Length Density Research Articles

Effect of wood and peanut shell hydrochars on the desiccation cracking characteristics of clayey soils

Soil cracking can significantly alter the water and nutrient migration pathways in the soil, influencing plant growth and development. While biochar usage has effectively addressed soil cracking, the feasibility of using less energy-intensive hydrochars in desiccating soils remains unexplored. This study investigates the impact of wood and peanut shell hydrochars on the desiccation cracking characteristics of clayey soil. A series of controlled environmental laboratory incubations with regular imaging was conducted to determine crack development's dynamic in unamended and hydrochar-amended soils. The results reveal that the addition of wood hydrochar at 2% and 4% dosage reduced the crack intensity factor (CIF) by 22% and 43%, respectively, compared to the unamended control soil. Similarly, the inclusion of peanut shell hydrochar at 2% and 4% lowered the CIF by 22% and 51%, respectively. The presence of hydrophilic groups on the surface of hydrochars, such as O–H, CH, and C–O–C, enhanced the water retention capacity, as confirmed by Fourier-transform infrared analysis. The CIF decrease is attributed to mitigated water evaporation rates, enabled by enhanced water retention within the hydrochar pore spaces. These findings are supported by scanning electron microscopy analyses of the hydrochar morphology. Despite CIF reduction with hydrochar incorporation, the crack length density (CLD) increased across all hydrochar-amended series. In contrast to unamended soil which exhibited pronounced widening of large cracks and extensive inter-pore voids, the incorporation of hydrochar resulted in higher CLD due to the formation of finer interconnecting crack meshes. Consequently, the unamended control soil suffered greater water loss due to heightened evaporation rates. This study sheds new light on the potential of hydrochars in addressing desiccation-induced soil cracking and its implications for water conservation.

Prediction of burden distribution and electrical resistance in submerged arc furnaces using discrete element method modelling

A computational model of a submerged arc furnace (SAF) used in the production of ferrochrome is presented. The model's intended use is to investigate the extent to which intrinsic and extrinsic properties of the raw materials affect burden distribution and electrical resistance within the furnace. The model is built on the discrete element method and calculates the mechanical interactions of particle distributions resulting from the flow motion of typical raw materials used in the smelting of chromium ore. This model excludes the effects of thermodynamics, furnace chemistry, and heat transfer. It illustrates how the consumption of materials (chromite pellets, flux, and reductant) is affected by changes in electrode length, reductant fractions, and reductant sizing and density during the formation of a reductant bed. The resistance calculation algorithm developed by Mintek was applied to construct networks developed from particle contacts, which can quantitatively generate estimates of the electrode-to-electrode and electrode-to-bath electrical conduction conditions.

Non-equilibrium dynamics of ultracold lattice bosons inside a cavity

We study the non-equilibrium quench dynamics crossing a continuous phase transition between the charge density wave (CDW) and supersolid (SS) phases of a bosonic lattice gas with cavity-mediated interactions. When changing the hopping amplitude in the Hamiltonian as a function of time, we investigate the scaling behavior of the correlation length and vortex density with respect to the quench time and find that there is a threshold of the quench rate separating two distinct scaling regimes. When slowly varying the system below that threshold, we find a power-law scaling as predicted by the Kibble–Zurek mechanism (KZM). While considering fast quench above that threshold, a deviation from the KZM prediction occurs, manifested by a saturation of the defect density. We further show that such distinct scaling behaviors during different dynamic procedures can be understood through comparing the relaxation time and the quench rate.

Water Use Strategies and Shoot and Root Traits of High-Yielding Winter Wheat Cultivars under Different Water Supply Conditions

