Diversity Of Soil Organisms Research Articles

A review on effect of different pesticides on earthworm

This review seeks to raise awareness of the value of earthworms in sustainable agriculture as well as the impact of pesticides on their activity. Enhancing agricultural sustainability requires a high level of soil biodiversity. The immense diversity of soil organisms allows for the best possible utilisation of the resources found in the varied habitats at different resolution levels. By turning organic waste and biodegradable material into nutrient-rich vermicast, earthworms play a significant role in the growth and upkeep of the soil's nutritional value. They go under the name of ecological engineers as well. Earthworms are the primary agents of the process, modifying the microbial activity significantly by splintering the substrate and aerating the environment, even though microbes biochemically decompose organic materials. The biodiversity of invertebrates, particularly earthworms, has been negatively impacted by the widespread use of pesticides. Although they are impacted by intensive practices like pesticide usage, earthworms play a vital role in many ecosystem functions that promote the sustainability of agrosystems. Not only do pesticides rank among the most expensive and widely used soil toxicants, but they also directly impact soil structure through supplementing and indirectly affect it through loss of biodiversity and serious injury to non-target organisms like earthworms.

Metabarcoding and Metabolomics Reveal the Effect of the Invasive Alien Tree Miconia calvescens DC. on Soil Diversity on the Tropical Island of Mo'orea (French Polynesia).

Miconia calvescens is a dominant invasive alien tree species that threatens several endemic plants in French Polynesia (South Pacific). While most analyses have been performed at the scale of plant communities, the effects on the rhizosphere have not been described so far. However, this compartment can be involved in plant fitness through inhibitory activities, nutritive exchanges, and communication with other organisms. In particular, it was not known whether M. calvescens forms specific associations with soil organisms or has a specific chemical composition of secondary metabolites. To tackle these issues, the rhizosphere of six plant species was sampled on the tropical island of Mo'orea in French Polynesia at both the seedling and tree stages. The diversity of soil organisms (bacteria, microeukaryotes, and metazoa) and of secondary metabolites was studied using high-throughput technologies (metabarcoding and metabolomics, respectively). We found that trees had higher effects on soil diversity than seedlings. Moreover, M. calvescens showed a specific association with microeukaryotes of the Cryptomycota family at the tree stage. This family was positively correlated with the terpenoids found in the soil. Many terpenoids were also found within the roots of M. calvescens, suggesting that these molecules were probably produced by the plant and favored the presence of Cryptomycota. Both terpenoids and Cryptomycota were thus specific chemicals and biomarkers of M. calvescens. Additional studies must be performed in the future to better understand if they contribute to the success of this invasive tree.

Comparing earthworm biodiversity estimated by DNA metabarcoding and morphology-based approaches

Conventional identification based on morphology is today's tool of choice for monitoring earthworm diversity. However, it requires skills to distinguish specific features, which can become the bottleneck in soil ecological studies. DNA-based metabarcoding is increasingly used to monitor diversity of soil organisms. Few studies have compared this method with conventional methods. The aim of the study was to compare metabarcoding based on the mitochondrial 16S rRNA region with conventional morphology-based identification, where metabarcoding captured more species (eight) than identified by conventional method (five). Additionally, we tested the effects of two commercial DNA extraction kits: PowerSoil based on 0.25 g of soil and PowerMax based on 10 g of soil (both from Qiagen), where the PowerMax covered higher richness than PowerSoil.

