Natural Forest Soil Research Articles

Differential bacterial ammonia oxidation patterns in soil particles from two contrasting forests: The importance of interfacial interactions

Soil inorganic nitrogen (N) deficiency limits forest productivity in subalpine regions. The traditional view holds that subalpine coniferous forests are characterized by lower soil inorganic N availability, and such differences are greatly affected by the diversity and abundance of ammonia-oxidizing bacteria. It is known that interfacial interactions between bacteria and solid particles in agricultural and aquatic ecosystems can alter bacterial metabolic activity and biogeochemical processes. However, whether bacteria-soil interfacial interactions induce different ammonia oxidation processes in distinct soil particles remain unknown. Herein, we collected soil particles of different sizes from two contrasting forest sites (a spruce-dominated natural forest and spruce plantation) and examined the effect of soil-Nitrosomonas europaea (a model ammonia-oxidizing bacteria) interfacial interactions on the oxidation of ammonium (NH4+-N) using batch adsorption and semipermeable membrane experiments. The metabolic activity of bacteria was also examined using an isothermal microcalorimetric method. Upon adsorption on soil particles, the ammonia oxidation rate and bacterial metabolism activity were slower than those of free bacteria. The inhibition effect ceased when the bacteria were physically isolated from the soil particles by a membrane, indicating the importance of interfacial interactions in the ammonia oxidation process. Additionally, clay particles were more effective than silts and sands in binding cells and greatly reduced the ammonia oxidation reaction. Across the two forests, natural forest soils exhibited a higher bacterial adsorption capacity but lower bacterial metabolic activity, resulting in a fewer loss of NH4+-N. Our results suggested that stronger bacteria-soil interfacial interactions (especially for clay fractions) were responsible for maintaining high soil inorganic N availability in forests, highlighting the need to incorporate interfacial interactions into biogeochemical models of N cycling in forest ecosystems.

Simulated nitrogen deposition reduces potential nitrous oxide emissions in a natural Castanopsis carlesii forest soil

The reactive nitrogen deposition in subtropical region of China has been increasing annually, which affects biogeochemical processes in forest soils. In this study, three treatments were established, including control (no N addition, CK), low nitrogen deposition (40 kg·hm-2·a-1, LN), and high nitrogen deposition (80 kg·hm-2·a-1, HN) to study the response of denitrifying functional genes and potential N2O emissions to simulated nitrogen deposition in the soils of a natural Castanopsis carlesii forest. Results showed that HN significantly decreased soil potential N2O emission, while 8-year nitrogen deposition did not affect the abundances of nirS, nirK, nosZ Ⅰ and nosZ Ⅱ. However, the abundance of nosZ Ⅰwas significantly higher than nosZ Ⅱ in all the treatments, indicating that nosZ Ⅰ dominated over nosZ Ⅱ in the acidic soils. HN significantly decreased the ratio of (nirK+nirS)/(nosZ Ⅰ+nosZ Ⅱ), which was positively correlated with soil pH. The results suggested that long-term high nitrogen deposition reduced soil pH and the abundance ratio of (nirK+nirS)/(nosZ Ⅰ+nosZ Ⅱ), which subsequently reduced the potential N2O emission.

Atmospheric N Deposition Significantly Enhanced Soil N2O Emission From Eastern China Forests

AbstractNitrous oxide (N2O) is an influential greenhouse gas (GHG) and an unregulated ozone‐depleting substance. The extent to which N2O emissions from natural forest soils have been enhanced by high atmospheric nitrogen (N) deposition in China during past decades is unclear; however, assessing land‐related N2O emissions for 2060 national “carbon neutrality” goal is urgent. In this study, we proposed a “gray box” conceptual model and deduced a linear relationship between soil N2O emissions and N deposition on a large scale. On this basis, we created a “process‐augmented data‐driven” approach using which we combined experimental N addition data from 38 Chinese forests with N deposition observation data to estimate regional soil N2O emissions. We found that the N2O emission budget of eastern China forest soils averaged 0.24 ± 0.07 TgN yr−1 from 1996 to 2015; of this, ∼36% (0.087 TgN yr−1) was directly induced by N deposition. Soil N2O emission rates (RN2O) fluctuated slightly after 2006, and the RN2Os of different ecoregions were significantly different (p < 0.001). Soil factors and N‐deposition‐related factors dominated the spatial variation of RN2O. Our findings provide country‐specific and ecoregion‐specific emission factors for national GHG inventories in China. Our approach bridges the gap between site‐level experiments and demand for regional N2O emissions, and is applicable for estimating N2O emissions in other countries/regions. Meanwhile, more N addition experiments are needed to comprehensively understand N cycling processes and extend the predictive capability of the approach.