Drought is the most important factor limiting winter wheat yield in the North China Plain (NCP). Choosing high-yielding cultivars is an important measure to minimize the negative effects of drought stress. Field studies were conducted with 10 cultivars in the 2020–2022 seasons under three irrigation treatments (I0, without irrigation; I1, irrigated at jointing stage; I2, irrigated at jointing and anthesis stages) in the NCP to examine the water use strategies and root and shoot traits of high-yielding cultivars under different water supply conditions. The results showed that yield variation among cultivars was 21.2–24.6%, 23.7–25.9% and 11.6–15.3% for the I0, I1 and I2 treatments, respectively. Under water deficit conditions (I0 and I1), high-yielding cultivars reduced water use during vegetative stages and increased soil water use during reproductive stages, especially water use from deeper soil layers. Those cultivars with higher root length density (RLD) in deep soil layers exhibited higher water uptake. Each additional millimeter of water used after anthesis from the 100–200 cm soil layers increased grain yield by 23.6–29.6 kg/ha and 16.4–28.5 kg/ha under I0 and I1, respectively. This water use strategy enhanced dry matter accumulation after anthesis, decreased canopy temperature (CT) and increased relative leaf water contents (RLWC), which ultimately improved grain yield. For winter wheat grown under I2, cultivars that decreased water use after anthesis had higher water productivity (WP). Root length (RL), root weight (RW) and root:shoot ratio were each negatively correlated with grain yield, while above-ground biomass was positively correlated with grain yield. Therefore, higher dry matter accumulation and smaller root systems are two important traits of high-yielding cultivars under sufficient water supply conditions (I2) in the NCP.

The Nanoscale Structure and Stability of Organic Photovoltaic Blends Processed with Solvent Additives.

Controlling the nanomorphology in bulk heterojunction photoactive blends is crucial for optimizing the performance and stability of organic photovoltaic (OPV) technologies. A promising approach is to alter the drying dynamics and consequently, the nanostructure of the blend film using solvent additives such as 1,8-diiodooctane (DIO). Although this approach is demonstrated extensively for OPV systems incorporating fullerene-based acceptors, it is unclear how solvent additive processing influences the morphology and stability of nonfullerene acceptor (NFA) systems. Here, small angle neutron scattering (SANS) is used to probe the nanomorphology of two model OPV systems processed with DIO: a fullerene-based system (PBDB-T:PC71BM) and an NFA-based system (PBDB-T:ITIC). To overcome the low intrinsic neutron scattering length density contrast in polymer:NFA blend films, the synthesis of a deuterated NFA analog (ITIC-d52) is reported. Using SANS, new insights into the nanoscale evolution of fullerene and NFA-based systems are provided by characterizing films immediately after fabrication, after thermal annealing, and after aging for 1year. It is found that DIO processing influences fullerene and NFA-based systems differently with NFA-based systems characterized by more phase-separated domains. After long-term aging, SANS reveals both systems demonstrate some level of thermodynamic induced domain coarsening.

High Conductivity and Diffusion Mechanism of Oxide Ions in Triple Fluorite-Like Layers of Oxyhalides.

Oxide ion conductors are attractive materials because of their wide range of applications, such as solid oxide fuel cells. Oxide ion conduction in oxyhalides (compounds containing both oxide ions and halide ions) is rare. In the present work, we found that Sillén oxychlorides, Bi2-xTexLuO4+x/2Cl (x = 0, 0.1, and 0.2), show high oxide ion conductivity. The bulk conductivity of Bi1.9Te0.1LuO4.05Cl reaches 10-2 S cm-1 at 431 °C, which is much lower than 644 °C of yttria-stabilized zirconia (YSZ) and 534 °C of La0.8Sr0.2Ga0.83Mg0.17O2.815 (LSGM). Thanks to the low activation energy, Bi1.9Te0.1LuO4.05Cl exhibits a high bulk conductivity of 1.5 × 10-3 S cm-1 even at a low temperature of 310 °C, which is 204 times higher than that of YSZ. The low activation energy is attributed to the interstitialcy oxide ion diffusion in the triple fluorite-like layer, as evidenced by neutron diffraction experiments (Rietveld and neutron scattering length density analyses), bond valence-based energy calculations, static DFT calculations, and ab initio molecular dynamics simulations. The electrical conductivity of Bi1.9Te0.1LuO4.05Cl is almost independent of the oxygen partial pressure from 10-18 to 10-4 atm at 431 °C, indicating the electrolyte domain. Bi1.9Te0.1LuO4.05Cl also exhibits high chemical stability under a CO2 flow and ambient air at 400 °C. The oxide ion conduction due to the two-dimensional interstitialcy diffusion is considered to be common in Sillén oxyhalides with triple fluorite-like layers, such as Bi1.9Te0.1RO4.05Cl (R = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu) and Bi6-2xTe2xO8+xBr2 (x = 0.1, 0.5). The present study opens a new field of materials chemistry: oxide ion-conducting Sillén oxyhalides with triple fluorite-like layers.

