Search Results (34)

Cashew (Anacardium occidentale L.), a vital tropical cash crop, may face yield declines in old plantations due to unexplored risks of autotoxicity. This study investigated the allelopathic and autotoxic potential of cashew plant under laboratory and greenhouse conditions. The laboratory bioassays with leaf and stem bark (10–200 mg) demonstrated a strong allelopathic effect, reducing lettuce radicle elongation to 7–46.0% and 9–79% of the control, respectively. Aqueous leaf extract (50 mg/mL) completely inhibited (0%) lettuce seed germination and reduced pepper germination to 42%. However, the root exudate of cashew seedlings did not have any inhibitory effect on the test plants. Greenhouse experiments simulating field litter fall revealed significant autotoxicity in cashew. Cashew seedlings grown in growth media amended with 10% cashew leaf powder exhibited severe growth suppression after 13 weeks, including a reduction in plant height by 58.2% compared to controls. Chlorophyll content, stem girth, and leaf number were also significantly reduced. This study concludes that cashew possesses significant allelopathic properties and a clear potential for autotoxicity, as directly evidenced by the suppressed growth of its own seedlings following the incorporation of leaf powder. These findings identify autotoxicity, mediated through leaf litter decomposition, as a critical risk factor for the replanting success and long-term sustainability of cashew orchards, necessitating further investigation into management strategies. Full article

As climate change accelerates, environmental factors are expected to fluctuate as well. To gain insight into soil respiration (Rs) dynamics, it is essential to conduct long-term measurements of Rs alongside environmental variations. To this end, we examined Rs associated with environmental variables from 2018 to 2024 at a site located on Mt. Jeombong, which is situated in a temperate deciduous broadleaf forest. The interannual variation in Rs was not explained by soil temperature but was primarily associated with rainfall regimes. The mean Rs for April–November was substantially different during the study period and was strongly correlated with cumulative rainfall at all measurement points (R² = 0.68–0.94). These variations were largely attributed to changes in autotrophic respiration (Ra). Furthermore, Rs differed significantly between nearby measurement points (p < 0.05), despite their proximity within a 100 m by 100 m plot, apparently reflecting point-level differences in responses of Rs to environmental drivers that were likely modulated by uneven litter accumulation. Overall, at our site located in temperate deciduous forests, Rs primarily fluctuates as a result of rainfall variation, and Rs variations are strongly influenced by the heterogeneity in the litter deposition. Full article

In the ecologically fragile western Shanxi Loess region, stand density regulation of artificial Robinia pseudoacacia L. forests plays a crucial role in sustaining the water regulation functions of the litter-soil system, yet multi-scale mechanistic analyses remain scarce. To address this gap, we established six stand density classes (ranging from 1200 to 3200 stems/ha) and quantified litter water-holding traits and soil physicochemical properties. We then applied principal component analysis (PCA) and structural equation modeling (SEM) to examine density-litter-soil relationships. Low-density stands (≤2000 stems/ha) exhibited significantly higher litter accumulation (6.08–6.37 t/ha) and greater litter water-holding capacity (maximum 20.58 t/ha) than the high-density stands (p < 0.05). Soil capillary water-holding capacity decreased with increasing density (4702.63–4863.28 t/ha overall), while non-capillary porosity (5.26–6.21%) and soil organic carbon (~12.5 g/kg) were higher in high-density stands (≥2800 stems/ha), reflecting a structural-carbon optimization trade-off. PCA revealed a primary hydrological function axis with low-density stands clustering in the positive quadrant, while high-density stands shifted toward nutrient-conservation traits. SEM confirmed that stand density affected soil capillary water-holding capacity indirectly through litter accumulation (significant indirect path; non-significant direct path), highlighting the central role of litter quantity. When density exceeded ~2400 stems/ha, litter decomposition rate decreased by ~56%, coinciding with capillary porosity falling below ~47%, a threshold linked to impaired balance between water storage and infiltration. These findings identify 1200–1600 stems/ha as the optimal density range; in this range, soil capillary water-holding capacity reached 4788–4863 t/ha, and available phosphorus remained ≥2.1 mg/kg, providing a density-centered, near-natural management paradigm for constructing “water-conservation vegetation” on the Loess Plateau. Full article

