Search

Stressor (biotic as well as abiotic) generally hijack the plant growth and yield characters in hostile environment leading to poor germination of the plants and yield. Among the plant growth promoting rhizobacteria, Azotobacter spp. (Gram-negative prokaryote) are considered to improve the plant health. Various mechanisms are implicated behind improved plant health in Azotobacter spp. inoculated plants. For example, acceleration of phytohormone like Indole-3-Acetic Acid production, obviation of various stressors, nitrogen fixation, pesticides and oil globules degradation, heavy metals metabolization, etc. are the key characteristics of Azotobacter spp. action. In addition, application of this bacteria has also become helpful in the reclamation of soil suggesting to be a putative agent which can be used in the transformation of virgin land to fertile one. Application of pesticides of chemical origin are being put on suspension mode as the related awareness program is still on. As far as the limitations of this microbe is concerned, commercial level formulations availability is still a great menace. Present review has been aimed to appraise the researchers pertaining to utility of Azotobacter spp. in the amelioration of plant health in sustainable agroecosystem. The article has been written with the target to gather maximum information into single pot so that it could reach to the dedicated researchers.

Nanotechnology is influencing life in many ways. Researchers are developing their interest in biofabrication of silver nanoparticles because of its excellent properties and boundless utilis...

Arbuscular mycorrhizal fungi (AMF) are an important component of a sustainable crop cultivation system, which may considerably enhance the health of soil and plant. Application of mycorrhizal fungi has obviated various abiotic stresses such as water, nutrient, drought and enhanced the crop produce. The nutrient-deprived soil showed good performance in the presence of AM fungi. To check the soil erosion and land degradation, and protection of plants from various plant diseases is other services being offered effectively by the AMF. In brief, inoculation of AMF may reduce the damaging potential of various plant pathogens (fungi and nematode) and eventually improve the plant growth and yield. Application of AMF accelerates the production of plant growth-promoting molecules (plant hormones), which eventually ameliorate the plant health considerably. These root symbionts have also the ability to fulfill the demand of nutrients (especially phosphorus) to the plants and make it available to the root of plants. The mycorrhizal fungi also work with other beneficial microorganisms and enhance ecological services. Generally, it has been seen that plant symbionts along with other microorganisms showed better performance in terms of improved plant growth and yield. This coexistence suggests that AMF can easily develop a compatible relationship with other beneficial microorganisms. Thus the application of AMF with other microbial agents can be used in sustainable agriculture.

Undoubtedly, phytoparasitic nematodes cause great damage to important agricultural crops, which signifies great monetary loss. Nematicides are used to kill the plant parasitic nematodes. These chemicals have caused greater losses to our biodiversity which are untargeted leading to a great perturbation of ecosystem ecology. The impact of these chemicals on human health cannot be ignored. PGPR uses various mechanisms to manage the plant nematodes. They are also known as plant growth enhancer, phytohormone producer, siderophore producer leading to enhanced plant health. They are also helpful in the enhancement of quantum of resistance of the plants against various pathogens including plant parasitic nematodes. Inoculation of suitable rhizobacteria not only enhances the plant growth and yield characters of plants but also restrict the multiplication of pathogens and pest populations. PGPR is one of the best alternatives which could be used against plant nematodes for bringing down their population below threshold level. There are several mechanisms implicated in the management of phytoparasitic nematodes and such mechanisms have been described in the chapter.

Phytonematodes can be considered as one of the main obstacles of quantitative and qualitative production of many important crops throughout the world. The strident importance of biological approaches for the management of phytonematodes might be because of friendly nature with reference to agroecosystem sustainability. Trichoderma, a mycoparasite, is an abundant bioagent that kills various plant pathogens and enhances crop productivity. Various mechanisms are implicated behind the effective management of plant disease such as induction of defense responses in plants, antibiosis, competition, direct parasitism, enzymatic hydrolysis, etc. These biocontrol agents offer synergistic effects when introduced through integrated approaches for the management of nematodal diseases. Identification of research priorities for the utilization of bio-nematicides especially Trichoderma spp. in sustainable agriculture, as well as understanding of their mechanisms of action and interaction with other agricultural inputs, is still needed. Application of Trichoderma spp. in controlling various phytopathogenic nematodes leading to improved plant health and yield is the current brainstorming session among the researchers.

