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Rhisosphere an area of soil surrounding plant roots in which soil’s most reactions takes place. The Rhizosphere word was given by Lorenz Hiltner and it is 1-2 mm wide. Rhizosphere is divided into three zones- endorhizosphere, rhizoplane and ectorhizosphere. The two dynamic properties of soil rhizosphere are root exudates and soil microbes. Root exu...
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... Vegetation changes may vastly affect the quality and quantity of organic matter (OM) returned to soil and its microbes, which integrally influence the dynamics of soil organic carbon (SOC) [1,2]. The rhizosphere, an area of soil in the vicinity of 1-2 mm from plant roots, has rich microbial diversity, making it closely related to biogeochemical processes [3,4]. Root exudates are composed of carbohydrates, amino acids, fatty acids, enzymes, and other organic compounds that affect soil's physicochemical properties, creating differences in the microbial composition and activity in the vicinity of the roots [5][6][7]. ...
The rhizosphere microenvironment is crucial to plant–soil physiological processes. The differences among microbial communities in the rhizosphere and non-rhizosphere peatland topsoil (0–15 cm) and subsoil (15–30 cm) in five plant communities dominated by Carex schmidtii, Chamaedaphne calyculata, Ledum palustre, Betula fruticosa, and Vaccinium uliginosum, as well as non-rhizosphere soil in discontinuous and continuous permafrost regions, were studied. We found that the bacteria and nifH gene abundances in the C. calyculata rhizosphere soil in the discontinuous permafrost region were higher than those in continuous permafrost region, while the nirK and nifH gene abundances in the non-rhizosphere soil of the discontinuous permafrost region were lower than those in the continuous permafrost region. The ratio of bacteria to fungi decreased and that of nirK to nirS increased significantly from the discontinuous to the continuous permafrost region, indicating that permafrost degradation can change soil microbial community composition. Fungal abundance was higher in the rhizosphere than the non-rhizosphere soils, suggesting that plant roots provide a more suitable environment for fungi. Moreover, the abundances of the topsoil bacteria; the fungi; and the nirK, nirS, and nifH genes were higher than those in the subsoil because of the organic matter from plant litter as a source of nutrients. The microbial abundance in the subsoil was also more affected by nutrient availability. To sum up, the microbial abundance varied among the different types of rhizosphere and non-rhizosphere soils, and the carbon and nitrogen cycling processes mediated by soil microorganisms may be greatly altered due to permafrost degradation under climate warming.
... The soil color is apparent character of chemical and mineralogical properties. The textural property of the soils as determined by moisture regime and topographic position also play dynamic part in soil color [49][50][51]47,52,53]. The data also revealed that surface soils were darker in color which may be due to large quantity of organic matter and clay humus complexes. ...
The scientific study of the soil started almost 70-80 years ago with two school of thoughts, one worked in the lab and others in field. The main aim of the researchers studying in the field was to determine the profiles of soil along with its horizons so as to extent the knowledge on physical, chemical and biological properties. The distinctness of soil with depth means that soil has unique profile. All the soils in the world has some specific depth functions. The change of soil color or soil texture in a soil profile can be considered a good indicator of the soil formation and process and has been used as a proxy for degree of development or soil age. Uniform, gradational and rapidly changing soil textures are examples of soil profile forms used for soil classification. In the current study we studied twelve profiles having four different land uses and observed several horizons having various boundaries. The upper horizons were having diffused and wavy boundaries than the lower horizons. There was seen a clear relationship between the horizons and the various land uses. The study is very important as the soils in Himalayas are not very well developed and are prone to erosion. The study will help researchers and policy makers.
