Ground Cover Research Articles

Increased winter‐killed cover crop seeding rate may not increase soil health outcomes

AbstractImplementing soil conservation practices can begin to restore degraded soils, improve soil health, and increase overall ecosystem services. Cover cropping is an effective strategy to rebuild soil quality through decreased erosion and increased residue inputs, which can help build soil organic matter. Cover crop seeding rate may have a positive relationship with ecosystem services; however, it is unknown whether this is realized at or below the recommended cover crop seeding rate. The goal of this study was to identify the relationship between cover crop seeding rate and soil health biogeochemical measures across the growing season using five oat (Avena sativa L.)–pea (Pisum sativum L.) cover crop treatments of 0%, 25%, 50%, 75%, and 100% the industry standard seeding rate at the University of Massachusetts Amherst Research Farm. Soils were tested for soil carbon (C), nitrogen (N), and microbial measures at winter kill, spring thaw, post‐planting, and succeeding cash crop harvest. Soil measures did not vary among seeding rates, but total ground cover was consistent among treatments due to weed growth. Soil health measures vary seasonally reflecting soil microbial activity. Our study provides initial evidence that soil biogeochemical responses do not respond to increased seeding rate within one growing season when the resulting groundcover—cover crop biomass plus weeds—is consistent across seeding rates, but sampling date can influence the magnitude of soil biological and chemical soil health metrics.

Multidecadal vegetation transformations of a New Mexico ponderosa pine landscape after severe fires and aerial seeding.

Wildfires and climate change increasingly are transforming vegetation composition and structure, and postfire management may have long-lasting effects on ecosystem reorganization. Postfire aerial seeding treatments are commonly used to reduce runoff and soil erosion, but little is known about how seeding treatments affect native vegetation recovery over long periods of time, particularly in type-converted forests that have been dramatically transformed by the effects of repeated, high-severity fire. In this study, we analyze and report on a rare long-term (23-year) dataset that documents vegetation dynamics following a 1996 post-fire aerial seeding treatment and a subsequent 2011 high-severity reburn in a dry conifer landscape of northern New Mexico, USA. Repeated surveys between 1997 and 2019 of 49 permanent transects were analyzed for differences in vegetation cover, richness, and diversity between seeded and unseeded areas, and to characterize the development of seeded and unseeded vegetation communities through time and across gradients of burn severity, elevation, and soil-available water capacity. Seeded plots showed no significant difference in bare ground cover during the initial years postfire relative to unseeded plots. Postfire seeding led to a clear and sustained divergence in herbaceous community composition. Seeded plots had a much higher cover of non-native graminoids, primarily Bromus inermis, a likely contaminant in the seed mix. High-severity reburning of all plots in 2011 reduced native graminoid cover by half at seeded plots compared with both prefire levels and with plots that were unseeded following the initial 1996 fire. In addition, higher fire severity was associated with increased non-native graminoid cover and reduced native graminoid cover. This study documents fire-driven ecosystem transformation from conifer forest into a shrub-and-grass-dominated system, reinforced by aerial seeding of grasses and high-severity reburning. This unique long-term dataset illustrates that post-fire seeding carries significant risks of unwanted non-native species invasions that persist through subsequent fires-thus alternative postfire management actions merit consideration to better support native ecosystem resilience given emergent climate change and increasing disturbance. This study also highlights the importance of long-term monitoring of postfire vegetation dynamics, as short-term assessments miss key elements of complex ecosystem responses to fire and postfire management actions.

Magnetotelluric imaging of an iron-oxide copper gold (IOCG) deposit under thick cover

