Distribution Of Soil Nematodes Research Articles

PLANT PARASITIC NEMATODE (PPNS) INVESTIGATION IN SELECTED SITE OF LOWER HILLS OF UTTARAKHAND, INDIA

These findings can be valuable tools for long-term monitoring and for comprehending regional soil. Nematodes are essential components of soil the soil community capable of surviving extreme and diverse climatic conditions. The diversity and distribution of soil nematodes were studied from the agricultural crop from the selected localities of Pauri Garhwal (1,814 mASL, 29.18ºC to 14.26ºC), A total of 110 soil samples were collected attitudinally from subarea of Pauri Gharwal. The present study revealed that the nematode diversity consist of 54 genera. The nematode diversity structure also demonstrated sensitivity to various other climatic parameters. Elevation significantly influenced biodiversity indices, diversity composition, and trophic levels. Nematode genera richness and all regular indexes indicated lower biodiversity of soil nematodes at higher altitudes. These findings can be valuable tools for long-term monitoring and for comprehending regional soil health in the face of changing environmental conditions.

Abundance, diversity and distribution of soil nematodes in Kangaita and Weru tea catchments of Kirinyaga and Tharaka Nithi counties, Kenya

Nematodes are the most abundant animals on earth and play essential roles in ecosystem functioning hence their abundance and diversity affect soil health. Nematodes have been reported in tea fields in some parts of Kenya and previous studies indicate that they may be a cause for the decline of tea population in some tea fields in Kenya. Nematodes of Moloidogyne spp have also been reported to be responsible for death of tea plants in nursery conditions. A survey was carried out in Weru and Kangaita tea factories catchment areas in Tharaka Nithi and Kirinyaga counties respectively. The survey aimed to determine the abundance and diversity of nematodes in small holder tea farms. Kangaita represented the high elevation site while Weru represented the low elevation site. Soil samples were collected from smallholder tea farms from which nematodes were extracted, identified based on their morphological characteristics, and classified according to their feeding habits then quantified using standard protocols. Nematodes from 23 genera were recovered in the two study sites representing all the five feeding groups: plant feeders, fungal feeders, bacterial feeders, omnivores, and predatory nematodes. Of the 23 genera, 11 were plant feeders, 6 bacterial feeders, 3 fungal feeders 2 omnivores and 1 predatory nematode. Kangaita, being a high elevation site reported higher population density in most genera reported than Weru which is a low elevation site. This is a departure from most studies that have reported higher nematode population densities in low altitudes. This can be attributed to differences in climatic and soil conditions in the two study sites in the same season. Kangaita was cooler with deep, well-ventilated, and loose soils while Weru was hotter with mostly compacted, shallow, and poorer soils in the tea farms. There is need for further research on the effect of elevation and farming practices on the distribution, abundance, and diversity of nematodes in tea fields. Key words: Nematodes, abundance, soil health, tea fields, elevation, diversity, feeding group

Responses of soil nematode community within soil aggregates to tea plantation age.

It is increasingly believed that soil nematodes play an important role in the soil community and have a pronounced influence on the evaluation of soil health and the monitoring of soil food web changes. Soil aggregates provide habitable pore space and resource availability for soil organisms. The distribution of soil nematodes, which are relatively small soil fauna, may be related to the degree of soil aggregates. Soil nematode communities were studied with different soil components: large macro-aggregates (> 2mm), medium macro-aggregates (2-1mm), small macro-aggregates (1-0.25mm), and micro-aggregates (< 0.25mm) extracted from the same crop variety plantings (Sichuan tea) of different ages (19years, 26years, 34years, and 56years) in Sichuan province, southwestern China, in 2018. The results showed that the tea plantation with 26years of cultivation was more suitable for the propagation of nematode communities, and the numbers of total nematodes were highest in the > 2mm fractions. Compared with other tea plantations, the Margalef index (SR) of 26-year-old tea plantation was significantly higher than that within the large and medium macro-aggregates, and the maturity index (MI) was higher in the large and small macro-aggregates in the 26-year-old tea plantation. In the large macro-aggregates, the value of functional metabolic footprints decreased with the tea plantation age. In addition, the functional metabolic footprints increased with the increase in soil aggregate size. Our finding suggests that nematode communities are limited by resource availability and resource quality played an important role in determining nematode communities. Moreover, the soil food web was degenerated with the age of tea cultivation. Therefore, in the study area, it is necessary to pay attention to the rational allocation and application of organic fertilizer in the late stage of tea planting, so as to maintain the soil fertility and soil food web structure of the tea garden.