Diversity of Root-Associated Fungi of the Terrestrial Orchids Gavilea lutea and Chloraea collicensis in a Temperate Forest Soil of South-Central Chile.

The diversity of orchid mycorrhizal fungi (OMF) and other beneficial root-associated fungi in temperate forests has scarcely been examined. This study aimed to analyze the diversity of mycorrhizal and rhizosphere-associated fungal communities in the terrestrial orchids Gavilea lutea and Chloraea collicensis growing in high-orchid-population-density areas in the piedmont of the Andes Cordillera with native forest (Nothofagus-Araucaria) and Coastal Cordillera with an exotic plantation (Pinus-Eucalyptus) in south-central Chile. We focused on rhizosphere-inhabiting and peloton-associated OMF in a native forest (Andes Cordillera) and a mixed forest (Coastal Cordillera). The native terrestrial orchids G. lutea and C. collicensis were localized, mycorrhizal root segments were taken to isolate peloton-associated OMF, and rhizosphere soil was taken to perform the metabarcoding approach. The results revealed that Basidiomycota and Ascomycota were the main rhizosphere-inhabiting fungal phyla, showing significant differences in the composition of fungal communities in both sites. Sebacina was the most-abundant OMF genera in the rhizosphere of G. lutea growing in the native forest soil. In contrast, Thanatephorus was the most abundant mycorrhizal taxa growing in the rhizosphere of orchids from the Coastal Cordillera. Besides, other OMF genera such as Inocybe, Tomentella, and Mycena were detected. The diversity of OMF in pelotons differed, being mainly related to Ceratobasidium sp. and Tulasnella sp. These results provide evidence of differences in OMF from pelotons and the rhizosphere soil in G. lutea growing in the Andes Cordillera and a selection of microbial communities in the rhizosphere of C. collicensis in the Coastal Cordillera. This raises questions about the efficiency of propagation strategies based only on mycorrhizal fungi obtained by culture-dependent methods, especially in orchids that depend on non-culturable taxa for seed germination and plantlet development.

A comparison of soil Staphylococcus aureus and fecal indicator bacteria concentrations across land uses in a Hawaiian watershed.

Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and fecal indicator bacteria (FIB; Enterococcus spp., Clostridium perfringens) concentrations increase in Hawaiian streams and estuaries following storms and pose a health threat to recreational water users. To reduce this risk, watershed bacteria sources need to be identified for management actions. This study's goals were to identify soil bacteria sources among different land uses and to determine if their concentrations were associated with different soil properties. Soil samples were collected three times on 24 d between October 2017 and November 2018 at urban, agriculture, and native-forest land uses in the Hilo Bay watershed, Hawai'i Island, Hawai'i. Soil bacteria concentrations were quantified using culturing techniques with selective media. Staphylococcus aureus, MRSA, and FIB were present in soil from all land uses. Bacteria concentrations were highest in urban soils and lowest in native-forest soils, with up to three orders of magnitude differences among land uses. Staphylococcus aureus, MRSA, and FIB soil concentrations were positively correlated with each other and with soil temperature and pH, but inversely correlated with soil moisture and organic matter content. Our results demonstrate that soils are a watershed bacteria source and that some soil properties affect their concentrations. Identifying these sources is critical for implementing management actions to reduce pathogen loads to estuaries and transmission to recreational water users.