Compatibilization of Immiscible Polypropylene/Poly(methyl methacrylate) Blends by Silica Particles with Janus and Random Component-Selective Grafts.

Introducing component-selective polymer chains onto the surface of a particle is an effective approach to improve the compatibilization efficiency of a particle-based compatibilizer. In this study, two particles with different kinds of component-selective polymer chains that have the same length and similar density but different graft locations were synthesized and their compatibilization effects were comparatively investigated. It was found that compared with the particle with homogeneous PMMA and PP grafts (R-P), the particle with a hemisphere of poly(methyl methacrylate) (PMMA) grafts and other hemisphere of polypropylene (PP) chains (J-P) showed a better compatibilization effect under equal loadings, although both particles exhibited high efficiency. The better compatibilization effect of particles with Janus grafts may be attributed to the stronger entanglements between grafted polymer chains and selective individual components. This work suggests that optimizing the graft location of a particle is an effective strategy for improving its compatibilization efficiency and helpful for the design of advanced particle compatibilizers.

Root growth dynamics and biomass input of four over-wintering herbaceous crops in boreal conditions

Root growth of winter wheat (Triticum aestivum L.), winter rye (Secale cereale L.), red clover (Trifolium pratense L.), and timothy (Phleum pratense L.) was recorded to evaluate the environmental potential of over-wintering crops in a Nordic agroecosystem. In a field experiment on Aquic Haplocryoll soil, root intensities (number of roots/area) were measured to 50 cm depth by minirhizotron microvideo camera technology over a two -year period (21 recording sessions). At anthesis, root biomass and morphological parameters were measured by destructive soil sampling and image analysis of washed roots. Winter cereal roots reached 50 cm depth as soon as the autumn of the seeding year. For both post-seeding years, timothy roots developed the most intensively in spring, while red clover had higher root intensity than timothy in late autumn. At anthesis, the crops were ranked timothy > red clover > winter wheat > winter rye according to root length density, surface area density, and biomass. Based on S:R ratios, red clover appears to offer the most intense carbon sink at 0–60 cm soil depth. Over-wintering crops had living roots in the subsoil both in late autumn and early spring, indicating potential to plant available nutrient uptake outside the growing season of annual crops.

Sclerotic bone: a sign of bone reaction in patients with medication related osteonecrosis of the jaw

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse reaction associated with antiresorptive drugs such as bisphosphonates and denosumab. When dealing with advanced and/or multiple MRONJ lesions undergoing surgical therapy, the extent of surgery is often a topic of discussion. The aim of this study was to identify the differences in bone density in and around the MRONJ lesion before and after surgical treatment to evaluate the needed surgical extend of the modelling osteotomy. In this retrospective study 26 patients with MRONJ lesions that were surgically treated in our department were observed. Length, width and bone density were measured in panoramic radiograph pre and postoperatively with the Imaging processing software Sidexis and ImageJ (Fiji). The necrotic area, the surrounding sclerotic area as well as the healthy contralateral side were observed. Measurements were performed by two independent observers. Pearson correlation was calculated to determine the interobserver variability. Bone density was significantly reduced in the necrotic bone area compared to the healthy unaffected contralateral reference side. The sclerotic bone area surrounding the necrosis showed increased bone density compared to the contralateral unaffected reference side. The density of the sclerotic bone area was increased in the previously affected MRONJ area in the postoperative panoramic radiograph. The pre and postoperative density showed no significant correlation to healing behaviour. The focus of the modelling osteotomy in surgical treatment of mature MRONJ lesions should be predominantly on the parts that appear necrotic and less dense in the panoramic radiograph as sclerotic areas might be an expression of bone reaction.