秸秆还田对中国农田土壤节肢动物数量及多样性影响的整合分析

PDF HTML阅读 XML下载 导出引用 引用提醒 秸秆还田对中国农田土壤节肢动物数量及多样性影响的整合分析 DOI: 10.5846/stxb202111053105 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 江苏省自然科学基金项目（BK20200552）；国家自然科学基金项目（32001181）；江苏省博士后基金项目（2020Z201）；南京农业大学中央高校基本业务费项目（KJQN202113） Impacts of straw returning on the number and diversity of soil arthropods in China: A meta-analysis 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:秸秆还田是提高土壤生物数量和多样性的有效手段，但土壤节肢动物对秸秆还田的响应尚未明确。搜集2005到2020年国内有关秸秆还田对农田土壤节肢动物数量及多样性影响的25篇田间试验文献，分别获得230对土壤节肢动物数量数据和112对土壤节肢动物多样性数据，并采用整合分析方法探究不同气候类型、土层深度、种植制度、秸秆还田量、还田方式及还田时间下秸秆还田对农田土壤节肢动物数量及多样性的影响。结果表明，与不还田相比，秸秆还田总体上显著增加了农田土壤节肢动物的数量，但在亚热带季风气候区或还田时间大于5 a时，秸秆还田对节肢动物数量的增加效应则不显著；此外，秸秆还田对土壤节肢动物数量的促进作用还受到节肢动物体型的影响，秸秆还田显著增加土壤中小型节肢动物的数量，特别是蜱螨目类土壤节肢动物，但是对大型土壤节肢动物的促进作用并不显著。秸秆还田总体上也提高了农田土壤节肢动物的多样性，特别是在温带季风气候、年均温小于5℃、年均降水量小于600 mm、秸秆还田量大于10000 kg/hm2、轮作以及还田时间大于5 a这些条件下，秸秆还田能显著提高土壤节肢动物的多样性。回归分析结果显示随着秸秆还田时间的增加，土壤节肢动物数量的增加率显著降低，而随着秸秆还田量的增加，节肢动物数量的增加率则显著升高；节肢动物多样性的增加率随着年均降水量的增加显著降低，而随着秸秆还田时间和还田量的增加显著升高。以上结果表明，秸秆还田有助于提高农田土壤节肢动物的数量和多样性，但此效应会受到气候因子及农田管理方式的影响。 Abstract:Straw returning is an effective way to enhance the number and diversity of soil organisms, but the responses of soil arthropods to straw returning are still unclear. In this study, we conducted a meta-analysis involving 230 comparisons of soil arthropod number and 112 comparisons of soil arthropod diversity collected from 25 related literatures during 2005-2020. The objectives of this study are to assess the effects of straw returning on the number and diversity of soil arthropods in agroecosystems of China, as well as the variation of these effects under different climates, soil depths, cropping systems, straw returning amounts, straw returning methods and time. The results showed that straw returning significantly increased the number of soil arthropods compared with no straw returning, except the studies conducted at subtropical monsoon climate regions, or the time of straw returning was more than 5 a. In addition, the promotional effect of straw returning on soil arthropod number was also affected by the size of arthropods, with straw returning significantly increasing the number of small and medium-sized soil arthropods, especially acari, rather than large soil arthropods. Straw returning also had a tendency to increase the diversity of soil arthropods, and this effect was significant under the conditions of temperate monsoon climates, mean annual temperature less than 5℃, mean annual precipitation less than 600 mm, rotation cropping, amount of straw returning more than 10000 kg/hm2 and straw returning time more than 5 a. The regression analysis showed that the increased rate of soil arthropod number under straw returning significantly decreased with straw returning time, but it significantly increased with straw returning amount; the increased rate of soil arthropod diversity under straw returning decreased significantly with mean annual precipitation, but it significantly increased with straw returning amount and time. Together, these results indicated that straw returning could improve the number and diversity of soil arthropods, which could be affected by climate factors and agricultural managements. 参考文献 相似文献 引证文献

Gejala Produktivitas Rendah dan Pertanian Degeneratif

Agronomy examines complex agricultural production concepts such as Sustainable Agriculture, Good Agricultural Practices, Regenerative Agriculture into the best practical technologies that farmers can apply. Important agronomic variables in agricultural cultivation include production and productivity. Plant productivity is influenced by many interacting factors. This paper aims to examine the symptoms of decreased productivity and symptoms of degenerative agriculture. The decline in production and productivity that continues in the long term indicates a degenerative agro-ecosystem. Degenerative agriculture is an agricultural practice that causes productivity to continue to decline as a result of a decrease in the carrying capacity of agro-ecosystems, including soil, plants and other flora, fauna, microbes, climate and society. The decrease in the carrying capacity of the soil is shown, among others, by land degradation, a decrease in soil organism diversity and activity, declining of organic matter content and the availability of nutrients in the soil due to nutrient depletion transported by harvest, erosion and inappropriate cultivation practices. In addition, it will discuss the factors driving the degenerative agroecosystem that interact with each other. These factors include land degradation, decreased biodiversity, continuous planting of varieties and species of plants, use of chemical inputs, pest and disease attacks, and climate change. Mitigating these factors means choosing a path to regenerative agriculture. Key words : Agroecosystem, biodiversity, degenerative, sustainable, regenerative, productivity

