Most of the times bio fertilizers/bio-inoculants will act as supplement to inorganic fertilizers rather complement one. Saving of chemical fertilizers due to the application of bio fertilizers may vary from 5 to 20%. This range based on the experimental results from IIHR due to the application of microbial consortium. Application of microbial consortium plays a role in suppressing soil borne diseases and in improving plant health. It was noticed in many of the horticultural crops at IIHR. Data is available only for plant health improvement due to the application of consortium but not for soil borne disease suppression. The data has to be generated with the help of pathologist. 

In natural soils or agricultural soil systems micro organisms work in  consortium mode and even they compete in community also.So use of  a consortium of organisms is better than single organism based culture as biofertilizer as highlighted by Dr.Hani.We know that there is substantial information on microorganisms involved or participating in a consortium for their ability fix or solubilize plant nutrients but the information on disease suppression and production of plant growth promoting substances is limited  and also not generated simultaneously .So we need more information on these two aspects from microbiologists and also need more studies in future.

In natural soils or agricultural soil systems micro organisms work in  consortium mode and even they compete in community also.So use of  a consortium of organisms is better than single organism based culture as biofertilizer as highlighted by Dr.Hani.We know that there is substantial information on microorganisms involved or participating in a consortium for their ability fix or solubilize plant nutrients but the information on disease suppression and production of plant growth promoting substances is limited  and also not generated simultaneously .So we need more information on these two aspects from microbiologists and also need more studies in future.

Very nice . These answers encourage  me to flag off few other very interesting points , which we can  respond while answering the my primary question .  The microbes under any natural  system function in tandem with each other , and in the process , they  constitute easy heaven like network often called microbial pool . How is such microbial pool identified?. Can a rhizo-competent microbe ( whether or not a member of consortium ) be a equally strong antagonist ? , since the ability of the microbe to trigger off growth response will improve the defense  system of plant ,  thereby , imparting greater flexibility to fight out against diseases.

Very nice . These answers encourage  me to flag off few other very interesting points , which we can  respond while answering the my primary question .  The microbes under any natural  system function in tandem with each other , and in the process , they  constitute easy heaven like network often called microbial pool . How is such microbial pool identified?. Can a rhizo-competent microbe ( whether or not a member of consortium ) be a equally strong antagonist ? , since the ability of the microbe to trigger off growth response will improve the defense  system of plant ,  thereby , imparting greater flexibility to fight out against diseases.

Estimado  Anoop Kumar Srivastava de forma sencilla le envío mi criterio sobre sus preguntas, espero le sean de utilidad, saludos

# Whether microbes used as bio-inoculants act as supplement or complement to inorganic /chemical/mineral fertilization ?.

La presencia de los microorganismos en el suelo nos indican el estado de salud del mismo y esto nos demuestra como está funcionando, existe una alta biodiversidad y están en un equilibrio dinámico. Ellos intervienen en los diferentes ciclos biogeoquímicos de los elementos químicos, que todos conocemos son necesarios para los organismos vivos. Al utilizar bio-inoculantes estamos potenciando funciones biológicas en ese suelo que es necesario para un cultivo, que conlleva por lo general a un mayor rendimiento en la cosecha y a su vez a la mejora en alguna cualidad de ese suelo. Por lo tanto mi punto de vista es que la fertilización mineral es la que puede complementar la utilización de bio-inoculantes microbianos.

# To what an extent , these bio-inoculants can save on use of inorganic fertilizers?.

Siempre habría que realizar ensayos en las condiciones en que se van a aplicar pero me atrevería a decir que hasta un 25 % de la dosis establecida por protocolo y si se utiliza enmiendas orgánicas se ahorraría más. A esto adiciono el uso de bio-inoculantes con presencia de hongos micorrízicos arbusculares  (siempre que la planta sea micótrofa), el cual empleando mezcla de cepas eficientes, la eficiencia de aprovechamiento de los nutrientes va a ser más elevada. Debo señalar que dentro de las esporas de las micorrizas arbusculares hay bacterias beneficiosas.