Sunflower root growth and distribution under varied water regimes in two edaphoclimatic conditions

Sunflower growth is adversely impacted by both excess and insufficient water. Research on root growth in this crop under water stress conditions remains limited and does not fully elucidate the plant's response to varying soil and climatic conditions. This study aimed to determine root growth, depth, and distribution of sunflower plants under different water stress conditions, such as deficit or excess, in two soil classes and sown during two distinct periods. Experiments were conducted after sowing at the beginning of September (first crop season) and at the beginning of January (second crop season) in an Ultisol (Santa Maria, Rio Grande do Sul State, Brazil) and an Oxisol (Panambi, Rio Grande do Sul State, Brazil). Water condition treatments applied from stage V6 included control, water deficit, and water excess. Roots were collected using an auger drill during the first crop season. The variables analyzed comprised root length density and accumulated root within the soil profile. During the second crop season, sunflower roots were visually assessed in the soil profile after trench excavation. Root system depth and root dry mass were evaluated during both sowing periods. Results indicated that sunflower root penetration is deeper in Ultisol than in Oxisol. Water deficit promotes root depth, while water excess promotes root growth near the surface. Sowing during the first crop season results in deeper root penetration and higher root dry mass production compared to the second crop season.

Prediction of Functional and Anatomic Progression in Lamellar Macular Holes

PurposeTo use artificial intelligence to identify imaging biomarkers for anatomical and functional progression of lamellar macular hole (LMH) and to elaborate a deep learning (DL) model based on optical coherence tomography (OCT) and OCT angiography (OCTA) for prediction of visual acuity (VA) loss in untreated LMHs. DesignMulticentric retrospective observational study ParticipantsPatients >18 years old diagnosed with idiopathic LMHs with availability of good quality OCT and OCTA acquisitions at baseline and a follow up>2 years were recruited. MethodsA DL model based on soft voting of two separate models (OCT and OCTA-based respectively) was trained for identification of cases with VA loss> 5 ETDRS letters (attributable to LMH progression only) during a 2-years follow-up. Biomarkers of anatomical and functional progression of LMH were evaluated with regression analysis, feature learning(support vector machine(SVM) model) and visualization maps. Main Outcome measuresEllipsoid zone(EZ) damage, volumetric tissue loss (TL), vitreopapillary adhesion (VPA), epiretinal proliferation, central macular thickness (CMT), parafoveal vessel density (VD) and vessel length density (VLD) of retinal capillary plexa, choriocapillaris (CC) flow deficit density (FDD). ResultsFunctionally progressing LMHs (VA-PROG group, 41/139 eyes (29.5%)) showed higher prevalence of EZ damage, higher volumetric TL, higher prevalence of VPA, lower superficial capillary plexus(SCP) VD and VLD and higher CC FDD compared to functionally stable LMHs (VA-STABLE group,98/139 eyes (70.5%)). The DL and SVM models showed 92.5% and 90.5% accuracy respectively. The best performing features in the SVM were EZ damage, TL, CC FDD and parafoveal SCP VD. Epiretinal proliferation and lower CMT were risk factors for anatomical progression only. ConclusionsDL can accurately predict functional progression of untreated LMHs over 2 years. The use of AI might improve our understanding of the natural course of retinal diseases. Integrity of CC and SCP might play an important role in the progression of LMHs.

Water and nitrogen supply at spatially distinct locations improves cotton water productivity and nitrogen use efficiency and yield under drip irrigation

The location of water and fertilizer supply directly affects the distribution of soil moisture and nutrients, thereby affecting crop yield and fertilizer use efficiency. However, the impact of water and nitrogen (N) supply location on cotton water and N use efficiency and yield is not yet clear, especially under drip irrigation conditions. A field experiment was conducted in 2022 and 2023. Four water and N supply patterns were set as: water and N supply at the same location (narrow row (PN) or wide row (PW)), water and N supply at spatially distinct (SD) and spatially and temporally distinct locations (STD). Soil water and N leaching, cotton root growth, water productivity (WP) and recovery efficiency of N (REN), and yield were quantified. The soil moisture and NO3--N vertical distribution range (0–60 cm) were deeper at the same location for water and N supply than at spatially distinct locations for water and N supply (0–40 cm). Compared to water and N supply at the same location, supply at spatially distinct locations significantly increased cotton root weight, root length density, and root surface area. In addition, water and NO3--N leaching of water and N supply at spatially distinct (SD and STD) were 12%-50% and 32%-59% lower, respectively, than those from the same location (PN and PW), while the yield and WP increased significantly by 7%-11% and 7%-10%, respectively. The REN of water and N supply at spatially and temporally distinct locations was the highest. Therefore, water and N supply at spatially distinct or spatially and temporally distinct locations can improve water productivity, recovery efficiency of N, and yield of cotton, and reduce soil water and N leaching loss under drip irrigation.