... Nannipieri et al., (2008). Soil microbial activity and its diversity in the rhizosphere have been extensively studied, Bashir et al., (2016); ; ; Kumar et al., (2016a);Swamy et al., (2016);de Medeiros et al., (2017), depending on the interaction between cultivated plants and rhizosphere properties Fig. (57), which include: -Effects of applied pesticides e.g., Álvarez-Martín et al., (2016);Franco-Andreu et al., (2016);Lv et al., (2017); Mauffret et al., (2017) -Effects of soil earthworm in presence of plants, Aghababaei et al., (2014); Aghababaei and Raiesi (2015); Lv et al., (2016);Zhang et al., (2016a); Kim et al., (2017;Liu et al., (2017b) -Effects of soil pollution including organic and inorganic pollutants, Parelho et al., (2016); Hansda et al., (2017); Tong et al., (2017); Wang et al., (2017b) -Effects of different soil characterizations like soil organic matter, soil redox potential, etc., ; Su et al., (2017);Xiao et al., (2017) -Effects of climate change, Bojko and Kabala (2017); Zhang et al., (2016b), (2017b) -Effects of plant characterization, ; Mohammadi et al., (2017);Zhang et al., (2017c) -Effects of application of soil amendments and fertilizers, Meena et al., (2016); Abad-Valle et al., (2017); Wang et al., (2017c, d) -Effects of applied nanomaterials, Nogueira et al., (2012); Oyelami and Semple (2015); Schlich and Hund-Rinke (2015); Schlich et al., (2016);Liang et al., (2017) -Effects of different stresses, Cheng et al., (2016); ; Xue et al., (2017); Wu et al., (2017) -Effects of tillage and other agricultural practices, Kabiri et al., (2016); Tautges et al., (2016); León et al., (2017); Yuan et al., (2017) -Effects of transgenic plants on microbial diversity in the rhizosphere soil, Chaudhry et al., (2012); Canfora et al., (2014); Sahoo et al., (2015); Turrini et al., (2015); Guan et al., (2016);Arpaia et al., (2017). Therefore, there is a crucial understanding for the principles of interaction among microbes-plants and microbes-microbes. ...
... Generally, there is close relationship between plant roots, their exudations and plant nutrition. There are direct and indirect effects of plant root exudates on plants nutrition including uptake, transformation, translocation and accumulation of different soluble compounds in the rhizosphere, Fig.(59), Neumann (2007); Nannipieri et al., (2008); Doornbos et al., (2012); Bashir et al., (2016);Liu et al., (2017c);Meier et al., (2017). Agric. ...
Global climatic has been changed and will continue to change because of the activity of unreasonable controlled of human activities, which gradually increase the concentrations of greenhouse gases in the atmosphere. Population is gradually increased at the same time and due to climate change, soil and water resources is threastened due to natural resource degradation. Many reports, by IPCC has clearly stated that warming of the climate system is unmistakable and it is very likely caused by natural and human activities. Climatic changes always affect hydrological cycle components, such as precipitation, evapotranspiration, temperature, stream flow, ground water and finally surface runoff, and may have stronger or weaker, permanent or periodical, favorable or unfavorable, harmful, direct or indirect impact on soil processes. Climatic changes will result in stimulated floods and drought, which will have significant impacts on the soil and the availability of water resource availability. Soils are linked to the climatic system through cycles of nitrogen, the carbon, and hydrologic. Because of climatic changes, soil processes and their characteristics will gradually be affected, by changing in temperature, that causing changes in global amounts of rainfall and their distribution patterns. Temperature and water are very important factors influencing the processes of soils, which causing changes in the soils throughout the world. Managements of water resources can affect on the counter balance of climatic changes on stream flow and water availability at certain level. This review studies the impacts of climate change on soil, water resources. Studies also dealing on hydrological responses to climate change, and possible adaptation options in the realm of climate change impacts on soil and water resources. Deficit of soil moisture affects crop productivity through its influence on the availability and transportation of nutrients which gradually increases vulnerability to nutrient losses from the rhizosphere soil by erosion. Nutrient elements are carried by soil moisture to the roots. Decreasing moisture in root zone resulted in decreasing nutrient diffusion and their availability, consequently decreasing mass flow of water-soluble nutrients such as nitrate, sulfate Ca, Mg and Si over longer distances. Roots extend their length, gradually increase their surface area and alter their architecture in an effort to capture less mobile nutrients such as phosphorus. Reduction of root under drought conditions reduces the nutrient acquisition capacity of root systems. Also reduce both carbon and oxygen fluxes, furthermore minimize the accumulation of nitrogen in root nodules particularly, in legume crops, furthermore, alters the composition and activity of soil microbial communities like the reduction of soil nitrifying bacteria.
