Bioindicators Of Soil Quality Research Articles

Grupos Funcionales de Microorganismos en Suelos de Páramo Perturbados por Incendios Forestales

El ecosistema estratégico del páramo de Rabanal (Boyacá - Colombia) fue afectado por incendios forestales que arrasaron 2000 hectáreas de vegetación nativa y las especies de fauna asociadas. Debido a esta problemática y a la reconocida importancia de los grupos funcionales de microorganismos como indicadores de calidad, se realizó un diagnóstico microbiológico de suelos para evaluar el efecto de la quema sobre estos grupos cultivables de microorganismos. También se efectuó el mismo diagnóstico en un suelo sin perturbar de la misma zona que se asumiría como control. Fueron evaluadas algunas poblaciones de bacterias cultivables implicadas en los ciclos del C, N y P por el método de recuento en placa estándar utilizando medios de cultivo selectivos. En general, las poblaciones microbianas cultivables nativas implicadas en el ciclado de nutrientes registraron valores de Log UFC/g de suelo similares en los dos tipos de suelos en estudio (p>0,05) a excepción de las poblaciones de bacterias proteolíticas y de bacterias solubilizadoras de fosfato. Las correlaciones lineales entre los diferentes grupos de microorganismos para los dos tipos de suelos evaluados resultaron en su mayoría estadísticamente signifi cativas y muestran interacciones positivas entre los grupos de microorganismos evaluados, lo que indicaría que las poblaciones estarían actuando sinérgicamente posibilitando procesos de cometabolismo, lo que conduciría a favorecer la recuperación del suelo degradado.

Formigas como bioindicadores da qualidade do solo em sistema integrado lavoura-pecuária

O objetivo deste trabalho foi avaliar a comunidade de formigas em sistemas envolvendo a rotação entre lavoura e pecuária, sob plantio direto, comparado a outros sistemas de manejo e com sistemas naturais da região. O estudo foi conduzido no Município de Dourados, MS, sob Argissolo Vermelho distroférrico típico, num sistema integrado lavoura-pecuária, em plantio direto, rotacionado a cada dois anos. Outros sistemas de manejo avaliados, para comparação, incluíram o sistema convencional (aração e gradagem), sistema plantio direto e pastagem cultivada continuamente com Brachiaria decumbens, além de dois fragmentos de vegetação nativa, nos biomas Cerrado e Floresta Semidecídua. A coleta de solo foi realizada no período chuvoso (safra 2009/2010), sendo as amostragens de serapilheira realizadas com a utilização de extratores do tipo mini-Winkler, seguindo o protocolo ALL (Ants of the Leaf Litter). Os resultados indicaram morfoespécies de Strumygenys sp. e Hypoponera sp. como potencial bioindicadores de qualidade do solo. O estudo demonstrou que a importância da manutenção de fragmentos florestais (Cerrado e Floresta Semidecídua) e implementação de sistemas integrados, tais como lavoura-pecuária, são menos impactantes para a mesofauna de solo e contribuem para a conservação da diversidade de formigas e manutenção da qualidade do solo.

Why is the influence of soil macrofauna on soil structure only considered by soil ecologists?

These last twenty years have seen the development of an abundant literature on the influence of soil macrofauna on soil structure. Amongst these organisms, earthworms, termites and ants are considered to play a key role in regulating the physical, chemical and microbiological properties of soils. Due to these influential impacts, soil ecologists consider these soil macro-invertebrates as ‘soil engineers’ and their diversity and abundance are nowadays considered as relevant bioindicators of soil quality by many scientists and policy makers. Despite this abundant literature, the soil engineering concept remains a ‘preach to the choir’ and bioturbation only perceived as important for soil ecologists.We discussed in this article the main mechanisms by which soil engineers impact soil structure and proposed to classify soil engineers with respect to their capacity to produce biostructures and modify them. We underlined the lack of studies considering biostructure dynamics and presented recent techniques in this purpose. We discussed why soil engineering concept is mainly considered by soil ecologists and call for a better collaboration between soil ecologists and soil physicists. Finally, we summarized main challenges and questions that need to be answered to integrate soil engineers activities in soil structure studies.

