Effects of crumb rubber waste as a soil conditioner on the nematode assemblage in a turfgrass soil

The impacts of waste crumb rubber soil amendment on nematode abundance, community structure and soil characteristics were studied in pot grown Lolium perenne L. Three treatments, no crumb rubber (CK), 10% and 15% crumb rubber (CR), were arranged in a randomized complete design. After 3 months’ turfgrass growth, soil nematodes were extracted and identified to genus level, and populations of total, bacterivorous, fungivorous, omnivorous, predatory and plant parasite nematodes were counted. Genus diversity, richness, evenness, plant parasite index (PPI) and maturity index (MI) were calculated to compare nematode community structure. Thirteen genera of soil nematodes in all treatments were identified, of which Helicotylenchus was dominant. Crumb rubber incorporation significantly decreased plant parasite and omnivorous nematode populations, but increased the abundance of predatory nematodes. However, fungivorous and bacterivorous nematode populations were not significantly affected by crumb rubber amendment. Pots treated with 15% CR had the lowest number of plant parasite, omnivorous nematodes and the highest number of fungivorous, predatory nematodes. Shannon's diversity index (H′), evenness (J′), PPI and PPI/MI reduced in pots receiving crumb rubber, whereas dominace (λ) and maturity index (MI) increased in crumb rubber treatments. In addition, CR application decreased soil bulk density and pH value, but increased soil moisture.     

Effect of compost and chemical fertilizer on soil nematode community in a Chinese maize field

Nematode density and biodiversity in maize field soil treated with compost, chemical fertilizer and with no amendments were investigated in a multi-year field experiment at the Qu-Zhou experimental station, China Agricultural University. The soils were collected from the upper (0–20 cm) soil layer during the maize growing stages in 2004. The results demonstrated that significant differences for the total nematode density, bacterivores, fungivores, plant parasites and omnivores-predators density were found between treatments and between dates. The total nematode density and bacterivores density were greater in compost-treated soil than in chemical fertilizer-treated soil, and were greater in chemical fertilizer-treated soil than in control soil during all sampling periods. The total nematodes density ranged from 106 to 657 individuals per 100 g dry soil in the present study. Total 40 nematode genera were found in all treatments and sampling periods, and 12 genera were bacterivores, 4 genera were fungivores, 16 genera were plant parasites and 8 genera were omnivores-predators. Cephalobus, Rhabditis, Tylenchorhynchus, Pratylenchus, Helicotylenchus and Rotylenchus were dominant genera in present study. The plant parasites and bacterivores were dominant trophic groups. The ratio of bacterivores plus fungivores to plant parasites was higher in compost-treated soil compared to chemical fertilizer-treated soil except October. Maturity index and combined maturity index were lower in compost-treated soil compared to chemical fertilizer-treated and control soil except July. The plant parasite index was higher in compost-treated soil compared to chemical fertilizer-treated soil except July. The multi-year application of compost and chemical fertilizer had effected on soil nematode population density and community structure.     

土壤线虫群落对过量施用农用化学品的响应

为研究施用过量的农用化学品对土壤线虫群落组成及多样性的影响,采用定点试验的方法,在哈尔滨市呼兰区选择典型农田生态系统进行试验,对比研究土壤线虫群落对施用过量的氮肥、磷肥、钾肥、除草剂及杀虫剂的响应。在试验田中共鉴定出土壤线虫27科45属,其中Cephalobus和Aphelenchus为优势属。施用不同浓度的各类农用化学品对土壤线虫群落组成、多样性均产生一定影响。线虫总数及食细菌线虫、食真菌线虫、植物寄生线虫数量在不同处理间均存在显著差异(P<0.05);其中,植物寄生线虫的相对丰度随化肥施用量的升高呈增加趋势。从土壤线虫的生态指数来看,除PPI(植物寄生线虫成熟指数)外,其他生态指数[MI(成熟度指数)、F/B(食真菌线虫与食细菌线虫数量比值)、Evenness(均匀度指数)、SR(丰富度指数)、H’(多样性指数)]在施用不同农用化学品处理之间也存在显著差异,并且,MI随着施用钾肥、氮肥浓度的增加而降低。土壤线虫可以作为揭示施用农用化学品过程中土壤质量变化的生物学指标,其群落及多样性的变化表明土壤线虫群落对农用化学品的过量施用产生了响应,过量施用农用化学品会增加土壤生态系统的干扰,对土壤环境造成威胁。     