Although rainfall is a major determinant of soil moisture content (SMC), various factors affect SMC. The effects of these environmental factors contribute to spatial heterogeneity in SMC, which influences diverse ecological processes. To better understand the dynamics in SMC, litter and slope gradient should be considered. To this end, we analyzed the impacts of litter and slope gradient on SMC from 2020 to 2021 on Mt. Jeombong, located in a temperate deciduous broadleaf forest. We classified the study period into foliage (with a developed canopy) and non-foliage (after leaf fall) seasons. Our results indicated that SMC was affected by slope gradient and litter layer. Rainfall absorption occurred more at gentle slope, leading to higher SMC. Additionally, rainfall absorption was interpreted as being intercepted by the litter layer. Consequently, the correlation coefficient between SMC increment and rainfall was lower in the non-foliage season (R² = 0.37–0.56) than in the foliage season (R² = 0.72–0.84). With temporal progression, however, SMC response to rainfall increased where the litter was thickly accumulated, suggesting that litter interception was gradually diminished by decomposition. In this study, spatial heterogeneity in the litter layer and slope gradient substantially influenced the supply of soil moisture from rainfall. Full article

Platforms have been shown to be a suitable environmental enrichment for broiler chickens, accommodating their motivation to roost and rest at an elevated position. In order to increase the animal welfare benefits, we designed prototype elevated platforms with additional functionalities: a local cooling system, a sheltered area underneath the platform and collection trays underneath the platform that prevent manure from falling on the litter. This study assessed the effects of these multifunctional platforms during thermoneutral and heat stress conditions on two key determinants of their commercial uptake potential, namely production performance, carcass and meat quality. In each of the three experimental rounds, 560 one-day-old male chicks (Ross 308) were equally assigned to four pens and reared for 43 days. The barn was divided into two compartments (thermoneutral and heat), each containing one enriched and one barren pen. To induce heat stress, the ambient temperature was increased to 32 °C during 6 h/day when the birds were 29–40 d old. The platforms did not compromise broiler performance. Heat stress negatively impacted body weight (p = 0.008), average daily gain (p = 0.009) and feed intake (p < 0.001) and improved the feed conversion ratio (p = 0.026). The platforms reduced mortality rate under heat stress but not under thermoneutral conditions (heat × enrichment p = 0.025), likely due to the cooling functionality. No major effects of the platforms on overall carcass and meat quality were observed, except for a reduction in the risk of breast muscle myopathies (p < 0.001), which could enhance consumer acceptance and improve profitability. To conclude, the use of cooled platforms under the conditions of this experiment mitigated the adverse effects of heat stress on mortality, reduced the risk of breast muscle myopathies and did not compromise any other production or carcass and meat quality parameters. Full article

The decomposition of plant litter, most of which is found in forests, is an important element of the global carbon cycle, as a result of which carbon enters the atmosphere in the form of not only CO₂ but also volatile organic compounds (VOCs). Although the formation of litter is associated with autumn cooling, in the spring, there is a very intense fall of faded inflorescences of woody plants. This study examined the chemical composition of the litter and VOCs emitted from decaying inflorescences of four species of forest-forming trees: silver birch, European hornbeam, black alder and aspen. All litter emissions consisted of 291 VOCs, mainly terpenes actively participating in atmospheric processes. The detection of a number of typical mushroom metabolites, such as 1-octen-3-ol, known as “mushroom alcohol”, and alkyl sulphides, suggests that inflorescence-derived VOCs are a mixture of components of plant and microbial origin. In methanol extracts of the fallen inflorescences of all types, 263 organic compounds were identified, the majority of which were related to carbohydrates. Their share in the extracts was 72–76%. In general, the composition of the extractive compounds indicates the easy availability of this material for assimilation by various types of destructors. Full article