# Whether use of microbial consortium could play twin role, addressing two very important issues viz., suppressing soil borne diseases acting as antagonists on one hand and triggering the growth response on the other hand ?.

Si podrían, de hecho lo hacen, existen varias condiciones que provocan este doble papel que juegan los consorcios microbianos. La alta concentración de microorganismos benéficos presente en el consorcio que se aplica va a competir por los nutrientes presentes, establecen una competencia también en la colonización de las raíces ocupando físicamente la misma e impidiendo que entre el patógeno y la producción de compuestos químicos que no son favorables a los microorganismos patógenos. Además contribuyen a evitar condiciones favorables para el desarrollo de patógenos. Y claro está la acción fijadora, solubilizadora, etc  de diferentes compuestos químicos haciéndolos disponibles y asimilables para las plantas contribuyen al crecimiento de la misma.  

Juan , thanks for responding so elaborately , but unfortunately most of us fail to  follow the language of the response. Could you please translate it into English so that we are able to grasp your answer. 

Dear Anoop Kumar Srivastava a simple way send him my opinion about your questions, I hope you find them useful, best regards

# Whether microbes used as bio-inoculants act as supplement or complement to inorganic /chemical/mineral fertilization ?.

The presence of microorganisms in the soil indicate the health of it and this shows it is working, there is a high biodiversity and are in a dynamic equilibrium, they are involved in various biogeochemical cycles of chemical elements, we all know they are necessary for living organisms. By using bio-inoculants we are promoting biological functions in that soil that is necessary for a culture that generally leads to higher yields at harvest and in turn improving some quality of the soil. So my view is that the mineral fertilizer is one that can complement the use of microbial bio-inoculants.

# To what an extent , these bio-inoculants can save on use of inorganic fertilizers?.

One should always perform tests at the conditions under which they will apply, but I would say that up to 25% of the dose protocol established, and if used organic amendments would save more. To this I added the use of bio-inoculants with presence of arbuscular mycorrhizal fungi (provided the plant be arbuscular mycorrhizic), using mix of efficient strains, the efficiency of using of nutrients will be higher. I should note that in the spores of arbuscular mycorrhizae there are beneficial bacteria.

# Whether use of microbial consortium could play twin role, addressing two very important issues viz., suppressing soil borne diseases acting as antagonists on one hand and triggering the growth response on the other hand ?.

If they could, in fact they do, there are several conditions that cause this double role of microbial consortia. The high concentration of beneficial microorganisms present in the consortium that applies will compete for nutrients, establishing a competition also in the colonization of the rootlets, this physical occupation prevents them from infecting pathogens and production of chemicals that are not favorable pathogenic microorganisms. Also contribute to avoid favorable conditions for the development of pathogens. And of course the binding action, solubilizing, etc of different chemical compounds making them available and assimilable to plants contribute to the growth of it.

Interesting Juan , what do you think , a rhizo-competent microbe necessarily, a growth stimulant , has  to be necessarily an effective antagonist against  soil borne diseases ?. My second  point is , what kind of inoculation strategy  should be adopted to make consortium inoculation more  effective , say for example , enough soil moisture , organic manure pre-treated soil /soil with optimum organic matter , temperature of the day/season etc.?....

Dr.Srivastava,there are probably  several  PGPB  or  PGPR already introduced in the  farmers  fields for verification or actual use by farmers .How they are performing ?Are they providing the benefits of nutrient fixing ,solubilization, disease suppression and growth promotion?Can any body highlight his/her experience.What problems they are encountering in the field in terms  the organisms survival and performance  ?