The presence of thick (>100 m) and electrically conductive (< 10 Ω.m) ground cover is a major impediment in mineral exploration of deep resources. Iron-oxide copper gold (IOCG) systems in Australia are often associated with a pronounced potential field anomaly, depending on the oxidation state of iron, but the gravity and magnetic field signatures have little vertical resolution unless constrained by drill hole petrophysics. Additionally, IOCG systems have deep magmatic sources, with their conductivity anomalies extending at least to the lithospheric mantle. The Vulcan IOCG prospect lies about 30 km northeast of the Olympic Dam IOCG mine and is defined by a significant gravity anomaly associated with brecciated haematite beneath 850 m of sedimentary cover sequences. To image the physical properties and structural geometry of the Vulcan IOCG prospect, a 100-site broadband MT and passive seismic array was deployed in a 1 km grid over a 9 by 9 km area. Three-dimensional inversion of MT responses resolve structure in three distinct domains. Firstly, broad limestone-quartzite-shale stratigraphy (1–30 Ω.m) in the 850 m cover is delineated in resistivity and corresponds well with changes in shear-wave velocity. Secondly, the region of brecciated haematite below the cover sequences is shown to have lower resistivity (< 60 Ω.m) than surrounding country rock (> 100 Ω.m). Thirdly, a more electrically conductive (< 30 Ω.m) vertical zone that extends > 5 km is imaged a few kilometers to the northeast of the Vulcan haematite breccia, and appears to be linked by a region of low shear-wave velocity in the depth range 1–2 km. Two-dimensional inversion of more regional MT responses along a 200-km line passing through the Vulcan prospect suggest this vertical region of low resistivity links to the lower-crust with anomalous resistivity of < 60 Ω.m in a similar way as imaged beneath the Olympic Dam mine. It is suggested that this conductive region is associated with graphite precipitated from magmatically derived CO2-rich fluids cooling in a reducing environment.

First Report of Agroathelia rolfsii Causing Southern Blight on Lippia (Phyla canescens) in Guangzhou, China.

Lippia (Phyla canescens) is a fast-growing, mat-forming, and prostrate perennial plant well adapted to infertile, high-saline, and drought environments (Leigh, et al. 2004). It arrived in China from Japan as a flowering ground cover in 2001 (Cai, et al. 2004). In June 2022, southern blight appeared in our nursery of the Floriculture Research Institute of Guangdong Academy of Agricultural Sciences. High temperature and damp environment are major factors for this disease. The symptoms of top-layer plants were not easily detected, but they were slightly yellowed. A yellowish-brown water-soak lesion appeared on the stems and lowest leaves exposed to soil. White mycelium appeared in the middle stage. Finally, the surface plants showed water-soak decay, and a mass of beige to black-brown rapeseed-shaped sclerotia appeared on the residue and surrounding soil; these plants died. Sclerotia and mycelia were collected from disease tissue, and after surface sterilization, sclerotia was cultured on potato dextrose agar (PDA) at 28±2°C in an incubator without light. Eight fungal isolates with similar colony morphologies were consistently isolated by purifying from different sampling areas. The isolates exhibited obvious septa and a clamp connection structure within the white mycelium. The average growth rate was 26.86±0.06 mm/day. Numerous white granular sclerotia were produced on the mycelium 6 days later. The sclerotia with a diameter of 1.24±0.07mm (n=189) gradually changed from diage to yellow to brown. A typical strain B1 was selected for further identification, targeting its 18S rRNA and LSU rRNA sequences (Yang, et al. 2011; Xue, et al. 2019). Its 18S rRNA sequence (GenBank Accession No. OR517233, 1626 bp) is 99.63% and 99.57% identical to Athelia rolfsii (AY665774, 1179bp; KC670714, 1775bp; JF819726, 1781bp). Its LSU rRNA sequence (OR539570, 757 bp) is 99.87% identical to Agroathelia rolfsii (OR526537, 904 bp). For Athelia rolfsii, a synonym of Agroathelia rolfsii, by combining the morphological characteristics and molecular identification, the isolate pathogen B1 was confirmed to be Agroathelia rolfsii (the teleomorph of Sclerotium rolfsii). To fullfill Koch's postulates, we inoculated the mycelial plugs to healthy lippia stems and leaves which has grown for one year, with PDA plugs free of mycelium as the control. All the plants were kept in a greenhouse at 28±2°C with a 14-h photoperiod and 80% relative humidity. Each treatment was repeated thrice and vaccinated with 6 points. At 7 d following inoculation, all plants inoculated with B1 showed typical symptoms, but the control group was asymptomatic, and sclerotia appeared 17d after inoculation. Using the same protocol mentioned above, pathogenic fungal was reisolated only from treated groups, but not from the control group. Chose three of the pathogens for 18S rRNA and LSU rRNA sequencing, the results showed 100% identity to B1, the same as its microstructure. There are few reports about the disease on P. canescens. Sosa (2007) investigated the pathogens on P. canescens in Argentina, 16 fungi were found but no A. rolfsii. Sclerotium rolfsii were identified on P. nodiflora or P. lanceolata (Michaux) Greene in America (Farr, et al. 1989). To our knowledge, this is the first report in China. Because this pathogen has wide-ranging hosts and causes serious damage, the results from this study will offer guidance for the prevention and treatment of this disease.