Relationship between soil diversity and inhabitant mites (Acari)

Mites are important regulators of soil food webs in the ecosystem. Soil diversity, pH, electrical conductivity and organic matters are dominant disturbance factors on community composition of soil mites. Impacts of these factors were assessed on the species composition of soil mites at Dakahleia and Kafrelshikh governorates in six different sites. In total, 14 families, 30 genera, and 37 mite species belonging to the four sub-orders Gamasida, Actinedida, Oribatida and Acaridida were recorded. Mite abundance and diversity in the soil in Kafrelshikh was poor compared with Dakahleia sites. The effect of soil type on mite community composition was significant. PH and organic matters have been established as good indicators for soil fertility. Soil mites were affected by soil fertility as it was observed that soil mites population increased with increasing nutrients. This study provided important information on soil mite populations in cultivated soils and could provide baseline data for studies of bioindicators of soil quality. In conclusion soil mites responded to land type, pH, EC (ds/m) and organic matter level.

Soil Eukaryotic Microorganism Succession as Affected by Continuous Cropping of Peanut - Pathogenic and Beneficial Fungi were Selected

Peanut is an important oil crop worldwide and shows considerable adaptability but growth and yield are negatively affected by continuous cropping. Soil micro-organisms are efficient bio-indicators of soil quality and plant health and are critical to the sustainability of soil-based ecosystem function and to successful plant growth. In this study, 18S rRNA gene clone library analyses were employed to study the succession progress of soil eukaryotic micro-organisms under continuous peanut cultivation. Eight libraries were constructed for peanut over three continuous cropping cycles and its representative growth stages. Cluster analyses indicated that soil micro-eukaryotic assemblages obtained from the same peanut cropping cycle were similar, regardless of growth period. Six eukaryotic groups were found and fungi predominated in all libraries. The fungal populations showed significant dynamic change and overall diversity increased over time under continuous peanut cropping. The abundance and/or diversity of clones affiliated with Eurotiales, Hypocreales, Glomerales, Orbiliales, Mucorales and Tremellales showed an increasing trend with continuous cropping but clones affiliated with Agaricales, Cantharellales, Pezizales and Pyxidiophorales decreased in abundance and/or diversity over time. The current data, along with data from previous studies, demonstrated that the soil microbial community was affected by continuous cropping, in particular, the pathogenic and beneficial fungi that were positively selected over time, which is commonplace in agro-ecosystems. The trend towards an increase in fungal pathogens and simplification of the beneficial fungal community could be important factors contributing to the decline in peanut growth and yield over many years of continuous cropping.

Bioindicators of soil quality in coffee organic cultivation systems

The objective of this work was to assess the effect of different coffee organic cultivation systems on chemical and biological soil characteristics, in different seasons of the year. The following systems were evaluated: coffee intercropped with one (CJ1), two (CJ2) or three (CJ3) pigeon pea (Cajanus cajan) alleys; coffee planted under full sun (CS); area planted with sweet pepper and snap bean in a conventional tillage system (AC); and secondary forest area (FFR). Row spacing in CJ1, CJ2, CJ3 and CS was 2.0x1.0, 2.8x1.0, 3.6x1.0, and 2.8x1.0 m, respectively. Soil samples were collected at 10-cm depth, during the four seasons of the year. The results were subjected to analysis of variance, principal component analysis, and redundancy analysis. There was an increase in edaphic macrofauna, soil basal respiration, and microbial quotient in the summer. Total macrofauna density was greater in CJ2 followed by CJ3, CS, CJ1, AC and FFR; Coleoptera, Formicidae, and Isoptera were the most abundant groups. There are no significant differences among the areas for soil basal respiration, and the metabolic quotient is higher in CJ1, CJ3, and FFR. Microbial biomass carbon and the contents of K, pH, Ca+Mg, and P show greater values in AC.

