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Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 580
Author(s):  
Emna Ayari ◽  
Zeineb Kassouk ◽  
Zohra Lili-Chabaane ◽  
Nicolas Baghdadi ◽  
Mehrez Zribi

The objective of this paper was to estimate soil moisture in pepper crops with drip irrigation in a semi-arid area in the center of Tunisia using synthetic aperture radar (SAR) data. Within this context, the sensitivity of L-band (ALOS-2) in horizontal-horizontal (HH) and horizontal-vertical (HV) polarizations and C-band (Sentinel-1) data in vertical-vertical (VV) and vertical-horizontal (VH) polarizations is examined as a function of soil moisture and vegetation properties using statistical correlations. SAR signals scattered by pepper-covered fields are simulated with a modified version of the water cloud model using L-HH and C-VV data. In spatially heterogeneous soil moisture cases, the total backscattering is the sum of the bare soil contribution weighted by the proportion of bare soil (one-cover fraction) and the vegetation fraction cover contribution. The vegetation fraction contribution is calculated as the volume scattering contribution of the vegetation and underlying soil components attenuated by the vegetation cover. The underlying soil is divided into irrigated and non-irrigated parts owing to the presence of drip irrigation, thus generating different levels of moisture underneath vegetation. Based on signal sensitivity results, the potential of L-HH data to retrieve soil moisture is demonstrated. L-HV data exhibit a higher potential to retrieve vegetation properties regarding a lower potential for soil moisture estimation. After calibration and validation of the proposed model, various simulations are performed to assess the model behavior patterns under different conditions of soil moisture and pepper biophysical properties. The results highlight the potential of the proposed model to simulate a radar signal over heterogeneous soil moisture fields using L-HH and C-VV data.


2022 ◽  
Author(s):  
Rika Ratna Sari ◽  
Danaë M. A. Rozendaal ◽  
Danny Dwi Saputra ◽  
Kurniatun Hairiah ◽  
James M. Roshetko ◽  
...  

Abstract Backgrounds and aims Litter protects the underlying soil, depending on litterfall and decomposition, but dynamics of the standing litter stock in agroforestry systems remain poorly understood. We aimed to unravel effects of litter quality, temporal patterns, microclimate, and a possible home-field advantage (HFA) on standing litter dynamics across a land-use gradient. Methods We quantified litterfall, the standing litter stock, and microclimate during a year in (remnant) forest, cacao-based simple and complex agroforestry, cacao monocultures, and annual crops in a cacao producing area in Indonesia. We conducted a reciprocal litter transfer experiment, and tested decomposition rates of pruning residues. Standing litter stocks during the year were estimated from monthly litterfall and decomposition rates. Results Variation in litter quality influenced decomposition rates more strongly than variation in microclimate or HFA. Lower litter quality in complex agroforestry and in the cacao monoculture decreased the decay rate compared to simple agroforestry systems; mean litter residence time was over a year. Mixing high- and low-quality material in pruning residues modified the decomposition rate, soil C and N changes, offering options for targeted management of soil protection and nutrient release. Conclusions The seasonal patterns of litterfall and relatively slow decomposition rates supported permanence of the litter layer in all cacao production systems, protecting the underlying soil.


2022 ◽  
Vol 9 ◽  
Author(s):  
Carmen Monterroso ◽  
María Balseiro-Romero ◽  
Carlos Garbisu ◽  
Petra S. Kidd ◽  
Nikolla P. Qafoku ◽  
...  

2021 ◽  
Author(s):  
Diego Leiva ◽  
Fernando Fernández-Mendoza ◽  
José Acevedo ◽  
Margarita Carú ◽  
Martin Grube ◽  
...  