Neural network analysis of neutron and X-ray reflectivity data incorporating prior knowledge.

Due to the ambiguity related to the lack of phase information, determining the physical parameters of multilayer thin films from measured neutron and X-ray reflectivity curves is, on a fundamental level, an underdetermined inverse problem. This ambiguity poses limitations on standard neural networks, constraining the range and number of considered parameters in previous machine learning solutions. To overcome this challenge, a novel training procedure has been designed which incorporates dynamic prior boundaries for each physical parameter as additional inputs to the neural network. In this manner, the neural network can be trained simultaneously on all well-posed subintervals of a larger parameter space in which the inverse problem is underdetermined. During inference, users can flexibly input their own prior knowledge about the physical system to constrain the neural network prediction to distinct target subintervals in the parameter space. The effectiveness of the method is demonstrated in various scenarios, including multilayer structures with a box model parameterization and a physics-inspired special parameterization of the scattering length density profile for a multilayer structure. In contrast to previous methods, this approach scales favourably when increasing the complexity of the inverse problem, working properly even for a five-layer multilayer model and a periodic multilayer model with up to 17 open parameters.

Bergamot essential oil improves CUMS-induced depression-like behaviour in rats by protecting the plasticity of hippocampal neurons.

Bergamot essential oil (BEO) is an extract of the bergamot fruit with significant neuroprotective effect. This study was to investigate the effects and the underlying mechanism of BEO in mitigating depression. GC-MS were used to identify its constituents. Antidepressive properties of BEO were evaluated by sucrose preference test (SPT), force swimming test (FST) and open field test (OFT). Nissl staining was used to determine the number of Nissl bodies in hippocampus (HIPP) of rats. Changes in HIPP dendritic length and dendritic spine density were detected by Golgi-Cox staining. Immunohistochemistry and Western blot were used to detect the postsynaptic density protein-95 (PSD-95) and synaptophysin (SYP) in the HIPP of rats. The enzyme-linked immunosorbent assay was used to determine the 5-hydroxytryptamine (5-HT), insulin-like growth factor 1 (IGF-1) and interleukin-1β (IL-1β) in the HIPP, serum and cerebrospinal fluid (CSF) of rats. Inhaled BEO significantly improved depressive behaviour in chronic unpredictable mild stress (CUMS) rats. BEO increased Nissl bodies, dendritic length and spine density, PSD-95 and SYP protein in the HIPP. Additionally, BEO upregulated serum 5-HT, serum and CSF IGF-1, while downregulating serum IL-1β. Collectively, inhaled BEO mitigates depression by protecting the plasticity of hippocampal neurons, hence, providing novel insights into treatment of depression.

Root Distribution and Water Uptake Applied by Hydrogen and Oxygen Stable Isotopes for Lianas in Northwest China

The root distribution and water uptake of irrigated vines (Vitis vinifera L.) in arid oasis areas remain poorly understood, particularly in terms of the variations in water uptake resulting from plant type and growing period. In this study, excavation and soil coring were employed to investigate the root distribution of vines. Meanwhile, the water uptake dynamics of irrigated vines in an arid oasis area were developed using stable isotopes of hydrogen and oxygen in water bodies (δD and δ18O) and in crops and soil water, coupled with a direct inference approach and a linear mixed model (IsoSource). The soil layers were divided into nine layers via hierarchical cluster analysis. The results indicated that the vertical distributions of the total and fine roots of grapevines were mainly in the range of 40–160 cm, accounting for 93.1% (91.2%) and 92.5% (90.0%) of the total root (200 cm) distribution during May and October, respectively. In the horizontal direction, both the total root and fine root systems were mainly distributed within 0–100 cm from the trunk and contributed 81.2% and 79.8% of the total root distribution, respectively. Meanwhile, both the total root weight (length) density and fine root weight (length) density decreased gradually with increasing radial distance from the trunk in the 0–80 cm range. The main water uptake of vines was at 0–40 cm in June, 20–80 cm in July, and 40–100 cm in August. These findings suggest that the main depth of root water uptake increases during the whole growth stage for grapevines in arid oasis ecosystems. This information will help growers to improve irrigation efficiency and provide a data analysis of water conservation in an arid oasis area during water stress.