... The concentration of heavy metals may affect the bacteria by reducing their number, size, biochemical activity, diversity, and change in the community structure (Pająk et al. 2016). The high concentration of bacteria in the rhizosphere occurs due to the presence of high levels of nutrients that are exuded from the roots that support bacterial growth and metabolism (Chandran 2014;Bashir et al. 2016). The occurrence of bacteria on sterilized Hoagland solution is due to the dissolution of inoculated bacterial cells from the rhizosphere to the culturing solution (So 2003). ...
The role of multi-heavy metal tolerant bacteria isolated from the rhizosphere of Eichhornia crassipes in the phytoremediation of Cu and Pb under laboratory conditions was investigated. The heavy metal tolerant rhizosphere bacteria were identified as Bacillus cereus, Paenibacillus alvei, Aeromonas caviae, Paenibacillus taiwanensis, and Achromobacter spanius. Results showed a significant variation in wet weight, Heterotrophic Plate Count (HPC) of the rhizosphere, HPC of water, removal and uptake of Cu and Pb by E. crassipes, either alone or in association with the rhizosphere bacteria. The removal of Cu by E. crassipes in different experimental conditions showed that OTC (Oxytetracycline) untreated E. crassipes with rhizosphere bacteria has maximum removal with 95%, followed by E. crassipes alone with 84%. The OTC treated E. crassipes with rhizosphere bacteria could remove 81% of Cu. The maximum Pb removal efficiency of 93.4% was shown by OTC untreated E. crassipes with rhizosphere bacteria, followed by E. crassipes alone with 86.8%. The OTC treated E. crassipes with rhizosphere bacteria showed the least removal efficiency with 82.32%. The translocation factor (TF) values for Cu and Pb were lower than 1 indicated that the absorption was mainly accomplished in the roots of E. crassipes. The order of accumulation of Cu and Pb in E. crassipes was noted as root > leaf > petiole.
... In the organic farming systems, there is basically the transformation of carbon compounds by macro and microorganisms and plants that provide energy and connects above and below surface energy by the formation of a cycle (Rossiter and Bouma 2018;Wade et al. 2018;Roper et al. 2017;Bonfante and Bouma 2015;Tiquia 2005). The plants assimilate carbon from atmosphere and form glucose and other complex plant biomolecules which, upon plant senescence, enter the soil through roots, litter, and root exudates (Zhang 2013;Zuber et al. 2018;Bashir et al. 2016). The plants supply energy to heterotrophs and, to a less extent, to chemotrophs (microbes, fungi, and earthworms) by the formation of recalcitrant organic matter (Adeniji and Babalola 2019) The carbon source acts as a source of energy and as long as net primary production exceeds respiration the organic carbon will accumulate in the soil (Miranda et al. 2019;Oburger and Jones 2018;Conrad et al. 2018;Mahanty et al. 2014;Dijkstra et al. 2013). ...
... Soil is species rich habitat on earth having diverse and abundant species which help in the formation and development of soil. The soil biodiversity is indicator of soil health, as greater biodiversity means greater soil stability in terms of certain functions, such as maintenance of soil structure, assimilation of organic wastes, and nutrient cycling (Miranda et al. 2019;Oburger and Jones 2018;Conrad et al. 2018;Mahanty et al. 2014;Bashir et al. 2016;Shen et al. 2014;Dijkstra et al. 2013;Wang et al. 2012;Bhatti et al. 2017). Soil organic matter, soil organic carbon, and soil biodiversity are closely related but distinct. ...