The Smart Soil Organism Detector: An instrument and machine learning pipeline for soil species identification

Understanding the diversity of soil organisms is complicated by both scale and substrate. Every footprint we leave in the soil covers hundreds to millions of organisms yet we cannot see them without extremely laborious extraction and microsopy endeavors. Studying them is also challenging. Keeping them alive so that we can understand their lifecycles and ecological roles ranges from difficult to impossible. Functional and taxonomic identification of soil organisms, while possible, is also challenging. Here we present the Smart Soil Organism Detector, an instrument and machine learning pipeline that combines high-resolution imaging, multi-spectral sensing, large-bore flow cytometry, and machine learning to extract, isolate, count, identify, and separate soil organisms in a high-throughput, high-resolution, non-destructive, and reproducible manner. This system is not only capable of separating alive nematodes, dead nematodes, and nematode cuticles from soil with 100% out-of-sample accuracy, but also capable of identifying nematode strains (sub-species) with 95.5% out-of-sample accuracy and 99.4% specificity. Soil micro-arthropods were identified to class with 96.1% out-of-sample accuracy. Broadly applicable across soil taxa, the Smart SOD system is a tool for understanding global soil biodiversity.

Biodiversity maintains soil multifunctionality and soil organic carbon in novel urban ecosystems

Abstract Biodiversity in urban ecosystems has the potential to increase ecosystem functions and support a suite of services valued by society, including services provided by soils. Specifically, the sequestration of carbon in soils has often been advocated as a solution to mitigate the steady increase in CO2 concentration in the atmosphere as a key driver of climate change. However, urban ecosystems are also characterized by an often high level of ecological novelty due to profound human‐mediated changes, such as the presence of high numbers of non‐native species, impervious surfaces or other disturbances. Yet it is poorly understood whether and how biodiversity affects ecosystem functioning and services of urban soils under these novel conditions. In this study, we assessed the influence of above‐ and below‐ground diversity, as well as urbanization and plant invasions, on multifunctionality and organic carbon stocks of soils in non‐manipulated grasslands along an urbanization gradient in Berlin, Germany. We focused on plant diversity (measured as species richness and functional trait diversity) and, in addition, on soil organism diversity as a potential mediator for the relationship of plant species diversity and ecosystem functioning. Our results showed positive effects of plant diversity on soil multifunctionality and soil organic carbon stocks along the entire gradient. Structural equation models revealed that plant diversity enhanced soil multifunctionality and soil organic carbon by increasing the diversity of below‐ground organisms. These positive effects of plant diversity on soil multifunctionality and soil fauna were not restricted to native plant species only, but were also exerted by non‐native species, although to a lesser degree. Synthesis. We conclude that enhancing diversity in plants and soil fauna of urban grasslands can increase the multifunctionality of urban soils and also add to their often underestimated but very valuable role in mitigating effects of climate change.