A circular approach to stone wool: Alkali-activated lightweight aggregates

This study investigates the high-value recycling of stone wool from construction and demolition waste into alkali-activated lightweight insulation aggregates, designed for ground cover insulation. Various proportions of milled and as-is stone wools are alkali-activated to produce aggregates. The aggregates demonstrate loose bulk densities ranging from 720 to 850 kg m−3 and dry thermal conductivity from 0.075 to 0.094 W m−1·K−1, with moderate water sorption capacities. The fibre morphology of as-is stone wool influences rheology, introducing a greater number of pores or defects, which results in a decrease in mechanical strength. Hydrothermal simulations reveal that the floor assembly of the rehabilitated crawl space, partially filled with the fabricated aggregates, shows a reduction in water content and an increase in floor surface temperature. This observation suggests potential benefits for maintaining the structural integrity of buildings and enhancing occupant comfort.

Analysis and forecasting of the scale and impact of forest fires on ecosystems of Ukraine

Forest fires are one of the most significant environmental problems that have a major impact on biodiversity and climate conditions. The purpose of the study was to investigate the impact of military operations on the ground cover in the area of the Bekhy forestry, which was disturbed by fire. It was revealed that for the period 2022-2023, 15 forest fires were recorded on the territory of the Korosten forest hunting enterprise of the state enterprise “Forests of Ukraine”, while the total area covered by fires was 15.13 ha. Overall, the number of fires increased from 5 to 10, but the total area covered by fires decreased from 12.1 to 3.03 ha. At the site of fires in 2022, the pH level increased to lower horizons, with the highest values at microhills (7.55) and microdepressions (7.35). There was a slight increase in the organic carbon content in the upper humus horizon of soils (0.42% on microhills and 0.46% on microdepressions). Bekhy forestry suffered a large forest fire in May 2023, which covered an area of 1.2 ha. The fire hazard assessment of each quarter was carried out separately. In the 50th and 51st compartments, Scots pine was the most fire-prone type of plantings. The 2023 fire site also showed an increase in pH in the lower horizons, with the highest values in microhills (7.35) and microdepressions (7.55). The 2023 fire site showed a decrease in organic carbon content compared to the background sites, with minimal values in the lower parts of the soil profile (0.33% on microdepressions and 0.38% on microhills). The results of the study can be used to develop and implement environmental measures and programmes aimed at restoring forests damaged by fire