Histological and Histochemical Analysis of the Fat Body of Rhinocricus padbergi (Diplopoda) Exposed to Contaminated Industrial Soil

Diplopods are components of the edaphic fauna, which makes them suitable bioindicators of soil quality. Some characteristics of the fat body of diplopods make it suitable for ecotoxicological studies. This organ, composed of diffuse tissue, fills the body cavity; it presents intense metabolic activity associated with lipid, glycogen, protein, and uric acid storage, being also responsible for storage, neutralization, and excretion of substances that are not useful to the organism. The present study aimed to investigate whether the perivisceral fat body of Rhinocricus padbergi can be used as a target organ in ecotoxicological studies and to identify possible histological and histochemical biomarkers in this organ. Upon examining the perivisceral fat body of individuals of R. padbergi exposed to different concentrations of industrial soil contaminated with polycyclic aromatic hydrocarbons (∑ 2,749.0 mg/kg) and metals (∑ 40,355.8 mg/kg), we have found evidence that this organ is sensitive to environmental pollutants present in the soil. The loss of integrity of the cell boundary associated with cytoplasmatic disorganization and depletion in total proteins, neutral polysaccharides, calcium, and lipids can be considered stress biomarkers for R. padbergi.

TiO2 and ZnO nanoparticles negatively affect wheat growth and soil enzyme activities in agricultural soil

The properties of nanoparticles and their increased use have raised concerns about their possible harmful effects within the environment. Most studies on their effects have been in aqueous systems. Here we investigated the effect of TiO(2) and ZnO nanoparticles on wheat growth and soil enzyme activities under field conditions. Both of the nanoparticles reduced the biomass of wheat. The TiO(2) nanoparticles were retained in the soil for long periods and primarily adhered to cell walls of wheat. The ZnO nanoparticles dissolved in the soil, thereby enhancing the uptake of toxic Zn by wheat. The nanoparticles also induced significant changes in soil enzyme activities, which are bioindicators of soil quality and health. Soil protease, catalase, and peroxidase activities were inhibited in the presence of the nanoparticles; urease activity was unaffected. The nanoparticles themselves or their dissolved ions were clearly toxic for the soil ecosystem.

Influence of agricultural soils on the growth and reproduction of the bio-indicator Folsomia candida

Soil organisms have been recommended as bio-indicators of soil quality due to their sensitivity to anthropogenic influences and their high degree of site-specificity. The objectives of this study were to determine if the relationship between the soil Collembola, Folsomia candida, and forest soil could be extended to other soils and, if not, to determine the relationship between its life parameters and soils from the different phases of an agricultural rotation sequence. A comparison of growth, reproduction and survival of 1 day old neonates and 10 day old juveniles subjected to a series of different soils (composted manure, pasture soil, forest soil, sand alone, and sand supplemented with yeast) established that the association between F. candida and forest soil quality cannot be automatically transferred to soils from other ecosystems. The test also showed that neonate (1 d) individuals were more sensitive to the different soil treatments than 10 d old juveniles and should be used in future tests. On this basis, neonate F. candida individuals were used to determine if the species could be employed to characterize the agricultural soils from the different phases of an organic or conventional rotation sequence. Results demonstrated that changes in body growth and reproduction constituted suitable criteria to characterize the soil quality of these different phases. The research required to develop these results as a standard bio-indicator test of agricultural soil quality is discussed.

Colémbolos (Hexapoda) como bioindicadores de la calidad de suelos

We evaluated invertebrates, with an emphasis on Collembola, as bioindicators of soil quality in hydrocarboncontaminated soils in southeastern Mexico. We carried out 2 sampling periods in summer-fall of 2004 in 4 parcels of 2 hectares each. From each parcel we processed 8 samples using the Berlese-Tullgren funnel technique and 4 using the flotation method. For Collembola we calculated the following ecological indices: abundance, richness, the Shannon index (H’), dominance (λ), equitativity (J’) and the similarity index (S). We also performed the following soil analyses: total petroleum hydrocarbon content (HTP), polycyclic aromatic hydrocarbon content (HAP), porosity, pH, CE, MO, N, P, K, CIC, and texture. In contaminated areas, HTP exceeded the safe limits sets by Mexican environmental legislation. In all studied areas we observed Collembola, mites, and dipteran larvae. The variation in abundance and diversity of these insects can be used as biondicators of the level of contamination and quality of the soil. We found very low abundances of Crustacea, Formicidae, Aranae, Diptera, Pseudoscopionida, and Diplopoda. The Collembola families that were most widely distributed were Sminthurididae and Isotomidae. Our correlation analysis showed that their diversity is affected by HAP level (fl uoranthene, naphfhalene, pyrene, chrysene and phenanthrene).