Flowers of Paulownia spp. wither and fall on a large scale after blooming in spring and have potential allelopathic effects on surrounding plants, including crops and weeds. In this study, the phytotoxic effects of water extracts of Paulownia tomentosa flower litter (EPF) on wheat (Triticum aestivum L.), lettuce (Lactuca sativa L.), green bristlegrass (Setaria viridis L.) and purslane (Portulaca oleracea L.) were evaluated in the laboratory. The mode of action of the phytotoxicity of EPF on lettuce seedlings was studied and the secondary metabolites in EPF were analyzed by liquid chromatography high-resolution mass spectrometry (LC-HRMS). The results show that EPF significantly inhibited the seed germination and seedling growth of four target plants in a concentration-dependent manner. In addition, EPF could induce the excessive accumulation of reactive oxygen species (ROS) flowing with oxidative damage of the lipid bilayer of the biofilm, resulting in reduced cell viability and even apoptosis in lettuce. There were 66 secondary metabolites identified by LC-HRMS in P. tomentosa flowers. Among them, 10 compounds, including salicylic acid, caffeic acid, parthenolide, 7-hydroxycoumarin and abscisic acid (ABA), were all known allelochemicals. In summary, P. tomentosa flower litter displayed significant allelopathic effects, which were related to the accumulation of ROS in target plants. Phenolic acids, flavonoids as well as ABA are probably the main allelochemicals of P. tomentosa flowers. Full article

The coastal strip, characterized by the urbanization of coastal tourist territories (CTTs), has expanded over decades through civil engineering, altering the shoreline dynamics and creating artificial beaches crucial for tourism. To examine the relationship between extensive land use in CTTs for tourism and residences and the presence of marine litter, a specific parametric study was conducted along the coast of Tenerife, the largest island in the Canary Islands. Due to Tenerife’s geographical location and exposure to the descending Gulf Stream flow, the coastal waters in the selected zone experience waste impact at both local and global scales. However, the presence of marine litter deposited by ocean currents is at a micro level and falls outside the scope of this report. This study parameterised urban reality in study areas, and the presence of macro waste has been parameterised using standardised units of measurement. This enables the establishment of source measurements that will contribute to preventative measures against this type of coastal pollution. The interdependence between tourist zoning, civil seafront engineering works along the seafront, and marine litter presence in inaccessible and visible areas for tourists requires a methodology to better understand waste origin and loading areas. This knowledge is crucial for an effective local monitoring system. A quantitative overlay reading methodology has been designed in the urban setting through calculations of urban densities, while examining the waste in these areas’ immediate infralittoral flooring through the use of visual underwater extraction. Anticipating the type and quantity of waste in each area will allow for the implementation of effective awareness, promoting action for preventative and corrective measures at the urban level. The results show a direct dependence between urban density and the presence of waste, as well as an equation that makes it possible to anticipate the amount of waste according to urban density and its relational vector. There is no discontinuity between them, as each area is affected by others to the extent that they establish the parametric continuity conditions determining each field. Therefore, it is possible to relate them beyond a one-on-one relationship. This approach fosters sustainable tourism development, reducing pressure on the sea and enhancing the utilisation of tourism revenues in measures to address waste-related challenges and promotes sustainable tourism development in Europe’s coastal regions. Full article

To examine the effect of litter on ANPP and species composition (using ground cover) in a Desert Steppe community by removing or adding litter, during plant dormancy, in a single event in either fall or spring. Litter was removed or added in three intensity treatments (heavy, moderate, control—undisturbed) as the main plot and season (fall or spring) as the secondary treatment in a split-plot design with five replications. The experiments were repeated in each of 5 years while three of those were resampled twice. The year effect was analyzed by classifying them into high or low precipitation categories and including those in the statistical model. We found few treatment effects one year after treatment and no persistent effect. Therefore, we focus our examination on the first year only. The total ANPP of individual plant types, or their proportions, were not affected by litter treatment or its interaction with season of treatment or precipitation category. Only the ground cover of selected species was influenced by the treatment. The ground cover of Stipa breviflora was greater with heavy litter removal in fall but unaffected by litter removal in spring while Neopallasia pectinata had a greater cover with moderate or heavy removal in years when precipitation was low. Litter addition resulted in a greater ground cover of Neopallasia pectinata and reduced the cover of Convolvulus ammannii in years of low precipitation. The marginal effectiveness of litter treatments on the plan community in the Desert Steppe suggests that it need not be a factor for consideration in grazing management. Full article