ТРАНСФОРМАЦИЯ ПЛОДОРОДИЯ ПОЧВ ЗАЛЕЖЕЙ ЛЕСОСТЕПНОЙ ЗОНЫ ПРИ РАЗЛИЧНОМ НАПРАВЛЕНИИ ИХ ИСПОЛЬЗОВАНИЯ

The purpose of research is to provide a comprehensive comparative assessment of the fertility of gray fallow soils in the forest-steppe zone of the Krasnoyarsk Region, overgrown with forest, used for hayma-king and re-developed into arable land. The studies were conducted in 2007–2020 in the Krasnoyarsk and Achinsk-Bogotol forest-steppe on gray soils of fallow lands no longer used for agricultural purposes. Stu-dies were carried out to assess the indicators of the potential and effective fertility of gray soils of fallow lands of the Krasnoyarsk and Achinsk-Bogotol forest-steppe with their various post-agrogenic use. It has been established that forests regenerated on fallow lands do not lead to degradation of soil fertility, especially in terms of the content of humus and agronomically valuable aggregates. The emerging forest litter and tree litter accelerate the accumulation of organic matter, a source of humus. There is weak spatial va¬riation in most indicators of effective and potential fertility in soils under regenerating forest compared to pure fallow lands. With the re-involvement of fallow land into arable land, nitrification somewhat increases, spatial variation in soil properties decreases, and the content of humus and absorbed bases decreases. The structural composition of the soils of all study objects is characterized as excellent (ACF 88–77 %) with an insignificant value of the coefficient of variation of fractions (4–7 %). When reclaiming fallow lands into arable land, the proportion of the blocky fraction is significantly reduced. The spatial variability of the structural composition of soils in fallow lands and hayfields is higher than on arable land, which is asso¬ciated with the “clumpiness” of the ground cover and root system of plants on uncultivated soils. In terms of fertility, post-agrogenic gray soils used for haymaking occupy an intermediate position between clean fallow lands and those overgrown with forest. The productivity of the phytomass of fallow lands, arable land and hayfields in the Krasnoyarsk and Achinsk-Bogotol forest-steppe is more closely correlated with the indicators of the potential fertility of post-agrogenic gray soils. In most cases, the values of the correlation coefficients are closer between phytomass reserves and indicators of effective fertility in the Achinsk-Bogotol forest-steppe, which is associated with more favorable hydrothermal conditions in this research area and optimal water-physical properties.

Changes in plant diversity of European lowland forests: Increased homogenization and expansion of shade-tolerant trees

European lowland forests have undergone significant transformations over the past century due to increased canopy closure, eutrophication and plant invasions. The new millennium has brought plant invasions, alien fungal pathogens, and extreme weather conditions, all contributing to forest diebacks. However, the response of plant diversity remains poorly understood. We examined changes in understorey vegetation following a decade (2012–2021) of severe drought in four temperate lowland forest types (dominated by oaks, hornbeams, ashes, and willows) to understand how water availability, canopy openness, and alien fungal pathogens altered diversity in interaction with climate change. Following an exceptionally warm decade, the vegetation exhibited increased homogeneity, with denser shrub and herb layers, likely resulting from diminished tree canopy, particularly in hornbeam and ash forests. Homogenization was manifested by the colonization of plants with conservative life-history strategies (higher leaf dry matter content) to cope with increased drought. Consequently, communities with fewer species increased their species richness, while species-rich communities experienced impoverishment. Conversely, herbaceous species with higher specific leaf area were declining. Compositional changes were particularly prominent in hornbeam and oakwoods at the drier end of moisture gradient where the understorey became dominated by woody plants. Ashwoods were opening up due to ash dieback by fungal pathogens, causing replacement of wetland forbs by nitrophilous forbs and woody saplings. The overall number of species decreased in oakwoods but increased in hornbeam and ashwoods due to increased cover of grasses and shade-tolerant woody species, mostly Acer campestre. Conversely, willow understorey vegetation at the wetter end of the moisture gradient remained relatively stable. Our findings suggest shifts towards more homogeneous vegetation. Conservation plans for managing the remnants of species-rich lowland forests should consider the accelerated environmental changes linked to canopy alterations, biological invasions, and extreme climate events.

Clonal response of a recalcitrant understory shrub, Labrador tea (Rhododendron groenlandicum Oeder.) to forest gaps

After canopy removing disturbance, recalcitrant understory shrubs can rapidly occupy the forest understory to the detriment of tree regeneration and growth. The expansion of recalcitrant species has been documented following stand replacing disturbances, such as fire and timber harvest. However, there is little information on how these species respond to much smaller canopy gaps created by the senescence and (or) death of single or groups of canopy trees. In this study, we determined the response of Labrador tea ( Rhododendron groenlandicum Oeder.), a recalcitrant ericaceous shrub, to canopy gaps in a late-successional boreal forest in northwestern Ontario, Canada. We evaluated functional traits related to the morphology and regeneration strategy of this plant to elucidate the mechanism of gap filling. We found that R. groenlandicum abundance and vigor were greater at the center of treefall gaps than in gap edges or the forest understory due to aggressive sprouting from buried clonal bud banks. Layering was higher in canopy gaps than in the understory. The composition of ground cover and rooting substrate was more influential on the adventitious rooting of the layered stems than increased light availability in gaps. We found a strong response of R. groenlandicum to small canopy openings, suggesting that the species can form recalcitrant understory layers even in the absence of stand replacing disturbance.