Earthworms and Plant Residues Modify Nematodes in Tropical Cropping Soils (Madagascar): A Mesocosm Experiment

Free-living nematodes present several characteristics that have led to their use as bioindicators of soil quality. Analyzing the structure of nematofauna is a pertinent way to understand soil biological processes. Earthworms play an important role in soil biological functioning and organic matter dynamics. Their effects on soil nematofauna have seldom been studied. We studied the effect of the tropical endogeic earthworm,Pontoscolex corethrurus, on nematode community structure in a 5-month field mesocosm experiment conducted in Madagascar. Ten different treatments with or without earthworms and with or without organic residues (rice, soybean) were compared. Organic residues were applied on the soil surface or mixed with the soil. The abundance of nematodes (bacterial and fungal feeders) was higher in presence ofP. corethrurusthan in their absence. The type of plant residues as well as their localisation had significant effects on the abundance and composition of soil nematodes. The analysis of nematode community structure showed that earthworm activity led to an overall activation of the microbial compartment without specific stimulation of the bacterial or fungal compartment.

Calorimetric seasonal characterization of culture and pasture soils

Isothermal and Differential Scanning Calorimetry is applied to analyze the evolution of soil using its microorganisms and organic matter as bioindicators of soil quality. This study was carried out with two similar soils under different agricultural activities: culture and pasture. Sampling and measurements were performed through 1 year in order to check the sensitivity of common calorimetric indicators of microbial activity and organic matter to the different climatic seasons in the sampling place: spring, summer, fall and winter. Results show that these indicators are sensitive to changes related to climatic conditions but the variability depended also on the nature of the soil: pasture or agricultural land. The results achieved through the present study show that the procedure here proposed could be used on any soil everywhere, providing the determination of the own parameters of soil and zones.

Geographical and climatic differences in long-term effect of organic and inorganic amendments on soil enzymatic activities and respiration in field experimental stations of China

Soil enzymatic activities and basal respiration are two important bio-indicators of soil quality and are closely related to soil fertility and sustainable crop growth. We collected soil samples from four long-term experimental stations of China differing both geographically and climatically – Shenyang Agro-Ecological Experimental Station (brown soil), Fengqiu State Key Agro-Ecological Experimental Station (fluvo-aquic soil), Taoyuan Agro-Ecological Experimental Station (paddy soil) and Qiyang Red Soil Experimental Station (red soil) – to investigate the effect of long-term application of chemical fertilizer and/or organic manure on soil enzymatic activities and basal respiration. In general, soil enzymatic activities and basal respiration increased in soils with long-term application of chemical fertilizers and manures, especially organic manure. Among stations, soil enzymatic activities were not consistently increased with organic manure alone (e.g. the sucrase and phosphatase activities in the paddy soil from Taoyuan and red soil from Qiyang). As well, soil enzymatic activities were characterized by distinct zonality. Soil cellulase and urease activity were the two main indicators of soil fertility as evaluated by principal component analysis. Regression analysis of the major abiotic factor(s) influencing enzyme activity revealed a dependence on the specific enzyme tested and the activity of specific soil enzymes depended on the location of the experimental station. Environmental factors, mainly soil temperature, moisture and pH, as well as soil texture, should be taken into account in evaluating the effects of long-term fertilization on soil biological activity and soil fertility in field experimental stations differing geographically and climatically.

