Eucalyptus Camaldulensis Dehnh Research Articles

Assessing the Optimal Antibacterial Action of Lavandula stoechas L., Thymus zygis L., and Eucalyptus camaldulensis Dehnh Essential Oils

The use of combined essential oils (EOs) is a new technique that can improve their preservative effects while minimizing their sensory impact in foods. The aim of this study was to determine the chemical profile of three essential oils (EOs) extracted from Lavandula stoechas L. (Ls), Thymus zygis L. (Tz), and Eucalyptus camaldulensis Dehnh (Ec) and to evaluate their synergistic antibacterial activity for optimal inhibition against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus using an augmented Simplex centroid mixing scheme. The essential oils were extracted by hydrodistillation and analyzed via gas chromatography–mass spectrometry. Anti-bacterial potency was evaluated by disk diffusion. Chemical analysis revealed the main compounds in Lavandula stoechas (Ls) essential oil: camphor (36.15%), followed by fenchone (16.57%) and Z-8-hydroxy linalool (8.28%). The Thymus zygis (Tz) essential oil is dominated by δ-terpineol (27.64%), δ-3-carene (15.7%), and thymol (14.17%). In contrast, the Eucalyptus camaldulensis (Ec) essential oil contains mainly 1,8-cineole (43.61%), γ-terpinene (11.71%), and α-terpineol (10.58%). The optimal mixture is the binary association of 40% E. camaldulensis EO and 60% T. zygis EO, which provides an effective inhibition diameter (ID) of 13.37 mm to inhibit S. aureus. Furthermore, the formulation of 27% and 73% EOs of E. camaldulensis and T. zygis, respectively, corresponds to the mixture required to achieve the optimum inhibition diameter (ID = 11.55 mm) against E. coli. In addition, the mixture of 29% EO of E. camaldulensis and 71% EO of T. zygis is the optimum mixture to inhibit B. subtilis, with an inhibition diameter of 12.31 mm. These findings highlight the potency of antibacterial formulations of these essential oils and suggest that they might be used as substitutes for conventional drugs to prevent the development of bacteria responsible for serious infections and food spoilage.

Contrasting regulation of leaf gas exchange of semi-arid tree species under repeated drought.

Predicting how plants respond to drought requires an understanding of how physiological mechanisms and drought response strategies occur, as these strategies underlie rates of gas exchange and productivity. We assessed the response of 11 plant traits to repeated experimental droughts in four co-occurring species of central Australia. The main goals of this study were to: (i) compare the response to drought between species; (ii) evaluate whether plants acclimated to repeated drought; and (iii) examine the degree of recovery in leaf gas exchange after cessation of drought. Our four species of study were two tree species and two shrub species, which field studies have shown to occupy different ecohydrological niches. The two tree species (Eucalyptus camaldulensis Dehnh. and Corymbia opaca (D.J.Carr & S.G.M.Carr) K.D.Hill & L.A.S.Johnson) had large reductions in stomatal conductance (gs) values, declining by 90% in the second drought. By contrast, the shrub species (Acacia aptaneura Maslin & J.E.Reid and Hakea macrocarpa A.Cunn. ex R.Br.) had smaller reductions gs in the second drought of 52 and 65%, respectively. Only A. aptaneura showed a physiological acclimatation to drought due to small declines in gs versus ᴪpd (0.08 slope) during repeated droughts, meaning they maintained higher rates of gs compared with plants that only experienced one final drought (0.19 slope). All species in all treatments rapidly recovered leaf gas exchange and leaf mass per area following drought, displaying physiological plasticity to drought exposure. This research refines our understanding of plant physiological responses to recurrent water stress, which has implications for modelling of vegetation, carbon assimilation and water use in semi-arid environments under drought.