A Local-Scale, Post-Fire Assessment in a Double-Burned Area: A Case Study from Peloponnisos, Greece

In the summer of 2021, Greece experienced significant forest fires and mega-fires across multiple regions, leading to human casualties and damage to the natural environment, infrastructure, livestock, and agriculture. The current study aims to assess the ecosystem condition in terms of the natural regeneration and soil conditions of an area burnt by a forest fire (2021), specifically in the Ancient Olympia region situated in West Peloponnese (Ilia Prefecture), Greece. A standardized field sampling methodology was applied to record natural regeneration at chosen sites where a forest fire had also previously occurred (in 2007), resulting in the natural re-growth of the Pinus halepensis forest. Furthermore, an analysis was conducted on the geochemical, mineralogical, and sedimentological properties of soils obtained from this location. The findings of the research demonstrate the decline in the established natural regeneration of the Pinus halepensis forest and the overall tree layer. Species characteristic of post-fire ecological succession were observed in the shrub and herb layers, displaying varying coverage. The examination of soil mineralogy, sedimentology, and geochemistry indicated that the soil characteristics in the area are conducive to either natural or artificial regeneration. Ultimately, recommendations for landscape rehabilitation strategies are provided to inform decision-making processes, considering future climate conditions.

Anthropogenic shrub encroachment has accelerated the degradation of desert steppe soil over the past four decades

Anthropogenic and natural shrub encroachment have similar ecological consequences on native grassland ecosystems. In fact, there is an accelerating trend toward anthropogenic shrub encroachment, as opposed to the century-long process of natural shrub encroachment. However, the soil quality during the transition of anthropogenic shrub encroachment into grasslands remains insufficiently understood. Here, we used a soil quality assessment method that utilized three datasets and two scoring methods to evaluate changes in soil quality during the anthropogenic transition from temperate desert grassland to shrubland. Our findings demonstrated that the soil quality index decreased with increasing shrub cover, from 0.49 in the desert grassland to 0.31 in the shrubland. Our final results revealed a gradual and significant decline of 36.73 % in soil quality during the transition from desert grassland to shrubland. Reduced soil moisture levels, nutrient availability, and microbial activity characterized this decline. Nearly four decades of anthropogenic shrub encroachment have exacerbated soil drought conditions while leading to a decrease in perennial herbaceous plants and an increase in bare ground cover; these factors can explain the observed decline in soil quality. These findings emphasize the importance of considering soil moisture availability and potential thresholds when implementing revegetation strategies in arid and semiarid regions.

Effects of Stand Density on Tree Growth, Diversity of Understory Vegetation, and Soil Properties in a Pinus koraiensis Plantation

The regulation of stand density has been studied in specific aspects of plantations with different age categories. A clearer understanding is still required of the extent to which stand density impacts multiple plantation attributes such as tree growth, understory vegetation diversity, and soil properties in Korean pine (Pinus koraeinsis Sieb. et Zucc) plantations. This study utilized a 43-year-old middle-aged Korean pine plantation in Qingping Forest Farm in northeast China to answer the research question posed. Three stand density levels, low stand density (LSD, 716 trees/ha), medium stand density (MSD, 850 trees/ha), and high stand density (HSD, 916 trees/ha) were studied for their effects on plantation attributes enumerated above. The results revealed a significant (p &lt; 0.05) effect of stand density on mean stand volume (m3). Medium stand density had the highest mean stand volume of 26.16 (±0.27) m3 while the lowest stand volume was recorded for the low stand density at 14.90 (±1.72) m3. Also, significant differences in total nitrogen, total potassium, available nitrogen, available potassium, and percentage soil moisture content were observed among stand density levels. Additionally, stand density was found to have significant effects on species richness, Shannon–Wiener, and Simpson’s diversity indexes for the shrub and herb layers of the plantation. This study shows that a medium stand density is the most optimal for promoting tree growth and understory biodiversity, as well as enhancing the status of certain soil nutrients. Thus, medium density achieves a balance between growth, nutrient availability, and biodiversity in middle-aged Korean pine plantations after a short period of thinning. These findings provide valuable knowledge for forest management, emphasizing the significance of continuous, long-term, and site-specific research.