... All these organisms depend on soil organic matter for their energy, nutrients, and habitat. The topmost soil of earth, where concentration of organic matter and roots are higher, forms the largest habitat for these organisms (Bashir et al. 2016). A vast diversity of the organisms is present in the soil but only limited microorganism has been explored (Table 7.4). ...
In 2050, the population of the world is expected to be 9 billion, which means we have to produce six times more food. With this population explosion and increase in food demand, the agricultural land is depleting at an alarming rate, jeopardizing future progress. In order to overcome this problem, the soil organic matter plays a dynamic role in the maintenance and improvement of soil properties. Organic matter determines larger part of soil and has tremendous ecological significance; it influences ecosystem productivity, soil health, and climate quality. The soil organic matter maintains and improves many physical, chemical, and biological properties. This chapter explicates the effect of organic matter on physical, chemical, and biological properties, including soil structure, water retention, available water capacity, thermal conductivity, erodibility, infiltration, soil aggregate formation, soil color, soil compaction, soil aeration, pH, buffering capacity, CEC, base saturation, zeta potential, exchangeable cations, soil fertility and nutrient release, microbial population, soil microbial biomass carbon, nitrogen transformation, mycorrhizal population, root length and root growth, and soil enzymes. It was concluded that increase in the organic matter enhanced these properties, while reduction in organic matter had a detrimental impact on these properties.
... Soil is species rich habitat on earth having diverse and abundant species which help in the formation and development of soil. The soil biodiversity is indicator of soil health, as greater biodiversity means greater soil stability in terms of certain functions, such as maintenance of soil structure, assimilation of organic wastes, and nutrient cycling (Miranda et al. 2019;Oburger and Jones 2018;Conrad et al. 2018;Mahanty et al. 2014;Bashir et al. 2016;Shen et al. 2014;Dijkstra et al. 2013;Wang et al. 2012;. Soil organic matter, soil organic carbon, and soil biodiversity are closely related but distinct. ...
... All these organisms depend on soil organic matter for their energy, nutrients, and habitat. The topmost soil of earth, where concentration of organic matter and roots are higher, forms the largest habitat for these organisms (Bashir et al. 2016). A vast diversity of the organisms is present in the soil but only limited microorganism has been explored (Table 7.4). ...
... Soil enzymes play a key role in organic matter decomposition and its recycling, with their activities being closely related to microbial activity, microbial biomass, soil physical property, and soil organic matter (Oburger and Jones 2018;Mahanty et al. 2014;Bashir et al. 2016;Dijkstra et al. 2013). These enzymes are either intracellular or extracellular, with intracellular being inside the cell in the cytoplasm bound by the cell wall. ...
Cyanobacteria (blue-green algae) are the photosynthetic organisms that are widely grown in all sorts of habitats including aquatic and terrestrial environments. Today, the agricultural sector is highly dependent on chemical fertilizers to enhance the crop production in order to meet the demand for food around the globe which have severe negative effects on both mankind and environment. Due to its pool of properties that are beneficial for sustainable agroecosystem, cyanobacterial biofertilizers are eco-friendly and can be an effective and economical alternative for synthetic fertilizers with less input of cost and energy. They can be explored for producing natural fertilizers, which provide positive alterations for both biotic and abiotic components. Cyanobacteria are potential sources of nitrogen fixation, cost-effective, and a major component of the nitrogen-fixing biomass. They have become paramount microbes for producing natural fertilizers, plant growth-promoting hormones, bioactive compounds, etc. These properties enable them in boosting soil fertility, control the activity of other microorganisms, and also can play a role in bioremediation of pesticides, herbicides, and combating pollution attributed to heavy metals and other toxicants as well. The agricultural importance of cyanobacterial biofertilizers is directly related to their nitrogen fixation ability and other effects for plants and enhances soil fertility. This chapter emphasizes on the use of cyanobacteria as a sustainable microbiome and biofertilizer in agriculture sector to enhance crop production and yield.