The phenology of Eucalyptus camaldulensis (Dehnh, 1832) and Eucalyptus coolabah (Blakely & Jacobs, 1934) in the northern Murray–Darling Basin and implications for recruitment on floodplains

Context Published evidence suggests recruitment of floodplain trees is declining in the northern Murray–Darling Basin (MDB) and that this is linked to river flow. Aims We investigated the reproductive phenology of Eucalyptus camaldulensis and Eucalyptus coolabah to better understand tree reproductive cycles and the influence of rainfall and flow on seed production. Methods We surveyed phenological events (bud, flower and fruit production) over 6 years, at nine sites along the Condamine–Balonne River and examined correlations between these events and meteorological parameters. Key results For both species, event timing was consistent across sites and years and event relative abundance scores were different between years. Bud abundance was correlated with rainfall, flooding and warming temperatures and E. coolabah produced additional bud crops after floods. Conclusions The timing of events did not differ significantly from published results for the southern MDB. Rainfall, river flows and flooding in spring resulted in more abundant bud crops in E. camaldulensis and E. coolabah, and subsequently more abundant fruit crops. Fruit dehiscence coincided with summer–autumn flooding, which provides seed for germination. Genetic and physiological factors may also influence the observed pattern. Implications These results will inform water planning in Queensland, Commonwealth Environmental Water Holder watering actions and long-term watering plans in the northern MDB.

Insecticidal Effect of Two Chemotypes of the Essential Oil of Eucalyptus camaldulensis Dehnh against Aphis fabae Scopoli

Background: The objective of this study was to study the insecticidal and repellent effect of the essential oil of the plant Eucalyptus camaldulensis Red Dehnh extracted by hydrodistillation method planted in the Ouargla region against the black aphid. Methods: The insecticidal effect of essential oils against aphid mortality by the introduction of bean leaflets in the different oily extracts with different concentrations and the count of dead individuals after 3, 6 and 24 h at the physiology laboratory in Ghardaïa University. Result: Through this study, the leaves treated with the major compounds of Eucalyptus camaldulensis essential oil such as Benzene,1-methyl-4-(1-methylethyl) at 35 per cent concentration after 24 hours, a 65 per cent aphid mortality was recorded which is more effective compared to Sabinene and essential oils of Eucalyptus camaldulensis at different concentrations (5; 35%; and 50 per cent). As for the repellent effect is 87 per cent after 6 hours for the pure essential oil of E. camaldulensis.

Contribution of urban trees to carbon sequestration and reduction of air pollutants in Lima, Peru

Urban green areas, such as parks, squares, and tree-lined streets, are part of nature-based solutions (NBS) that provide ecosystem services to address these urban issues. However, there is limited knowledge about the contribution of tree species and overall ecosystem services provided by urban trees under public management, especially in Latin America. This study aimed to provide information on the contribution of urban trees in reducing highly incident pollutants, such as CO2, particulate matter (PM 2. 5 and 10), and greenhouse effect gas compounds (GEG) in the city of Lima (Peru), using the I-tree package software tool for estimating ecosystem services. The results demonstrate that urban trees under public management in Lima significantly contribute to pollutant reduction and the sequestration and storage of CO2 in the city, being that storage is nearly 50% of the levels observed in native temperate forests in Latin America and higher than the value measured in some xerophytic native forests in the same region. Other evaluated pollutantś levels are significantly reduced. Differences among tree species were observed, showing amatillo (Ficus pertusa L. f.) and red eucalyptus (Eucalyptus camaldulensis Dehnh.) as higher contributions to pollutant reduction, with Erythrina falcata Benth. as a native species having significant carbon storage (1,27 t/individual).This information is highly relevant for professionals and public institutions involved in urban planning and management, particularly urban tree management. It shows that tree species selection influences the mitigation of pollutant levels in cities while increasing other ecosystem services, thereby contributing to improving citizens' health.

Electrospun PCL Filtration Membranes Enhanced with an Electrosprayed Lignin Coating to Control Wettability and Anti-Bacterial Properties.