The study of litter can provide an important reference for understanding patterns of forest nutrient cycling and sustainable management. Here, we measured litterfall (leaves, branches, etc.) from a wet, evergreen, broad-leaved forest in Ailao Mountains of southwestern China on a monthly basis for 11 years (2005–2015). We measured the total biomass of litter fall as well as its components, and estimated the amount of C, N, P, K, S, Ca, and Mg in the amount of litterfall. We found that: The total litter of evergreen, broadleaved forest in Ailao Mountains from 2005 to 2015 was 7.70–9.46 t/ha, and the output of litterfall differed between years. This provides a safeguard for the soil fertility and biodiversity of the area. The total amount of litterfall and its components showed obvious seasonal variation, with most showing a bimodal pattern (peak from March to May and October to November). The majority of litterfall came from leaves, and the total amount as well as its components were correlated with meteorological factors (wind speed, temperate and precipitation) as well as extreme weather events. We found that among years, the nutrient concentration was sorted as C > Ca > N > K > Mg > S > P. The nutrient concentration in the fallen litter and the amount of nutrients returned showed a decreasing trend, but the decreasing rate was slowed through time. Nutrient cycling was influenced by meteorological factors, such as temperature, precipitation, and wind speed, but the nutrient utilization efficiency is high, the circulation capacity is strong, and the turnover time is short. Our results showed that although there was nutrient loss in this evergreen, broad-leaved forest, the presence of forest litterfall can effectively curb potential ecological problems in the area. Full article

This paper essentially aims to identify coastal sites of great scenic value not (or barely) affected by human intrusions and propose sound management interventions to improve their landscape quality. Today, management of coastal areas in Italy is a very complex task essentially because of institutional fragmentation and overlapping of laws/regulations at the national, regional and municipal levels. It is estimated that only half of the country’s beaches are freely accessible and usable for bathing, i.e., 43% are occupied by private concessions and in 7.2% bathing is not allowed because of water pollution. Sites’ scenic quality was assessed using the Coastal Scenic Evaluation System (CSES), a robust semi-quantitative methodology based on a set of 26 physical/human parameters, weighting matrices parameters and fuzzy logic mathematics. An evaluation index (D) was afterward obtained for each site and used to classify them into five scenic classes. After a long process of field testing along the coasts of the Tyrrhenian, Ionic and Adriatic seas (25 municipalities, 7 provinces and 4 regions: Campania, Basilicata, Calabria and Apulia), a total of 36 sites were selected for this paper. Twenty-four sites fall within Class I, i.e., were extremely attractive (D ≥ 0.85; CSES) because of their exceptional geomorphological settings that favour a wide variety of coastal sceneries. Most of Class II (8) and Class III (4) sites could be upgraded by implementing clean-up operations or by reducing intrusive beach facilities. Meanwhile “private” beaches are usually cleaned; beach litter at remote/public sites represents a big concern to be challenged. Today, finding a free/aesthetic/clean beach without human intrusions in a fully natural environment is far more complex than it seems. Given this context, emphasis was particularly placed on beach litter and concessions aspects. Full article

Litter humification is an essential process of soil carbon sequestration in forest ecosystems, but the relationship between soil fauna and humic substances has not been well understood. Therefore, a field litterbag experiment with manipulation of soil fauna was carried out in different soil frozen seasons over one year in cold forests. The foliar litter of four dominated tree species was selected as Birch (Betula albosinensis), Fir (Abies fargesii var. faxoniana), Willow (Salix paraplesia), and Cypress (Juniperus saltuaria). We studied the contribution of soil fauna to the accumulation of humic substances (including humic acid and fulvic acid) and humification degree as litter humification proceeding. The results showed that soil fauna with litter property and environmental factor jointly determined the accumulation of humic substances (humic acid and fulvic acid) and humification degree of four litters. After one year of incubation, the contribution rates of soil fauna to the accumulation of humic substances were 109.06%, 71.48%, 11.22%, and −44.43% for the litter of fir, cypress, birch, and willow, respectively. Compared with other stages, both growing season and leaf falling stage could be favorable to the contributions of soil fauna to the accumulation of humic substances in the litter of birch, fir, and cypress rather than in willow litter. In contrast, the contribution rates of soil fauna to humification degree were −49.20%, −7.63%, −13.27%, and 12.66% for the litter of fir, cypress, birch, and willow, respectively. Statistical analysis indicated that temperature changes at different sampling stages and litter quality exhibited dominant roles in the contributions of soil fauna on the accumulation of humus and litter humifiaction degree in the cold forests. Overall, the present results highlight that soil fauna could play vital roles in the process of litter humification and those strengths varied among species and seasons. Full article