Biodiversity and distribution of soil nematodes at surroundings of the ancient city of Prusias ad Hypium, Konuralp, Düzce (Turkey)

The diversity and distribution of soil nematodes were studied in Prusias ad Hypium (Konuralp) Ancient City, Düzce (Türkiye) in 2021. A total of 1.388 individuals were discovered within 17 families, 25 genera and 30 species. Species richness and the nematode abundance show closely related distribution at each ecological characteristic and the number of species reaches a maximum where low disturbance of soil is observed. Nematodes feeding with bacteria are dominating the total community (53%) in all sampling sites, followed by omnivorous (31.6%), plant parasitic (6%), fungivorous (4.8%) and predatory nematodes (4.6%).

陇东黄土高原石油开采对土壤线虫群落的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 陇东黄土高原石油开采对土壤线虫群落的影响 DOI: 10.5846/stxb201406131230 作者: 作者单位: 中国环境科学研究院,中国环境科学研究院,中国环境科学研究院,中国环境科学研究院,中国环境科学研究院 作者简介: 通讯作者: 中图分类号: 基金项目: 中央级公益性科研院所基本科研业务专项(2013-YSKY-16);国家科技支撑项目(2008BAC43B01) Impacts of oil exploration on soil nematode communities in the Loess Plateau of East Gansu Province, China Author: Affiliation: Nanjing Agricultural University,State Key Laboratory of Environmental Criteria and Risk Assessment，Chinese Research Academy of Environmental Sciences,State Key Laboratory of Environmental Criteria and Risk Assessment，Chinese Research Academy of Environmental Sciences,State Key Laboratory of Environmental Criteria and Risk Assessment，Chinese Research Academy of Environmental Sciences,State Key Laboratory of Environmental Criteria and Risk Assessment，Chinese Research Academy of Environmental Sciences 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:为研究陇东黄土高原石油开采对土壤线虫影响的强度与范围,选择长庆油田不同开采年限(1、10a和20a)油井共6口,按照距井基不同距离(3、6、10、20m和50m)采集土壤样品90个,共鉴定出土壤线虫22科43属;其中,食细菌线虫26属、食真菌线虫2属、植物寄生线虫9属、杂食/捕食线虫6属,优势类群为小杆属Rhabditis和孔咽属Aporcelaimus。土壤线虫生活史策略以c-p 2类群占优势,不同距离采样点,土壤线虫c-p 2和c-p 5差异极显著(P < 0.01)。随着距井基距离增加(3、6、10、20m和50m)线虫总数显著增加;其中,植食类、捕食杂食类和食真菌类线虫数量增加显著,且线虫群落多样性指数(H')显著增加(P < 0.05)。但不同距离之间优势度指数(λ),均匀度指数(J)和瓦斯乐斯卡指数(WI)差异不显著。不同开采年限油井,以10a土壤线虫群落多样性指数(H')、成熟度指数(MI)和瓦斯乐斯卡指数(WI)最低,而1a油井和20a油井较高,且与10a油井差异显著(P < 0.05)。油井作业改变周围土壤性质,导致土壤含水率降低、总石油烃(TPH)含量增高,但土壤线虫分布与土壤TPH无明显相关。研究结果表明,油田开采影响土壤线虫的组成与群落结构,但影响范围一般局限在作业区范围,指数H'和MI能较好的指示油田开采对线虫群落的影响。 Abstract:Pollution generated during the processes of oil drilling and extraction is caused primarily by crude oil leaks, drilling mud, wastewater from washing equipment, and flushing of wells. After contamination by petroleum, the physical and chemical properties of soil may change and the community structure and species diversity of soil animals may be altered. This study aimed to evaluate whether oil exploitation affects soil nematode communities and the range of such effects. Six oil wells(38°00' 35.2" to 38°01' 29.9" N and 118°37' 21.4" to 118°39' 43.8" E)in the Loess Plateau of East Gansu Province, with different exploitation periods (1,10, and 20 a), were selected for study. Triplicate soil samples were collected at distances of 3, 6, 10, 20, and 50m from wellheads and in three directions from the well bases. Soil nematodes were identified to the genus level.There were a total of 43 genera in 22 families, including 26 genera of bacterivores, nine genera of herbivores, two genera of fungivores, and six genera of omnivore-predator nematodes. Dominant groups belonged to Rhabditis and Aporcelaimus, with 15.2% and 10.0% of total nematodes, respectively. Common groups (17 genera), accounted for 68.7% of all nematodes, whereas rare groups (15 genera), accounted for only 6.1% of the total.The largest colonizer-persister (c-p) proportion of nematodes belonged to the c-p 2 guild with 48.2% of total nematodes.The smallest c-p proportion was c-p 4, with 2.2% of the total.The proportion of c-p 2 and c-p 5 nematodes changed significantly with sample distance from the wellheads(P < 0.01).The minimum nematode abundance occurred at 3 m ((23.5±7.1)ind/100 cm3) from a wellhead.The minimum nematode abundance was greatest ((122.7±15.5) ind/100 cm3)outside of the work area (50m).Nematode abundance was significantly higher at 50m than within the oilfield operations area (3 m,6 m,10m,20m). The most abundant feeding type was bacterivores, followed by herbivores.The number of herbivores,fungivores, and omnivores-predators increased significantly with increase in the distance from the wellheads (3m, 6m, 10m, 20m and 50m).The Shannon-Wiener index (H') of soil nematodes was also significantly higher at 50m than within the operation areas (P < 0.05).However, the differences in Simpson index (λ), Evenness index (J), and Wasilewska index(WI)of soil nematodes between distances was not significant in operation and non-operation areas.The H',Maturity index(MI)and WI indices were significantly different between 1, 10, and 20 a oil wells (P <0.05).The wells with 10 a of exploitation showed the lowest H', MI, and WI for the soil nematode community, compared to oil wells used for 1 or 20 years. Oil exploitation reduced soil moisture and increased total petroleum hydrocarbon (TPH) content. However, no significant correlation was found between the distribution of soil nematodes and soil moisture or TPH. The results showed that oil exploration did affect the composition and community structure of soil nematodes, but the effect range was limited to wellsite operationsin the range of about 20m around the well bases.The Shannon-Wiener index and MI was useful for evaluating the effect of oil exploration on the soil nematode community. 参考文献 相似文献 引证文献