Nematode and Microarthropod Communities: Comparative Use of Soil Quality Bioindicators in Covered Dump and Natural Soils

Reclaimed waste disposal sites usually have problems regarding soil quality. Their topsoil is generally affected by physical, biological and sometimes chemical degradation. These conditions in turn affect both site plant and animal communities and, in a more general sense, the effectiveness of the restoration process itself. The site's fauna, either inherited with the soil or established after its introduction, has a community complexity defined by the structure of the soil: generally the more structured the soil, the more complex the community. There exists a relevant number of fauna bioindicators that can be used to evaluate soil quality and monitor the restoration process. We have used two bioindicators to compare our research results: the Maturity Index (MI), based on the nematode population and the Soil Biology Quality (QBS-ar) index, based on soil microarthropods. These indicators were applied to the topsoil of a reclaimed waste disposal site and to wild grassland and wood soils.

Impacts of Metals and Metalloids on Soil Microbial Diversity and Ecosystem Function

Metal and metalloid concentrations in soil exert an enormous influence on the diversity, composition, and activity of soil microorganisms that carry out essential ecosystem services. At low concentrations, microorganisms can compete for essential trace elements that are required to support their growth and in this manner affect plant nutrition and disease through the production of metal chelators. At high concentrations, the toxic effects of metals result in reduced microbial diversity and altered rates of key biological processes that underlie ecosystem function. The latter is now of great concern as large land areas across the globe have become contaminated with metals from land application of wastes and atmospheric deposition of heavy metals. An understanding of how plants, soils, organic matter, and microorganisms influence metal transformations in the rhizosphere is thus critical for managing soils to assure the long term protection of soil quality, food safety, and ecosystem function. One of the major difficulties in making practical management decisions with respect to metal pollution for different types of soils has been our inability to derive bioindicators of soil quality that can provide indices of soil quality across the landscape at different scales and over time. Ecosystems respond very differently to acute and chronic metal toxicities depending on their chemical properties and prior exposure histories. Toxicities are particularly influenced by physico-chemical conditions in soils that influence the bioavailability of metals and metalloids to plants and microorganisms. Nonetheless, the dynamic nature of microbial communities, which respond much faster to changes in management practices than do soil physical and chemical properties enables us to use bioindicators as a sensitive tools for predicting possible long term changes in soil properties. From a land management perspective, it is critical that soil microbiologists offer appropriate bioindicators for use in measuring the impacts of soil pollution on soil biological properties and extend knowledge as to how specific bioindicators may reflect long term changes in soil quality that can be used to guide land management practices and remediation of contaminated soils. Responses of Microbial Communities to Metal Contamination The microbial community concept is based on the interactions among in all of the various species of bacteria, fungi, protozoa, and microfauna that carry out the various broad level functions of the soil, ranging from nutrient cycling to organic matter formation, and plant disease protection. Differences in the species composition of various soils are linked to changes in soil biological properties that in turn affect the long term chemical and physical properties and ability to support plant growth. Among the most basic functions are respiration

DNOC, a model pollutant, adversely affects the potential of soil microbial communities to mineralise the herbicide 2,4-D: an investigation using micro-sampling procedures

The effects of the herbicide, DNOC, 4,6-dinitro- o-cresol, a model pollutant, have been studied by comparing the potential of soil microbial communities present in individual soil aggregates or in larger soil microcosms as samples of soil aggregates to mineralise the herbicide 2,4-D. We have shown that 2–3 mm soil aggregates vary widely in their 2,4-D mineralisation potential and that ageing or exposure to DNOC considerably simplified the distribution patterns of this capacity. The main factors of variation have been quantified and classified using a quasi-likelihood method derived from the Generalised Linear Model approach. Besides DNOC concentration and duration of exposure, an additional ‘rank’ factor reflecting a desiccation gradient of the aggregates on the microtiter plates was found to have statistical significance. We concluded that it should be possible to derive an experimental approach, designated as ‘functional profiling’, with potential use to detect soil chemical contamination. Curves of 2,4-D mineralisation in individual soil aggregates could be classified according to three different types of kinetics, which were assumed to reflect heterogeneous spatial distribution, differences in microbial community composition and varying efficiency of the microbial consortia involved in 2,4-D degradation. Exposure to DNOC considerably simplified the distribution patterns of the different types of kinetics with one type, showing slow rate and low cumulative mineralisation, becoming predominant as ageing, concentration and duration of DNOC exposure increased. We argue on the possible use of ‘kinetic profiling’ as a sensitive bioindicator of soil quality. By comparison, in soil microcosms, 2,4-D mineralisation showed an extra mineralisation potential of 64% over individual aggregates in the control soil and exposure to DNOC was followed by concentration and time-dependent recovery of the 2,4-D mineralisation potential. It is likely that 2 g size soil microcosms gather a larger number of biochemical capacities which could complement each other to increase the potential of soil to mineralise xenobiotic compounds.