Nematode communities in continuous tomato-cropping field soil infested by root-knot nematodes

Abstract

Soil nematode communities in greenhouses with different duration of continuous cropping were investigated from October 2007 to June 2008. Total nematode populations and trophic groups were observed. Fourteen families and 24 genera were identified; the genera Protorhabditis, Diploscapter, Meloidogyne and Helicotylenchus comprised 74.4% of the total population (from all tested samples). Plant-parasitic and bacterivorous nematodes were most abundant among the trophic groups. Populations of both trophic groups increased with increasing times of continuous cropping. The numbers of soil nematodes at different soil depths were significantly different (p <0.05). Shannon–Wiener index (H′) and Simpson index of diversity (D) were highest in 0-yr soil of all soils. Plant parasite index (PPI) and PPI/MI (maturity index) of soil nematodes increased with the increasing times of continuous cropping suggesting that continuous cropping resulted in gradual shift of plant-parasitic nematodes from k-strategists to r-strategists.     

Diversity and distribution of nematode communities in grasslands from Romania in relation to vegetation and soil characteristics

The nematode communities of 36 grassland ecosystems in Romania, belonging to different plant associations and soil types, were studied. The abundance of nematodes, the species and trophic types present, as well as their distribution in relation to plant community and soil characteristics are analyzed and discussed.The abundance of nematodes from the 36 grasslands studied ranged between 0.41 × 10⁶ and 8.57 × 10⁶ individuals/m², and a total of 121 genera and 145 species of nematodes were found. The highest diversity was found in grasslands developed on brown earth soil (65–67 genera and 74–76 species), with least diversity in those evolving on podzol and lithosol (33–36 genera with 25–28 identified species). Most of the dominant taxa were found in specific soil layers; some obligate plant parasitic genera (e.g., Paratylenchus, Rotylenchus, Criconema) showed preference for deeper soil layers. The nematode diversity index (H′), with values ranging between 2.38 and 3.47, did not differ significantly between the different types of grasslands. Plant feeding, bacterial feeding, hyphal feeding and omnivorous nematodes were the main groups in mountainous grasslands developed on different soil types. Plant feeding and bacterial feeding nematodes dominated the trophic structure and more plant feeders (62–69%) were found in communities of subalpine and alpine grasslands developed on podzol and alpine meadow soil, than in those developed on rendzina and lithosol (27–33%). The ratio of hyphal feeding to bacterial feeding nematodes (Hf/Bf) is constantly in favour of the bacterial feeding group, the values being an indicator of good soil fertility for most studied grasslands. The nematode communities of grasslands are grouped into six main clusters according to their genera affinity and distinguished by different grassland and soil types. Communities from subalpine grasslands developed on rendzina, acid brown and lithosol have the greatest similarities. An ordination of nematode communities in relation to important environmental variables is presented. Environmental variables relevant in explaining the patterns of nematode composition in grasslands, using canonical correspondence analysis (CCA), are: humus, pH, total nitrogen, exchangeable bases and soil type. No single factor could be selected.     

Influence of phytoparasitic nematodes on symbiotic N2 fixation in tropical herbaceous legume cover crops

 Populations of plant parasitic nematodes and their effects on symbiotic nitrogen (N) fixation in herbaceous legumes and on some selected characteristics of other plant species associated with such cover crops were studied. Two legume species [mucuna, Mucuna pruriens (L) DC. var. utilis (Wright) Bruck and lablab, Lablab purpureus L. Sweet], one grass/weed species [imperata, Imperata cylindrica (L.) Rauschel] and a cereal (maize, Zea mays L.) were used. There were three soil treatments (fumigation, fumigation plus inoculation with Meloidogyne species, and an untreated control). Plant parasitic nematode populations in soil, roots and nodules were determined at 4, 8 and 12 weeks after planting. The response of the phytoparasitic nematodes to soil treatments varied according to the plant species present. The predominant nematodes in soils, roots and nodules of legumes were of the genus Meloidogyne, whereas other genera of parasitic nematodes dominated the fauna in soils and roots of maize and imperata. Biomass yield of mucuna was not significantly affected by either Meloidogyne spp. or the other genera of phytoparasitic nematodes. In contrast, the dry matter yield of lablab measured at 12 weeks was reduced by 16% in inoculated compared with fumigated soils. Similarly, the biomass yields of maize and imperata were reduced by 10% and 29%, respectively, in unfumigated rather than fumigated soils. The amounts of N accumulated in mucuna, maize and imperata were not significantly affected by the two groups of plant parasitic nematodes. However, at 12 weeks, lablab grown on inoculated soils accumulated only 69% of the N found in plants grown on fumigated soils. Inoculation of soil with Meloidogyne spp. significantly increased the number of nodules on lablab roots compared with the non-inoculated treatments, whereas nodulation in mucuna was not affected by soil treatment. After 12 weeks, the quantity of N₂ derived from symbiotic fixation in mucuna was not significantly affected by soil treatments whereas the amount of fixed N in lablab was 32% lower in inoculated than in fumigated soils. Possible mechanisms for the non-suppressive effect of plant parasitic nematodes on mucuna are discussed. Received: 12 March 1999     