STRUKTUR KOMUNITAS MESOFAUNA TANAH PEROMBAK BAHAN ORGANIK PADA VEGETASI KOPI DAN KAKAO

The use of inorganic fertilizers and pesticides can change the agroecosystem gradually. These changes may result in a decrease in the diversity of soil organisms. These organisms are very important in the decomposition process of reforming the organic matter into compounds that are readily absorbed by plants. Other changes include a change in the soil structure which will affect the soil chemical and physical characteristic and ultimately affect the soil productivity leading to a decreased agricultural product. The return of the remains from harvest, litter and crop residues from coffee and cocoa crops to the soil will provide energy for soil organisms and it will help maintain the soil environment that supports the life of other organisms. This research aimed at identifying the composition and diversity of mesofauna formed by the composted organic matter in cocoa and coffee plantations. Soil sampling was conducted on coffee and cocoa plantations in the Onelako village of Ndona District. Soil sampling was conducted in September 2010. Soil sampling used Neuman method of 0-15 cm and 16-30 cm depth. Each soil sample was taken to the laboratory. The separation of mesofauna from soil used Berlese-tullgran method that had been modified for 4 days. The separated Meso fauna was identified under the light microscope. The result of this research showed that the highest composition of mesofauna decomposer of organic matter in cocoa and coffee vegetation is Collembola. Collembola is very tolerant to acidic soil condition and they are dominant in the soil and surface habitats that contain lots of litter. Collembola is microarthropods that have large distribution both in quantity and diversity. The highest diversity of mesofauna on coffee vegetation is 1.525 and on cocoa, vegetation is 1.273. It was also noted that at a depth of 0-15 cm there was a higher concentration of mesofauna in the coffee vegetation area, which was about 7.3960, while in the cocoa vegetation there where 3.6376. The high level of the diversity index caused an increase in decomposition and therefore better soil fertility.

Variables que afectan a la diversidad de organismos del suelo en zonas verdes de la ciudad de Donostia-San Sebastián

Epelde, L., Salazar, O., Martín, I., Garbisu, C. 2020. Variables affecting the diversity of soil organisms in green areas of the city of Donostia-San Sebastián. Ecosistemas 29(1):1881. https://doi.org/10.7818/ECOS.1881 Urban green areas are suitable habitats for conserving soil biodiversity. The biota of urban soil performs a set of functions and associated ecosystem services of enormous importance. Unfortunately, the knowledge we currently have about soil organisms in urban environments is still very limited. The aim of this study was to identify those abiotic and biotic variables that have the greatest influence on the soil biodiversity of urban green areas. To this aim, thirty-eight urban green areas with different sizes, level of isolation (i.e., habitat fragmentation), soil physicochemical properties and type of vegetation were sampled in the city of Donostia-San Sebastián (Spain) to measure the diversity and composition of macrofauna, mesofauna and microorganisms (i.e., bacterial communities). Variables related to the soil carbon content and habitat fragmentation significantly explained the diversity and composition of soil organisms in the studied urban green areas. Even so, the percentage of the variance explained by these two variables was very low. Understanding the ecological processes in urban environments will be helpful for the design and management of urban green areas to promote conservation of the biodiversity of multiple taxonomic groups in urban soil.

EFFECT OF DIFFERENT FOREST MANAGEMENT PRACTICES ON THE SOIL MACROFAUNA IN THE ARBOREAL CAATINGA

ABSTRACT Forest management can lead to numerous changes of different magnitudes in the composition and diversity of soil organisms, according to the level of interference with the habitat. Within this context, this study aimed to test the influence of different types of forest management on the edaphic macrofauna community in a region of arboreal Caatinga. The study was carried out in Contendas do Sincorá National Forest, Contendas do Sincorá - Bahia. The experimental area consisted of three types of management (clear cutting, selective cutting by diameter at breast height and selective cutting by species), and a condition of unmanaged Caatinga, which was used as control. The macrofauna was sampled twice a year (March and November) using the soil monolith method. Densities, total number of individuals, total richness, average richness, and Shannon and Pielou rates were estimated. The soil macrofauna was shown to be sensitive to different forest management practices, which indicates that selective cutting is a more conservative system to manage the Caatinga. Among these, selective cutting by species proved to be less impacting on the soil macrofauna, providing more expressive diversity and abundance indexes, and the occurrence of more demanding organisms in microclimate conditions, characteristic of preserved areas. The predominant groups of edaphic fauna, both in the unmanaged as in managed Caatinga, were Isoptera, Formicidae, Chilopoda, and Coleoptera Larvae.

