Why am I saying this , there is possibly a valid reason to think so. If we consider the active pool of nutrients available to plants in a given timeframe , then why do we use the concept of nutrient-use -efficiency to adjust the recommended doses of fertilizer as per nature of crop , annual or perennial. I understand its such a complex exercise , but surely deserves  due attention . I will take up different issues one by one as the  discussion prolongs  , dear friends.

Dear Prof,

I think we need to take nutrient mobility into consideration. Perhaps those who do this instinctively are the ones with green fingers. They are the PLANT artists, not just scientists.  (It's not a topic where I have expertise, but I surely have interest. Thanks.)

It is a very practical question. In that case there will be two different mobilities, one within soil another within plant and both will never act together. 

How do you define nutrient mobility with regard to constraints and how do you address such great diversity in nutrient mobility in order to achieve improved use efficiency.

The question is broad and needs to be accurate answers, but in general the plant needs elements in all stages of growth, but it needs a certain element in the post depends on the type and the actual need at this stage, and the process of fertilization if they were not in accordance with the pre-study of the need for the plant will lead to an example of increase fruits growth on quality, and not all the fertilizer that lead to increased production quality improvement.

Dear Dr. Anoop, interesting question as usual.  Understanding which nutrients/elements are mobile or immobile within plants is helpful in diagnosing deficiency symptoms, which is also useful in soils. After nutrients are inside plants, they are transported to where they are required, normally to growing points. Once nutrients are incorporated plants, some elements can be immobile while others can be remobilized inside plants. Immobile elements basically are locked in place and that is where they remain, while those which can be mobilized again may leave their original place and move to areas of where they are needed greatly.

Because immobile elements do not easily move within the plant, they show up in new growth when deficiency symptoms occur. For example, NPK are mobile within plants, while Ca and sulfur are immobile. In case of micro-nutrients, molybdenum is mobile within plants, but boron not. The mobility and immobility essential elements are governed by their specific role within plants. I think the participation of plant physiologist s is very important to get more scientific explanations and bring the attention of the participants in the discussion.

Dear all, I am participating in ResearchGate discussions almost after three weeks due to my Annual leave. As usual Dr. Anoop Kumar has placed an excellent question which will provide a chance for all of us to brainstorm and share our knowledge and experience on the subject.

Nutrient mobility is very important subject and needed to be understood well. Yes, it takes place in soil as well as within the plant. It is peculiar to nutrients, however some of the factors like soil texture + OM and CEC affect nutrient mobility in soil. The nutrient radii role in mobility is still hot topic of research and may need further investigations. May be any of researchers have done work on this aspect..

However, nutrient mobility is very important from fertilizer application but mostly not considered in our precipices. Dr. Anoop has rightly pointed out this deficiency.  

Hi, your question needs a bit more elaboration in terms of what you mean by mobility. if you mean mobility by movement from old plant parts to new plant parts, we studied that nutrient mobility in plants is mostly a nutrient function rather than crop-specific. For example, nitrogen is highly mobile while calcium is not. As a result, we see some nutrient deficiencies in old plant parts (e.g. N) while others in newly developing plant parts (e.g. Ca). There may be some exceptions due to specific plant adaptations but I am not very familiar about them. 

If you mean mobility by the ability of nutrients to be absorbed by plant parts other than roots, which I believe is an important consideration for recommending the method of application, then most cation-based nutrients can be effectively recommended for foliage application provided the environmental aspects are taken care for optimal absorption (e.g. plant surface wax, cuticle thickness,wind, temperature etc). 

Mobility of a nutrient has different implications when we delineate the function within soil versus within plant as very rightly highlighted by Dr Nazir. Prabhakar let me pose another counter question . I agree with you to some extent about the mobility of a nutrient is mostly a nutrient specific rather than crop specific . If this is the case  , why do we try to tailor the crop nutrient requirement a per soil active  nutrient pool ( Intensity level). Let me cite another example , phosphorous , a nutrient so immobile within the soil ( Acidic , alkaline or calcareous  in nature ) , but its mobility is hardly influenced by within the plant . Do you feel , the mobility of phosphorous( As an example) within the plant  will be of same magnitude to that  on  soils having either  calcareousness , acidity or any other form of alkalinity?  As Dr Getachew expresses , and I feel strongly so,  about the mobility and immobility of nutrient is governed by  the specific function of different nutrients within the plant. I invite my colleagues to respond please , its getting very interesting . On the other hand , you simply cannot overlook the mobility of a nutrient either within soil or within a plant as endorsed by Dr Miranda.