Moderately haloalkaliphilic actinomycetes in salt-affected soils

It was found that the population density of actinomycetes in solonchaks and saline desert soils varied from hundreds to tens of thousands of colony-forming units (CFUs) per 1 g of soil depending on soil type and was by 1–3 orders of magnitude lower than the number of mycelial bacteria in main soil types. Actinomycetes grow actively in saline soils, and the length of their mycelium reaches 140 m per 1 g of soil. Domination of moderately halophilic, alkaliphilic, and haloalkaliphilic actinomycetes, which grow well under 5% NaCl and pH 8–9, is a specific feature of actinomycetal complexes in saline soils. Representatives of Streptomyces and Micromonospora genera were found among the haloalkaliphilic actinomycetes. Micromonospores demonstrated lower (than streptomycetes) adaptability to high salt concentrations. Investigation of the phylogenetic position of isolated dominant haloalkaliphilic strains of streptomycetes performed on the basis of sequencing of the gene 16S rRNA enabled identifying these strains as Streptomyces pluricolorescens and S. prunicolor.     

Bedeutung der Aktinomyceten für den Abbau von Cellulose,Lignin und Huminstoffen im Boden

Importance of Actinomycetes for the decomposition of cellulose, lignin, and humic substances in soil Actinomycetes are a group of microorganisms frequently occurring in neutral soils. They are part of the autochthonous microflora. A great number of families and genera which exhibit various and partly unusual physiological behaviour, belong to the Actinomycetales. Thermophilic actinomycetes in particular play an important role in the degradation of organic matter, e.g. Thermoactinomyces and Thermomonospora. Arthrobacter and Nocardia contain species which are able to decompose aromatic lignin-precursors and lignin itself. Even humic acids being composed by aromatic compounds can be utilized by Nocardiae as C- and N-source. Streptomycetes by their phenoloxidases take part in the formation of humic acids from the residues of slowly degradable organic substances. Referring to the succession fungi are the first while actinomycetes are the last colonizers of organic matter (Mischustin 1978).     

连作番茄根区病土对番茄生长及土壤线虫与微生物的影响

探索连作番茄根区病土对番茄根结线虫病的诱导效果及引起连作障碍的微生态机制,可为深入了解番茄连作障碍发生机理及探究番茄连作障碍防治方法提供科学依据。本研究利用盆栽试验,测定了番茄在健康土壤及接种病土土壤中生物学特性变化及根结线虫侵染状况,并分析鉴定了土壤中微生物及线虫的种类与数量。结果表明,接种连作番茄根结线虫病株根区病土会对番茄生长及根结线虫侵染产生影响:1)番茄苗期根系根结数达9个?株~(-1),健康土壤无根结;土壤线虫数量较健康土壤增加390.4%;收获期番茄根结线虫侵染率达62.7%,病情指数为80.0%。2)番茄生长受到抑制,叶片防御酶活性降低,收获期茎叶及根系鲜质量较健康土壤分别减少50.2%及33.1%,苗期番茄叶片PPO活性较健康土壤降低15.8%,POD活性较健康土壤增加24.0%,差异均达显著水平(P0.05)。3)番茄根系更易感染有害菌,根系内病原菌甘蓝假单胞菌数量较健康土壤增加463倍,根区土壤细菌、真菌及放线菌总数分别增加46.3%、94.5%及134.0%。4)食细菌线虫、食真菌线虫及植物寄生性线虫数量分别为健康根区土壤的3.3倍、1.6倍及7.3倍,其中的植物寄生线虫95.6%为根结线虫。综上所述,接入连作番茄根结线虫病株根区病土不仅导致番茄遭受根结线虫侵染,而且会导致土壤线虫总量及植物寄生线虫所占比例大幅增加,并使番茄根系内有害细菌数量显著增加,对番茄生长造成显著抑制作用,同时影响番茄的生理生化特性,受线虫侵染番茄防御性酶活性降低,使其更易被根结线虫及病原菌侵染,番茄根区土壤线虫、微生物及根系内优势细菌的种类与数量及其之间的作用发生改变。     