Ridge-furrow planting patterns with film mulching improve water use efficiency by enhancing arbuscular mycorrhizal fungi in the rhizosphere and endophyte of summer maize

In a rainfed agroecosystem with limited water resources, the symbiotic interactions between crop-arbuscular mycorrhizal fungi may have a significant impact on field productivity and water absorption and utilization. However, the interaction between AMF characteristics of root endophyte and rhizosphere soil and water use patterns of summer maize has not been studied under ridge-furrow with film mulching planting patterns (RFPM) in dry farmland. Based on a field experiment, we aimed to reveal the effects of different RFPM planting patterns (i.e., ridge/furrow ratio of 40:70 cm (RF40:70), ridge/furrow ratio of 55:55 cm (RF55:55), and ridge/furrow ratio of 70:40 cm (RF70:40)) on the root water use patterns of summer maize, the distribution characteristics of AMF in root endophyte and rhizosphere soil, and their interaction relationship by using the water isotope (δD and δ18O) tracer technique, the high-throughput sequencing technology, MixSIAR model, and the structural equation models. As a result, compared to flat planting without mulching (FP), RF40:70, RF55:55, and RF70:40 significantly increased grain yield by 29.74%, 35.24%, and 45.53%, and water use efficiency by 23.13%, 35.99%, and 50.25%, across the two growing seasons, respectively (P < 0.05). The root characteristic parameters of summer maize decreased with the increase in soil depth, and were mainly distributed in the shallow layer (0–20 cm) and middle layer (20–60 cm). Compared with FP, the distribution ratio of root surface area density, root length density, and root dry weight density in shallow soil layer was significantly increased by 5.03%, 7.46%, and 9.70% averaging the different RFPM treatments, respectively (P<0.05). Besides, compared to FP, the AMF abundance and diversity in rhizosphere soil and root endogenous averaged RFPM treatments increased by 32.32% and 29.66% and 5.88% and 28.43% respectively, in which the abundance and diversity gradually increased with the increase of the ratio of ridge-furrow. The PLS-PM results found that the larger ridge-furrow ratio could significantly increase the yield and WUE of summer maize mainly by increasing the root surface area density, root length density, and the abundance and diversity of AMF in the root endophyte and rhizosphere soil, which increased the water use of the middle and deep layer soils. In summary, the large ridge-furrow ratio can significantly increase the yield and WUE of summer maize by extending the hyphal network of maize root symbiotic AMF, which increases the water uptake of middle and deep layer soil.

Root traits and biomass production of drought‐resistant and drought‐sensitive arabica coffee varieties growing under contrasting watering regimes

AbstractDrought is a major factor affecting coffee production, and different genotypes exhibit varying degrees of resistance to drought stress. We examined root traits and biomasses of drought‐resistant (74110, Angafa, Bultum, Chala, and Gawe) and drought‐sensitive (75227, Koti, Melko CH2, Menasibu, and Mokah) Coffea arabica varieties at seedling stage under contrasting watering regimes (water stressed and well watered) for 30 days followed by 15 days of recovery to identify the association between drought resistance and root traits and dry matter partitioning, and the impact of drought stress on growth performance of arabica coffee varieties. We used a split‐plot design with three blocks, where watering regime was the whole‐plot factor and variety was the subplot factor. During water‐stress and recovery periods, the interaction effect between watering regime and variety significantly affected root traits and dry matter partitioning, while the watering‐regime main effect affected biomass. We observed a higher (1) tap root diameter (0.34 cm), lateral root number (80.7), and root volume (4.7 cm−3) for 74110; (2) lateral root number (79.3), specific root length (24.8 cm g−1), and root‐mass ratio (0.41 g g−1) for Bultum; and (3) root length density (3.3–5.2 cm cm−3), root angle (42.6°–47.8°), root‐mass ratio (0.40–0.42 g g−1), and root‐shoot ratio (0.67–0.72 g g−1) for Angafa, Chala, and Gawe under water‐stressed condition. During both study periods, biomasses were much lower under water‐stressed than under well‐watered condition. The findings show the association between drought resistance and root traits and dry matter partitioning, and the impact of drought stress on growth performance of young arabica coffee.