Occurrence and distribution of soil nematodes in cotton (Gossypium hirsutum L.) production areas of Kenya

A baseline survey was conducted to determine the occurrence and distribution of soil nematodes associated with cotton in major growing areas in Kenya. Such baseline data on soil nematode abundance, diversity and ecosystem function in cotton ecosystems are valuable in providing a basis for comparison with organisms from transgenic cotton fields. Transgenic cotton plants expressing Cry1Ac and Cry2Ab proteins, from the soil bacterium Bacillus thuringiensis (Bt), provide effective control of lepidopteran pests. However, the potential effects of these proteins on soil nematofauna are unknown in Kenya. Soil samples were collected from nine locations of western (Odiado, Angorom and Ochundo locations), coast (Baharini, Mpeketoni and Witu locations) and central (Kajiji, Tebere and Nyangati locations) province. Nematodes were extracted and recovered from soil samples using the Whitehead and Hemming tray method and identified under a light microscope according to their morphological characters. They were classified according to their feeding habits. Twenty seven genera of plant parasites, bacteriovores, fungivores, predators and omnivores were identified. Bacterial, fungal feeding and parasitic nematodes were the most abundant trophic groups across all provinces. There were significant differences in the numbers of bacteriovores (P £ 0.01) and plant parasites (P £ 0.05) between the provinces but no difference was observed in the numbers of fungal feeding nematodes. There was a significant difference in genus richness within locations in western and coast provinces (P < 0.001). The combined maturity index (_MI) did not vary significantly within the locations. The Shannon index (H’) showed variations within locations in western (P < 0.001) and coast province (P £ 0.01). Soil texture, P and K were correlated with abundance of some nematode genera. The bacteria feeders, Acrobeles and Rhabditis showed positive correlations to K (r = 0.592, P < 0.05 and r = 0.128, P £ 0.05) and P (r = 0.406, P£ 0.05, and r = 0.252, P < 0.05) while Aphelenchus was positively correlated to P (r = 0.375, P £ 0.05). The plant parasitic genera Meloidogyne and Pratylenchus showed significant negative correlation to N (r = -0.513, P £ 0.05 and r = -0.226, P £ 0.05). It is clear from this baseline data that plant parasitic and free living nematodes are widespread in cotton fields and any potential effects of Bt cotton on these nematodes may affect the nematode community structure and their ecosystem functions. Key words: Cotton, soil nematodes, survey.

Responses of nematode communities to different land uses in an aquic brown soil

An analysis of the seasonal and vertical distribution of soil nematode communities under three contrasting land uses, i.e., cropland, abandoned cropland and woodland was conducted in an aquic brown soil. The results showed that different land-use types affected the spatiotemporal distribution of soil nematodes and their dominant genera, and different dominant genera showed different responses to land use. In the abandoned cropland and woodland, most dominant genera were present in the 0–20 cm layers and Chiloplacus was mainly distributed in the 5–30 cm layers, while in the cropland, Pratylenchus exhibited an even distribution from the 0–5 cm to the 40–50 cm depth. Soil environmental parameters under different land use could influence soil nematodes; soil porosity, total organic C, total N and the C/N ratio could positively influence the abundance of some dominant genera. Faunal profiles revealed that environmental stability and the homeostasis in the abandoned cropland and woodland lead to higher levels of community structure, and the soil food web tends to succeed to maturity. Nematode faunal analyses are a useful indicator for interpreting the stress and/or nutrient conditions under different land uses.