Microcosm experiments on the development of different plant parasitic nematode fauna in two soils from the Soudanese-Sahelian zone of West Africa

To test the hypothesis that the structure of plant parasitic nematode communities is affected by soil characteristics, experiments were conducted in a greenhouse with two soils with different physical and chemical characteristics and land management histories (fallow and a cultivated field) from adjacent plots. The cultivated soil was more sandy and had lower organic matter and nutrient contents than the fallow soil. Four nematode assemblages of Scutellonema cavenessi, Helicotylenchus dihystera and Tylenchorhynchus gladiolatus were inoculated in the soils. The pot experiment was conducted on millet during 2 months. Multiplication rates of H. dihystera were not significantly different in the two soils. T. gladiolatus had a lower multiplication rate in the fine-textured soil. S. cavenessi seemed to reproduce better in the coarse-textured soil when inoculated in low density with H. dihystera. The presence of plant parasitic nematodes in the cultivated soil caused a significant decrease of millet biomass, whereas plants in the fallow soil were less sensitive to nematode damage and were only affected when the soil was inoculated with T. gladiolatus alone. This experiment did not explain the distribution of plant parasitic species observed in the field. However, parameters other than the presence of a favourable host plant and micro-climatic conditions were found to induce differences in the reproductive rates of several species of plant parasitic nematodes. Received: 14 January 1996     

Extremophilic and extremotolerant actinomycetes in different soil types

Problems on the resistance of soil actinomycetes to various environmental factors (pH, salinity, temperature, and moisture) are discussed. Actinomycetes as a special group of prokaryotes were revealed to have a greater range of tolerance to these factors than was thought earlier. The regularities of the distribution of extremophilic and extremotolerant actinomycetes developing in unusual for mycelial bacteria conditions, their structural-functional characteristics, and their taxonomic composition were determined. The predominance of acidophilic representatives of the Micromonospora genus in acid soils (typical peat, soddy-podzolic, and taiga podzol) and the haloalkaliphilic Streptomyces pluricilirescens and S. prunicolor species in desert saline soils are shown. The specific features of the actinomycete complexes on thermal fields of the weakly developed stratified volcanic soils are described. In these complexes, the thermophilic forms were represented only by species of the Micromonospora genus; and the mesophilic forms, by Microbispora species. In the periodically heated desert soils, among the thermophilic actinomycetes, representatives of rare Actinomadura, Saccharopolyspora and Streptosporangium genera along with Streptomyces species were indicated. The mechanisms of the resistance of the actinomycetes to the extreme environmental conditions are discussed.     

Responses of soil nematode community to monoculture or mixed culture of a grass and a legume forage species in China

Mixed cultivation of fast-growing grasses and nitrogen(N)-fixing legumes for forage production is widely considered effective for obtaining sustained high forage yields without depleting soil N levels. However, the effects of monoculture and mixed culture of these species on soil food webs are poorly understood.In this study, soil nematode communities were examined as indicators of the soil food web structure of monoculture and mixed culture of grass and legume at three N levels, i.e., 338(low),...     

Nematode communities of grazed and ungrazed semi-natural steppe grasslands in Eastern Austria

Soil nematode communities were investigated at eight semi-natural steppe grasslands in the National Park Seewinkel, eastern Austria. Four sites were moderately grazed by horses, cattle and donkeys, four were ungrazed. Nematodes were sampled on four occasions from mineral soil, and their total abundance, diversity of genera, trophic structure and functional guilds were determined. Altogether 58 nematode genera inhabited the grasslands, with Acrobeloides, Anaplectus, Heterocephalobus, Prismatolaimus, Aphelenchoides, Aphelenchus, Tylenchus and Pratylenchus dominating. Mean total abundance at sites was 185–590 individuals per 100 g soil. Diversity indices did not separate communities well, but cluster analysis showed distinct site effects on nematode generic structure. Within feeding groups the relative proportion of bacterial-feeding nematodes was the highest, followed by the fungal- and plant-feeding group. Omnivores and predators occurred in low abundance. The maturity indices and plant parasite indices were characteristic for temperate grasslands, but the abundance of early colonizers (c-p 1 nematodes) was low. A high density of fungal-feeding c-p 2 families (Aphelenchoidae, Aphelenchoididae) resulted in remarkably high channel index values, suggesting that decomposition pathways are driven by fungi. Nematode community indices of all sites pointed towards a structured, non-enriched soil food web. At most sites, grazing showed little or no effect on nematode community parameters, but total abundance was higher at ungrazed areas. Significant differences in the percentage of omnivorous nematodes, the sum of the maturity index, the number of genera and Simpson's index of diversity were found at one long-term grazed pasture, and this site was also separated by multi-dimensional scaling (MDS).     

