Abundance, diversity, and resilience of nematode assemblages in forest soilsThis article is one of a selection of papers published in the Special Forum on Towards Sustainable Forestry — The Living Soil: Soil Biodiversity and Ecosystem Function.

2007 ◽  
Vol 37 (2) ◽  
pp. 216-225 ◽  
Author(s):  
G.W. Yeates

Forest litter and soil may contain >10 × 106 individual nematodes·m–2 and, regionally, >400 species. Root-feeding nematodes may be pathogenic to young plants; microbial-feeding nematodes may increase turnover of the microbial pool; predacious and omnivorous nematodes represent higher trophic levels. The spatial distribution and abundance of nematode species in forests reflect soil type, soil fertility, climate, canopy and understorey plant species, litter depth, forest age, and management. Nematodes may be important in forest nurseries; they occur throughout the rooting depth of forest trees; hyphal-feeding species may influence mycorrhizae; and insect-vectored Bursaphelenchus species are a quarantine risk. Nematode populations interact with those of other soil animals (e.g., mites, tardigrades, enchytraeids, and protozoa). The diversity and abundance of the nematode assemblage make nematodes a useful indicator of soil condition and soil processes. Information available from forest systems suggests that, as long as physical disturbance is minimized and remaining trees or herb layer moderate the microclimate, logging and other forestry operations have only transitory effects on nematode populations. Extreme disturbance, such as bulldozing and slash-and-burn management, can significantly reduce nematode abundance and diversity. In contrast, management that enhances growth of understorey or herb layer can stimulate nematode populations. Each of these changes can be related to changes in food resource availability and environmental conditions, such as soil temperature and moisture. Although details of soil nematode contributions to nutrient processes in forest soils are sparse, that their populations are maintained through cycles of moderate management practices suggest that their beneficial contributions will also be maintained.

Nematology ◽  
2015 ◽  
Vol 17 (1) ◽  
pp. 11-26 ◽  
Author(s):  
Marina Carrascosa ◽  
Sara Sánchez-Moreno ◽  
José Luis Alonso-Prados

Due to the uncertain future of the soil fumigants most commonly used in the EU, there is a need to develop new integrated pest management programmes to control crop diseases. Different nematode management practices, such as solarisation and the use of ecological nematicides, including nematophagous fungi, are used to control populations of plant-parasitic nematodes, one of the most common pests affecting crops. The objective of this study was to determine the effects of organic (neem seed paste and a mixture of nematophagous fungi) and conventional (oxamyl and fenamiphos) nematicides on soil physical chemical properties, soil biodiversity and plant biomass. Such effects were investigated in two types of habitats: low diversity soils from an agricultural farm and high diversity soils from a natural vegetation area. The greater effect was observed with the neem treatment, which induced a large boost of dauer juveniles in the nutrient-depleted soil, while the same treatment induced an increase of populations of less opportunistic, generalist bacterivore nematodes in the pine forest soil, rich in organic matter. We have studied the effects of different biological and chemical nematicides on the whole soil nematode community through ecological indices and their relationship with plant biomass, but further research is needed to improve understanding of the effect of these products on nematode assemblages.


Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1241
Author(s):  
Stanko Vršič ◽  
Marko Breznik ◽  
Borut Pulko ◽  
Jesús Rodrigo-Comino

Earthworms are key indicators of soil quality and health in vineyards, but research that considers different soil management systems, especially in Slovenian viticultural areas is scarce. In this investigation, the impact of different soil management practices such as permanent green cover, the use of herbicides in row and inter-row areas, use of straw mulch, and shallow soil tillage compared to meadow control for earthworm abundance, were assessed. The biomass and abundance of earthworms (m2) and distribution in various soil layers were quantified for three years. Monitoring and a survey covering 22 May 2014 to 5 October 2016 in seven different sampling dates, along with a soil profile at the depth from 0 to 60 cm, were carried out. Our results showed that the lowest mean abundance and biomass of earthworms in all sampling periods were registered along the herbicide strip (within the rows). The highest abundance was found in the straw mulch and permanent green cover treatments (higher than in the control). On the plots where the herbicide was applied to the complete inter-row area, the abundance of the earthworm community decreased from the beginning to the end of the monitoring period. In contrast, shallow tillage showed a similar trend of declining earthworm abundance, which could indicate a deterioration of soil biodiversity conditions. We concluded that different soil management practices greatly affect the soil’s environmental conditions (temperature and humidity), especially in the upper soil layer (up to 15 cm deep), which affects the abundance of the earthworm community. Our results demonstrated that these practices need to be adapted to the climate and weather conditions, and also to human impacts.