Hi Dr Anoop, we simply consider active soil nutrient pool since only that part of the entire nutrient content of the soil is readily available to plants within the timescales that plants can get benefit from. As per your point on phosphorus, I believe this point applies to many other nutrients as well. We simply dont need to apply nutrients to soil but rather directly to plants; but we have been doing it for the sake of convenience (e.g. slow release over the time period of crop as against repeated foliar applications) and tradition.

Dr. Anoop, you raised very pertinent comments about the mobility of nutrients in the soil and within the plant. I think, mobility of nutrients in the soil should not be confused or mixed up with the mobility of nutrients within plants, which is physiological process. In fact, mobility and availability of P in the soil solution is a prerequisite for specific function of each nutrient inside plants. For instance, in contrast to N, P  is the most immobile nutrient  in the soil because of its sorption at higher and low pH soils.

Why am I saying this , there is possibly a valid reason to think so. If we consider the active pool of nutrients available to plants in a given timeframe , then why do we use the concept of nutrient-use -efficiency to adjust the recommended doses of fertilizer as per nature of crop , annual or perennial. I understand its such a complex exercise , but surely deserves  due attention . I will take up different issues one by one as the  discussion prolongs  , dear friends.

Yes, if mobility of nutrient is independent of plant type, do you feel mobility of nutrient is a functionality of plant functions. As I said earlier how should I address two different dynamics of nutrients one in soil different to another in plant. Dr Gatachew, Nazir Prabhakar if you can provide any supplement please.

Sikha Deka,

Thank you for your comments. I agree that nutrient mobility is in soil as well in plant. I think that Dr. Anoop Kumar is now speaking of mobility in plants. This mobility is specific to nutrients which behave almost similarly in all plants. I am not sure that it is functionality of plant functions because I have not read any work on this aspect. May be some one point out or upload his findings.

Regarding addressing of dynamics of nutrients in soil and plant can be in two important ways. Inorganic Nitrogen, especially Nitrates and Nitrites, is the most  dynamic nutrient in soil causing leaching losses on one side and pollution of groundwater on the other side. It can be addressed by application of N in split doses, slow release N fertilizers and application of organic matter. Problem of mobility in plants can be addressed by applying appropriate quantities of the immobile nutrient so that deficiencies may not cause growth and yield losses because growing tissues mostly suffer.

However, we should become more logical by producing data on this aspect, the fact Dr. Anoop Kumar is pointing out and the core issue of discussion.       

Thanks Dr Nazir for excellent explanation and steering the discussion further.  Dr Nazir my point of contention was , if immobility or mobility of different essential nutrients are least varying amongst different plant species , why do the magnitude of nutrient- use- efficiency varying so much from one plant species to another ?. And why do we choose some nutrients through foliar feeding and others through  soil application ?. For example boron , it is such a nutrient which has mobility both ways through xylem as well as phloem.

Dr. Anoop, you raised again good point. Plant nutrient use efficiency is inherently complex, because each step including nutrient uptake, translocation, assimilation, and remobilization is governed by multiple interacting genetic and environmental factors. Identification of traits such as nutrient absorption, transportation/translocation, utilization, and mobilization in plant cultivars can greatly enhance nutrient use efficiency. In regards nutrient application, each nutrient may vary with the amount applied, solubility and efficacy of them. As micronutrients are needed in small quantities, application method may influence the uptake of them in the required proportion. Whether a certain micronutrient is quick or slow acting is the other factor. Some micronutrients like Cu and Zn are formulated separately or with NPK and other secondary nutrients. I think this topic is very wide and complex.

Dr Getachew nice to listen your very thought provoking response  again . I agree with you . if you take nutrient absorption , it is a nature of root cell wall featuring the presence of intensity of specific nutrient transporters; if it is nutrient translocation from xylem to phloem or vice-versa, it is the plants metabolic efficiency  in terms of differential nutrient sink demand ; and finally the production of dry matter ( Annual growth plus growth of economic parts of plants ) , it is the genetic traits expressed at various levels of plant functionality .In these  functions , to what an extent , the mobility of different nutrients ( Could be governed by ionic radii , water hydration energy , ionic composition of transpiration stream etc etc ...) affect the use efficiency vis-a-vis crop performance . This is my core issue.