A methodological framework to embrace soil biodiversity

Soils host the vast majority of life on Earth including microorganisms and animals, and supporting all terrestrial vegetation. While soil organisms are pivotal for ecosystem functioning, the assemblages of different biota from a taxonomic and functional perspective, as well as how these different organisms interact, remains poorly known. We provide a brief overview of the taxonomic and functional diversity of all major groups of soil biota across different scales and organism sizes, ranging from viruses to prokaryotes and eukaryotes. This reveals knowledge gaps in relation to all soil biodiversity groups, which are especially evident for viruses, protists, micro- and meso-fauna. We review currently-available methods to study the taxonomic and functional diversity of soil organisms by grouping all commonly-used methods into morphological, biochemical and molecular approaches. We list potentials and limitations of the methods to reveal that there is, as yet, no single method to fully characterize the biodiversity even of a single group of soil biota. Yet, we stress that we now have the methods available to enable scientists to disentangle the taxonomic and functional diversity of virtually all soil organisms. We provide a user-friendly guide to help researchers address a wider variety of soil biodiversity in their studies by discussing and critically analysing the various potentials and limitations of diverse methods to study distinct groups of soil life. We highlight that integrative methodological approaches, ideally in collaborative interactions, are key to advancing our understanding of soil biodiversity, such as the combination of morphological and molecular approaches to overcome method-specific limitations. Together, integrative efforts can provide information on the abundance, biomass, diversity and function of several groups of soil biota simultaneously. This newly-obtained integrative information on soil biodiversity will help to define the importance of soil biodiversity in ecosystem processes, functions, and services, and serve to refine food-web and earth system models.

Effects of long-term tillage on carbon partitioning of nematode metabolism in a Black soil of Northeast China

Conservation tillage is one of the major strategies for maintaining agricultural sustainability and has significant beneficial effects on soil organic carbon (C) retention and soil organism diversity. However, how changes in soil organism populations and/or community structure under different tillage practices contribute to C sequestration in soil is not well documented. In this paper, soil nematode assemblages were used as a model to quantify C allocation in production and respiration of soil organisms in a long-term tillage trial initiated in 2001 on a Black soil (Typic Hapludoll) of Northeastern China. Soils were sampled from no tillage (NT), ridge tillage (RT) and conventional tillage (CT) practices in the soybean (Glycine max Merr.) phase of the maize (Zea mays L.) -soybean rotation. In comparison with CT, RT and NT significantly increased production and respiration C of nematodes as a consequence of more basal C flowing into soil food web. The significantly increased bacterivore metabolic C in both production and respiration under RT and NT suggests that a bacterial-channel was the predominant pathway for C entering the food web. However, the efficiency of C allocation into soil nematodes, as indicated by the ratio of respiration C to production C (R/P), varied widely between RT and NT. NT significantly improved the C storage capacity of almost all nematode trophic groups while RT predominantly promoted the C storage capacity of bacterivores. Our results suggest that NT is more favorable than RT for allocating C into soil organisms under long-term application in the Black soil of Northeast China.

Soil biological responses to, and feedbacks on, trophic rewilding.

Trophic rewilding-the (re)introduction of missing large herbivores and/or their predators-is increasingly proposed to restore biodiversity and biotic interactions, but its effects on soils have been largely neglected. The high diversity of soil organisms and the ecological functions they perform mean that the full impact of rewilding on ecosystems cannot be assessed considering only above-ground food webs. Here we outline current understanding on how animal species of rewilding interest affect soil structure, processes and communities, and how in turn soil biota may affect species above ground. We highlight considerable uncertainty in soil responses to and feedbacks on above-ground consumers, with potentially large implications for rewilding interactions with global change. For example, the impact of large herbivores on soil decomposers and plant-soil interactions could lead to reduced carbon sequestration, whereas herbivore interactions with keystone biota such as mycorrhizal fungi, dung beetles and bioturbators could promote native plants and ecosystem heterogeneity. Moreover, (re)inoculation of keystone soil biota could be considered as a strategy to meet some of the objectives of trophic rewilding. Overall, we call for the rewilding research community to engage more with soil ecology experts and consider above-ground-below-ground linkages as integral to assess potential benefits as well as pitfalls.This article is part of the theme issue 'Trophic rewilding: consequences for ecosystems under global change'.