Dr Rao , I am talking of the those PGPB or PGPR having compatibility  in consortium mode . There are hardly few  successful  crop -specific microbial consortium available as per  published world literature . I do not deny , there could be still many more  in the pipeline. One of the major limitations describing response of PGPR is  the distinctive absence of data on disease control. There is huge database available for agronomic response of microbes , but mostly through single or double inoculation , but surely not for microbial consortium . What do you think , if a rhizo-competent microbe capable of promoting growth  , will it be effective as antagonist as well ?. The inoculation of microbes in consortium mode got into the way , only because of the disease  control ability of candidate microbe , especially the soil borne diseases.

Dear Dr.Srivastava, good morning! The soil is a complex system. The activity and diversity of microbes that operate in this system may vary by soil type, management, local climate and rainfall. Recently performed a study evaluating areas with soil management records from more than two decades. I found that the fertilization with urea provides decrease of microorganisms activity in no-tillage system with legumes / corn succession, and increase in no-tillage system with succession maize / maize. Therefore, due to the great variability of responses also seen in the literature, each particular case must be tested, there is not a generalized response. I believe in the use of bio-inoculants only as a supplement to the management of fertilization, not to be able to replace there. For these microorganisms to make available nutrients paras plants, it is necessary carbon sources in the soil. In order not to break the nutrient cycling processes.

Nice answer  Marcelo , do  you mean that  microbes  have only compliment the efficacy of applied fertilizers. The  very purpose of floating this question was , that what an extent these microbes will save the use of chemical /inorganic fertilizers , and  in this regard , there is a unanimity of about the 20-25% saving on use of inorganic fertilizers , which is  a substantial reduction . For any nutrient recycling , use of microbes is almost a mandatory exercise  , not necessarily , you apply bio-inoculants externally , there could be some conservation practices  , they aid in establishing the excellent microbial buildup in soil , especially under non-tillage/zero tillage practices across annual or perennial crops.  But , the other side of the coin , is that do we have any strong database to support our so called hypothetical assumption that continuous use of chemical fertilizers , have really damaged the nutrient-microbe synergy to  an ir-repairable damage?. And , that is why we frequently raise the question  to apply some rhizo-competent microbes in consortium mode , instead of having single or dual inoculation , in most of the crops.  

Yes Ms Reyhaneh , there are some reports of  commercially very viable microbial consortium in number of crops like wheat , barley , soybean , chickpea, strawberry , pomegranate  , but distinctly missing in perennial fruit crops., simply because of limited efforts to exploit the excellent nutrient-microbe synergy in perennial fruit crops. Enclosed  PDF will further furnish more precise information with regard to your query.

Deare colleagues,can any microbiologist provide information on the consortium of organisms tested and available for use ,being tested before release and under experimentation for some common field crops like rice ,wheat ,maize, soybean, gram(chickpea) etc.

Any soil inoculation of microbes carrying even two or three or more than that  as double   or triple or multiple inoculation,  could  be a part of microbial consortium .    

I have worked with rhizobia for improvement of rice yield. I found no significant N2 fixation in association with rice, but IAA (or indole like substances) was secreted that promoted growth of rice seedling and root surface area. Our present investigation showed that inoculation of micrbia in consortium in organic media reduced about 25% N requirement and quite a significant portion of chemical P requirement with no grain yield reduction compared to chemical based rice production. In amother trial with greengram and rice cultivation under upland conditions showed that rice plants near to greengram plants were more greener than others indicating beneficial association.

The soil naturally hosts a wide diversity of microorganisms. Thus, after inoculation microbes in the applied fertilizer have to compete with the native counterparts. All organic manures are natural carrier of microbial consortium and their positive effects are well documented and established. During composting and decomposition of wastes there must be some equilibrium in the population and activity of individual microorganisms, and in the harvested manure. The relative abundance and activity of the microorganisms should be influenced by the raw materials and decomposition environment, while it’s affected by soil-plant interaction after their application. It should be interesting and worth study to prepare such consortium artificially for commercial use. What should be the population of each microorganism to be maintained? Would it be same for all crops? How long the material can be stored before application?

