Site-Specific Nutrient Management (SSNM) provides guidance relevant to the context of farmers’ fields. SSNM maintains or enhances crop yields, while providing savings for farmers through more efficient fertilizer use. By minimizing fertilizer overuse, greenhouse gas emissions can be reduced, in some cases up to 50%

KEY MESSAGES:

1 Site-Specific Nutrient Management (SSNM) optimizes the supply of soil nutrients over space and time to match crop requirements.

2 SSNM increases crop productivity and improves efficiency of fertilizer use.

3 SSNM mitigates greenhouse gases from agriculture in areas with high nitrogen fertilizer use.

4 Incentives for adoption of SSNM depend strongly on fertilizer prices.

https://cgspace.cgiar.org/bitstream/handle/10568/69016/CCAFSpbNutrient.pdf

Site-Specific Nutrient Management (SSNM) provides guidance relevant to the context of farmers’ fields. SSNM maintains or enhances crop yields, while providing savings for farmers through more efficient fertilizer use. By minimizing fertilizer overuse, greenhouse gas emissions can be reduced, in some cases up to 50%

KEY MESSAGES:

1 Site-Specific Nutrient Management (SSNM) optimizes the supply of soil nutrients over space and time to match crop requirements.

2 SSNM increases crop productivity and improves efficiency of fertilizer use.

3 SSNM mitigates greenhouse gases from agriculture in areas with high nitrogen fertilizer use.

4 Incentives for adoption of SSNM depend strongly on fertilizer prices.

https://cgspace.cgiar.org/bitstream/handle/10568/69016/CCAFSpbNutrient.pdf

Good points about SSNM Dr Kundu . How do you feel about the role of customised fertilizers  in fulfilling the objectives of SSNM . Hope to get back your another fascinating response. 

Very nice response Pierlorenzo . But , we will be distinctly limited by the fact that how to tailor the fretilizer requirement of the crop in the absence of soil fertility constraints . in this case , we need to have precise nutrient requirement of the crop , so that such requiremnts could be customised ?.

Another point , you raised to improve the CEC of the soil . infact , increase in CEC other  than soil mineralogy , very often does not contribute to permanent improvements in nutrient-use efficiency . I  think , this  is what you exactly mean ?

I believe this technology will revolutionize the agricultural production in India. However, two major hurdles need to be surmounted in near future: 1. Miniaturization of equipment for developing field variograms keeping India's small scale holdings in mind. 2. Variable applicators suitable for small holdings. If significant progress is not made in near future, we cannot benefit from the advantages of customized fertilizers.

Customised fertilizers will play lead role in customising the nutrient requirement of any crop in years to come but basis of this has to be precisely worked out. 

Dr. Kalidasu, let us know more about utility of customised fertilizers in meeting the nutrient requirement of small holding farmers.

Yes coated fertilizers are now on the way to slow release regime for getting nutrient management

Thanks Pierlorenzo , i got it  . No doubt, soils poor in fertility status will respond more emphatically than soils having comparatively higher levels of availbale supply of different nutrients. 

Thanks Dr Kalidasu for adding your response and taking this meaningful discussion further. So , unless the domestication of development of variogram percolates down to small holding farmers , and then next challenge would be to link it with  variable rate application technique. My bigger question is , how will you arrive at levels of variable rate application of fertilizers? 

Dr Ashwani Kumar , discussion is on customised fertilisers vis-a-vis SSNM..?

Thanks Abhishek for very interesting piece of information , along with some pertinent links on the subject .  We surely need to be on guard  to justify the large scale use of customised fertilizers while comparing with the conventional fertilizers . Prior to that , we need to delineate the easy to handle BASIS for developing customised fertilizers. I am yet to get  the logical answer for this very basic question .   

Very pertinent question by Dr. Kumar ans well answered by different scientists. Customized fertilizers are very good development to address multi nutritional deficiencies, as Dr. kumar pointed out. Yes, basis for such fertilizers are still to be defined.  A customized fertilizer may not meet all the requirements of nutrients being addressed on a particular soil. The recipe may not be the same as exact deficiencies are present. It mean that even then we have to add straight fertilizer to address the remaining deficit.  