Agriculture throughout the globe is subject to both biotic and abiotic stresses. Among biotic stresses that crop plants have to face, plant-parasitic nematodes along with other parasitic microorganisms and insect pests are an age-old destructive force, resulting in the drastic decrease in yields. With the advancement in scientific research, chemical pesticides came into existence. This resolved the problem posed by pests to a great extent. But over the years repeated use of chemical pesticides has given rise to some ecological issues like soil health disruption, groundwater pollution, etc. which cause a greater imbalanced and unproductive agroecosystem. The hazardous effects of these chemicals are creating the hurdles in the exportation of various food commodities. Therefore, current demand is to search some new alternatives which can provide better solutions and also protect the agroecosystem from non-judicious chemical pesticides. Biological control is considered one of the good options to manage the plant pathogens and pests infesting various crops. Biopesticides do not pose a great threat to the environment and protect the human health from various unexpected diseases. Therefore, the aim of this chapter is to shed light on the importance of biopesticides in relation to management of plant-parasitic nematodes (PPNs).

Phytoparasitic nematodes are recognized as one of the important limiting factors for successful cultivation of crops. Compared to other pathogens, plant parasitic nematodes are sometimes difficult to control because they live in the soil and possess a great ability to attack almost every part of the plant. They can be effectively managed by application of chemical nematicides, but at the cost of environmental pollution, toxicity, as well as residual hazards and effect on food chain. Plant protectionists have been evaluating many nematode management strategies like soil solarization, use of fungal and bacterial biological control agents, trap as well as antagonistic crops, and GAP for management of plant parasitic nematodes in crops. Application of organic amendments therefore is a successful alternative strategy for managing plant parasitic nematodes in soil. A good number of organic amendments such as vermicompost, nematicidal plants, farm yard manure, protein-rich wastes, and animal and green manures have been effective in the management of plant parasitic nematodes infesting a wide range of agricultural crops. The use of organic amendments can reduce disease caused by nematodes directly by affecting soil properties and indirectly by improving plant growth, changing root physiology, and enhancing populations of antagonistic microorganisms and productivity. Several nematotoxic chemicals have been reported to be released during decomposition of the organic amendments in soil which are detrimental to nematodes. Also, various factors such as soil type, agronomic practices, rate of application of organic additives, etc. are greatly implicated in bringing down the population below economic threshold. Application of organic amendment improves the soil physicochemical properties, alters the C/N ratio, adds different micronutrients, and thereby improves the plant growth, which ultimately help the plant to withstand nematode attack. We have discussed different types of organic amendments that are used during the management process. We also give emphasis on how they can reduce the nematode population. Due to the chemical released during the process, the nematode population was found to be less harmful to the crop. It has been discussed how this organic matter is important to soil health and the environment of the soil rhizosphere through changes which make the nematodes to thrive less in the soil and how it increases the soil’s properties and the yield of the crops. Many reports indicated that the performance of organic amendments as bionematicides is not satisfactory. In the present chapter, an emphasis has been given to discuss the current understanding pertaining to application of organic additives in the management of phytoparasitic nematodes. Recent progress in plant nematology in terms of their management through organic approaches has been put forth.

Utilization of organic matter as a chief substrate for agricultural crops and beneficial microorganisms is gaining interest of plant pathologists, agronomists, manufacturing and processing industries, regulators, growers, tycoons and consumers. These organic inputs provide energy and nutrients to soil leading to a considerable change in the environment which becomes appropriate for survival of crops and proliferation of microorganisms. More likely, this exercise is further reinforced by the consumers’ demand as they are more conscious towards their health. Moreover, use of organic matter rather than disposal is preferred because it imparts in the market value and recycles back to the land leading towards the enhanced sustainable agricultural system. Various types of organic materials are now available and growers have been familiar with these wastes. However, efficacious nature of each organic matter is different maybe partly due to their chemical constituents, types, origin and duration of decomposition. Henceforth, the results of these natural products are inconsistent from site to site as well as from field to field. Similarly, there is no single mechanism which can advocate the queries prudently pertaining to disease management caused by various soilborne plant pathogens. Some common instances have, however, been exemplified like secretion of pathogen toxic compounds, alteration in soil physico-chemical properties, enhanced microbial activities and induction of host resistance against wide spectrum of soilborne pathogens. Moreover, soil is indistinct part of the ecosystem which may regulate the plants response. Application of low rate of organics is suggested as this will be affordable to the growers. In our opinion, this may be possible through appropriate site selection, formulation, storage and handling as well as consortia of organic matter with other compatible modules. Major problem in the adoption of this technology is insufficient supply of ready-made organics which needs a prudent optimization in order to attain sustainable agriculture.