This study reports on the two-step manufacturing process of a filtration media obtained by first electrospinning a layer of polycaprolactone (PCL) non-woven fibers onto a paper filter backing and subsequently coating it by electrospraying with a second layer made of pure acidolysis lignin. The manufacturing of pure lignin coatings by solution electrospraying represents a novel development that requires fine control of the underlying electrodynamic processing. The effect of increasing deposition time on the lignin coating was investigated for electrospray time from 2.5 min to 120 min. Microstructural and physical characterization included SEM, surface roughness analysis, porosity tests, permeability tests by a Gurley densometer, ATR-FTIR analysis, and contact angle measurements vs. both water and oil. The results indicate that, from a functional viewpoint, such a natural coating endowed the membrane with an amphiphilic behavior that enabled modulating the nature of the bare PCL non-woven substrate. Accordingly, the intrinsic hydrophobic behavior of bare PCL electrospun fibers could be reduced, with a marked decrease already for a thin coating of less than 50 nm. Instead, the wettability of PCL vs. apolar liquids was altered in a less predictable manner, i.e., producing an initial increase of the oil contact angles (OCA) for thin lignin coating, followed by a steady decrease in OCA for higher densities of deposited lignin. To highlight the effect of the lignin type on the results, two grades of oak (AL-OA) of the Quercus cerris L. species and eucalyptus (AL-EU) of the Eucalyptus camaldulensis Dehnh species were compared throughout the investigation. All grades of lignin yielded coatings with measurable antibacterial properties, which were investigated against Staphylococcus aureus and Escherichia coli, yielding superior results for AL-EU. Remarkably, the lignin coatings did not change overall porosity but smoothed the surface roughness and allowed modulating air permeability, which is relevant for filtration applications. The findings are relevant for applications of this abundant biopolymer not only for filtration but also in biotechnology, health, packaging, and circular economy applications in general, where the reuse of such natural byproducts also brings a fundamental demanufacturing advantage.

Optimization of the Extraction of Phenolic Compounds from Eucalyptus camaldulensis Dehnh Leaves Using Response Surface Methodology

Optimization of the Extraction of Phenolic Compounds from Eucalyptus camaldulensis Dehnh Leaves Using Response Surface Methodology

Evaluation of clones of Eucalyptus planted in an experimental plot for Forest Landscape Restoration in Paraguay

The adoption of strategies involving the combination of Eucalyptus plantations with native species emerges as an effective alternative to mitigate the issues of deforestation, degradation, and fragmentation affecting native forests. Eucalyptus, in this context, presents itself as a species that offers a rapid economic return, making it an appealing resource for private landowners aiming to carry out land restoration processes. The aim of this study was to compare the growth in diameter at breast height, diameter at collar height, crown coverage area, and height of the Eucalyptus urophylla S.T. Blake × Eucalyptus grandis W. Hill (clone i144) and Eucalyptus urophylla S.T. Blake × Eucalyptus camaldulensis Dehnh. (Clone vm01) hybrids. The study was conducted in the district of Hernandarias, Alto Paraná Department, Paraguay. It was structured into 5 blocks and 2 treatments randomly distributed. Both treatments were selected for this study, with the first treatment consisting of a strip of eucalyptus for timber purposes, and the second treatment serving energy purposes. The design of each experimental unit comprised two major strips, one for conservation and the other for production. The focus of the study was on the second strip, which included 32 trees per experimental unit on treatment 1, and the second treatment, with 44 trees, covering an area of 1080 m2 per unit. The parameters evaluated for this study were as follows: diameter at collar height (DAC), total height (Ht), Diameter at breast height (DAP), and crown coverage area (ACP) over a 24-month plantation period. Statistically, no significant differences were found in the analyzed variables; on average, it was determined that the means were 1167.3 cm, 11 cm, 3.9 m2, 132.3 cm for Ht, DAP, ACP, and DAC, respectively.

Eucalyptus camaldulensis Dehnh Leaf Essential Oil from Palestine Exhibits Antimicrobial and Antioxidant Activity but No Effect on Porcine Pancreatic Lipase and α-Amylase.