Soil aggregate-associated carbon and organic carbon pools as affected by conversion of forest lands to agriculture in an acid soil of India

Aggregate-associated soil organic carbon (SOC) controls organic carbon stabilization. The research question of this paper was: what were the effects of conversion of forest land uses to agriculture at Ranchi, India on SOC pools, soil aggregation and aggregate-associated C? The samples were taken from six different land uses viz. native forest (NF), agri-horticulture (AH), native grass land (NG), rice-wheat (RW), rice- vegetable (RV) and maize-wheat (MW) from three soil depths (0–15, 15–30 and 30–45 cm). Soil aggregation, SOC pools and aggregate-associated C were determined. Results revealed that SOC concentration in NF was 36%, 67% and 127% higher than RW, RV and MW land uses, respectively, at 0–15 cm depth. The microbial biomass carbon (MBC) was higher in NF land uses than rice-based systems in the soil surface (0–15 cm) due to less disturbance. In surface soils (0–15 cm depth) under NF, the large macroaggregates had 21% and 40% higher SOC concentration than RW and RV, respectively. Similarly, NF soil had larger small macroaggregate-associated C than RW, RV and MW systems in the 0–15 and 15–30 cm layers. This result supports that tillage and regular crop removal under arable (MW, RW and RV) systems adversely affect loss of SOC contents in the surface layers and C storage inside aggregates, both in the 0–15 and 15–30 cm soil layers at Ranchi, India.

Responses of soil ammonia-oxidizing microorganisms to simulated nitrogen deposition in a natural Castanopsis carlesii forest

Subtropical region of China is one of the global hotspots receiving nitrogen deposition. Nitrogen deposition could affect the abundance and community structure of ammonia oxidizers including ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA) and complete ammonia oxidizer (comammox Nitrospira), with consequences on soil nutrient cycling that are driven by microorganisms. There is limited understanding for the newly discovered comammox Nitrospira in the subtropical forest soils. Here, we investigated the effect of simulated N deposition on abundances of soil ammonia oxidizers in the Castanopsis fargesii Nature Reserve in Xinkou Town, Sanming City, Fujian Province, China. Soil samples were collected from the field plots which received long-term nitrogen deposition with different dosages, including: CK, no additional treatment; LN, low nitrogen deposition treatment, dosage of 40 kg N·hm-2·a-1; and HN, high nitrogen deposition treatment, dosage of 80 kg N·hm-2·a-1. After 8-year treatment, simulated N deposition decreased soil pH and organic matter content, and increased nitrate content. We failed to amplify the amoA gene of AOB in the tested soils. High nitrogen deposition increased the abundance of AOA, but did not affect the abundance of comammox Nitrospira clade A and clade B. The ratio of comammox Nitrospira to AOA decreased with N addition, indicating that N addition weakened the role of comammox Nitrospira in nitrification in the subtropical forest soils. However, there were strong non-specific amplifications for both comammox Nitrospira clades A and B, highlighting the demand for the development of high coverage and specificity primers for comammox Nitrospira investigations in the future. The abundance of comammox Nitrospira clade A was positively correlated with total nitrogen (TN) and NH4+ concentration, while that of clade B was positively associated with soil organic carbon (SOC), TN and NH4+ Concentration. Overall, our findings demonstrated that simulated N deposition increased the relative importance of AOA in nitrification in the natural Castanopsis carlesii forest soil. These findings could provide theoretical support in coping with global change and N deposition in these regions.