Plant growth promoting rhizobacteria (PGPR) are well known to ameliorate the plant health. A large number of rhizobacteria possess the growth promoting activities. Some of them are very common and has been also commercialised to large/industrial scale. Plant growth regulators have been found to induce the growth and development of various crop plants. Some hormones like auxin, cytokinin, IAA, etc. are the key hormones in the plant growth promotion. However, their ratio of auxin to cytokinin may be determinant in the lateral root or root hair formation. The root surface area and root lengths are also conceived to play very important role in the accumulation of nutrient and are significantly influenced by the application of PGPR. Moreover, PGPR also have the biocontrol activities against a wide range of soil-borne plant pathogens. Some organic molecules such as siderophores, antibiotics, and bacteriocins producing PGPR arrest the pathogen populations and improve the plant health indirectly. Presence of more PGPR in rhizosphere exhibits more vigour plant health. Therefore, PGPR is considered as an alternative and effective way in the management of plant pathogens and plant growth promotion.

The impact of amending soil with composted sawdusts derived from different woods [Neem (Azadirachta indica), sheesham (Dalbergia sissoo), teak (Tectona grandis) and chir (Pinus roxburghii)] at different concentrations (12.5, 25 and 50 g per pot) and a bio-inoculant, Pseudomonas fluorescens, singly and in combination, was investigated in terms of plant growth parameters of chickpea, both in the presence and absence of root-knot nematode, Meloidogyne incognita. Effect of these amendments on nematode reproduction was also assessed. All the sawdusts at all the concentrations and the bioinoculants either singly or in combination, improved plant growth parameters in terms of plant length, fresh weight, dry weight and number of nodules per plant and suppressed root-knot nematode infection in terms of number of galls/plant and nematode population. Among the four sawdusts, neem was found to be most effective followed by sheesham, teak and chir. The effectiveness of all the four sawdusts was proportional to their doses. However, addition of Pseudomonas fluorescens along with the different sawdusts was more efficient than either of them applied alone, the maximum improvement was recorded in all growth variables in the plants those received the combined application of neem sawdust at 50 g/pot+Pseudomonas fluorescens.

Efficiency of an organic matter like Tagetes erecta and bioinoculants Azotobacter chroococcum and Glomus fasciculatum was investigated in tomato cultivar ‘Pusa Ruby’ when inoculated individually as well as concomitantly for the management of the root-knot nematode, Meloidogyne incognita in terms of growth parameters such as plant length, fresh and dry weights, chlorophyll content, per cent pollen fertility and mycorrhization. Greatest reduction in the numbers of second-stage juveniles in soil, number of root-galls, egg-masses and nematode multiplication was recorded with combined application of T. erecta and bio-inoculants A. chroococcum and G. fasciculatum as compared to untreated control and other treatments. Similarly, the greatest improvement in the plant growth and biomass of tomato was noted in the same treatments. However, individual inoculation of these bio-inoculants and organic fertilizers also showed significant enhancement but was less as compared to combined treatment. A. chroococcum was found most effective against disease incidence followed by G. fasciculatum and T. erecta. Parameters like NP and K contents were significantly enhanced in those plants which received combined treatments of organic matter and bio-inoculants. Azotobacter was found more efficacious against nematodes than Glomus fasciculatum. Organic matter also influenced the activity of bio-inoculants, more with the Azotobacter than G. fasciculatum. DOI: http://dx.doi.org/10.3126/ije.v4i2.12643 International Journal of Environment Vol.4(2) 2015: 206-220