CONDITIONS OF THE OAK FORESTS GROWTH AND CULTIVATION ON THE TOP SURFACES AND SLOPES OF THE NEAR-VOLGA AND ERGENI UPLANDS AND THE PLAINS OF THE SAL-MANYCH INTERFLUVE

Planted oak forests in the south of European Russia are of great conservation and economic importance. The widespread practice of their creation in dry steppes and semideserts dates back to the 1950-1970s and allows to form oak (Quercus robur L.) plantations with longevity up to 40-60 years. The aim of the study is to investigate the growth features of oak trees under different soil-climatic and biocenotic conditions and to suggest methods to increase their longevity.The research was carried out in 2011-2016 in the south of the Near-Volga Upland, the northern part of the Ergeni Upland and lowland plains of the Sal-Manych interfluve at 28 temporary sample plots using common methods of forest inventory and regression data analysis.It has been established that the viability of oak is limited by unfavorable topographic position of plantations, increased climate dryness (HC 0,4-0,6), high content of soil carbonates and shallow-lying horizon of their accumulation, as well as the presence of shrub layer and other competitors for moisture. Under these conditions, afforestation of depressions on the plains and shady slopes with pure plantations of oak and other species without shrubs should gain advantage. The methods of their creation should be modified depending on the topographic position of particular forest area and the climate dryness.So, the main soil cultivation in depressions could last 1-2 years, applying the system of black fallow with plantation plowing. It is advisable to keep 3,5-4,0-meter row spacing, frequent tending, and intensive clearing of young tree stands. Maturer plantations need careful sanitary-selective cuttings, mainly the low-type ones, and preservation of high canopy density. Poor water availability and deterioration of plantations should be prevented by construction of dams.Reclamation plantations of low marketability are created on flat areas after 2-3 years of deeper basic tillage. The carbonate horizon should be loosened and a large moisture reserve is needed. Row spacing of 2,5-3,0 meters is reasonable, accelerating the canopy closure. The area of tree nutrition is expanded by low-intensive uniformly selective cuttings, forming more open stands. The longevity of oak in already existing plantations could be increased by eliminating its competitors, such as living ground cover, shrubs and associated species.

DISPERAL OF THE LILIACEAE REPRESENTATIVES IN RELATION TO THE STRUCTURE OF THEIR REPRODUCTIVE ORGANS

The Liliaceae family is a terminal one in the order Liliales sensu APG IV (2016) and consists of 15 genera with more than 700 species. The family’s geographical range covers most of the Northern hemisphere and extends through several natural zones, from forest tundra (Gagea species) to tropical forests (Tricyrtis imeldae Guthnick), within three continents, i. e. Eurasia, North America and Africa. Most Liliaceous genera occur both in Eurasia and North America. Representatives of Liliaceae develop coenocarpous fleshly indehiscent berries or dry dehiscent capsules. In most cases, multi-seeded berries themselves are a diaspore, whereas in the case of capsules, the seeds are normally a diaspora. The capsules play a vital role in seed dispersal. Structural adaptations of fruits allowed representatives of Liliaceae to spread into the territories that make up the modern range of the family.The aim of the study is to determine the principal patterns of fruit development for the representatives of Liliaceae with different types of dissemination. The study is based on the investigation of morphological and anatomical structure of fruits which is related to geography, ecology and biology of the Liliaceae taxa dissemination.The study has revealed that the wind is the most typical and widespread agent of dissemination for the investigated representatives of Liliaceae. The specialized capsules responsible for anemochory, i.e. auto-anemochory and anemochionochory (mainly in representatives of the ground cover of deciduous forests in temperate and subtropical climatic zones of the Holarctic Kingdom), are characteristic of representatives of the Lilioideae subfamily. Unlike the capsules supporting the anemochory, which actively participate in dissemination, the primary function of capsules of baromyrmecochorous representatives of Liliaceae is seed production rather than their dispersal, which is reflected in the anatomical structure of the capsules, with numerous intercellular spaces in the pericarp and almost complete lack of its lignification. The endozoochory of fleshly berries of Liliaceae is effective for dispersal by long-distance transport, primarily by birds. Supposedly, the ornitochory prevents dispersal among a large number of ecosystems, which is echoed in the ranges of Clintonia, Prosartes and Streptopus genera, representatives of the ground cover of coniferous and broadleaf forests of the Holarctic Kingdom.