Nematology ◽  
2016 ◽  
Vol 18 (8) ◽  
pp. 879-903 ◽  
Author(s):  
Thomas O. Powers ◽  
Peter Mullin ◽  
Rebecca Higgins ◽  
Timothy Harris ◽  
Kirsten S. Powers

A new species of Mesocriconema and a unique assemblage of plant-parasitic nematodes was discovered in a heath bald atop Brushy Mountain in Great Smoky Mountains National Park. Mesocriconema ericaceum n. sp., a species with males, superficially resembles M. xenoplax. DNA barcoding with the mitochondrial COI gene provided evidence of the new species as a distinct lineage. SEM revealed significant variability in arrangement of labial submedian lobes, plates, and anterior and posterior annuli. Three other nematodes in the family Criconematidae were characterised from the heath bald. Ogma seymouri, when analysed by statistical parsimony, established connections with isolates from north-eastern Atlantic coastal and north-western Pacific coastal wet forests. Criconema loofi has a southern Gulf Coast distribution associated with boggy soils. Criconema cf. acriculum is known from northern coastal forests of California. Understanding linkages between these species and their distribution may lead to the broader development of a terrestrial soil nematode biogeography.


1978 ◽  
Vol 58 (4) ◽  
pp. 961-969 ◽  
Author(s):  
D. H. WEBSTER

Within orchards or groups of similar samples, the abundance of apple roots [Formula: see text] diameter was related to total soil porosity (Sta). Below a boundary soil porosity, roots were sparse or absent, and above this porosity, maximum root abundance tended to increase with increase in soil porosity. Depending upon soil texture, this boundary porosity varied from 29 to 39%. A previously derived model, which estimates boundary soil porosity (Stc) as a function of texture, accounted for most of these differences. If the model was correct, all boundary Sta – Stc values should have been zero and in four of six groups of samples the derived values were zero, + 1 or − 1. The greater departures from the expected in the remaining two groups (− 2 and + 4) may have been due to a tolerance of M. 12 rootstock to poor aeration and incomplete exploitation of potential rooting depth, respectively. With the exception of M. 12, apple roots were sparse or absent in samples with less than 10% air porosity at a tension of 100 cm (S100 cm). Poor development of roots in these samples was predicted by the model. In many samples with S100 cm > 10% there were few or no roots. Soil strength of many samples was within the range known to interfere with root development. For the purpose of recognizing a soil condition that will prevent apple root growth, Sta – Stc appears to be superior to the other criteria examined, i.e. Sta, S100 cm or soil strength.


2016 ◽  
Vol 7 (1) ◽  
pp. 9-14
Author(s):  
Duong Duc Hieu

Soil nematodes play an important role in indication for assessing soil environments and ecosystems. Previous studies of nematode community analyses based on molecular identification have shown to be useful for assessing soil environments. Here we applied PCR-DGGE method for molecular analysisoffive soil nematode communities (designed as S1 to S5) collected from four provinces in Southeastern Vietnam (Binh Duong, Ba Ria Vung Tau, Binh Phuoc and Dong Nai) based on SSU gene. By sequencing DNA bands derived from S5 community sample, our data show 15 species containing soil nematode, other nematode and non-nematode (fungi) species. Genus Meloidogyne was found as abundant one. The genetic relationship of soil nematode species in S5 community were determined by Maximum Likelihood tree re-construction based on SSU gene. This molecular approach is applied for the first time in Vietnam for identification of soil nematode communities. Tuyến trùng đất đóng vai trò chỉ thị quan trọng trong công tác đánh giá môi trường và hệ sinh thái đất. Các nghiên cứu trước đây đã cho thấy lợi ích của việc phân tích cộng đồng tuyến trùng đất bằng định danh sinh học phân tử đối với việc đánh giá môi trường đất. Ở đây, chúng tôi ứng dụng phương pháp PCR-DGGE dựa trên gene SSU để phân tích năm (ký hiệu từ S1 đến S5) cộng đồng tuyến trùng đất thuộc các vùng trồng chuyên canh cây hồ tiêu ở miền nam Việt Nam (Bình Dương, Bà Rịa Vũng Tàu, Bình Phước và Đồng Nai). Bằng cách giải trình tự các vạch của mẫu tuyến trùng S5, kết quả cho thấy cộng đồng tuyến trùng này có 15 loài gồm nhóm tuyến trùng đất, nhóm các loại tuyến trùng khác và nhóm không phải tuyến trùng (nấm) và trong đó Meloidogyne là giống ưu thế. Mối quan hệ di truyền của các các loài tuyến trùng đất thuộc cộng đồng S5 được xác định bằng việc thiết lập cây phát sinh loài Maximum Likelihood dựa trên gene SSU. Đây là nghiên cứu đầu tiên ở Việt Nam sử dụng kỹ thuật PCR-DGGE để phân tích các cộng đồng tuyến trùng đất trồng hồ tiêu.