Environment and host as large-scale controls of ectomycorrhizal fungi.

Explaining the large-scale diversity of soil organisms that drive biogeochemical processes-and their responses to environmental change-is critical. However, identifying consistent drivers of belowground diversity and abundance for some soil organisms at large spatial scales remains problematic. Here we investigate a major guild, the ectomycorrhizal fungi, across European forests at a spatial scale and resolution that is-to our knowledge-unprecedented, to explore key biotic and abiotic predictors of ectomycorrhizal diversity and to identify dominant responses and thresholds for change across complex environmental gradients. We show the effect of 38 host, environment, climate and geographical variables on ectomycorrhizal diversity, and define thresholds of community change for key variables. We quantify host specificity and reveal plasticity in functional traits involved in soil foraging across gradients. We conclude that environmental and host factors explain most of the variation in ectomycorrhizal diversity, that the environmental thresholds used as major ecosystem assessment tools need adjustment and that the importance of belowground specificity and plasticity has previously been underappreciated.

Standard methods for the assessment of structural and functional diversity of soil organisms: A review.

The lack of standardized methods to study soil organisms prevents comparisons across data sets and the development of new global and regional experiments and assessments. Moreover, standardized methods are needed to evaluate the impact of anthropogenic stressors, such as chemicals, on soil organism communities in the regulatory context. The goal of this contribution is to summarize current methodological approaches to measure structural and functional diversity of soil organisms, and to identify gaps and methodological improvements so as to cross data sets generated worldwide. This is urgently needed because several currently ongoing regional and global soil biodiversity studies are not coordinated with one another in terms of methodology, including database development. Therefore, we evaluated the standard methods to sample, identify, determine, and assess soil organisms currently applied or proposed, using well-accepted criteria such as ecological relevance; practicability of usage in terms of resources, time, and costs; and the level of standardization. Methods addressing both the structure and the functions of soil organisms (populations or communities) are included, with a special focus on new molecular methods based on nucleic acid extraction and further analyses by polymerase chain reaction (PCR)-based approaches for microorganisms and invertebrates. We particularly highlight the activities of the Technical Committee (TC) 190 of the International Organization for Standardization (ISO) because ISO guidelines are legally accredited by many national or international authorities when they put conservation laws and regulations into practice. Finally, we propose detailed recommendations regarding gaps in the available set of standards, in order to identify a list of new methods to be standardized. We propose to organize this whole process under the Global Soil Biodiversity Initiative (GSBI) in order to ensure a truly global approach for the assessment of soil biodiversity. Integr Environ Assess Manag 2018;14:463-479. © 2018 SETAC.

Response of soil arthropods population to different farming systems under cotton integrated with groundnut and pigeonpea crops

A study was carried out to know the response of organic, integrated and conventional farming systems on the diversity of soil meso and macro arthropod populations in the cotton inter cropped with groundnut and pigeonpea at MARS, UAS, Dharwad during kharif -2015-16. The organic farming system has recorded highest meso and macro arthropod population of 21.35 per 100 g of soil and 42.00 per pitfall trap respectively. Cotton intercropped with groundnut has recorded higher population of meso and macro arthropods (15.50 /100 g of soil and 41.26/ pitfall trap, respectively). The seasonal abundance of soil arthropods was high in October (25.89/100g of soil) and least in December (5.78/ 100g of soil) months. The diversity of soil arthropod populations assessed on the Shannon’s index of below ground arthropod populations recorded was highest in organic farming (0.61) and least in conventional farming (0.51) system. Hence, the organic farming system increases abundance and diversity of soil organisms and soil fertility, and it adds large amounts of organic residue inputs, which in turn increases the biological activity in soil.