The Early to Late Cretaceous (Albian–Cenomanian) transition in Putumayo, Colombia: a biostratigraphic and carbon isotope stratigraphic correlation for northwestern South America

Despite the rich geological and paleontological record of Colombia, the Putumayo region near Ecuador remains one of the least explored regions in the equatorial Neotropics, mainly due to its thick vegetation, deep rock weathering, soil formation, and ground cover, geographic remoteness, and inaccessibility of well-exposed outcrops. This has resulted in limited comparisons with neighboring basins and thus the generation of more comprehensive biostratigraphic correlations with western and northern South America, as well as other paleobiogeographic regions (e.g., Tethys, Western Interior Seaway). Here, we present 67 occurrences of uppermost Lower Cretaceous to lowermost Upper Cretaceous ammonoids and other macrofossils (e.g., bivalves, decapod crustaceans, osteichthyan fish remains, plant remains), as well as a δ13Corg chemostratigraphic curve derived from 105 samples from the middle Albian of the uppermost Caballos Formation and the upper Albian to lower Cenomanian lower Villeta Formation, collected in situ from a stratigraphic section exposed along the Mocoa–San Francisco Road, Putumayo, Colombia, here called the San Francisco section. The chemostratigraphic, carbon-isotope curve for the region shows a great similarity with the shape of the accepted curve for the late Albian Oceanic Anoxic Event 1d, which is characterized by a worldwide long positive δ13C excursion anomaly. The new biostratigraphic and isotopic data serve as a point of reference to compare the Putumayo Basin with neighboring basins (e.g., Marañon Basin in Perú, Oriente Basin in Ecuador, Upper Magdalena Valley Basin in Colombia), and thus the generation of more comprehensive upper Lower Cretaceous and lower Upper Cretaceous biostratigraphic and chemostratigraphic correlations for northwestern South America.

Effect of ground cover on soil carbon storage in a citrus orchard: challenges and preliminary results

Effect of ground cover on soil carbon storage in a citrus orchard: challenges and preliminary results

THE IMPACT OF TRAFFIC NOISE ON THE ENVIRONMENT OF HEALTHY LIVING IN URBAN AREAS

&amp;lt;p style=&amp;quot;text-align: justify;&amp;quot;&amp;gt;Traffic noise has a great impact on the quality of public health. The paper shows the main characteristics and importance of green dams in urban areas, the role of green dams; area, layout, ground cover, planting density, vegetation and the like. Green dams were demonstrated and presented as the best solution for noise regulation arising from traffic in urban areas.&amp;lt;/p&amp;gt; &amp;lt;p style=&amp;quot;text-align: justify;&amp;quot;&amp;gt;For the purpose of researching this issue, a survey was conducted with the aim of gaining insight into the attitudes of the population in terms of traffic noise in urban areas.&amp;lt;/p&amp;gt; &amp;lt;p style=&amp;quot;text-align: justify;&amp;quot;&amp;gt;Green dams play a major role in urban areas, firstly they affect the reduction of environmental pollution, and then they play a major role in the reduction of noise in urban areas from city traffic.&amp;lt;/p&amp;gt;

Productivity, Soil Health, and Tree Diversity in Dynamic Cacao Agroforestry Systems in Ecuador