Phosphorus fractions in Andisol and Ultisol inoculated with Bacillus thuringiensis and phosphorus uptake by wheat

Abstract

Only a small portion of soil phosphorus (P) is available to plants on a short-term basis, and therefore, P taken up by crops in one growing season is small compared to total P (Pt) content of the soil. A group of soil microorganisms capable of transforming insoluble P into soluble and plant accessible forms. The objective of this study was to evaluate the changes in soil P-pools and P uptake by wheat crops as influenced by inoculation with Bacillus thuringiensis in two soils (Andisol and Ultisol), the experiment was conducted in pots under greenhouse conditions using a completely randomized design. Wheat plants were inoculated and re-inoculated at 20 and 46?days after sowing, respectively, with B. thuringiensis; and, plant sampling were performed after 46, 66 and 87 and soil at 87?days based on the Zadoks growth scale, and the soil was submitted by Hedley’s P fractions. The inoculation with B. thuringiensis affected significantly some P organic P (P_o) and inorganic P (P_i) fractions in both soils (Andisol and Ultisol), improved P uptake by wheat crop in (Ultisol) and decreased significantly in (Andisol). The positive effect was more consistent in Ultisol than in Andisol, this strain can be solubilized P fraction extracted with conc. HCl-P_o and HCl 1?mol.     

Exotic plant influences soil nematode communities through litter input

The impact of exotic plant invasions on soil communities and nutrient cycling processes has received an increasing attention in recent years. To test whether the exotic plant invasions affect nematode communities through altering litter quality, we compared mass loss and nematode colonization during the stem litter decomposition of invasive Spartina alterniflora and native Phragmites australis in salt marshes of the Yangtze River estuary, China. Plastic drinking straws were synchronously used as controls. The addition of plant residues was found stimulating the growth of nematodes, particularly bacterial feeders on day 16 after burial. A top-down control of bacterivous nematodes by carnivores existed in nematode succession during the litter decomposition. With higher nitrogen content and lower C:N ratio, stem litter of the invasive S. alterniflora decayed faster and supported more abundant nematodes than the native P. australis. The greater nematode abundance in S. alterniflora was mainly due to two dominant genera of bacterial nematodes, namely Diplolaimelloides and Diplolaimella. Lower values of maturity index and structure index in S. alterniflora than in P. australis litter indicate that a more degraded food web condition resulted from the faster litter decay. A considerable difference in nematode community structures between two litter types only occurred in a certain period of the decomposition (from 8 to 32 days after burial), suggesting that the changes in faunal community structure are time dependent. In summary, this study confirmed the hypothesis that the invasion of S. alterniflora stimulates the growth of bacterial nematodes by producing higher quality of litter than the native P. australis. The results obtained here suggest that the invasion of exotic plant is likely to alter ecosystem functions indirectly through exerting its effect on soil decomposer communities such as nematodes.     

Psychrotolerant actinomycetes in soils of the tundra and northern taiga

Actinomycetes adapted to low-temperature conditions are present in the cold soils of the tundra and northern taiga in quantities comparable to mesophylic forms and dominate in the soil actinomycete complex. Actinomycetes isolated from cold soils were identified as Streptomyces. Most actinomycetes relate to psychrotolerant forms according to habitation temperature. Two of them are conditionally psychrophilic. Specific properties of the investigated populations were identified by multirespirometrical testing.     

嘎隆拉山铁杉林土壤线虫群落结构与多样性研究

为了解西藏墨脱嘎隆拉山铁杉林土壤生态系统线虫群落的结构及多样性特征,采用种类组成、个体密度、多样性指数、功能性指数等特征值分析土壤线虫群落结构及多样性特点,并通过冗余分析及线性相关性分析探讨线虫群落与土壤理化性质间的关系.结果显示,嘎隆拉山铁杉林土壤线虫隶属于5目29科34属,个体密度介于0～1231条?100 g–1...     