Mycorrhizal fungi are a wide ranging group of heterogeneous fungal taxa found to be allied with the roots of over 90% of all plant species. Among several types of mycorrhizal associations, two types are of high ecological and economic importance, i.e. arbuscular and ectotrophic mycorrhizal interactions. We have given a brief account on habitat, host specificity, and structural components of these mycorrhizal groups. An elaborated discussion on mineral absorption, different absorption pathways and the mechanisms involved has been presented in this chapter. Besides improving plant uptake of mineral nutrients already present in soil, many mycorrhizal fungi play a significant role in mobilizing nutrients either from organic substrate, mineral particles or rock surface. Mycorrhizal fungi take on several mechanisms to accomplish the function successfully, such as enhanced absorbing area of plant roots, release of biochemicals and consortium with other microorganisms. In addition to mobilizing nutrients, mycorrhizal fungi also serves as an important C sink in the soil, thus having an important influence on the cycling of these elements. The contributions of each partner in a mycorrhizal association are starting to be revealed by the use of molecular and genetic tools, coupled to high-throughput sequencing and advanced microscopy. Signalling pathways between plants and fungi have now been marked out, and the recognition of various novel nutrient transporters has unveiled some of the cellular processes that are fundamental to the mycorrhizal symbiosis. Different transporters, especially proton-coupled phosphate transporters, have been recognized on both the plant and fungal membranes and contribute to delivering phosphate from fungi to plants. Although much work has been previously done on several aspects of such symbioses, the extent to which they are functionally important in agriculture remains unclear. We are in urgent need to focus on the questions, the answers of which will give the new perspectives on mycorrhizal function.

Nowadays a large scale of crop produce are pesticide ridden. Heavy application of these hazardous pesticides is not only very costly which leaves financial burden to the farmers but is also harmful to our biodiversity leading to loss of various endangered living species. However, growers are being trained worldwide, and they are progressively switching over their agriculture from chemical or conventional agriculture to organic or sustainable agriculture. Sustainable agriculture reveals crop cultivation with “no chemicals.” But organically cultivated produce are mirage due to their exorbitant prices, at least for the urban dwellers. To resolve this conundrum, the role of plant growth-promoting rhizobacteria (PGPR) has been discussed in the process of plant growth promotion, with their mechanisms and their importance in crop production on sustainable basis. The application of PGPR strain is conducive and creates thrust toward organic farming at every level of farmers, whether it be large landowner or small-scale farmers. However, PGPR strain performance varies from lab to field and even from field to field due to host specificity. Besides, some strains of PGPR have the potential to promote growth of a particular plant, while in another plant they do not respond. There are various ways that promote plant growth such as N2 fixation, P solubilization, siderophore production, phytohormone production, and also the control of phytoparasitic pathogens. In addition to the beneficial role, some important aspects of negativity inducted by the PGPR have also been discussed. Sustainable agriculture, if done in the light of PGPR module, will not only remove the financial burden of the farmers but also prove to be conducive, congenial, and putative. Further studies to commercialize the potent strain of PGPR are stridently needed which will unravel certain yet to be explored mechanisms.

Microorganisms harbouring in the soil are extremely important in the sustainable agriculture. They play a very crucial role in the sustenance of ecological services/balance. Siderophore-producing microorganisms have enormous range of application for the sustainable crop production. Application of siderophores has recently caught fire of discussion and being used in the plant disease management, maintenance of healthy soil, plant growth promotion, SAR induction, acceleration of phytohormone production, bioaugmentation of heavy metal (HM), etc. Moreover, nearly all living beings shine their cellular reactions such as electron transportation, different metabolic reactions and organic molecule formations with the help of iron. In iron-deprived environment, siderophores are the chief media by which maximum cellular reactions get completed. However, a wide range of variations among the siderophores has been noticed like bacterial siderophores that have extremely high binding affinities than fungi; however, phytosiderophores have less binding affinities than microbial siderophores. A lot of variations among the microbial siderophores such as algae, bacteria, fungi and actinomycetes have been noticed in significant manner. Additionally, beneficial job of siderophore in other sector of agriculture and allied branch of science may not be ignored. However, there are some hurdles such as lack of infrastructure and communication gap among the concerned researcher which has put such important research on hold. Research on siderophore-producing organisms will provide an arena to formulate bioprocess technology which is indeed needed to maximize the production of microbial siderophores because of its wide range of applicability. Overall, siderophores and siderophore-producing organisms are conducive to human kind as well as in the sustenance of ecological balance. Thus, this article discusses about the present scenario of research pertaining to siderophore applications in agriculture.

Plant diseases are economically very important. The increasing realization of role of plant niche environment particularly the rhizosphere has triggered the application of management strategies to manage soilborne diseases below threshold. Among these regulatory strategies, one important aspect is to break the pathogenic symbioses as disease complexes. The present chapter has been divided into two parts: the first part focuses on the important soil pathogens in the vicinity with host plants with the role of edaphic climate in their association as disease complexes, while the second one deals with the changing strategy of soil environment using eco-friendly botanicals to discourage formation of disease complexes.