Dr. Anoop Kumar! The valid points you raised have very well answered by Dr. Agegnehu. His explanations are appreciable. Regarding your point that why we choose application of some nutrients through soil and some through foliar, this depends upon quantities to be applied. Because macro and secondary nutrients are to be applied in larger quantities, therefore soil application mode is chosen. Foliar application cannot meet the demand of plants. Micro nutrients can either be applied or supplemented through foliar sprays. Of course, some times little quantities of macro nutrients can be applied through foliar sprays to remove deficiency immediately, if appearing. 

Dr Nazir,  let me appreciate both ,  you  and Dr Getachew for making this discussion really so logically understood through some scientific principles. You mean,  selection of nutrients and their mode of application are  largely governed by amount of those nutrients required by the plants , not by the nature and properties of those nutrients whether or not they will be effectively absorbed , translocated and partitioned within the plant . 

From the discussion can we conclude some nutrients have different mobility in soil while some are equally immobile in plants. Question comes how strike a balance between two to observe their best metabolic usage.

It very often strikes me friends . Do  such differential mobility of nutrients ( Please see the relevant PDF enclosed) has any relation with their uptake ?. Shall we attempt to match the fertilizer application with nutrient uptake ?.   Whether nutrient mobility soil  affects how shall we fertilize a plant . For example , we frequently practice broadcasting N-fertilizers , while P and K-fertilizers , we prefer to  do band placement ( Relevant PDF enclosed). What is the basis of such differential strategies in fertilizer application , it is simply the variation in nutrient  mobility  within the soil  , which dictates such changes.

Very impressive argument . How do we explain an antagonistic effects  on uptake and mobility in view of  these discussion points? 

Sulphur has limited mobility in plants and its metabolism is inextricably associated with that of Nitrogen. Because of this  a fertilizer  ratio of 3 for  N:S applications is  recommended to obtain a suitable N:S ratio in wheat grain (Wooding A.R., Kavale S., Wilson A.J., Stoddard E.L. 2000. Effects of nitrogen and sulfur fertilization on commercial-scale wheat quality and mixing requirements: Cereal Chem. 77 (6): 791-797)

Good information addition by Ron to explain further the nutrient mobility. It means that mobility of one nutrient may be affected by another. This is very important point to be considered.

Thanks Amare and Ron for adding some new information . This is what I am stressing and my other colleagues Dr Nazir. There has to be nutrient recommendation module s for different set of nutrients , depending upon their mobility , since some nutrients are simply charged cations like K, Fe, Mn, Cu, Zn etc , while others are associated with their oxides like S04,M004,P04  etc , surely they will move within soil and within plant through different routes. Examining  relation amongst the nutrients is while important , type of crops will further influence such relation. Fro example , the relation between N and K , in cereals they complement , while in fruits , after certain level , they will start competing with each other. And under such conditions, we start monitoring their efficiency through their ratio , may be dual ratio , or amalgated nutrient ratio.

the question by Dr. Haileselassie is important, which was raised, I think,  by Dr. Annop previously and discussed in depth. The presence of a particular nutrient in excess or low amount can have significant influence in uptake of nutrients. Nutrient ratios can also be informative. For instance, a 10:1 ratio of N:P is considered optimum for many crops, which means a large discrepancy in this range may affect nutrient uptake and mobility within plants. Because both internal mobility is depend on external availability and uptake of nutrients by plants. DRIS indexes also help show which nutrient is most limiting though DRIS indexes have not yet been established for many crops. Sufficiency ranges are also available for most crops for each nutrient at various growth stages, even if they are unable to rank which nutrient is most limiting.

Yes Dr  Getachew I remember , we discussed this issue at length. I need  your feedback on first portion of my  todays supplement about the possible difference in efficacy of nutrients , ionic versus oxides  . This is very important in the context of whole discussion dear friend.

We often debate about the participation of root configuration in neutralizing the nutrient mobility. Nutrients  come directly  in contact with some nutrients ( called  Root interception ' ) as they grow .However , this only accounts for approximately 1- 2.5% of the total N, P, and K uptake by a  plant. Water  moves towards and into the root as the plant uses water  or transpires. This process, called Mass Flow   accounts for a substantial amount of nutrient movement towards the plant root, especially for the mobile nutrients such as NO3. Specifically, mass flow has been found to account for about 80% of N movement into the root system of a plant , yet only 5% of the more immobile P. Diffusion is the process where chemicals move from an area of high concentration to an area of low concentration. 