Nematofauna associated with exotic and native leguminous plant species in West Africa: effect of<Emphasis Type="Italic"> Glomus intraradices</Emphasis> arbuscular mycorrhizal symbiosis

Ten leguminous trees, four exotic species (Australian Acacia) and six indigenous species (three Sahelian Acacia spp. and three Sesbania spp.), were grown for 4 months in a natural Sahelian soil inoculated with or without the endomycorrhizal fungus, Glomus intraradices. In control trials, the determinant factor structuring the soil nematode fauna was the plant species, related plants having a similar influence on the nematode community in the soil. Soil nematode abundance increased from exotic acacias (3.3 g^-1 dry soil) to native acacias (11.5 g^-1 dry soil) and Sesbania species (17.6 g^-1 dry soil). Plant feeding nematodes (mainly Scutellonema and Tylenchorhynchus) were significantly less abundant under exotic acacias (1.4 g^-1 dry soil) than under native acacias (7.2 g^-1 dry soil) or Sesbania species (7.3 g^-1 dry soil). Bacterial feeding nematode density increased from exotic acacias (1.2 g^-1 dry soil) to native acacias (3.0 g^-1 dry soil) and Sesbania species (7.7 g^-1 dry soil) as total densities. However, the differences in the structure of the nematode communities between plant groups were suppressed in the presence of the mycorrhizal fungus. In fact, no difference in nematode densities remained between plant groups when G. intraradices developed in several dominant taxa belonging to different trophic groups, particularly: Tylenchorhynchus, Apelenchina, Cephalobus and Dorylaimoidea. This study clearly indicated that inoculation with the arbuscular mycorrhizal fungus G. intraradices diminished the plant-specific effect on the structure of the soil nematode community.     

Effect of organic amendment amount on soil nematode community structure and metabolic footprints in soybean phase of a soybean-maize rotation on Mollisols

It has been well documented that organic amendment affects soil nematode community structure. However, little is known about the effect of organic amendment amount on soil nematodes. To assess the effect of the amount of organic amendments on soil nematode community structure and metabolic activity, the community composition, abundance, and metabolic footprints of soil nematodes were determined in a long-term field experiment with various amounts of organic amendment in Northeast China. Fertilization treatments included an unfertilized control (CK), chemical fertilizer without manure amendment (OM₀), manure applied at 7.5 Mg ha^-1 plus chemical fertilizer (OM₁), and manure applied at 22.5 Mg ha^-1 plus chemical fertilizer (OM₂). A total of 46 nematode genera were found. Treatments with the largest amount of organic amendment had the smallest number of plant parasite genera (5), but a largest number of dominant genera (7). Soil nematodes, bacterivores, and fungivores were the most abundant in OM₂, followed by OM₁, and the lowest in OM₀ and CK. Organic amendment increased the enrichment index (EI), and the large amount of organic amendment increased the metabolic footprints of bacterivore (Baf) and fungivore (Fuf) and enrichment footprint (Ef). The relationships between Baf (or Fuf) and the increases in soil organic carbon (ΔSOC) and total nitrogen (ΔTN) were stronger than those of bacterivore (or fungivore) abundance with ΔSOC and ΔTN, except for the relationship between bacterivore abundance and ΔSOC. The EI and Ef were positively correlated with ΔSOC and ΔTN. These findings suggest that the amount of organic amendment affects soil nematode activity and function at entry levels in soil food web, and that metabolic footprints of soil nematodes may be better indicators than their abundances in assessing their relationships with soil nutrients.     

Filamentous actinobacteria of the saline soils of arid territories

A large number of actinomycetes (hundreds, thousands, and millions of CFU/g of soil) were isolated from saline soils in the territory of the landscapes of the Ber hillocks. A significantly smaller quantity of actinomycetes was isolated from the soda saline soils and sor saline soils that formed at the bottom of the ephemeral salty lakes in Buryatiya and in the estuary of the Syr-Darya River. Actinomycetes were represented in the studied soils by the Streptomyces, Micromonospora, Actinomadura, and Nocardiopsis genera. Among streptomycetes, the species of the Albus section and the Albus series predominated. The activity of the consumption of substrates by cultures of actinomycetes was largely influenced by conditions of preincubation. Obviously, the influence was related to the alteration in the metabolism of actinomycetes as one of the mechanisms of adaptation to the increased osmolarity of environment. The alcalotolerance, thermotolerance, and xerotolerance of halotolerant actinomycetes of the saline soils of arid territories were experimentally revealed.