Aqueous extracts of 35 medicinal plants from different families were tested for their antimicrobial potential against six important phytopathogenic micro-organisms viz. Pseudomonas syringae, Xanthonomonas axonopodis, Rhizoctonia solani, Aspergillus flavus, Aspergillus fumigatus and Aspergillus nidulans, causing considerable yield loss. Among the 35 plants tested, aqueous extracts of 16 plants have recorded significant antibacterial and antifungal potential against one or the other species tested. Findings of the present study conclude that the antimicrobials of plant origin are responsible for significant reduction in bacterial and fungal pathogens, and thus, they prove to be good sources of bioactive compounds. However, further experiments are currently in progress to isolate and purify active antimicrobials.

Soil application of organics has been explored as an alternative means of organic management of plant-parasitic nematodes. Efficiency of different oil-seed cakes of neem (Azadirachta indica), castor (Ricinus communis), groundnut (Arachis hypogaea), linseed (Linum usitatissimum), sunflower (Helianthus annuus) and soybean (Glycine max) were evaluated in field conditions with association of Pseudomonas fluorescens in relation to growth parameters of chickpea and population of plant-parasitic nematodes. Their efficacious nature was highly effective in reducing the population of these dominant soil nematodes. Significant improvement was observed in plant-growth parameters such as plant weight, percent pollen fertility, pod numbers, root-nodulation and chlorophyll content of chickpea, seemed to be due to reduction in disease incidence and might be due to growth promoting substances secreted by P. fluorescens. The multiplication rate of nematodes was less in the presence of P. fluorescens as compared to its absence. Most effective combination of P. fluorescens was observed with neem cake.

Experiments were conducted at the University Agricultural Research Farm for the two consecutive years, 2013–2014 and 2014–2015 to study the individual and interactive effects of different plant symbionts (Glomus fasciculatum, Mesorhizobium ciceri), bio-organic waste (Avena sativa straw) and antagonistic fungi, Trichoderma harzianum in all possible combinations for biocontrol of root-knot nematode, Meloidogyne incognita infecting chickpea var. Avrodhi. Biocontrol agents and organic wastes were evaluated for their efficacy in terms of growth characteristics, chlorophyll content, nutrients status, mycorrhization and nematode-related parameters. Combined treatments resulted in higher plant growth, biomass, chlorophyll and nutrient status (N, P and K). Antagonistic fungi, Trichoderma harzianum @ 106 spores plant−1 proved to be most effective of all the plant symbionts (G. fasciculatum, M. ciceri) and organic waste in suppressing the nematode-related parameters in chickpea plants. Of all the treatments, combined inoculation of AM fungus (Glomus fasciculatum @ 800 spores plant−1) + root-nodulating bacteria (Mesorhizobium ciceri @ 1gplant−1) + organic waste (Avena sativa straw @ 10gplant−1) and antagonistic fungi (Trichoderma harzianum @ 106 spores plant−1) was found to be the most efficient in improving the plant growth parameters and decreasing the root-knot development of M. incognita in chickpea plants. Keywords: AM fungi, Chickpea, Interaction, Root-knot nematode, Rhizobium, Trichoderma harzianum

A pot experiment was conducted on tomato (Solanum lycopersicum cv. Pusa Ruby) to assess the effect of different phosphorus (P) levels (0, 125, 250 and 500 mg/pot) and the plant growth promoting rhizobacterium, Pseudomonas fluorescens, on the growth of tomato and on the reproduction of Meloidogyne incognita. Maximum growth of tomato occurred at P rates of 125 mg/kg soil, irrespective of whether plants were uninoculated or inoculated with P. fluorescens or M. incognita or inoculated with both the agents. Nematodes per gram of roots, egg masses per root, eggs per egg mass and galls per root significantly increased by increasing levels of P. P. fluorescens performed better than other treatments and different P levels in improving tomato growth and reducing galling and multiplication of M. incognita.

A disease complex involving Meloidogyne incognita–Rhizoctonia solani was studied on tomato (Lycopersicon esculentum var. Pusa Ruby) under glasshouse conditions to determine their concomitant effect on plant growth variables. Biofertilizers Nerium indicum and Trichoderma harzianum were tested against both pathogens individually as well as concomitantly and found its role in minimizing disease severity. Inoculation of M. incognita and R. solani resulted a significant reduction in plant growth variables over control. The plant growth variables reduction was more pronounced by M. incognita as compared to R. solani. However, T. harzianum exhibited their potential against the disease complex but was less effective than N. indicum. A manifold improvement in plant growth parameters was observed when plants were treated with biofertilizers, N. indicum and T. harzianum simultaneously. The present work has revealed that the combined application of N. indicum and T. harzianum may be a better option for the management of disease complex M. incognita–R. solani on tomato. Application of these biofertilizers after field trials may be suitable module of organic farming.