... Soil is species rich habitat on earth having diverse and abundant species which help in the formation and development of soil. The soil biodiversity is indicator of soil health, as greater biodiversity means greater soil stability in terms of certain functions, such as maintenance of soil structure, assimilation of organic wastes, and nutrient cycling (Miranda et al. 2019;Oburger and Jones 2018;Conrad et al. 2018;Mahanty et al. 2014;Bashir et al. 2016;Shen et al. 2014;Dijkstra et al. 2013;Wang et al. 2012;. Soil organic matter, soil organic carbon, and soil biodiversity are closely related but distinct. ...
... All these organisms depend on soil organic matter for their energy, nutrients, and habitat. The topmost soil of earth, where concentration of organic matter and roots are higher, forms the largest habitat for these organisms (Bashir et al. 2016). A vast diversity of the organisms is present in the soil but only limited microorganism has been explored (Table 7.4). ...
... Soil enzymes play a key role in organic matter decomposition and its recycling, with their activities being closely related to microbial activity, microbial biomass, soil physical property, and soil organic matter (Oburger and Jones 2018;Mahanty et al. 2014;Bashir et al. 2016;Dijkstra et al. 2013). These enzymes are either intracellular or extracellular, with intracellular being inside the cell in the cytoplasm bound by the cell wall. ...
The traditional way of monocropping and current strategies of use of inorganic chemical-based pesticides and fertilizers are the main barriers in development of sustainable agriculture. Similarly, sickness is a growing issue because of degradation of agricultural land due to continuous sole cropping. On the other hand, intercropping is an old but efficient and eco-friendly way to get rid of soil sickness and to improve crop production. During intercropping, two or more crops either work symbiotically to facilitate each other or compete on available resources for their survival. These both ways can be utilized for the purpose of reclaiming degraded agricultural soils, utilization of resources, management of disease and pests, and eventually increase in crop production. This chapter explains the mechanisms underlying intercropping facilitating plant acquisition of nitrogen and phosphorus and suppressing insect pest and disease incidence with examples of some effective intercropping systems. Moreover, the phenomenon of soil sickness has been described to understand how intercropping can be manipulated to reclaim agricultural land.
... Bacterial diversity in beet rhizosphere. Differences in rhizosphere soil physicochemical properties observed in our study, may be due to greater nutritional demands of the two beet genotypes (TN, Na) or varying exudates composition (OC), as it was found that rhizodeposition is the primary organic carbon source in the rhizosphere 30 . Alternatively, they might be caused by changes in microbial activity resulting from microbial metabolic activity or interaction between microorganisms 31,32 . ...
The increase of human population and associated increasing demand for agricultural products lead to soil over-exploitation. Biofertilizers based on lyophilized plant material containing living plant growth-promoting microorganisms (PGPM) could be an alternative to conventional fertilizers that fits into sustainable agricultural technologies ideas. We aimed to: (1) assess the diversity of endophytic bacteria in sugar and sea beet roots and (2) determine the influence of osmoprotectants (trehalose and ectoine) addition during lyophilization on bacterial density, viability and salt tolerance. Microbiome diversity was assessed based on 16S rRNA amplicons sequencing, bacterial density and salt tolerance was evaluated in cultures, while bacterial viability was calculated by using fluorescence microscopy and flow cytometry. Here we show that plant genotype shapes its endophytic microbiome diversity and determines rhizosphere soil properties. Sea beet endophytic microbiome, consisting of genera characteristic for extreme environments, is more diverse and salt resistant than its crop relative. Supplementing osmoprotectants during root tissue lyophilization exerts a positive effect on bacterial community salt stress tolerance, viability and density. Trehalose improves the above-mentioned parameters more effectively than ectoine, moreover its use is economically advantageous, thus it may be used to formulate improved biofertilizers.