Very impressive feedback Dr Nazir , i am impressed  with your argument . If soil fertility-based spatial variogram is taken as the base , how can you then address the problem of small er fileds ?. Or shall we disgnate one village or block as unit for developing spatial variogram , and then customizing the nutrient requirement , different land uses come into picture , this will not be uniform....that you can execute customised fertilizer application ...?

Dr. Kumar! Apparently, the situation is complex. One of our studies we took one village as a unit for fertility mapping. However, you can imagine the variation of soil fertility within one village.  Computer has now made the things some what workable. You can create data base for soil fertility, firstly by villages and then by farmers. 

Yes, different land uses could also disturb the soil fertility. Some pretested models may be another solution. Finally, we have to compromise some where. 

Dr Srivastava, the best way of developing customised fertilizers is the development of soil fertility variogram under a given land use and then develop the diagnostic values to delineate what kind of nutrient deficiencies are occuring in a given location to customise the fertilization program. This is what I feel. If any one has difference of  opinion, please respond.

Dr Deka , nice response , that could be one  viable option . As  Dr Kalidasu expressed miniaturisation of GIS for developing filed variogram and domestication in variable rate fertilizer applicator need to be addressed. And i agree with Dr Nazir , its so complex . if we are using customised fertilizers , we should be in a position of customise fertilizatioj program.   

Costomised fertilizers are equally effective through fertigation coupled with variable rate applicator including SSNM. But, you are right , how to arrive at which nutrient in which part of field is low or high to design variable rate application?

Let us discuss,  how can we customise fertilization according to fertility constraints of major soi types, if the customised fertilizer application for each and every small field is so complex as expressed by  Dr Nazir.

Yes Dr Deka , you have raised a good issue ,  i am  also of the same opinion. 

We should also consider points raised by Brignoli and discuss integrated nutrient management as a whole for nutrient supply and enhancing soil fertility.

With respect Anoop Kumar Srivastava,

Responding to your question, I strongly agree that we are in earnest attention to everything in implementing an application, despite being quite proven useful in the agricultural sector, that at least we should consider include cost, time, soil conditions, weather conditions, and applied technology and the ability of executing power. This is not due to the agricultural sector is very vulnerable to any change of the factors that influence it and in general farmers are groups of people who are very limited and highly dependent on their crops.

Greetings,

Teguh Juniarto

Dr Srivastava, customised  fertilization strategy we need to develop according to nutritional behavior of different crops even if they are grown on same soil type. Such practical attitude is needed to develop the rationale of fertilizer use. 

Dear Anoop Kumar ,

Macro and Micro combination of Multi-Nutrient forms is called customized Fertilizers,

Fertilizers Just Boost the nutrients From the soil to Plantations ,

But after the Crop  must give good Natural vegetation to the soil .

This Nutrient Management

strategy is always Type of Crop and Crop Rotation .

the customized nutrients is a better option for plants better growth, but the selection of respective conc of nutrients is a tough job. It may envolves the analysis of soil so that one can know that weather we need more nutrients or not, especially for the micro nutirents. It also depends on plant to plant. 

I agree with prof. Pierlorenzo Brignoli. 

Dear Ponkumar and Husain , thanks for your responses. I do agree customised fertilizer is like tailor made fertilizer source developed for selected crop in a specific region and a defined  soil  type coupled with water quality  . Use of customised fertilizers are already in practice for crops like wheat , paddy, sugarcane, mentha, potato, etc..

No doubt doubt about that , customised fertilizer ( combination of both macro-and micornutrients )is far more better and effective , provided fertilizers are ably customised keeping mind the crop requirement .  you are very much on line , Husain. But , such requireemnts will vary as per crop requirement , and we need to find out ways and means to address this most complex issue. 

Good elaboration provided by Dr. Kumar.

Thanks for appreciating Dr Nazir . i was wondering , while developing customised fertilizers with regard to specific  crop , dont you feel , some crops are very vulnerable to certain group of nutrients when applied together , they express distinct toxicity symptoms, especially with combination of Fe, Mn, Zn , and B.  How does , such cares are taken while commercially recommending  different  customised fertilizers? 