An experiment was conducted to assess the effect of Rhizobium sp., waste tea leaves, eggshell powder, and composted cow dung manure on the root-knot nematode, Meloidogyne incognita, on lentil in Botany department AMU, Aligarh, India. When used alone, composted cow dung was better in reducing galling and nematode multiplication and improving lentil growth followed by eggshell powder, Rhizobium sp., and waste tea leaves. Significant result in the integrated management of M. incognita was obtained when Rhizobium sp. was used in combination with cow dung and eggshell powder (with or without waste tea leaves). Combined application of root nodule bacterium and organic wastes like waste tea leaves, eggshell, and cow dung may be suggested to the farmers/growers or related persons who are having great enthusiasm to establish a lentil production business. Application of these organic materials along with the root nodule bacteria may be helpful to foster soil ecosystem which has been a hot topic in the present scenario.

A field experiment was conducted to assess the effect of inoculations of biological nitrogen fixers using Azotobacter and Azospirillum individually and concomitantly with different recommended doses of inorganic nitrogen fertilizers and organic matter in the form of sesame (Sesame indicum) cake on the growth, yield and quality traits of tomato (Solanum lycopersicon L.) in relation to the management of plant-parasitic nematodes. The multiplication rate, egg masses, and root-galls per plant of these nematodes were reduced significantly by the individual inoculation of biological nitrogen fixers as well as with organic matter; while concomitant inoculation of bio-inoculants showed a synergistic effect in increasing crop growth and yield. Azospirillum was found to be more effective than Azotobacter. The highest improvement was recorded in the yield and growth parameters, plant height, fresh and dry weights, percent pollen fertility, green fruits yield per plant, chlorophyll content and ascorbic acid content when these biological nitrogen fixers were added concomitantly in various combinations. The Nitrogen-Phosphorus-Potassium (NPK) contents in plants and in soil increased considerably in almost all the combinations whenever these bio-fertilizers were inoculated and thus, reduce the fertilizers needed for commercial tomato production. The best results were obtained with 100% recommended dose of nitrogenous fertilizers along with the bio-fertilizers and farm yard manure.

An extensive survey was conducted to identify common arbuscular mycorrhizal (AM) fungi present in rhizosphere of some commonly cultivated crops such as Maize, Tomato, Pea, Bean, Chilli, Cauliflower and Brinjal from four different sites viz., Bhaderwah (A), Kotli (B), Bhalla (C) and Malni (D) from Bhaderwah of Doda district, Jammu and Kashmir. A total of nearly 6 AM fungal species were recorded, which included of Glomus Jasciculatum, G. mosseae, G. etunicatum, G. constrictum, G. macrocarpum and Gigaspora gigantea. The frequency of occurrence was recorded in order of Glomus Jasciculatum > G. mosseae > G. etunicatum > G. constrictum > G. macrocarpum > Gigaspora gigantean. Most of the plants are found to be associated with AM fungi in natural ecosystem in this region and showed variation in the extent of infection from plant variety soil nature and climatic surroundings.

Plant growth, yield, pigment and protein content of cow-pea were increased significantly at lower levels (20 and 40%) of fly ash but reverse was true at higher levels (80 and 100%). Soil amended by 60% fly ash could cause suppression in growth and yield in respect to 40% fly ash treated cow-pea plants but former was found at par with control (fly ash untreated plants). Maximum growth occurred in plants grown in soil amended with 40% fly ash. Nitrogen content of cow-pea was suppressed progressively in increasing levels of fly ash. Moreover, Rhizobium leguminosarum influenced the growth and yield positively but Meloidogyne javanica caused opposite effects particularly at 20 and 40% fly ash levels. The positive effects of R. leguminosarum were marked by M. javanica at initial levels. However, at 80 and 100% fly ash levels, the positive and negative effects of R. leguminosarum and/or M. javanica did not appear as insignificant difference persist among such treatments. Key words: Meloidogyne javanica ; Rhizobium leguminosarum ; Fly ash; Growth; Yield DOI: 10.3126/eco.v17i0.4098 Ecoprint An International Journal of Ecology Vol. 17, 2010 Page: 17-22 Uploaded date: 28 December, 2010