... The highest population and biodiversity of organisms are found in the area of the root system, known as rhizosphere and the bacteria that occupy the rhizosphere are called the rhizobacteria, the community of organisms being called the rhizomicrobiome (Mendes et al. 2013;Bashir et al. 2016). The term rhizosphere is from the Greek words "rhiza" which means root and "sphere" which means field or area of influence (Hiltner 1904;.The rhizosphere as the key habitat of soil organisms is a rich zone of highly available nutrients, acting as a junction for nutrient exchange between plants, soil, and microbes Bashir et al. 2016) and as the hot spot and harbor for the beneficially microbial community. ...
... The highest population and biodiversity of organisms are found in the area of the root system, known as rhizosphere and the bacteria that occupy the rhizosphere are called the rhizobacteria, the community of organisms being called the rhizomicrobiome (Mendes et al. 2013;Bashir et al. 2016). The term rhizosphere is from the Greek words "rhiza" which means root and "sphere" which means field or area of influence (Hiltner 1904;.The rhizosphere as the key habitat of soil organisms is a rich zone of highly available nutrients, acting as a junction for nutrient exchange between plants, soil, and microbes Bashir et al. 2016) and as the hot spot and harbor for the beneficially microbial community. The activity and biodiversity of the microbial community composition of the rhizosphere are highly dependent on root exudates (Dias et al. 2012;Aranda et al. 2013).The rhizosphere as an effective root zone may contain up to 10 11 microbes cells per gram of root and more than 30,000 prokaryotic species (Manoharachary and Mukerji 2006;Parmar and Dufresne 2011). ...
... The zone of ectorhizosphere is formed from soil particles adjacent to the roots (Figure 9.1). Bulk soil is the portion of soil which is not the component of the rhizosphere (Lambers et al. 2008;Bashir et al. 2016) (Figure 9.1). In addition, the rhizoplane is referred to as the surface of the plant tissues in contact with the soil (i.e. ...
In a context of a changing environment, it is crucial to maximize our knowledge on all the mechanisms involved in plant microbiome interactions at the genetic, physiological, and ecological levels. This chapter reviews some recent advances in plant microbiome investigations and describes potential applications of such associations for the mitigation of both abiotic and biotic stresses to improve crop health and productivity. Understanding the full potential of microbes in the ecosystem functioning in general and their complex beneficial interactions in improving agriculture productivity in particular requires the development and improvement of compatible tools that can be verified in biological assays, always bearing in mind their reproducibility in situ on different scales. Progress in the engineering microbiome have made it possible to show how meta‐omics (metataxonomic, metagenomics, metatranscriptomics, and metaproteomics) can be potentially powerful tools to gain deeper knowledge of the functional capabilities of the microbiome and how they can shape ecosystems.
... These results are confirmed by the studies of Koohakan et al. [40], who were detecting more bacteria and fungi on roots than in nutrient solution, in various types of tomato soilless production systems. The higher number of microorganisms in the root zone is the result of the passive and active leakage of root exudates, which serve as nutrient source for these organisms [41,42]. ...
The aim was to determine the suitability of various substrates for application in a closed system of soilless tomato cultivation, based on the potential fitness of drainage waters from these substrates for recirculation. Four substrates were used: rockwool, coir substrate, lignite substrate (Carbomat) and biodegradable organic substrate (Biopot). Tomato plants grown in these substrates were fertilized with the same amount of nutrient solution, containing the same concentration of nutrients. The characteristics of drainage water from these substrates were analyzed during cultivation. The highest amount of drainage water was collected from the lignite substrate Carbomat. However, these leachates showed good properties for further recirculation: low electro conductivity and turbidity, high nutrient content, moderate microbial load with high population of Trichoderma fungi, and being beneficial for plant growth. Moreover, Carbomat produced the highest tomato yield compared to other substrates. This indicates that this organic substrate is an efficient alternative to rockwool and its drainage water may be reused in a recirculation system. On the contrary, the drainage water from the Biopot substrate showed the worst qualities: high pH and low EC, low concentration of nitrate nitrogen and phosphorus, very high turbidity and a high number of microorganisms. These parameters do not qualify Biopot drainage waters for reuse.