PECULIARITIES OF THE URBAN SOILS OF THE CITY OF LVIV

The soil cover of the city of Lviv has been changed or has undergone radical modifications by the direct influence of human activities. The urban soils are the most common in the city, occupying about 2/3 of its territory. They change under the influence of vehicles, industry, construction and reconstruction processes and carry a constant load on the natural soils, causing changes in almost all their components: a morphological structure, from physical and chemical properties to microbiological and biochemical parameters, depriving the soils in the city of the ability to perform important environmental functions such as an effective absorption of industrial and automotive emissions, forming a new urban horizon and displacing the natural soils. The natural soils cover has been preserved only in small areas in city and forest parks and on the outskirts of the city.
 The urban soils of the central area of the city on the territory of the lower front part of the Ivan Franko Park in Lviv have been studied. The study of the soil profiles of this area showed special features: the soil is completely loose, and the thickness of the profiles reaches two meters or more, consisting of an anthropogenic material; a significant number of artifacts in particular (ceramic ware and fragments of pots, glass, metal, leather, as well as numerous finds of ancient coins dating from the sixteenth - nineteenth centuries) have been found in the soil profiles. There are also buried horizons in the profiles of the urban soils, darker in color due to the accumulation of an organic material and a looser consistency, with a high content of the plant roots and the soil microorganisms. The studied soil profiles of this area have testified to the specificity of their features. The soils of this part of the city are completely loose with a lot of an anthropogenic material. If the natural forest soils within a complex green zone of the city are characterized by the high acidity (pH 4.5-4.9) and a lack of nutrients, the anthropogenically altered bulk soils are characterized by a neutral or alkaline reaction (pH 7.1-7.9) and, as a rule, enough nutrients. There is a high content of calcium carbonates due to the presence of inclusions of a lime plaster, which is caused by a slight alkaline reaction, low hydrolytic acidity and a high degree of the saturation of the bases. Different concentrations of humus in the horizons or its absence lead to the fact that the urban soils have many similar and individual features, and only with a small degree of probability can we assume what properties certain urban soils have. There is a significant tendency to contaminate the soil with heavy metals. It is difficult to clearly and unambiguously connect the features of the morphology of the urban soils of the city of Lviv with the functional zoning of a city. Therefore, the condition of the soils of the urban area requires constant monitoring by scientists and special attention because due to the growth of the urban environment almost all their components are changing.
 Key words: urban soil, soil profile, urban soil, cultural layer, urban ecosystems.

Effects of Moisture and Temperature on Soil Organic Carbon Decomposition along a Vegetation Restoration Gradient of Subtropical China

Vegetation restoration can affect the process of soil organic carbon (SOC) decomposition, but how this effect is related to soil moisture and temperature remains uncertain. Thus, we performed an incubation of 120 days using soils of degraded land, plantation forest, and secondary natural forest, at two levels of temperature under two moisture levels. We found that the amount of cumulative SOC decomposition in the plantation and secondary natural forest soil was ca. 11.7 times higher than that in the soil from degraded land. Higher soil moisture and temperature treatment increased SOC decomposition in the plantation and secondary natural forest soils. However, in the soil from degraded land, higher soil moisture did not increase SOC decomposition, and higher temperature only increased SOC decomposition in the 60%WHC treatment. The amount of cumulative SOC decomposition was positively correlated with soil MBC and DOC content. The responses of SOC decomposition and the decomposability of DOC to moisture and temperature along the vegetation restoration gradient were highly consistent. Furthermore, in the 60%WHC treatment group, the temperature sensitivity (Q10) of SOC decomposition declined with vegetation restoration age increase. Higher soil moisture did not affect Q10 in the plantation and secondary natural forest soil, but increased Q10 in the soil from degraded land. Our results indicate that higher soil temperature and moisture would stimulate SOC decomposition, but it is highly dependent on labile carbon supply and microbial metabolic activity along the vegetation restoration gradient.

EFFECTS OF DIFFERENT LAND USE SYSTEMS ON SELECTED PHYSICO-CHEMICAL PROPERTIES OF SOILS IN INDUSTRIAL AREA OF SELAQUI, DEHRADUN, INDIA

A study conducted in the Selaqui area of Dehradun, Uttarakhand, India was to assess and compare the changes in the physical and chemical properties of soils under different land-use viz. natural forest soil, agricultural (cultivated) soil, abandoned soil, and industrial soil. Soil samples collected randomly from the four sites with three replications for each land-use system, at two varied depth levels (0-15 cm and 15-30 cm). Results of this study indicated that the forest land recorded the highest moisture content, electrical conductivity, total nitrogen, organic carbon, available phosphorous and available potassium while the higher pH and calcium content were observed in an abandoned land and industrial land use respectively. However, the lowest moisture content, electrical conductivity, total nitrogen, and calcium content were recorded from abandoned land use; the pH from industrial land use and the available phosphorous and available potassium from agriculture (cultivated) land use.