Eucalyptus camaldulensis Dehnh is a tree species that is commonly used for various purposes, including forestry, agroforestry, and conservation. The present investigation was designed to determine the composition of E. camaldulensis leaves essential oil and estimate its free radicals, porcine pancreatic lipase, α-amylase inhibitory, and antimicrobial properties in vitro. The chemical constituents were analyzed using the gas chromatography-mass spectrometry (GC-MS) technique. DPPH (2,2-diphenyl-1-picrylhydrazyl), p-nitrophenyl butyrate, and 3,5-dinitro salicylic acid (DNSA) methods were employed to estimate the antioxidant, antiobesity, and antidiabetic effects of the essential oil. The microdilution assay was employed to assess the antimicrobial efficacy of the substance against a total of seven distinct microbial species. The GC-MS results revealed that E. camaldulensis essential oil contains 52 components that makeup 100% of the entire oil. The main chemical constituents in E. camaldulensis essential oil are p-cymene (38.64%), followed by aromadendrene (29.65%), and 1,8-cineol (6.45%), with monocyclic monoterpene being the most abundant phytochemical group, followed by the sesquiterpene hydrocarbon group, representing 44.27 and 31.46%, respectively. The essential oil showed a weak antioxidant effect and had no antilipase or antiamylase effects. At the same time, the oil showed a strong antimicrobial effect against methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, and Proteus vulgaris, which was even more potent than the positive controls, ciprofloxacin and ampicillin, which had MIC doses of 0.2 ± 0.01, 0.2 ± 0.01, and 6.25 ± 0.1 µg/mL, respectively. It also has a strong anti-Candida albicans effect with a MIC of 0.2 ± 0.01 µg/mL. In light of these findings, in vivo studies should be conducted to determine the efficiency of the E. camaldulensis essential oil in treating microbial infections.

Conditioning and Germination Control bio-assays of Quercus suber L. acorns under the allelopathic and Residual effects of Volatile Oils and Hydrolates from Aromatic Plants in Northeastern Algeria

The present works reported a new technique for conditioning and controlling the germination of healthy Quercus suber L. acorns under the antifungal, allelopathic and residual effects of five volatile oils and their hydrolates obtained by hydrodistillation of plant material and then were subjected to a GC/MS to identify their chemical composition. Monoterpenes were found to be dominant in both oils with amount ranging between 57.59 and 98.88%, followed by sesquitepenes (1.28- 40.07%), whereas ditepenes were found only in Pistacia lentiscus L. volatile oil (15.54%). Pistacia lentiscus L. and Myrtus communis L. volatile oils had the potent antifungal and fungistatic activity where no contamination were registered, a contamination percentage of 10% succeeded by a fungistatic effect was registered in both oils from Calamintha hispidula Boissier and reuter., Lavandula dentata L. and Eucalyptus camaldulensis Dehnh, whereas the control exhibited the weakest antifungal activity with 70% of contamination. Moreover, early germination during storage was more inhibited by volatile oils (10- 20%) than by the control (50%). Hydrolates were less effective than volatile oils in both fungi-infestaion (10- 80%) and germination (50- 90%). The second bio-assay conducted in non allelopathic conditions revealed that acorns previously treated by both volatile oils and hydrolates have resumed their germination with respective increases of 30 to 80% and 10%, respectively. Radicle elongation was, however, more pronounced for Hydrolates (0.13 - 0.62cm) than for volatile oils (0.06- 0.44cm). Owing to the antifungal, fungistatic and stimulating effects observed, the results of this study may help to develop new plant-based biocide for the control of fungi-infestation and early germination limiting the long-term safe storage of acorns.