Application of composts, incubated with consortium of microorganisms, produced significant positive effect on growth and yield of vegetables, ornamental (flower) crops and wheat under aerobic condition (upland), but the effect was not pronounced in wetland rice. Among vegetables, the effect was not comparable between chilli and tomato. Another important aspect may be the method of application, i.e. localized or blanket applications. Similarly, the impact of such application over short-term or long-term should be an interesting area for different cropping systems.

Thanks Pierlorenzo fro an excellent response. Some good points , you have added in  your response, especially the mycorrhiza to increase root absorptive surface  . Equally exciting to realise the role microbes as biosurfacetants to degrade the contaminants...

Impressed with your convincing response Dr Biswas. What is your opinion , under acropping system involving greengram-rice , why not to have a consortium of seven cross inoculation groups( japonicum, meliloti,phaseoli, etc..) to expand the possible response of microbial inoculation..?

thank you prof for initiating such a useful discussion on a hot issue facing by our countries now a days. In my view the inoculation of bio fertilizers which includes bacteria and fungi, can only fix nitrogen from the atmosphere while, fungi can help in absorption of Phosphorus from the soil. it cannot produce or fix phosphorus.

Still the question arises that how to prevent the use of inorganic fertilization?

there are some conventional techniques like, green manuring, crop rotation etc which might help in this regard including the addition of farmyard manure and bio fertilizers.

Thanks Dr Nilay  for an excellent response . There is absolutely no doubt , organic manures inoculated with microbial consortium will produce a much better value added response than either of the alone. however , the bigger question lies in isolating and identifying the rhizo-competent microbes to be able to complement with each other in a consortium mode, a million dollar question , not so easy to handle..?

Hi!

This is a deep question. With pleasure would answer you but my English knowledge is not enough for this purpose. In addition I know of the best specialists in this sphere of scientific activity.

Sincerely regards.

When we talk about consortia the plural of singular consortium we are talking about a community.

In relation to improving or regenerating our land the role of symbiosis and synergy are important to dwell on.

Although we are awash in Nitrogen in the stmosphere our ability for most plants to access limits our crop production. Applying fertilizer N has many environmental, energetic and health issues when Biological Nitrogen Fixation through bacteria are used the agriculture can be weaned against these issues. A second big obstacle is Phosphurus which is generally insufficient in aavailability to optimize our cropping system. The rhizosphere bacteria that stimulate

Phosphorus release are very important view. The champion symbiotic consorita is legume based cropping systems with excellent activity of mycorrhizal fungi and supported by Phosphorus mobilizing root sphere bacteria. When these are inoculated the community A, B, and C components will show responses greater then either organism alone and their sum.

Symbiosis synergism needs to be identified and measured and better methods of promoting it sought out.

For the offer all cropping system to work most effectively concentrate on symbiosis and synergism and measuring the positive interactions.

Dr Anoop,

It would be really worthy to work with diverse group of microbes as inoculants.

Currently, a consortium of Azotobacter, Azospirillum and PSB as bio-fertilizer is being sold by our University.

Thanks all the three gentlemen , Dr Hepperly, Dr Biswas and Dr Borah...

Dr Hepperly , we are still short some distinct silicate solubilizers  to be tested consortium mode. good point , synergism about microbes in consortium mode , is another very vital point.  I agree with you Dr Biswas , our efforts must concentrate on using rhizocompetent crop specific microbes . I am not too sure , Dr Borah, is it crop specific or general consortium...? 

It's for use in all crops

Why dont we develop crop specific microbial consortium .? Is it a matter efforts required to achieve this , or technically doesnt sound well convincing ..

Anoop As you suggest the benefits of specific consortia for different situation is probably a result of a lack of support systems and appreciation for this important area. The academic demonstration is building but the implementation and commercialization are lagging. Our academic community is not giving this the priority it might deserve. This area might be stimulated if awards were granted for superior work in this area and other creative approaches. PRH

Making profit with living organisms is difficult. It requires nourishment and proper handling. Business community wants stable commodities having ease of handling that can be preserved for a longer time, could be one of the hardest obstacle of biofertilizer use.