Effects of forest reclamation methods on soil physicochemical properties in North-Central Vietnam

Globally, forest loss is happening because of timber harvesting, agricultural expansion, wildfires, mining extraction and service transportation networks via roads. This study was conducted during 2016 to 2019 at Ngoc Lam Commune, Thanh Chuong District, Nghe An Province, Vietnam on the effect of forest reclamation methods (FRMs), including the slash-and-burn method (SBM), the clear-cutting method (CCM), and agricultural cultivation methods on the interaction of soil physicochemical properties across the study area. To conduct this study, soil samples were collected in natural forest areas in the study area. The results indicated that the bulk density (BD) of the natural forest soils across the study area ranged from 0.86 to 1.12 g/cm1 at depths varying from 0 to 60 cm from the surface. The concentrations of total carbon (T-C), exchangeable potassium (Exch. K+), and exchangeable magnesium (Exch. Mg2+) in the deeper layer were normally lower than in the upper layer. Forest reclamation using the CCM influenced the increase of the BD at depths varying from 0–20 cm, but the soil texture remained same, while forest reclamation applying the CCM showed an increase in the BD in the plots depending on the land-use management (LUM). Based on these findings, LUM has a significant influence on the concentration of Exch. Ca2+, Exch. K+, Exch. Mg2+, and T-C compared to FRMs across the North-Central Vietnam.

Effect of silica bionanoparticles obtained from rice husk for the treatment of wood of Pinus elliottii

Renewable products can ensure environmental sustainability, human health, and reduce the use of traditional products that have toxic compounds in their formulation. Therefore, the research aimed to evaluate the biological resistance of Pinus elliottii wood against xylophagous fungi and termites through impregnation with silica bioparticles (SiO2) obtained from rice husks. To obtain the silica, the material underwent chemical treatment, two cycles of acid leaching with hydrochloric acid, and heat treatment at 500 °C, 550 °C or 600 °C. The purity of the silica obtained was characterized by X-ray fluorescence technique (XRF), and the mean particle size by scanning electron microscopy (SEM). SiO2 was applied to the specimens at concentrations of 0.5%, 1.0%, and 2.0%, and the impregnated samples were subjected to tests with brown rot fungi (Gloeophyllum trabeum, Rhodonia placenta and Neolentinus lepideus), soft rot (taken from natural forest soil) and xylophagous termites (Nasutitermes corniger and Cryptotermes brevis). The thermal treatments promoted the obtainment of high purity bioparticles, with value of approximately 90% and diameter of 263.7 nm. In the termite test, the smallest loss of mass and damage were for the impregnated samples. Termite mortality increased with the concentration of solutions. SiO2 was not effective against xylophagous fungi, with no difference between treatments and controls, indicating that resistance was inherent in the wood itself.

De Novo Metagenomic Analysis of Microbial Community Contributing in Lignocellulose Degradation in Humus Samples Harvested from Cuc Phuong Tropical Forest in Vietnam

We aimed to investigate the microbial diversity, mine lignocellulose-degrading enzymes/proteins, and analyze the domain structures of the mined enzymes/proteins in humus samples collected from the Cuc Phuong National Park, Vietnam. Using a high-throughput Illumina sequencer, 52 Gbs of microbial DNA were assembled in 2,611,883 contigs, from which 4,104,872 open reading frames (ORFs) were identified. Among the total microbiome analyzed, bacteria occupied 99.69%; the five ubiquitous bacterial phyla included Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, and Acidobacteria, which accounted for 92.59%. Proteobacteria (75.68%), the most dominant, was 5.77 folds higher than the second abundant phylum Bacteroidetes (13.11%). Considering the enzymes/proteins involved in lignocellulose degradation, 22,226 ORFs were obtained from the annotation analysis using a KEGG database. The estimated ratio of Proteobacteria/Bacteroidetes was approximately 1:1 for pretreatment and hemicellulases groups and 2.4:1 for cellulases. Furthermore, analysis of domain structures revealed their diversity in lignocellulose-degrading enzymes. CE and PL were two main families in pretreatment; GH1 and GH3-FN3 were the highest domains in the cellulase group, whereas GH2 and GH43 represented the hemicellulase group. These results validate that natural tropical forest soil could be considered as an important source to explore bacteria and novel enzymes/proteins for the degradation of lignocellulose.