Field assessment of the effects of Citrus aurantifolia Christm and Eucalyptus camaldulensis Dehnh extracts for the management of Bemisia tabaci Gennadius on Solanum melongena L. in north west Nigeria

Field assessment of the effects of Citrus aurantifolia Christm and Eucalyptus camaldulensis Dehnh extracts for the management of Bemisia tabaci Gennadius on Solanum melongena L. in north west Nigeria

GC–MS, quantum mechanics calculation and the antifungal activity of river red gum essential oil when applied to four natural textiles

The most important uses of old fabrics include clothing, mummification, and bookbinding. However, because they are predominantly constructed of natural materials, they are particularly susceptible to physical and chemical deterioration brought on by fungi. The treatments that are typically used to preserve old textiles focus on the use of synthetic fungicides, which have the potential to be dangerous for both human health and the environment. Essential oils (EOs), which are safe for the environment and have no negative effects on human health, have been widely advocated as an alternative to conventional antifungals. Four natural fabrics—linen, cotton, wool, and silk—were utilized in the current work. The extracted EO from leaves of river red gum (Eucalyptus camaldulensis Dehnh.) were prepared at 125, 250, and 500 µL/L. Aspergillus flavus, Fusarium culmorum and Aspergillus niger were inoculated separately into the treated four fabrics with the EO at concentrations of 125, 250, and 500 µL/L or the main compounds (spathulenol and eucalyptol) at the concentrations of 6, 12, 25, and 50 µL/L and were then compared to the un-treated samples. GC–MS was used to analyze the EO chemical composition, while visual observations and scanning electron microscopic (SEM) were used to study the fungal growth inhibition. Spathulenol (26.56%), eucalyptol (14.91%), and p-cymene (12.40%) were the principal chemical components found in E. camaldulensis EO by GC–MS. Spathulenol molecule displayed the highest electrostatic potential (ESP) compared with the other primary compound, as calculated by quantum mechanics. In the untreated textile samples, SEM analysis revealed substantial proliferation of hyphae from A. flavus, F. culmorum, and A. niger. The fungal growth was completely inhibited at a concentration of 500 µL/L from the EO. Both eucalyptol and spathulenol completely inhibited the formation of the fungal spores at a concentration of 50 µL/L, although eucalyptol was more effective than spathulenol across the board for all four textiles. The results support E. camaldulensis EO functionalized textiles as an effective active antifungal agent.

Extraction and Characterization of Acidolysis Lignin from Turkey Oak (Quercus cerris L.) and Eucalypt (Eucalyptus camaldulensis Dehnh.) Wood from Population Stands in Italy.

Acidolysis lignins from the species Quercus cerris L. and Eucalyptus camaldulensis Dehnh. were isolated and characterized using high pressure size exclusion chromatography (HP-SEC), Fourier-transform (FTIR) infrared spectroscopy, analytical pyrolysis-gas chromatography-mass spectrometry (Py-GCMS), and two-dimensional heteronuclear single quantum coherence (2D HSQC) NMR spectroscopy. The acidolysis lignins from the two different species varied in chemical composition and structural characteristics, with Q. cerris L. lignin having a higher S/G ratio and higher molar mass averages with a bimodal molar mass distribution. The different analytical techniques FTIR spectroscopy, Py-GCMS, and 2D NMR spectroscopy provided consistent results regarding the S/G ratio of the lignins from the two wood species. Based on the determined high S/G ratio of both oak and eucalypt lignin, the two wood sources could be promoted as substrates for efficient lignin isolation in modern forest biorefineries in order to develop innovative lignin-based value-added biorefinery products.

Camaldulensals A-C, the First Meroterpenoids Possessing Two Spatially Separated Formyl Phloroglucinols Conjugated to a Terpene Core from the Leaves of Eucalyptus camaldulensis Dehnh.