The Relationship between the Edge Density of the Forest Fragments and the Tree Species Richness in the Detached Fragments of Kakamega Forest.

Purpose: The theoretical approach guiding this study was based on the Island Biogeography Theory. The purpose of this study was to assess the influence of the edge density of the forest fragments on tree species richness.&#x0D; Methodology: The study adopted a cross-sectional correlational research design. Proportionate random sampling was used. A sample of 30 plots each measuring 2m by 2m was established randomly in the fragments (0-200m from the edge towards the interior);Malava: Kisere: Ikuywa in that order for field sampling and measurements. Data was collected using tools such as measuring tapes,metre rule,GPS 64s Garmain and suunto inclinometer. A total of 39 species of trees were recorded from the three fragments with Funtumia africana being recorded as the most abundant species.&#x0D; Findings: The findings show 83%, 85%, and 92% variation of tree species richness in. Malava (r2 = 0.83), Kisere (r2 = 0.85) and Ikuywa (r2 = 0.92) in that order can be explained by the edge density of the fragments. The edge density also explained 87%, 94% and 94% variation of tree species relative abundance in Malava (r2 = 0.87), Kisere (r2 = 0.94) and Ikuywa (r2 = 0.94) in that order.&#x0D; Unique Contributor to Theory, Policy and Practice: It was concluded that tree species richness and tree species abundance in the detached portions of Kakamega forest were dominantly influenced by forest fragment total edge length and fragment edge density. For us to conserve more tree species we recommend maintenance of the total edge length of the fragments above 15km with edge density (3.413.79m\m2) in order to maintain high tree species richness and tree species relative abundance.

Changes in preferential flow caused by root effects in black locust plantations of different stand ages in the semi-arid region of the Loess Plateau

Preferential flow significantly influences regional water cycles, and affecting surface and subsurface runoff processes. By comparing soil infiltration characteristics across various forest ages, it can be evaluated how artificial black locust forests on the Loess Plateau contribute to the resilience of soil and water conservation. In this study, we analyzed the spatial distribution characteristics of roots of black locust plants using field investigations and statistical analyses and determined the effects of the root characteristics on the preferential flow in the semi-arid of the Loess Plateau, China. The results showed that the root biomass, root length density, and root volume ratio of young forests were significantly lower than those of middle-aged and mature forests (P < 0.05), and root characteristic parameters varied significantly among different root diameters and soil layers.. The average volume of decayed root channels in mature forests, accounting for approximately 0.16 % in a unit volume of soil, was 3.1 times that of young forests and 4.9 times that of middle-aged forests. Preferential flow increased with forest age in artificial black locust forests. 2–5 mm, 30–40 mm and > 50 mm roots promoted preferential flow to varying degrees, while roots of 5–15 mm inhibited the preferential flow. < 2 mm, 10–30 mm and 40–50 mm roots has no effect on preferential flow (P > 0.05). The size and density of decayed root channels significantly improve soil preferential flow, and the differences among forest ages are linked to the network created by rotten roots. These findings indicate that living roots of different diameters and decayed roots contribute to soil preferential flow to varying extents. The results provided a conceptual basis for understanding the potential impact of vegetation roots on surface runoff during the vegetation restoration ecosystems process in the Loess Plateau.

Stereo-video landers can rapidly assess marine fish diversity and community assemblages

Climate change and anthropogenic stressors affect the distribution, abundance, and diversity of fish communities across the world. To understand rapidly changing biotic communities, resource managers need a method to quickly and efficiently document temporal and spatial changes in community assemblages across various spatial scales. In this study, we describe the use of new video lander tools to survey fish communities in rocky marine habitats on the continental shelf and slope in California, USA. We evaluate how fish diversity metrics determined by video surveys vary among geographically distinct areas. Our results demonstrate that species diversity, evenness, and richness vary spatially across the coast. Furthermore, community assemblages differ at both broad and fine spatial scales because of differences among habitats. Length frequencies and densities of species in this study were similar to those reported in previous studies. As community assemblages and biodiversity metrics shift in response to changing stressors, it is increasingly important to develop tools and methodologies to detect and rapidly monitor these changes.