Characterization and Taxonomic Classification of Soils in Onigambari Forest Reserve South Western Nigeria

A soil survey of Onigambari forest reserve in Oyo State, Nigeria was carried out. Three soil mapping units Established-Teak-Plantation (ETP), Natural-Forest (NF) and Farm-Land (FL) were identified with observation base on vegetative pattern. Morphological properties of the study area show that the soil unit ETP is deep and texture ranges from loamy-sand at the surface to sandy clay loam in the subsurface. The soil unit NFand FL is not deep due to presence of hard pan but the texture ranges from sandy-loam to sandy-clay and loamy-sand to sandy-clay respectively. Physical properties of the soils showed the bulk density of the soils to be moderately good for growing plant with high porosity. The soils chemical properties indicate that the pH value of the soils in ETP, NF and FL are slightly acidic and organic-matter was very low in the soils of ETP compared to NF and FL soils. The total-nitrogen values of the soils in the area changed irregularly with depth and values ranged from 0.028 to 0.1g kg-1 in ETP, 0.05 to 0.25g kg-1 in NF, the value ranged from 0.03 to 0.26 g kg-1 in FL. 0.03 to 0.26 g kg-1. According to USDA soil Taxonomy system, all the profiles pits in the study area showed distinguishing characteristics of the order Alfisols, therefore the soils are classified as Alfisols. Profile in the Established-Teak-Plantation is classified as Typic isohyperthermic paleustalfs, Profiles Natural-Forest and Farm-Land with petro-plinthic material within 100cm of the soil surface qualified as plinthic isohyperthermic paleustalfs.

Phosphorus Fractions and Arbuscular Mycorrhizal Fungi Communities in a Tropical Coarse-Textured Soil under Natural Forest and Para Rubber Ecosystems

Soil phosphorus (P) plays an essential role in rubber tree plantations that are rapidly and extensively being established in Southeast Asia. However, available information is quite limited on soil P fractions and arbuscular mycorrhizal fungi (AMF) in the tropical region. Herein, we investigated P fractions and AMF community under natural forest and rubber plantations at different ages of 5 years, 11 years, and 22 years in tropical coarse-textured soils from Thailand. The studied loamy sand soils were acidic (pH=5.0-5.7) with low available P concentrations (1.73-6.48 mg/kg). Data on the P fractions data revealed that the labile P (water-extractable Pi and NaHCO3-extractable Pi) and moderately labile P (NaOH0.1-extractable Po and HCl-extractable Pi) pools in rubber-growing soils were higher than those in the natural forest soil. Elevated values of these properties were substantial with increasing stand ages. The rubber monocropping systems declined in the density and diversity of AMF spores compared to the natural forest site. Glomus badium, Rhizophagus fasciculatus, Acaulospora Laevis, and Ambispora appendiculata were the most dominant and tolerant AMF species across the rubber stands (>50% of the total species). The P fractions and AMF were correlated with soil labile-P forms. Soil labile and moderately P fractions were the important factors affecting the difference in AMF community. This study highlighted that long-term rubber plantations in tropical ecosystems promoted labile P fraction but demoted AMF density and diversity.

Forest and Plantation Soil Microbiomes Differ in Their Capacity to Suppress Feedback Between Geosmithia morbida and Rhizosphere Pathogens of Juglans nigra Seedlings

Thousand cankers disease (TCD) is hypothesized to have a greater impact on eastern black walnut (Juglans nigra) in urban forests and plantations compared with natural forest stands. Along with other factors such as resource availability, the phytobiome could partly account for observed differences in disease severity across management regimes. We investigated the extent to which J. nigra-associated soil microbiomes from plantations and natural forests modulate (i) the amount of necrosis caused by Geosmithia morbida in 1-year-old seedlings, and (ii) relative abundance of rhizosphere endophytes and opportunistic pathogens Fusarium and Rhizoctonia in response to aboveground inoculation with G. morbida. Our results suggest that the microbiome from natural forest soil in central Indiana suppresses Fusarium spp. and is indirectly suppressive of G. morbida. Natural forest soil had a greater ability to reduce the size of necrotic area caused by G. morbida compared with steam-treated soil. Inoculating stems of seedlings with G. morbida induced a shift in fungal community composition in the rhizosphere, including Fusarium and Rhizoctonia spp.; however, the direction and magnitude of the shift depended on whether seedlings were amended with forest, plantation, or steam-treated soil. In a companion experiment, necrotic area in G. morbida-inoculated seedlings was twice as high in seedlings grown from seeds that were treated with Fusarium solani relative to those grown from seed treated with water. Our findings support the hypothesis that TCD severity can be modulated by host-mediated feedback between above- and belowground pathogens, as well as by microbial interactions in the rhizosphere.