Dear Anoop Kumar

Please You Can Visit the Link and have lot of information,

https://edis.ifas.ufl.edu/pdffiles/SS/SS61600.pdf

Thanks Ponkumar , unfortunately , i do not see much relevant  information with the subject area of the question  on the suggested link. 

yes prof, you have very clearly elaborated the answer, but If we see, different soils have different pH, 2ndly if we want to plant one kind of vegetable and next time other one so it will be quite difficult to analyze the soil and check the amount of nutrients. As we will give some fertilizers to enhance its yield.

How we will cop with this situation?

Very nice counter response Husain . You are very much right . On a soil , if you grow three crops , there is no doubt , after harvesting of each crop , you analyse the soil sample , you will different nutrients level in the soil , This is where,  real customization in our fertilization program comes into picture , and this is where,  whole art of fertilization takes prime significance in terms of nutrient use efficiency vis-a-vis productivity  

We need to customise fertilizer application  as per then existing residual and cumulative effects of fertilizers ?

We apply hundred times more fertilizers and pollute waters where there is no need for the same Where we lack is precise soil analysis a good department of soil chemistry Soil science and soil chemistry does not come as a department in many universities and has low priority even in advanced countries. Soil science Plant nutrition make the most of the studies in crop physiology but we put more emphasis on agronomy than soil science. Plants need site specific nutrient regime which will vary with site its pH soil composition and cropping pattern which has to be studied in detail to make a suggestion. SOIL HEALTH CARD  as suggested by our beloved PM and promoted  is answer to these problems and site specific fertilization is need of the hour. Nutrient availability is very specific e.g. Phosphate nutrition phosphate may be available in soil but not available in the form which plants can use. Hence phosphate solubilizing bacteria could make this nutrient available. Most of the soils of India are not Potassium deficient but its provided in most of the cases. Nitrogen is more required in organic form while its provided as nitrates which is great pollutant of ground water. FYM is need of the hour but most of the cowdung is used for fuel

I support the author that site specific studies are need for providing nutrition to the plants.  

Thanks so  much Dr Ashwani Kumar for analysing the whole scenario so impressively . And , i am in total agreement with your comments . This is the factual scenario . Customising fertilization according to nutrient stock ( available or total ) of the soil is , therefore utmost important . And , this approach should be in a position to address every small field , so that , such kind of technology intervention percolates to last end users. Customising doesnt mean , let us use only the conventionally available customised fertilizers , crop needs can be customised at our own level.  

Thanks Dr Anil Kumar for comprehensively satisfying response. On a larger perspective  , we need very strong principles of customisation for synchronising the soils ability to supply different nutrient and crop nutrient demand ...i agree with you ..

Dr Deka , so sorry , i missed your response to respond. . Yes , you are very much right , we need to take into consideration the residual and cumulative effects of fertilizers as well , this is what the exact meaning of customisation advocates..Same opinion was earlier expressed by Husain . possibly , then only , the objectives of nutrient -use-efficiency will be meted out ..as rightly expressed by Dr Anil Kumar.

Please find a very interesting paper on your question, i was part of Customized fertilizer development in western UP, with Tata Chemicals Ltd.

Thanks Dr Singh ,. Very interesting PDF and equally informative. I liked that concluding remarks that life cycle assessment of specific nutrients used in customised fertilizers needs to be studied with respect to specific test crop. Kudos Dr Kalra. 

