for improving the physical description of the process of splash erosion. A more thorough understanding and better recognition of the mechanisms governing this phenomenon at all stages could contribute to the development of more effective methods for protecting soil against erosion.


2022 ◽  
Vol 12 (1) ◽  
pp. 512
Author(s):  
Salvatore Brischetto ◽  
Roberto Torre

This paper presents the steady-state stress analysis of single-layered and multilayered plates and shells embedding Functionally Graded Material (FGM) layers under moisture conditions. This solution relies on an exact layer-wise approach; the formulation is unique despite the geometry. It studies spherical and cylindrical shells, cylinders, and plates in an orthogonal mixed curvilinear coordinate system (α, β, z). The moisture conditions are defined at the external surfaces and evaluated in the thickness direction under steady-state conditions following three procedures. This solution handles the 3D Fick diffusion equation, the 1D Fick diffusion equation, and the a priori assumed linear profile. The paper discusses their assumptions and the different results they deliver. Once defined, the moisture content acts as an external load; this leads to a system of three non-homogeneous second-order differential equilibrium equations. The 3D problem is reduced to a system of partial differential equations in the thickness coordinate, solved via the exponential matrix method. It returns the displacements and their z-derivatives as a direct result. The paper validates the model by comparing the results with 3D analytical models proposed in the literature and numerical models. Then, new results are presented for one-layered and multilayered FGM plates, cylinders, and cylindrical and spherical shells, considering different moisture contents, thickness ratios, and material laws.


2022 ◽  
Vol 101 (1) ◽  
pp. 27-42
Author(s):  
ZHIWEI GAO ◽  
◽  
DONGPO WANG ◽  
BAOMING GONG ◽  
CAIYAN DENG ◽  
...  

Fatigue tests of cruciform welded joints made of Q355B steel at very-high-cycle fatigue (VHCF) regimes were carried out on as-welded specimens using highfrequency mechanical impact (HFMI) treatment in dry air and water-spray environments, respectively. The influence of the environment on fatigue life was more obvious in the VHCF regime. It was found that S-N curves became flat over the range of 106–108 cycles for as-welded specimens, while a continuously decreasing S-N curve existed for HFMI-treated specimens. Fatigue cracks initiated from the weld toe of the as-welded specimens in dry air and water-spray environments. Due to residual stress, the crack initiation site transition of HFMI-treated specimens from the weld toe to the weld root and base metal was observed at lower stress levels. Moreover, hydrogen-assisted quasi-cleavage and intergranular fracture were captured using a scanning electron microscope and a hydrogen permeation test.


Author(s):  
V. I. Sichkar ◽  
A. O. Vasylenko ◽  
A. I. Kryvenko ◽  
R. V. Solomonov

Introduction. Peas are among the most common legumes in Ukraine, so the creation and introduction into production of new varieties has a significant economic effect. The main purpose of its breeding is to create highly adaptable to biotic and abiotic factors varieties, the yield of which would be stable for many years. Matcrials and mcth0ds. Field studies were conducted in the central zone of Odessa region during 2018–2021. Control nursery, ecological, preliminary and competitive testing were sown in plots 10 m long with a seeder “Klen-1.5C”, sowing of breeding and collection nurseries was carried out manually in a wide rows with 45 sm. In the process of vegetation conducted phenological ob- servations, the necessary accounting and evaluation. Plots of control, ecological, preliminary and competitive testing were harvested with a breeding combine “Sampo-130”, plants of selection and collection nurseries were tied into sheaves and then threshed on a thresher. Seed yield was calculated at 14% humidity. Rcsults and discussi0n. Under arid condi- tions in 2018–2020, the yield of all varieties and breeding lines was low, which indicates the need to strengthen breeding research to improve the adaptive characteristics of the new source material. Analysis of the results of our own research and a large volume of literature sources show that the creation of varieties with a more stable level of productivity will take place gradually through the consistent accumulation of positive gene loci using complex stepwise crosses and large volumes of hybrid populations of early generations, and effective selection highly adaptive forms. The network of ecological tests is of great importance. Under optimal moisture conditions, the yield of the best varieties reaches 5.0 t / ha, and in some recombinant lines exceeds this value. The identification of donors and sources of drought and heat resistance among the world gene pool is becoming increasingly important. It is especially important to identify the genetic loci of these traits by genetic molecular research methods.