秦岭天然林凋落物去除对土壤团聚体稳定性及细根分布的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 秦岭天然林凋落物去除对土壤团聚体稳定性及细根分布的影响 DOI: 10.5846/stxb201912272807 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 农业部农业环境重点实验室开放基金(K4030217149);国家林业公益性行业科研专项(201304307) Effects of litter removal on soil aggregate stability and distribution of fine roots in natural forests of Qinling Mountains Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:研究凋落物去除对秦岭天然林土壤团聚体稳定性及细根分布特征的影响机制,为森林生态治理提供理论依据。结果表明:(1)凋落物去除导致云杉林10-40 cm土层土壤中粒径大于0.25 mm水稳性团聚体含量(WR0.25)较对照显著降低(P<0.05);混交林10-40 cm土层的大于0.25 mm机械稳定性团聚体含量(DR0.25)显著降低(P<0.05);红桦林表层0-10 cm土壤团聚体的平均质量直径(MWD)显著降低(P<0.05);(2)凋落物去除导致三种天然林0-20 cm土层的细根生物量密度(FRBD)较对照显著降低44.18%-57.24%,细根体积(FRV)显著降低24.64%-60.41%;三种天然林中红桦林0-40 cm各土层的FRV最高;(3)凋落物去除导致云杉林0-40 cm土层的土壤容重较对照显著增加5.24%-13.04%,三种天然林0-40 cm土层的土壤有机碳含量显著降低7.92%-25.21%,全氮含量显著降低10.17%-18.10%;(4)相关分析表明,云杉林土壤的团聚体破坏率(PAD)和土壤不稳定团粒指数(ELT)与FRBD、细根根长密度(FRLD)和FRV均呈极显著负相关,混交林土壤的PAD与FRBD呈极显著负相关关系(r=-0.814),红桦林土壤团聚体MWD与FRBD、FRLD和细根比根长(FSRL)均呈显著负相关关系(r=-0.777、-0.771和-0.786)。综上,凋落物去除在总体上降低了天然林土壤团聚体的稳定性及有机碳和全氮含量,并且不利于林木细根的生长。 Abstract:The objective of this study is to investigate the effects of litter removal on the characteristics of soil aggregates stability and fine root distribution so as to provide theoretical bases for vegetation restoration and ecological protection in Qinling Mountains. Results indicated that (1) the litter removal significantly decreased the percentages of >0.25 mm water-stable aggregates (WR0.25) in 10-40 cm soil layer (P<0.05). The percentage of >0.25 mm mechanical-stable aggregates (DR0.25) in 10-40 cm soil layer of mixed forest was also decreased significantly (P<0.05). The mean weight diameter (MWD) of aggregates in 0-10 cm soil layer of Betula albosinensis forest was decreased (P<0.05) by litter removal. (2) By litter removal, the fine root biomass density (FRBD) in 0-20 cm soil layer of the three forests significantly decreased by 44.18%-57.24%; the fine root volume (FRV) significantly decreased by 24.64% to 60.41%. The FRV in 0-40 cm soil layer of Betula albosinensis forest was the highest among the three forests. (3) After 3-year litter removal, the soil bulk density in 0-40 cm soil layer of Picea asperata forest significantly decreased by 5.24%-13.04%. The soil organic carbon contents in 0-40 cm soil layer of the three forests significantly decreased by 7.92%-25.21%, and the contents of total nitrogen significantly decreased by 10.17%-18.10%. (4) The results of correlation analysis showed that percentage of aggregate destruction (PAD) and unstable soil aggregate index (ELT) of Picea asperata forest soil had significantly negative correlations (P<0.01) with FRBD, fine root length density (FRLD), and FRV. The PAD of mixed forest soil showed a significantly negative correlation (P < 0.01) with FRBD (r=-0.814). The aggregate MWD of Betula albosinensis forest soil had significantly negative correlations (P < 0.01) with FRBD, FRLD and fine specific root length (FSRL) (r=-0.777, -0.771 and -0.786). Overall, the litter removal decreased the stability of soil aggregates, the contents of soil organic carbon and total nitrogen in soils of natural forests, which also inhibited the growth of fine roots. 参考文献 相似文献 引证文献

Potential of peat carbon storage in natural forests Tripa Peat Swamp at Aceh Barat Daya District