Dear Dr Anoop you can see more publication on Dr Kalra Profile...

https://www.researchgate.net/profile/Naveen_Kalra3 

Anoop Sir,

Customised Fertilizers are produced normally based on fast moving complex fertilizers in the market.  Examples are 17:17:17, 20:20:0, 15:15:15, and etc.,.  The site specific nutrient management can only be done by combination of straight and complex fertilizers (NPK).  However, on a large area basis the CGF can also be used for specific grade of fertilizer.  Majority of CGFs have the capacity of 10 TPH.  In a day almost 200 tons will be produced.  At least this much quantity indent must be there for production of CGF with specific grade for managing the site specific deficiency./ requirement.  Though it is possible to produce crop specific and soil specific CGF, it is not advisible, as the farmers grow different crops and use different fertilizers.  One can not force them to use CGFs.  How ever CGFs have great advantage over complex fertilizers. They can be produced at low cost.  They are more preferred over complex as the straight fertilizers are coated (through melting) one over the other at  nano (liquid-semi solid) level . All the three NPK nutrients are available in one granule.  It is possible to use affected fertilizers in production of CGFs.  Decentralization to District level is possible for establishment of CGF units. So, the future fertilizer scenario will be CGFs with few marketable grades, +Urea and MOP. Generalized grade CGF can be applied as a basal dose  to any crop and top dressing can be done by Urea and MOP.

Soil application CGFs are not suitable for Fertigation and Hydroponics.  However, Customised mixing of Water soluble NPK fertilizers with or with out micro-nutrients can be used for the above, besides spray.  In-spite of availability of these in the market, only few farmers use those, due to high cost. Moreover 10-15 percent of  nutrient requirement of the crop can be fulfilled by spray supplement.  Fertigation can be used in place of soil application.

Thats a point Dr Rajakumar looking at the kind of different crops being grown , customised  could find utility , but on a broader scale at the block level , or district level or depending upon major soil types , customised fertilizers can be developed , or else customised fertilization can be exercised. With unprecedented  popularisation in fertigation , customised fertilization is increasingly  finding large scale application. And , above all , the concept site specific nutrient management  , i think customised fertilizer application hold some promise , other wide , you will implementing the same age old practice of umbrella kind of fertilizer application , leaving some fields under-fertilized , while others over-fertilized. 

Abhishek for appreciating words. I am equally impressed with you as well . There is absolutely no two opinions about that . Can we pick up some more success stories of customised fertlizers finding their utility in field , irrespective of crops. And, more importantly , the procedural steps involved in developing the customised fertilizers based on filed variability in soil fertility of various dimenstions , probably carry more weightage in the context of whole discussion . 

Very good point Dr Singh , why cant we develop customised fertilizers as foliar spray . why is there minimum efforts to customise the fertilization as foliar nutrition ?Is it better ease of adjustment or soil fertility - based customisation is more crop responsive ?

Dr Anil yes  foliar nutrition in customized fertilizer application is very effective way of application of nutrient, already crop specific customized foliar products are available in the market but by foliar way we can only supplement few deficient or necessary amount of nutrients only. Foliar nutrition application is not intended for replacement for soil based nutrient application; it has to be added in addition to optimum fertiliser application to soil. 

we can develop crop specific customized fertigation products for maximum yield with highest quality of produce, but only concern is that these kind of customization is always expensive.

In spite of developing the customized fertilizer we can promote blending concept with same nutrient composition for better utilization of nutrient use efficiency at very reasonable rate. This will also solve the problem of marginal and small hold farmers to address the soil and crop specific fertilizer recommendation.    

Thanks Dr Singh for uploading another very meaningful response , worth appreciating. you can surely customise the foliar application of nutrients but as said rightly , cannot be solution to soil -based customisation in fertilizer application . However , where is the origin of clues for customisation , its soil fertility constraints only . Sometimes , i feel , customisation goes both ways , tailoring fertilizer requirement of a crop  through grievances felt within soil , in form of constraints. So , eventually harness the greatest of productivity through exploiting upon the nexus between crop and soil..?

Customization of soil specific nutrient management has been relevant in soil fertility thru soil testing .Which itself answers our concern related to  soil and crop specific nutrient customization.So in my view its not different theory all together.

Ajit , thanks for your response. Actually , in perennial crops , very often , soil test values do not work in tandem with leaf analysis  values. And , we attach greater importance to leaf analyis -based constraints than soil test -based interpretation . Under such conditions, customisation based on foliar analysis is more useful , as usually adopted in all annual crops. 