<p>The lichen microbiome includes a diverse community of organisms, spanning widely across the bacterial tree of life. Lichens have been proposed to form partially open symbiotic systems, in which some microorganisms may be transmitted along within lichen propagules, while others are acquired from the surrounding environmental community.</p><p>In this survey, we discuss the extent to which the lichen microbiome is connected to that of its immediate substrate. For this we sampled ten specimens of the Patagonian foliose cyanolichen <em>Peltigera frigida</em> and their underlying soil substrates in two forest sites of the Coyhaique National Reserve (Aysén Region, Chile). Using 16S metabarcoding with primers that exclude cyanobacteria, we identified a significant taxonomic divergence between the bacterial communities of lichens and substrates.</p><p>At the Phylum level, Proteobacteria (37% of relative abundance) are most abundant within lichens, while soil substrates are dominated by Acidobacteriota (39%). At the Genus level, some bacteria are significantly more abundant in lichens, such as <em>Sphingomonas</em> (8% in lichens vs 0.2% in substrates) or an unassigned genus of Chitinophagaceae (10% vs 2%). Conversely, genera like the unassigned acidobacterial genus SCN-69-37 (0.9% vs 12%) are more abundant in substrates.</p><p>Overall, our results are consistent with the idea that lichens shape their microbiome obtaining components from various sources, including reproductive propagules and the substrate on which they grow. Further experimental and ecological approaches are needed to assess the contribution of these microorganisms to the fitness of the symbiotic system.</p><p>Funding: FONDECYT 1181510.</p>


2021 ◽  
Vol 298-299 ◽  
pp. 108294
Author(s):  
Luyang Wang ◽  
Guanli Jiang ◽  
Ziteng Fu ◽  
Yali Liu ◽  
Siru Gao ◽  
...  

Author(s):  
R. Esten Mason ◽  
Trenton L. Roberts ◽  
Richard Boyles ◽  
Andrea Acuna ◽  
Maria N. Arguello ◽  
...  

Abstract This chapter summarizes the current understanding of the response of wheat to waterlogging stress, the genetic control of uptake and transport of macro- and micronutrients, and the QTLs and genes associated with tolerance mechanisms. Potential targets for molecular breeding through marker-assisted selection and the potential for genomic selection are discussed in order to provide a better understanding of the biology and genes underlying soil waterlogging tolerance, as well as clarity and direction for breeders for future molecular breeding targets to expedite cultivar development.


Author(s):  
Andrey Alekseev ◽  
◽  
Mikhail Rabinovich ◽  

Prospects for the development of Russia’s northern territories requires active improvement of existing and development of new regulatory documents regulating the usage of permafrost soils as underlying soil bases for buildings and structures. The introduction of new materials and technologies, the arrival of modern technologies, machines and mechanisms to the construction industry, has exacerbated the need to revise the civil engineering regulatory framework concerning permafrost conditions.


2021 ◽  
Vol 280 ◽  
pp. 01008
Author(s):  
Natalya Remez ◽  
Alina Dychko ◽  
Vadym Bronytskyi ◽  
Tetiana Hrebeniuk ◽  
Rafael Bambirra Pereira ◽  
...  

The paper provides numerical simulation of the influence of dynamic loading on the stress-strain state of the natural and geoengineering technogenic environment taking into account the soil basis for forecasting its use as the basis of the structure. Paper demonstrates the impact of static and dynamic loading on the subsidence of the landfill. To take into account the liquid phase of the waste and the viscoplastic medium, Darcy's law is used as an equation of balance of forces. The body of the landfill is modeled by weak soil taking into account the creep, using the Soft Soil Creep model. The covering and underlying soil layers are described by the Coulomb – Mohr model. An effective method for calculating the sedimentation of natural and geoengineering environment on the example of a solid waste landfill, based on numerical modeling of the stress-strain state of the landfill and underlying soil using finite elements is developed. It is demonstrated that the largest subsidence is experienced by the landfill with sand, as the base soil, but in percentage terms the amount of subsidence with the maximum load relative to the initial subsidence without loading is the largest in clay (33.7%). The obtained results must be taken into account when using landfills as a basis for buildings, structures, routes, recreational areas, etc.


Author(s):  
Roman G. Shaydurov

The problem of sensing subsurface objects by the method of excitation of the earth’s surface by Rayleigh seismic waves and obtaining information about the displacement of the ground above the target by radar method, taking into account the electromagnetic parameters of the underlying soil in the frequency range of 10 GHz, is considered. Recommendations are given on the optimal operating frequency of the radar in operating conditions on a statistically uneven ground surface


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