Litter, LS, is the organic material in which locates in the top A soil horizon, playing key ecological roles in forests. Models, in contrast to common allocation factors, must be used in LS assessments as they are currently absent in the scientific literature. Its evaluation assess the mass, input and flux of several bio-geo-chemicals, rainfall interception as one component of the local hydrology, and wildfire regimes, among others, hence its importance in forestry. The aim of this study was to: (i) develop models to assess LS, accumulation, and loss rates; and (ii) assess rainfall interception and fire regimes in 133 northern forest plantations of Mexico. Two developed techniques: the statistical model (SM_LS) and the mass balance budget model (MBM_LS) tested and validated local and regional LS datasets. Models use basal area, timber, aboveground tree biomass, litter fall, accumulation, and loss sub-models. The best fitting model was used to predict rainfall interception and fire behavior in forest plantations. Results showed the SM_LS model predicted and validated LS datasets (p = 0.0001; r² = 0.82 and p = 0.0001; r² = 0.79) better than the MBM_LS model (p = 0.0001; r² = 0.32 and p = 0.0001; r² = 0.66) but the later followed well tendencies of Mexican and World datasets; counts for inputs, stocks, and losses from all processes and revealed decomposition loss may explain ≈40% of the total LS variance. SM_LS predicted forest plantations growing in high productivity 40-year-old stands accumulate LS > 30 Mg ha⁻¹ shifting to the new high-severity wildfire regime and intercepting ≈15% of the annual rainfall. SM_LS is preliminarily recommended for LS assessments and predicts the need of LS management in forest plantations (>40-year-old) to reduce rainfall interception as well as the risk of high-severity wildfires. The novel, flexible, simple, contrasting and consistent modeling approaches is a piece of scientific information required in forest management. Full article

Riparian forests are important ecosystems located along the margins of freshwaters. Riparian zones provide many ecosystem services, such as nutrient modification, erosion and temperature control, leading to improvements in water quality in adjacent water ecosystems. In many areas, riparian forest management is restricted to improve adjacent water quality. The potential influence of forest management on water quality of small streams was assessed by analysing species composition and structural diversity in riparian forests. We collected data in riparian forests along 15 streams in the eastern Baltics (Latvia) with different water quality classes. We used detrended correspondence analysis and indicator species’ analysis to determine relationships between woody plants and understory vegetation. We also used ADONIS and ANOSIM analysis to determine possible factors that affect species composition. Our results suggested that water quality is affected by ground vegetation, which in turn was altered by stand density and total yield. Site-specific decision making in management is required in riparian forests to ensure the required conditions in the streams, because species composition differs between sites, dominant tree species and stand parameters (density, total yield, stand age). Introduction of Betula pubescens Ehrh. in coniferous stands is favourable to ensure litter fall quality and provide shade for streams during summer. Full article

Although new inputs of acidic anions are decreasing, soil acidification still deserves more academic attention because of the effects of historical stores of SO₄²⁻ already absorbed into soils. Forest canopy has large, species-specific effects on rainwater chemistry, for which the hydrological mechanism remains unclear. We investigated precipitation, throughfall, stemflow, and litter leachate across three forest types in a severely acid-polluted site located in Southwest China. Precipitation monitored over 4 months, representing summer, fall, winter, and spring, indicated neutral precipitation in Tieshanping with pH ranging from 6.58–7.33. Throughfall and litter leachate in Pinus massoniana Lamb. stands were enriched with greater cation and anion fluxes, as well as more dissolved organic carbon (DOC) flux. Rainwater from pure stands of Cinnamomum camphora (Linn) Presl yielded lower N and DOC inputs to soils with higher base saturation, which would reduce soil acidification and, therefore, improve the sustainability of forest ecosystems. Full article