Customized fertilizers being a multi nutrient carrier have proved best for achieving high nutrient use efficiency if applied through micro-irrigation system in open field or in protected cultivation or foliar spray systems. In India total requirement of fertilizers is 32 million ton annually including 7.8 million ton for horticulture crops. The requirement in particular for horticulture crops can be further reduced to 4 million ton if fertigation and foliar applications are adopted at large scale. Crop based fertilizers based on soil test are required to be customized for satisfying the crop’s nutritional needs, specific to its site, soil and stage. At this moment specific crop models to determine the optimal grades of customized fertilizer are lacking. In India, neem coated urea has been customized and made available to farmers, will you keep this in customized fertilizer category.

Comprehensive response dr Malhotra . I do agree with your comments. Unfortunately customisation is only possible at certain level only , thereafter i do not think , you can customise plant nutrient requirement , addressing each and every filed in a given area .  We have so much of variation in soil fertility level , even within the same field , we need to customise the fertilization . in a way , neem coated urea , we can say customised( since it acters to the needs where there is greater leaching losses or denitrification rate )  , but in strict sense , i dont think so . 

Your another very good point was crop models .These models undergo frequent changes according to soil fertlity level , which is again highly variable . So such crop models are effective only at certain levels , say soil sub-group level or great group level taxonomically . Otherwise , broadly if you want , categorise soils into certain broad groups with minimum set of soil properties , and then effect customisation ...

Let me flag off another very important issue. We often claim , different nutrients have diverse dynamics when traced across growth stages. How can we customise fertilization with different nutrients at different growth stages of a crop ..?

Abhishek thank you for further update on the discussion , which is so productive and informative , digging out every piece of scientific information on the issue , so appreciative of you . we do need customisation in our fertilization strategy based on soil type and crop type ..matching both the needs is a stupendous task . ?And  when differential nutrient requirements at crop phenophases further take their stand in whole sequence of balanced fertilization , our task becomes doubly difficult . Why have i raised this issue , all the nutrients are not required at all growth stages , and this will vary distinctively with crop . under such condition , are we prepared to address such an  issue , more than exception ..?

That's a point how to customize ferlilization at different growth stages

Good explanation Anoop. 

Thanks Dr Malhotra.  Good point raised by Dr Deka . Infact,  that is the need of our efforts dedicated towards customised fertilization . And such efforts need to be dynamic as per nutrient demand at different critical growth stages.  Can we customise the fertilizer application at different growth stages based on the nutrient composition of index plant parts at different growth stages..?

Thanks Anoop, you have tempted us to brain storm. There is no doubt, production and utilization of customized fertilizers will ensure improved fertilizer use efficiency. The basic principle lying behind customized fertilizer will also satisfy site specific nutritional demand of crop, soil at various stages of plant growth and development. It has also been cited that it will create a new virtual source of nutrients, implying from the existing quantity of Urea, A.S, DAP, MOP, SSP available & consumed in India. Micronutrients are also added with the granulated NPK fertilizer so that the plants can absorb the micronutrient along with macronutrient which prevents nutrient deficiency in food crops. But we ignore the added advantage of improved distribution & availability of fertilizer apart from increase in the agricultural produce output. But the focal point where we need to think is that how best we can tailor fertilizers which are compatible with existing farmers system and are accepted by the farmers easily.

Dr Malhotra, you are right but our biggest constraint is how to tailor fertilizer requirement at different growth stages through customized fertilizers. For one time application it’s ok, but adjusting through growth period is a real challenge you must admit that.

I agree with you Sikha, I do not want to repeat those points again which have been discussed by other participants. Mr. Pierlorenzo Brignoli has already given the most appropriate explanation here. I suggest to consider those points. Regards

Dr Malhotra,  in a way you are right but nowadays some commercially well known customized fertilizers are occupying centre stage in fertilizer use in cereal crops.  Such efforts are missing in fruit crops. Yes I do agree about the role of customized fertilizers in soilless culture but here also we need customization as per different growth stages as highlighted by Dr Srivastava which is a correct strategy with regards to precision agriculture.