Author(s):  
Chinedu Egbunike ◽  
Nonso Okoye ◽  
Okoroji-Nma Okechukwu

Climate change is a major threat to agricultural food production globally and locally. It poses both direct and indirect effects on soil functions. Thus, agricultural management practices has evolved to adaptation strategies in order to mitigate the risks and threats from climate change. The study concludes with a recommendation the coconut farmers should explore the idea of soil biodiversity in a bid to mitigate the potential negative impact of climate related risk on the farming. The study proffers the need for adopting sustainable agricultural practices to boost local coconut production. This can contribute to the simultaneous realisation of two of the Sustainable Development Goals (SDGs) of the United Nations: SDG 2 on food security and sustainable agriculture and SDG 13 on action to combat climate change and its impacts. The study findings has implications for tackling climate change in Sub-Saharan Africa and in particular Nigeria in order to boost local agricultural production and coconut in particular without negative environmental consequences and an ability to cope with climate change related risks.


2007 ◽  
Vol 13 ◽  
pp. 107-110
Author(s):  
M. Omacini ◽  
E.J. Chaneton ◽  
C.M. Ghersa

There is a growing recognition that endophyte effects on host plant traits may be propagated through food chains. We studied Neotyphodium occultans effects on soil nematode communities mediated by current and past patch occupancy by endophyteinfected Lolium multiflorum populations. A microcosm experiment was performed to evaluate whether abundance and diversity of nematodes at different trophic levels were affected by endophyte infection through rhizosphere-mediated or littermediated effects. We found that presence of endophyte-infected plants and their aerial litter both triggered a bottom-up trophic cascade enhancing the abundance of herbivorous and predaceous nematode taxa. Endophyte infection also increased overall nematode richness, mostly through changes induced at the highest trophic level in this soil food web. Our results suggest that fungal endophytes can modify the linkages between aboveand belowground community compartments, with potential consequences on plant patch dynamics. Keywords: soil food webs, Lolium multiflorum, Neotyphodium occultans, plant-soil feedback, after-life effects, indirect interactions, trophic cascades


2008 ◽  
Vol 38 (2) ◽  
pp. 174-184 ◽  
Author(s):  
Z. Cheng ◽  
P.S. Grewal ◽  
B.R. Stinner ◽  
K.A. Hurto ◽  
H.B. Hamza

2018 ◽  
Vol 22 (2) ◽  
pp. 45-55
Author(s):  
Dipak Gupta ◽  
Daya Ram Bhusal

The need of eco-friendly pest management practice is important to maintain soil biodiversity and sustainable agriculture. Therefore rigorous investigation is needed for the environmentally friendly pest management techniques worldwide including Nepalese Tomato growing farms. We conducted field experiment to monitor the diversity and community structure of soil nematodes under different pest management practices in Tomato (Lycopersicon esculentum) growing farm. The study was conducted during summer and winter season in 2015 in Tokha area of Northern part of Kathmandu valley. The field was designed as Urine mixture plot (MP), Pesticides plot (PP), Botanicals plots (BP) and Control plot (CP). Our result indicated the variation of abundance and diversity of nemato-fauna with treatment plots and seasons. The generic diversity and community composition of nematodes in Urine mixture treating plots (MP) was increased significantly whereas decreased in pesticide applying plot (PP). The F/B ratio was significantly affected with treatment system rather than seasonality and found to be increased in pesticides applying plots. The abundance samples of nematodes genera were well separated in our discriminate ordination. We highlight the need of further exploration on the diversity and community dynamics of soil nematodes under different pest management practices in Tomato growing Nepalese agro-farms for sustainable soil ecosystem service. Journal of Institute of Science and Technology Volume 22, Issue 2, January 2018, Page: 45-55


Sign in / Sign up

Export Citation Format

Share Document