Three new bis-formyl phloroglucinol-meroterpenoids (1-3), three new euglobal type formyl phloroglucinol-meroterpenoids (4-6), and one new dimeric formyl phloroglucinol (7) were isolated from the leaves of Eucalyptus camaldulensis. Camaldulensal A (1) is the first bis-isovaleryl-formyl-phloroglucinol-sesquiterpenoid. It features a novel 6/6/10/3/6/6 fused ring system and contains six stereogenic centers. Camaldulensals B (2) and C (3) are the first bis-isovaleryl-formyl-phloroglucinols, each conjugated to a monoterpene. Formyl phloroglucinol compounds (FPCs) containing two spatially separated formyl phloroglucinols conjugated to a terpene core such as 1-3 have not been reported previously. The structures of these compounds were elucidated by spectroscopic methods and computational analysis. Camaldulensals B (2) and C (3) exhibited significant antibacterial activity against methicillin-susceptible and methicillin-resistant Staphylococcus aureus. Structure activity relationships are discussed in relation to previously reported antibacterial activities of other molecules from the FPC structure class.

Detrimental Effects of Induced Soil Compaction on Morphological Adaptation and Physiological Plasticity of Selected Multipurpose Tree Species.

Soil compaction has become a global problem affecting soil worldwide. With an increased population, more demands for food and wood have resulted in intensive cultivation and increased mechanization of our farmlands and irrigated plantations. The use of heavy machinery results in soil compaction, which affects the entire soil ecosystem. This study was conducted to analyze the impact of compacted soil on germination and initial growth stages of four major agro-forest trees of central Punjab, Pakistan. Morpho-physiological traits of all selected species (Eucalyptus camaldulensis, Albizia lebbeck, Vachellia nilotica, and Zyziphus mauritiana) were measured against soil compaction. Results indicated that the root and shoot length, biomass, root-shoot ratio, diameter at root collar, no. of leaves and branches, leaf area, germination, and survival %, and physiological traits (i.e., photosynthetic rate, transpiration rate, stomatal conductance, internal CO2 concentration, and photosynthetic water use efficiency) were significantly affected by the induced soil compaction. Eucalyptus camaldulensis Dehnh. performed better and exhibited 96% germination percentage under (1.40 mg m-3) compaction level and gradually decreased by 11% with the increase of compaction level (1.80 mg m-3). It shows that the shorter roots developed due to soil compaction decreased water use efficiency, photosynthesis, and whole-plant physiological performance. The findings concluded that judicious use of machinery is highly desired for sustainable and good-quality wood production from farm trees.

In vitro Antifungal Effects of Plant Essential Oils Against Some Fungal Disease Agents Causing Internal Rot of Dried Pepper Fruits

Hasat öncesi ve sonrası tarımsal ürünlerde meyve iç çürüklüğüne neden olan fungal etmenler ciddi kalite ve verim kayıplarına neden olurken, gıdalarda ürettikleri mikotoksinler tüketiciler için sağlık riski oluşturur. Bu çalışmada, Hatay ilinde yetiştirilen ve yerel pazarlarda satılan kurutmalık biber meyvelerinde iç çürüklüğü belirtisine neden olan fungal hastalık etmenlerinin, izolasyonu, morfolojik ve MALDI-TOF yöntemleri ile tanılanması, yaygın hastalık etmenlerine karşı farklı bitki uçucu yağlarının antifungal etkilerinin belirlenmesi amaçlanmıştır. Hastalık belirtisi gösteren meyve örneklerinden yapılan izolasyonları müteakiben yapılan morfolojik ve MALDI-TOF tanılama çalışmaları sonucunda Alternaria alternata ve Aspergillus niger en sık rastlanan fungal hastalık etmenleri olarak belirlenmiştir. Hastalık etmenlerine karşı kekik (Thymus vulgaris L., Tymbra spicata L. ve Origanum syriacum L.), rezene (Foeniculum vulgare Mill.), defne (Laurus nobilis L.) ve okaliptüs (Eucalyptus camaldulensis Dehnh) uçucu yağlarının buhar fazında farklı dozlarının antifungal etkinlikleri in vitro koşullarda araştırılmıştır. Fungus izolatlarına karşı en yüksek antifungal etkinlik (% 100 engelleme) Thymbra spicata, Origanum syriacum ve Thymus vulgaris uçucu yağlarının 4.0-6.0 µl petri-1 dozlarında gözlenmiştir. Test edilen fungal izolatlara karşı en düşük antifungal etkinlik ise Eucalyptus camaldulensis (16.0-40.0 µl petri-1) uçucu yağı tarafından gösterilmiştir. Yapılan çalışmalarla uçucu yağların antifungal özellikleri ve EC50 değerleri belirlenmiştir. Elde edilen sonuçlara göre bitki uçucu yağları, doza bağlı bir şekilde test edilen izolatlara karşı antifungal etkinlik göstermişlerdir. Elde edilen sonuçlar bitki uçucu yağlarının, kurutmalık tarımsal ürünlerde biyofumigant olarak uygulanabileceğini göstermiştir.