Hidrólise de diacetato de fluoresceína como bioindicador da atividade microbiológica de um solo submetido a reflorestamento

A atividade microbiológica tem sido utilizada como bioindicador da qualidade de solos. Neste trabalho, testou-se o método de hidrólise de diacetato de fluoresceína (FDA) para determinar a atividade microbiológica de um solo submetido a quatro tratamentos: reflorestamento com espécies nativas da mata atlântica, reflorestamento com espécies exóticas, reflorestamento com nim, sucupira e pau-pombo, solo não submetido a reflorestamento, além de solo sob mata atlântica nativa que foi utilizada como padrão de comparação. Os tratamentos que apresentaram maior atividade microbiológica foram os solos reflorestados com espécies nativas e exóticas. A hidrólise de FDA mostrou-se eficaz como indicador da atividade microbiológica nos solos submetidos a reflorestamentos.

Impact of Soil Management and Two Botanical Insecticides on Urease and Invertase Activity

Yard waste compost provides an organic amendment useful for improving soil structure and nutrient status. The activities of the enzymes hydrolyzing urea (urease) and sucrose (invertase) in the rhizosphere of potato plants were determined under field conditions. Soil urease and invertase activities were monitored in compost amended soil, grass buffer strips, and in adjacent bare soils during 35 d following soil treatment. Soil urease activity was increased by application of yard waste compost compared to untreated soil which provide evidence of increased soil microbial population following application of compost. Some transitional effects on urease activities were observed following Pyrethrins and Neemix‐4E application, these effects were neither drastic nor prolonged enough to be considered deleterious to the soil microorganisms and their activities important to soil fertility. No relationship was found between invertase activity and the three management practices or soil organic matter content. It is suggested that application of botanical insecticides like pyrethrins and Neemix‐4E may be useful in delaying urea fertilizer mineralization to maintain N in a form less leachable, so that the duration of N availability to plants is prolonged. The present study may also provide information on urease activity as a sensitive bioindicator of soil quality that reflects the effects of land management on soil quality and may assist land managers in monitoring long‐term productivity and sustainability of agricultural lands.

Ants as bioindicators of soil function in rural environments

Farmers are being encouraged to redress the problems of land degradation by implementing a series of changes in their land management. However, there are few tools to monitor soil condition which can reliably inform farmers of the state of their soil. This paper examines ants and their importance in ecosystem functioning, principally their ability to maintain or restore soil quality in rural environments, and their value as bioindicators of soil quality. The reader is provided with a summary of those studies which have recorded the species composition and activity of ant fauna in agricultural soils and naturally vegetated environments. However, it is rare to find studies which sample both environments concurrently. An overview of the types of measures available to assess ant biodiversity is followed by a discussion of the current status of biopedological research into ant–soil relationships and the trends and gaps in current research knowledge, principally in the areas of water and soil movement and nutrient effects. Lastly the paper seeks to forecast the future directions of ant biopedological research, and to identify the type of research required to fully appreciate the value of ants as soil quality indicators to monitor the sustainability of the soil resource. Ants should be considered an important group of soil fauna, yet they have received meagre attention in comparison with other soil fauna such as earthworms. There is a need for specific experiments to test the hypothesis that ants can be used as bioindicators of soil quality.