Nutrients vary greatly in their relative mobility within a soil. For example , nitrate ( NO3 -) is highly mobile , yet phosphate ( HPO4 -2 , H2PO4 - ) is relatively immobile. These differences are key to developing effective nutrient management programs, and explain why applying immobile nutrients such as P near the root system is important for optimum nutrient uptake. Subsequent modules will address each specific nutrient in more detail, with emphasis on factors affecting mobility, uptake, and fertilizers requirements.  

No one yet answered my question. Shall we consider nutrient mobility in soil or plant or mobility in both. What should be our strategy  to soil fertilization or crop fertilization. Very interesting issue you have initiated Dr Srivastava.

Ms Reyhaneh  very pertinent issues , you have brought into the whole discussion . I am leaving the first aprt of your question to my other colleagues to respond . But in your second  question , can you please further supplement , what were the parameters , you took for working out the coefficient of determination under Frendleuch , Temkin and  Langmuir equations  , so that the discussion finds some  solid direction .

Coefficient of determination can be worked out through bivariate or through multivariate correlation. Most important is which variable governs the variation in independent variable.

Nutrient mobility criterion within a plant while recommending the method of fertilizer application should not be consider because of all major nutrients are mobile while immobile nutrient are not use alone anywhere in the world, one another nutrients enhances and develops nutrient mobility. However in general agricultural practices for increasing of nutrients use efficiency the method of fertilizer application should be changed according soil and other factors.

Mr. Shah, you have given a new twist to whole discussion. Then how the method of  fertilizer application is dependent on nature of soil. Is it not nutrient mobility in soil.

Yes, method of fertilizer application addresses nutrient mobility in soil.

In relation to issue of nutrient mobility and efficiency there is some conundrum. That being that when we increase the mobility of nutrients be can also have a increase in their losses. Because of this we need a Goldilocks solution not too much not too little but jjust right.  The approach can include conventionally a use of spoon feeding the plants according to their needs but I believe we need a broader context. . If we look at this from a systematic viewpoint we want to engage the factors of mobility in the soil rather than a soil addition alone focus.

Chief among factors having broad nutrient impact is soil pH in most agricultural systems. this includes the very important issue of mobility of nutrients.

We are in a goldilocks situation about one third of the world tillable lands are alkaline and constrained by water and about one third are acid and constrained by infertility and about one third are Ok for the pH issues.

More than any other factor the use of amendment to adjust soil pH out of unsustainable levels should be the prime importance for our world agricultural system. This should focus on bringing the acid infertile soils to 5.7 pH via liming and the alkaline soils to 7.3 through practices to promote acidification such as sulfur and ammonium use. So many of our micronutrient issues and major element problems and toxicities are best addressed by addressing the core issue of pH adjustment which is intrinsically related to pH.

Even in highly technically advanced agricultural nations and institutions the continual need to pinpoint the soil pH and have it within an optimal range is large not applied or optimized. How many of the researchers and farmers understand and have pinpoint information on their soil pH and its variation within their fields yet pH has a overwhelming effect on soil nutrient mobility and is the first step to a Goldilocks soil (lution).

Yes, Dr. Paul, soil pH is the basic factor in plant nutrition and the whole building is constructed on this foundation. However, the problem is permanently changing soil pH and the factors causing natural development of pH in an area. The buffering capacity of soil and the climatic factors operative in the area do not allow major permanent pH changes. Of course short lived changes are possible due to liming or gypsum application in acidic and alkaline soils respectively. It means that liming and gypsum application should be made a part of soil fertilization. But this cannot be done through fertigation and we have to apply these amendments on annual basis. 

Interesting Dr Hepperly and Dr Nazir . There are two parts of your response as I can understand. Soil pH is absolutely necessary to keep an eye on  acidity , salinity or possible sodicity development . And nutrient mobility is likewise arrested by acidity with respect to phosphorous , zinc,boron , molybdenum ; by salinity/sodicity  with respect to nutrients like phosphorous, iron , manganese , zinc . Accordingly , the fertilizer recommendation will be affected  . The second part is , how to adjust the fertilizer recommendation , especially based on nutrient -use -efficiency in such given scenario .  Do we need to develop some correction factor , as we use in case of fertilizer recommendation through conventional  basin application versus fertigation .