Customization in fertilization basically means , lets add only those nutrients , which are required by a crop , either at different growth stages or in an entire growing period . How we do it , it is our smartness . You can do it either by taking individual fertilizers and fine tune them with regard to crop requirement at a given growth stage , or alternatively , you use the commercially prepared complex fertilizer suiting to specific crop ( For example rice , wheat , maize  etc). In lieu of these developments , the concepts like 4R Nutrient Stewardship Concept , Site Specific Nutrient Management  were brought in . 

Thanks Abhishek for yet another beautifully addressed response. You are so indispensable to such discussion . 

Customized Fertilizers (CFs) are unique, ready-to-use granulated fertilizers designed to optimize the use of nutrients in order to obtain quality crops, high farm productivity and profitability. The Government of India designated Customized Fertilizers as a separate category under the Fertilizer Control Order, effective from 2008. NFCL is the first company in India to receive official approval for Customized Fertilizers from the Department of Agriculture and Cooperation, the Ministry of Agriculture and the Government of India for manufacture and marketing. Specific guidelines on the process of approving Customized Fertilizer formulations manufactured for sale have been issued by the Government of India. This process includes the selection of a targeted geographical location/cluster; collection of agro-ecological and socio-economic information about the location/ cluster; selection of the crop or cropping system; collection of soil samples, lab analysis, and identification of limiting nutrients and availability status; derivation of Customized Fertilizer (CF) formulations using crop models and decision support systems; trial manufacture of CF formulations; conducting multi-location on-farm trials at specific geographical locations with variable rates; compilation of information and finalization of optimum rates; obtaining official approval from the Government of India; market promotion; and manufacturing and marketing of officially  approved CFs. The CF development process is complex, but the end results are very promising.

 4R is the centre stage of customised fertilization programme.  Right fertilizer placement is one of the 4Rs of an effective nutrient stewardship system and should be combined with considerations for the right fertilizer source, rate, and timing. Fertilizer placement decisions depend on mobility of applied nutrients in the soil and the depth and distribution of the crop’s root system. Various methods are used to apply fertilizers to horticultural crops, including broadcasting, banding, fertigation, foliar application, and microinjection. Generally, the most appropriate method for any crop increases productivity and profitability and improves fertilizer use efficiency but varies depending on the nutrient element, fertilizer source, soil characteristics, cultural practices, stage of crop development, weather conditions, and farming enterprise constraints. Comparisons among application methods are available for many crops and provide useful information for improving fertilizer placement practices, but many practical questions such as how fertilizer source and availability are affected by irrigation interactions or whether there are ways to manage crop roots for more effective nutrient uptake still remain.( Source : David Bryla, 2011 Hortechnology 21: 674-680)

Find below an interesting PDf for further reading friends, hope you will like it . 

4R Stewardship is now we are talking. The central theme of this concept earlier also existed regardless of crops. What’s the new in it?

I agree with you Dr Deka . The very success of any effective nutrient management program revolves around the 4Rs only , whether its past , or present or even in future , since these are basic premises on which plant nutrition acts.  We need to see , what kind of developments have taken place since then to optimise the nutrient use spatially or temporally . In recent past , the introduction of concept like Site Specific nutrient Management has produced some distinctive dividends in not only fertilizer savings , but elevated the fertilizer-use-efficiency as well , besides tailoring the fertilizer requirement considering the spatial variability in soil fertility.  This is how , spatial tools have brought changes in nutrient use..popularly , we call it precision agriculture ..

Many of the commercially available customized fertilizers do not have the ability to be customized according to existing soil fertility constraints of perennial crops. Whether customization will differ for annual crops against perennial crops.

Research efforts need to be more systematic with regard to fertigation in different options. Nutrient and water partitioning studies across crop critical growth stages have to be the take off point. Interlinking these studies later with conventional fertiliser types to domesticate them into efficient fertigation prospect need to be gradually fine-tuned.

Customised fertiliser use, especially, in fruit crops must find a definite attempt in trials so that it tunes with the nutrient demand. 

Please read following publication:

Article Fertiliser Requirement of Indian Horticulture An Analysis

Dr. Srivastava,

IISS has come out with very nice STCR equations from across India. So the discussion and recommendation stage has already completed. The role of science is over now.