Spate irrigation slightly ameliorates an arid soil's quality, but tree planting enhances its characteristics

Spate irrigation (SI) is an appropriate technology to utilize the harvested floodwater, which besides providing the required water for plant consumption ameliorates the soil quality in arid and semi-arid areas. The long-term effects of SI on the soil quality, especially enzymatic and biological activities of rangelands and farm fields, remain virtually unknown. A desertification control project through floodwater spreading was initiated in the Gareh Bygone Plain (GBP) in the Province of Fars, Iran in 1983 with aims of augmenting groundwater, stabilizing the moving sand, and particularly improving the rangeland yield through SI. We have investigated the physico-chemical, biological and biochemical qualities of the soil in the spate-irrigated fields planted to river red gum (Eucalyptus camaldulensis Dehnh.), cooba (Acacia salicina Lindl.), and quail bush [Atriplex lentiformis (Torr.) (Wats.)], and a native rangeland and compared them with the same fields without SI. The loamy sand texture has changed to silt loam, which has improved water availability. Improvements have also occurred in the soil pH, organic carbon content, nutrients, enzymatic activities, and microbial respiration; however, the magnitude of these improvements varied among the different vegetative covers. Furthermore, the impacts of SI on soil functions enhanced by tree planting. The soil's higher fertility indicators, increased enzymatic activities and microbial respiration were attributed to the Eucalyptus plantation under SI by the principal component analysis (PCA). We recommend simultaneous implementation SI and tree planting in the arid and semi-arid regions for the enhancement of soil productivity.

Soil Carbon and Nitrogen Stocks under Agrosilvopastoral Systems with Different Arrangements in a Transition Area between Cerrado and Caatinga Biomes in Brazil

Production systems that promote the accumulation of soil organic matter (SOM) must be implemented to maintain the sustainability of agriculture, livestock, and forestry. Since increases in MOS content contribute to improving the chemical, physical, and biological quality of the soil, as well as helping to reduce carbon emissions to mitigate climate change. Therefore, the objective of this study was to evaluate soil organic carbon (SOC) and nitrogen (N) stocks after the implementation of agrosilvopastoral (ASP) systems in a Cerrado-Caatinga transition zone in Brazil. Native vegetation of Cerrado-Caatinga (NV), regenerating stratum of Cerrado-Caatinga (RS), two arrangements of ASP systems cultivating Cenchrus ciliaris L. intercropped with Eucalyptus camaldulensis Dehnh. × Eucalyptus tereticornis Sm. hybrid (ASP1 and ASP2), and intercropped with Eucalyptus urophylla S.T. Blake × Eucalyptus grandis W. Mill ex Maiden hybrid (ASP3 and ASP4) were evaluated. Soil C and N stocks and the C content in the humic fractions of SOM were evaluated at 0–10, 10–20, and 20–30 cm soil depths. The introduction of ASP2, ASP3, and ASP4 systems in an area previously occupied by low productivity pasture increased and restored SOC stocks to levels found in NV, at a depth of 0–30 cm. N stocks were higher in ASP systems, regardless of the arrangement studied. As a result, the ASP systems provided accumulations that ranged from 1.0 to 4.31 Mg SOC ha−1 yr−1 and from 0.33 to 0.36 Mg N ha−1 yr−1. The carbon contents in humic fractions remained higher in NV. The hierarchical grouping and principal component analysis showed that the implementation of the ASP systems was efficient in increasing soil C and N stocks over time. In conclusion, the present study identified that integrated production systems can support land use intensification strategies based on sustainable and low-carbon agriculture in a transition area between the Cerrado and Caatinga biomes in Brazil.