From personal experience has been that drastic pH changes are found within areas of fields and even within a single plant. Good challenge and constant constraint. 

The use of hydrangea is biological litmus which can reveal pH differences within both the field and the plant. With modern assay technology the ability to resolve these issues are in our hands. In my experimental station work I used the sorghum plant as a biological detector becoming familiar with the acid and alkaline reaction and correcting according. In respect to the issues many of nutrient issues are resolved when the pH is within an optimized range.

From an agriculture production aspect we do not get high economic yields generally unless we can generate optimized results over all the fields.

With this being said I also consider the targeted application of micronutrients according to problems and issues highly effective. If we look at mobility and nutrients the Iron situation is very compelling where almost never is the Iron lacking in the soil per se but the interference of alkalinity, carbonation carbonates, salts are the underlying factor. While dicots address the alkalinity by producing organic acids secreted into the rhizosphere the grass apparently have a very different mechanism in that where a plant like soybean show Iron chlorosis in the same environment the maize plant will likely be Zinc deficient.

When pH is addressed both of these issues can be much less problematic. In the Iron chlorosis reign as in soybean the use of a grass cover that takes up nitrates and has more effective siderphores can when interplanted early although more Iron to be mobilized for the legume give control of chlorosis on soybean for example. Even when we have ability to apply micronutrients to the foliage many times these wlll not be effectively mobilized in the symplastic system and be conducted to the roots.

Although I favor targeted applications foliarly there is distinctive advantage of getting the soil right which pH is a prime consideration as well as a gamut of other important issues such as organic matter and mineral nutrient balances. When these factors are aligned than the nutritional state allows the vibrant microbial communities which are bioindicators and active plant health agents.

In the mix of all of this the most cost effective yet overlooked practices is the use of seed treatments which are low cost based on the minute matter needed for them and their efficacy at such low rates.

Very interesting issues , you have raised Dr Hepperly . Other day , we were discussing about the crop specific soil properties criteria , which are acutely missing . you have very rightly said , on a soil , where soybean  expresses Fe-deficiency , in the same soil , maize will express Zn-deficiency , simply because of the difference in plant metabolism , and , hence  different soil conditions  requirement . Unfortunately , we cannot so abruptly  tailor soil conditions suiting to a crop or cropping system . There is absolutely no doubt whatsoever , soil pH hold the most centre stage  for success of our agriculture system . then again ,  inducing significant changes in  soil pH  is not easily attained , especially in soils  having high buffering capacity ( For example smectite rich clay soils  as Vertisols or illite-dominant Entisols or Inceptisols). Soil nutrient pool and microbial pool are intricately inked to each other . And,  it is  is more or less a common feature to observe the wider microbial diversity in fertile soils than  in soils of poor fertility.

The information on Iron chlorosis in soybean is quite interesting in my view. In an alkaline soil situation the chlorosis is combated by genotypes which apparently have organic acid excretion production. The ability of maize in the same soil to avoid the iron issue almost completely is related to superior ability to mobilize insoluble iron by use of more effective mobilizing  siderophores characteristic of the grass. In fact when researchers plant grasses interplanted with beans such as soybean the siderphore of the grass can eliminate the iron chlorosis issues. In that soil situation the grass can be used as a nurse crop and eliminated before the critical period of crop interference. Just as interplants can contribute to mobility of key nutrients its clear that soil and root microbes are also involved. Considering the number of variables and levels the information can be mind boogling!

Dr Hepperly , I still remember , you stressed not  long back about the role of AMs in mobilising ability of non-mobile nutrients . Establishment of CMN between AM species and host plant  facilitates the influx of nutrients into the host plant , preferably from insoluble sources .

I believe the successful crop production in the Rodale Farming Systems Trial is firmly rooted in the ability of rotation and crop covers to stimulate much better soil mycorrhizae capacity. While the Carbon could increase about 1% for every year the mycorrhizae spores where 200% higher from the base line in 10 years and the mycorrhizae are also a source of the low term slow increase in Carbon and Nitrogen. Another very important consideration is that most farmed areas can be losing substantial resource from unsustainable rates of water and wind erosion. Before we regenerate soils we usually need to go to the emergency room and stop the bleeding. Then our treatment to the patient can be effective. In stead of tilling we need to concentrating on the biological sources of our soil fertility me thinks.