The lacking part is implementation. 

The question should rather be like "Can Indian farmers adopt customized fertilization based on soil testing?"

Regards,

MKD

Dr Srivastava, let the discussion continue and it should not be restricted to Indian context. Lets take the views of other esteemed researchers. Some researchers could join at later stages. I appreciate the views of Dr Malhotra.

Thanks Dr Malhotra  fro interesting feedback . We are missing some serious efforts with regard to fertilizer recommendation in perennial crops . And , we have not good experience with STCR , especially at levels of targeted yields  . Therefore , before , we pass on such recommendation , we should restrain in giving any sweeping statement .

Lets invite our other colleagues to interact and share their experiences , or any other methodology to arrive at fertilizer prescriptions at higher targeted yields , especially in perennial crops.  

My bigger question to you Dr Srivastava and colleagues is how long recommended doses of fertilizer remains valid in field. my experience says RDF we do not change some times for decades. How does STCR address these issues ? 

We have been debating this issue quite frequently . If a RDF  for any crop is worked out , it is given to the different state agencies for implementation  , and to your surprise , there is hardly any attempt whatsoever to  test whether or not,  a RDF given 20 years back , is still functional on the field ..?

If you are having a robust and dynamic calibration equation featuring soil test value and yield response for fertilizer prescriptions , STCR can address this issue of revising RDF any time , since it is based on nearly real time basis through periodical soil test basis.  But , such facility may not be avaialble to small and marginal farmers..?

How can we customise the fertilizer application in small and marginal farmers field and derive maximum fertilizer use efficiency. Tools too customize are surely missing. Customization should not be in ready made form.  

This is a very good issue raised by Dr Deka. Lets ask Dr Malhotra to discuss this issue. 

Dr. Shirgure, I am sorry I could not see your request, it escaped from my notice, anyway i am writing my views here. Horticultural crops adopted largely by small and marginal farmers have now attained a status, parallel to not only field crops, but stake strong claim of offering nutritional security, thereby, cutting the unnecessary load on consumption of cereals. However raising productivity of horticultural crops is still a constraint. One of the prime reasons is the abysmal use of fertilizers, hardly 10% of total fertilizer use is diverted towards the share of horticultural crops. Of different fertilizers, liquid fertilizers are again a special class of fertilizers, hold very strong promise in protected cultivation, hydroponic/aeroponic or even open field hydroponic for perennial fruit crops. The liquid fertilizers, as special class of fertilizers provide an enormous possibility of tailoring nutrient use across critical growth stages, a pre-requisite for better nutrient-use-efficiency. Customized fertilization/fertigation is another potential reality, besides its suitability in site specific nutrient managements. 

Dr Malhotra , i fully agree with your all comments , they are so apt to your feedback , especially with regard to small and marginal farmers. Customised fertilizers hold so much pf promise to customise the fertilization programme. Yes, customised fertigation is the cal of the day ...

Dr Malhotra very good response. Such custamisation is most suitable to low income farmers, fertigation in that regard is a way forward approach . 

There is a need to have a decision support to arrive at different types of customization in fertilization according to spatial variability in  availability of different nutrients. fertigation linked to variable rate application of fertilizers is another way forward....

Yes, customized fertilization will always boost the better effectiveness of fertilizers on the principles of SSNM. What is your opinion whether SSNM suits to small land holdings ?  

The liquid fertilizers, as special class of fertilizers provide an enormous   possibility of tailoring nutrient use across critical growth stages, a pre-requisite for better nutrient-use-efficiency. Customized fertilization/  fertigation is another potential reality, besides its suitability in site specific nutrient managements. In this background, these issues have been addressed in this review published very recently.

Please see the link:

https://www.researchgate.net/publication/306092504_Water_Soluble_Fertilizers_in_Horticultural_Crops_-_An_appraisal

Article Water Soluble Fertilizers in Horticultural Crops – An appraisal.

Yes, Dr. Srivastava. Customized fertilization can definitely compliment the site-specific nutrient management strategy.

Customized fertilizer are further needed to be customized on the basis of either soil type or cropping system.