2021 ◽  
pp. 1-12
Author(s):  
Julie Dabkowski ◽  
Nicole Limondin-Lozouet

Abstract Many recent palaeoclimatic studies have focused on Pleistocene interglacials, especially Marine Isotopic Stages (MIS) 5e and 11, as analogs to our modern interglacial (MIS 1). In continental area, archives allowing comparison between interglacials remain scarce. Calcareous tufa deposits, as they are characteristic of these periods and can provide long, almost continuous, palaeoclimatic records through their isotopic content, appear highly suitable for such investigation. In this paper, δ18O and δ13C values from the three well-dated tufas of Saint-Germain-le-Vasson, Caours, and La Celle are combined to compare temperature and moisture conditions prevailing during MIS 1, 5e, and 11, in the Paris Basin. Both Pleistocene interglacials, and especially their optima, appear stronger than the Holocene: MIS 11 was wetter and warmer than both the Holocene and MIS 5e, which itself experienced wetter conditions than the Holocene. These observations are consistent with palaeontological data from the studied sites, especially malacological assemblages, which record, as at other European tufa sites, a relative depletion of molluscan diversity during the Holocene compared with the Pleistocene (MIS 5 and 11) interglacials.


Author(s):  
V. E. Yeshenko ◽  
◽  
G. V. Koval

Formulation of the problem. Crop rotations of modern field agriculture should be developed according to the principle of classical fruit change, which is an important factor in the high productivity of individual crops on different agro-backgrounds, which can be different ways of the depth of the main tillage. Verification of the latter was the main task of our research. Conditions and methodology. Field studies were carried out in a stationary experiment on podzolized chernozem with a 5-field crop rotation with such an alternation of spring crops: soybeans – rapeseed – wheat – oil flax – barley. The experiment compared the effect of plowing and flat-cut loosening at 15–17, 20–22 and 25–27 cm on the weediness of crops, crop yield and the productivity of crop rotation in terms of the yield of feed units and assimilated protein. Research results. It has been established that a significant part of weed seeds after flat-cutting loosening is concentrated in a layer of 0–10 cm, from where, under favorable moisture conditions, it can germinate with the formation of seedlings, which can bloom before cold weather and replenish the stock of weed seeds in the soil. During moldboard plowing, weed seeds are evenly distributed over the entire arable layer, as a result of which it can be half as much in the 0-10 cm layer as after non-moldboard plowing. Therefore, the actual weediness of crops cultivated in crop rotation has always been higher after flat-cutting loosening: soybeans – by 22.1 %, rapeseed – by 72.6 %, and wheat, oil flax and barley – 15.0, respectively; 20.4 and 20.3%. On average for the crop rotation, this increase averaged 25.2 % over three years. A decrease in the depth of cultivation also caused contamination of crops, and its deepening as a whole in the crop rotation had a positive effect on the cleanliness of crops from weeds. The level of weediness of crops of cultivated crops at the beginning of the growing season should be considered a determining factor in the formation of the productivity of these crops due to the presence of a strong and very strong correlation between these indicators. Wheat was the most productive in terms of the yield of feed units, and soy was the most productive in terms of the yield of digestible protein. This applied to both methods or techniques of the main processing, and individual crops against the background of plowing had an advantage in both productivity indicators over flat-cut loosening. The productivity of crops and crop rotation was higher against the background of deep cultivation compared to medium and shallow cultivation. Conclusions. The use of flat-cut loosening instead of moldboard plowing, as well as a decrease in the depth of both methods of processing, is accompanied by a significant increase in the contamination of crops. As well as a decrease in the yield of the main products and a noticeable decrease in the productivity of a 5-field crop rotation in terms of the yield of feed units and assimilated protein.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7852
Author(s):  
Agata Stolarska ◽  
Teresa Rucińska

The subjects of this study were mortars with varying amounts of recycled ceramic aggregate (RCA). As part of the fine aggregate, the RCA volume share is 10%, 20%, 30%, 50% and 100%. First, fresh mixture parameters were evaluated, such as consistency and air content measurement by pressure method. Next, specimens were molded for compressive strength and flexural strength tests after 7, 28 and 56 days of curing. The thermo-humidity parameters of the composites, i.e., coefficient of capillary action and thermal conductivity coefficient were also investigated using nonstationary method. Sorption kinetics of the mortars at different moisture conditions at 20 °C were also evaluated. Sorption tests were carried out using two methods: TM and DVS. The sorption isotherms were plotted on the basis of equilibrium moisture content for the materials tested. The isotherms obtained by the two methods were evaluated. The results allowed us to draw conclusions on the physical and mechanical parameters of the composites with different amounts of RCA and to evaluate the ability to absorb moisture from the environment by these types of materials. A clear decrease in the compressive strength after 28 days of curing compared to the reference mortar was recorded after using 30% to 100% of RCA (approx. 26% to approx. 39%). Changes in flexural strength were significantly smaller, reaching no more than approx. 7.5%. It was shown that the amount of RCA translates into the ability to sorb moisture, which may affect the application of this type of composites. The amount of RCA translates also into the thermal conductivity coefficient, which decreased with increasing amount of RCA.


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