Biomass and carbon accumulation in Northern Bangladesh Eucalyptus plantations: Effects of stand structure and age

Abstract. Dey T, Islam MDA, Jubair SMR. 2022. Biomass and carbon accumulation in Northern Bangladesh Eucalyptus plantations: Effects of stand structure and age. Asian J For 6: 126-132. Eucalyptus plantations are a significant carbon sink as a fast-growing species in Bangladesh, but little is known regarding biomass, carbon output, and dynamics with stand age. We, therefore, assessed the stand structure, biomass accumulation, carbon storage, and their changing patterns with age in Eucalyptus camaldulensis Dehnh. plantations in the northern part of Bangladesh in early 2021. Biomass and carbon stocks were estimated using the allometric models specific for E. camaldulensis from the biophysical tree parameters (i.e., height and DBH). We used the data from 45 sample plots (100 sq. m each) covering different age classes such as 2, 5, 7, 8, 11, 13, and 21 years. The aboveground, belowground, total biomass, and carbon significantly varied between stand ages (p<0.05). The highest aboveground, belowground, and total carbon stocks were observed at 21 years, and the lowest was found at two years. We observed a positive and strong relationship between total carbon and stand variables such as stand height, diameter at breast height, basal area, crown width, crown length, and bole height but a negative relationship with density. The mean annual increment of both biomass and carbon increased sharply up to seven years and then decreased. Despite having some ecological constraints, E. camaldulensis accumulate a large amount of carbon from the atmosphere, perhaps aiding climate change mitigation.

Impact of aqueous extracts of Cassia occidentalis, Eucalyptus camaldulensis and Hyptis suaveolens on the entomofauna and the seed yield of Gossypium hirsutum at Boklé (Garoua, Cameroon)

There is a frightening decline in the population pollinators around the world due to the over usage of synthetic pesticides, leading to the directly reduce of plant production. Plant extracts with insecticidal properties could be eco-friendly alternatives to synthetic pesticides in maintaining the pollinator population and the diversity of the ecosystem. The impact of aqueous extracts of Cassia occidentalis L., Eucalyptus camaldulensis Dehnh. and Hyptis suaveolens L. was investigated on the entomofauna and the seed yield of Gossypium hirsutum L. cotton. The study was carried out in RCBD, four times replicated: 3 extracts x 1 standard synthetic insecticide (TEMA) x 1 control x 4 groups of flowers (group 1: flowers free to insect visits, group 2: flowers protected from insects using gauze bags, group 3: protected flowers and opened exclusively to Amegilla sp. and group 4: protected flowers opened from time to time without any visit of insect). Gossypium hirsutum was found to be visited by the insects belonging to five orders, 10 families and 18 species. Amegilla sp.1 and Apis mellifera were the major pollinators during the rainy and dry seasons, respectively. The number and quality of seeds visited exclusively by Amegilla sp.1 were significantly improved by H. suaveolens extract. During the dry season, E. camaldulensis and H. suaveolens extracts as well as the standard insecticide improved the number of seeds and the percentage of normal seeds harvested from the flowers allowed to be visited by insects; that was probably due to their insecticidal effects which protected plants from pest damage. Therefore, aqueous extracts of E. camaldulensis and H. suaveolens are good candidates for incorporation in integrated pest management programs to minimize the risk of synthetic pesticides to pollinators, hence to increase the yield and the quality of seeds.