Agroforestry has the potential to support more resilient livelihoods, soil health, and biodiversity, when compared to monocropping. In Ecuador, the Union of Cacao Peasant Organizations (UNOCACE) has been working with producers since 2016 to transition cacao plots to a dynamic agroforestry system that includes timber and fruit species as well as ground cover in addition to cacao. This study evaluates the application of this model and its implications for agricultural production, livelihoods, and soil health through producer surveys and field-based sampling. The program is resulting in significantly more timber and fruit trees on the cacao plots. Despite this, cacao production and income have not decreased in a significant way, once accounting for the number of producing trees on the plots. In addition, while additional labor is utilized on the dynamic agroforestry plots, after utilizing a matching procedure, no significant difference is seen in total crop productivity for each day of labor utilized. Over time, total productivity could increase for the dynamic agroforestry plots as the companion crops and trees mature. As the program is relatively new and has undergone some changes, additional studies are needed to understand the benefits or challenges, especially for soil health, that might be realized further in the lifespan of the program.

Features of the structure of the herbaceous cover and natural regeneration in the spruce forests of the Kologrivsky Forest Nature Reserve

The aim of the study was to identify the features of the structure of the herbaceous cover and natural regeneration in the southern taiga spruce forests of the Kostroma region using the example of the Kologrivsky Forest Nature Reserve. To achieve this goal, twelve temporary square sample plots (SP) with an area of 0.0625 ha were established. Forest type, canopy density, soil and topography were determined. To characterize the forest stands, a taxonomic survey of the sample plots was carried out. To describe the vegetation cover, a combined method was used, including the Braun-Blanke and Drude-Uranov methods, which assumes the distribution of typical plant complexes over a large number of plant species growing together. Geobotanical descriptions were processed according to the method of D.N. Tsyganov, which consisted in using two tables: ecological amplitudes of species and scales of factors. Correlation analysis was used for data processing. The obtained statistical data set was presented in histograms and graphs for the sake of clarity. The frequency of occurrence, errors, participation rate, and average projective cover of the species were calculated according to generally accepted methods. In the course of the work, all sample plots were characterized by a tree-by-tree census. As the sample plots were located in very different parts of the reserve, the taxonomic indicators varied. In most cases, however, the dominant species was spruce. Its viable regrowth was 95%, indicating a high renewal potential. In the studied forest areas, the dominant species of the living ground cover were Northern linseed (Linnaea borealis) and blueberry (Vaccinium myrtillus), oak fern (Gymnocarpium dryopteris) and wood sorrel (Oxalis acetosella). The practical significance of the conducted research lies in the expansion of the ideas about the structure of the herbaceous cover formed under the canopy of spruce forests in the conditions of the Kologrivsky Forest Nature Reserve, as well as about the peculiarities of the process of natural regeneration in different conditions of the growth site.

Biocrusts Critical Regulation of Soil Water Vapor Transport (Diffusion, Sorption, and Late‐Stage Evaporation) in Drylands

AbstractSoil surface cover is one of the most critical factors affecting soil water vapor transport, especially in drylands where water is limited, and the water movement occurs predominantly in the form of vapor instead of liquid. Biocrusts are an important living ground cover of dryland soils and play a vital role in modifying near‐surface soil properties and maintaining soil structure. The role of biocrusts in mediating soil water vapor transport during daytime water evaporation and nighttime condensation remains unclear. We investigated the differences in vapor diffusion properties, vapor adsorption capacity, and water evaporation between bare soil and three types of biocrusts (cyanobacterial, cyanobacterial‐moss mixed, and moss crusts) in the Chinese Loess Plateau. Our results showed that the three types of biocrusts had 5%–39% higher vapor diffusivity than bare soil. At the same level of ambient relative humidity and temperature, the initial vapor adsorption rates and cumulative adsorption amounts of the biocrusts were 10%–70% and 11%–85% higher than those of bare soil, respectively. Additionally, the late‐stage evaporation rate of cyanobacterial‐, cyanobacterial‐moss mixed‐, and moss‐biocrusts were 31%–217%, 79%–492%, and 146%–775% higher than that of bare soil, respectively. The effect of biocrusts on increasing vapor transport properties was attributed to the higher soil porosity, clay content, and specific surface area induced by the biocrust layer. All of these modifications caused by biocrusts on surface soil vapor transport properties suggest that biocrusts play a vital role in reshaping surface soil water and energy balance in drylands.