Carbon storage is the total weight of carbon stored in the ecosystem at a certain time, especially in natural forests in the Tripa peat swamp area of Aceh Barat Daya. Peatlands are wetland ecosystems that are formed by the accumulation of organic matter on the forest floor from weathering of the vegetation on it over a long period of time. The research objectives were 1) to calculate peat soil carbon storage and 2) to measure the depth of peat soil in natural forest in the Tripa peat swamp area, Aceh Barat Daya Regency. The research activity was carried out from February to March 2021, in a natural forest in the Tripa Aceh Barat peat swamp area, divided into three stations and at each station, three sampling plots were made. Data collection using purposive sampling technique, Analysis of carbon stock was analyzed using the formula for calculating carbon stock by entering data on the percentage of soil organic carbon in the laboratory, and data on peat depth in a descriptive analysis. The results showed that the amount of peat soil carbon storage, especially in natural forest in the Tripa Aceh Barat Daya peat swamp area, was 2.556 tons/ha and the peat depth range was fibric with a depth of 0-95 cm, hemic 96-292 cm, and substance 293-310.

Soil Carbon Storage as Influenced by Land Use Types in Akure Forest Reserve, Ondo State, Nigeria

The study aimed to investigate the effect of land use on carbon storage in Akure forest reserve. The study site was stratified into three different land uses (Natural forest, Arable land and Cocoa agroforest). One hectare was marked out in each land use. Sixteen (16) sample plots of 25 m by 25 m was established randomly in each of the land use. Three (3) plots were randomly selected within each stratum. Soil samples were collected at three points diagonally on each plot along three different soil depths (0-15 cm, 15-30 cm and 30-45 cm) using soil auger. The samples were analyzed using standard laboratory procedures. Result on soil type of the study sites were loamy sand except for Cocoa agroforestry land which was sandy loam at 30-45 cm soil depth. At 0-15 cm depth, arable land has the highest organic carbon (3.58 %) and organic matter content (6.18 %); followed by cocoa agroforest land, with 1.95 % organic carbon and 3.37 % organic matter content. Results at 15-30 cm and 30-45 cm depths followed similar pattern with the results obtained for 0-15 cm soil depth. At 0-15 cm soil depth, total carbon stock under arable land was 20394.00kg/ha followed by cocoa agroforest (17419.00kg/ha) and natural forest (6342.50kg/ha) respectively, while natural forest soil has the least value along the soil profile. The study therefore concluded that it is important to manage the different land uses such that they remain a carbon sink than a carbon source.

Quantification of soil element changes in long-term agriculture: A case study in Northeast China

Anthropogenic measures that are implemented to improve the nutrient status of soil for growing food can lead to soil and environmental contamination. The influence of agricultural measures (cultivation and fertilization) on a cropland soil can be explained and quantified by exploring the variety and distribution of elements (calcium iron, rubidium, titanium, etc) in the soil profile. In this study, a cropland soil subjected to long-term (1948–2019, 72 years) anthropogenic agricultural activity was compared with a natural, undisturbed forest soil. Results showed that the anthropogenic activity affected the correlation of different elements in the cropland soil to different degrees, with the degree of the effects ranked as follows: calcium (Ca) > iron (Fe) = rubidium (Rb) > titanium (Ti) = chromium (Cr) > potassium (K) = zirconium (Zr) = strontium (Sr) > sulfur (S) = nickel (Ni) = scandium (Sc) > manganese (Mn) > vanadium (V) = zinc (Zn) = tungsten (W) > copper (Cu) = lead (Pb) = cobalt (Co). The elements were distributed much more evenly throughout the profile of the natural forest soil than the disturbed cropland soil. Some elements, such as Fe, Ti, V, Pb, Cr, Rb, K, Ca, Mn, Sc, Sr, and Cu, can be absorbed by vegetable growth and participate in the plant physiological cycle, while others, such as K, Rb, Cr, and Ti, may be lost readily as the soil is tilled. Elements such as Pb, Sc, Zn, and Sr, gradually accumulate over time from continuous fertilizer applications. In order to maintain the health of cropland soils, both farmers and policy makers should strive to mitigate elemental pollution by carefully managing applications of micronutrient fertilizers.