I thought let me share with you some of the excellent works , Prof Ortas from University of Cucurova , Turkey  recently shared with me these PDFs on role of AMs about the mobilisation of P , besides different micronutrients . They will be extremely useful for further reading and mechanistic insights involved in nutrient mobilisation .

Sir,

No laboratory recommends on this basis.  Very good approach  if we use this for method of application.  I take an example, phosphorous being non-mobile in soil, it becomes mobile in plant, found along with ATPs.  Sulfur and Nitrogen both being mobile in soil behaves differently in plants. Nitrogen becomes mobile and S becomes immobile.  Based on deficiency of nutrients on diffrent parts of the plant (young / old) one can decide the mobility nature in plants based on which recommendations can be done.

Nice response Dr Rajakumar . But then , why do we consider the  approximate use efficiency of every nutrient , and accordingly we adjust the fertilizer rates. 

You are right sir.  Nutrient Use Efficiency can be used for adjusting fertilizer doses. But no laboratory does this! Now there is a national movement on soil testing.  Year 2015 denoted for soil health. Now we are moving to 2016. No achievement has been made by the movement in respect of yield increase because of soil health management  programme during the year.  Or expected?  Soil Health Card should include fertility status, physical properties and microbiological properties :

pH, EC, OC, NPK, CaMgS, Zn, Fe, B, WHC, Texture, BD, Bact, Fungi, Act, BioC

with recommendations for management

In addition to these NUE and mobility of nutrients in plants if we use we can achieve one more green revolution in India

Faiza Hallouz to you16 hours ago

Hi Dr Anoop,

I do not have great knowledge about it but I think it is very esssentiel how to apply these fertilizers on the plants and what their advantages and disadvantages on the soil and on plants

Best

Fertilizers are recommended only based on their dynamics in soil.

Can you please elaborate your response for the sake of better discussion , Dr Dabi...?

Dr. Srivastava,

Thanks! I would be happy to elaborate this.

* Laying out the universal criteria for nutrient mobility in plants is very difficult task.

* In my opinion, plant species do not differ significantly in terms of nutrient mobility, rather they differ in total and temporal requirements of nutrients.

* Probably, ionic radii do not affect much in terms of mobility once ions are within the plant body. Size is more or less compensated by the degree of hydration of the ions. Plants cleverly select nutrient ions based on their oxidation states. They prefer relatively less oxidized forms of nutrients. The nutrients which are directly related to osmo-regulation and phosphorylation (viz. K and P, respectively) are taken up only actively (requires ATP-dependent pumps)

* We only consider plant mobility in soils, not that in plants while recommending fertilizers. The fate of nutrients in plant body is far more complex than that in soils.

Regards,

MKD

Good points Dr Dabi  followed by another nice response from  Dr  Sawicka, appreciate both of you  for some thoughtful discussion . I agree implementing universal concept of nutrient mobility would be the most stupendous task , especially while looking at fertilizer recommendation , since mobility of different nutrients is  further governed by prevailing soil conditions .Neither, we look into the nutrient  mobility   while defining the nutrient-use-efficiency  . Its a different story , when you compare the uptake of mobile versus immobile nutrients . My concern is , if do not consider nutrient mobility while deciding the fertilizer recommendation , is fine . does it come somewhere in the context of even while  defining the nutrient -use-efficiency...?

Dr Sawicka is right , we need to partition total nutrient requirement across critical growth stages of any crop , in order to improve the use -efficiency applied nutrients . Here again , whether or not nutrient mobility will dictate the use efficiency of nutrients , mobile versus immobile...?

I think , improving remobilization of nutrients , thereby , affecting the internal distribution of assimilated nutrients will be of utmost concern with regard to use efficiency of will  be of utmost concern. 

Do you think than nutrient mobility within a plant is dependent on vegetation stage of the plant ? In my experimental pots i with serpentine soil and Nickel hyperracumulator plant A murale the efficiency of fertilization depend of the stage of the vegetation but also the dose of the fertilizers.

Thanks for update Aida, i agree with you . However , the bigger question is how does if affect the conventional fertilizer recommendation..?