土壌の生物攪乱 : 土壌生物の多様性と土壌構造の関係(2009年度日本動物分類学会シンポジウム)

土壌の生物攪乱 : 土壌生物の多様性と土壌構造の関係(2009年度日本動物分類学会シンポジウム)

Review: Diversity of soil organisms and their relationship with diversity of plant species in tropical rainforest of Pinang-Pinang Padang, Indonesia

Marsandi F, Hermansah, Agustian, Yasin S. 2017. Review: Diversity of soil organisms and their relationship with diversity of plant species in tropical rainforest of Pinang-Pinang Padang, Indonesia. Pros Sem Nas Masy Biodiv Indon 3: 309-318. Tropical rain forests are the Earth's richest biological community as holder of an important role in maintaining the proportion of global biodiversity. These forests provide many ecosystem services in order fulfillment of human well-being. Land as a tropical rain forest floor also has an important role in maintaining ecological sustainability in the forest, where many living creatures that have direct or indirect dependency on the ground. This causes the soil is a medium that can provide nutrients for living things in it. The tropical rain forest of PinanangPinang (Padang, West Sumatra, Indonesia) has high diversity of tree and varied so that it becomes an attraction for scientists to conduct research. Researchers have grouped of Pinang-Pinang plots into three categories according to the degree of diversity of tree species, namely the high diversity, middle diversity and low diversity. The results of previous research on the plot state that Pinang-Pinang plot with a high degree of diversity of trees has the infertile soil and vice versa. Such phenomena are affected by plant group hyperaccumulator. So as to ensure the necessary study of soil organisms (microbes and soil fauna) as well as its relation to the diversity of species of tropical rainforest tree at Pinang-Pinang plot, West Sumatra, Indonesia.

Biosolids applied to agricultural land: Influence on structural and functional endpoints of soil fauna on a short- and long-term scale

Biosolids have well-documented crop and soil benefits similar to other sources of organic amendment, but there is environmental concern due to biosolids-associated pollutants. The present study investigated two field sites that had received biosolids at commercial-scale rates in parallel to associated field sections which were managed similarly but without receiving biosolids (controls). The investigated endpoints were abundance and diversity of soil organisms (nematodes, enchytraeids and earthworms) and soil fauna feeding activity as measured by the bait lamina assay. Repeated sampling of one of the field sites following the only biosolids application demonstrated an enrichment effect typical for organic amendments, which was mostly exhausted after 44months. After an initial suppression, the proportion of free-living plant-parasitic nematodes tended to increase in the biosolids-amended soil over time. Yet, none of the endpoints at this site indicated significant negative effects resulting from the biosolids until 44months post application. In contrast to the repeatedly tilled first field site, the second one was left fallow after three biosolids applications, and was sampled 96months post last application. It was only at this field site that potential evidence for a long-term impact of biosolids was detected with regard to two endpoints: earthworm abundance and structure of the nematode assemblage. Agricultural management and correlation with abiotic soil parameters explained the observed difference in earthworm abundance. Yet, the development of a highly structured and mature nematode assemblage at the control but not at the biosolids-amended section of this fallow field could not be explained by such correlations nor by soil metal concentrations. Overall, the present study found only weak evidence for negative long-term impacts of biosolids applied at commercial rates on soil fauna. High-level community parameters such as the nematode structure index (SI) appeared more suitable to detect deleterious effects on soil fauna than simple abundance measurements.

Effects of Wastewater from Oil Exploration on Soil Mesofauna.

Wastewater from oil exploration may contain substances that can alter the diversity of soil organisms. This study evaluated whether produced water treated by filtration or reverse osmosis and glutaraldehyde from reverse osmosis treatments negatively affected the mesofauna in an irrigated area. In the field, irrigation with produced water treated by reverse osmosis and filtration influenced Hymenoptera and Cosmochthonius sp., while Entomobryomorpha springtails were affected only by the reverse osmosis water. In the ecotoxicological tests, reproduction in the springtail Folsomia candida was inhibited by the reverse osmosis treatment, while reproduction in the earthworm Enchytraeus crypticus was affected by both water treatments. Although glutaraldehyde did not affect the survival of F. candida, the reproduction was inhibited (EC50=44.4mg/L). No adverse effect of glutaraldehyde was observed on reproduction or survival of E. crypticus. These results indicate that produced water, when used in irrigated agriculture, may affect soil functional mesofauna.