Thanks Anil Kumar . Let me put another counter question , how can we address the nutrient requirement at different critical growth stages, if at all we need to develop a substrate . Do you mean , application of substrate  at one time and taking care of total nutrient requirement at all the critical growth stages of the crop?

Dear Anoop Kumar Srivastava,

Land has always occupied a leading position among the national wealth of any nation.

 At each stage of the agricultural process should take into account the laws of interaction of plants with the environment and the soil, the laws of the circulation of matter and energy. Ecological Agriculture Law is formulated as follows: human impact on soil, plants, the environment must not exceed the limits beyond which decreases agroecosystem productivity, impaired strength and stability of its functioning. Enhancing agro-ecosystem productivity can only be achieved in parallel improvement of all its elements. Consequently, the increase in the agro-ecosystem productivity economically and ecologically expedient and while improving its elements. Every crop is to be cultivated in an environment to which it is the most environmentally adapted. Minimum performance improvement of agricultural systems should always be above the maximum performance before the improvement: the standard of comparison is necessary to take the optimal conditions for the data and time option agro-ecosystems.

Soil-forming rocks - the substrate on which the formation of the soil; They are composed of various mineral components in varying degrees involved in soil.

Regards, Shafagat

Dear friends, substrate could be organic or inorganic in nature. Nowadays we are talking a lot about tailoring the crop requirement as per soil properties.

Anil Kumar , how substrate is different than a simple fertilizer mixture, is it the period  to which nutrients are available to a crop , a kind of slow release  with  prolonged nutrient availability ? . That's a  usual concept with any nutrient source , you use , nutrient availability must match with physiological demand , to imply higher nutrient-use-efficiency.  

Interesting answer Anil Kumar . We are often in two minds , whether to tailor the crop requirement according to nature and properties of soil or tailor the soil according to crop nutrient demand at crop phenophases ? . If you ask me, I will say both the ways , it will do . that is what we intend to look at ? 

How should we go about for nutrient partitioning in relation to physiological growth stages? I still wonder substrate is organic in nature.

Dear Anoop Kumar and All

If I understand your question my answer is this:

Soil starts as soon as the plant and animal life comes to live in the debris of the decomposition of a rock. On the death of these creatures, their material is incorporated into the soil, mixing with mineral substances. They then represent Soltner as "organic ingredients" or "organics"

Given the different types of organic matter (live, fresh, humic matter) that have multiple functions: processing, energy substrate, physical fertility. It follows a physicochemical fertility (mineral intake, therefore soil structure a long-term stability)

It is quite right dear Fadel that the dynamics of the substrate is related to the contributions of the organic type

Yes friends , I entirely agree , substrate has to be predominantly organic , then only it will release the nutrients over a prolonged period , much to match with the nutrient demand  . There could be other components as well . Inorganic fertilizers and bunch of rhizo-competent microbes also can come into play .Looking forward to expend the discussion further to what kind of developments have taken place in  this regard .

A dynamic substrate will have components comprising organic manures, chemical fertilizers and biofertilizers in such a way that their scheduling address the total nutrient requirement of a crop.

Prof,

In my view, usually we uses substrates for plant growth because their nutrients percentage is known and usually approx. all of the nutrients are added in in a specific ratio. The possible components for establishing better plant growth may be the amount of nutrients, texture of substrate and amount of organic matter.

Yes Husain , you are right . but most important is to have a comprehensive substrate , its composition in terms of components , the possible complimentarity between different components , their behavior in soil after incorporating into the soil , so many properties need further investigation before a substrate is  able to behave according to nutrient demand by a crop. Hope , you like the answer.

Let me share with you  my one review on substrate dynamics for  further reading and feedback .  

Ye prof, I got it and the paper you uploaded is very interesting. Thank you prof

Barbara , an excellent account , you have narrated , thanks dear.

Thanks my dear friend Barbara for adding philososphy to science . Science is always better dealt with philosophical aids. i agree with you . Lets listen to our other colleagues , what is their take on the issue. 

Dear all:

We have to think about a dynamic soil nutrient solution with a proper and balanced concentration of the all essential nutrients.

Thanks Arturo for adding good response . Regulating the nutrients availability in soil ( You understand the complexity of soil ) and then developing a substrate , which has a nutrient release pattern comensurating with the nutrient demand at different growth stages in  variety of crops , is a real state of art . How to go about it , is still not so very clear..?

 But conceptually the subject attracts whole lot of dynamics to addressed at various angles.To have a dynamic substrate , role of organic matter and litter is  undeniable. Litter and soil organic matter represent different forms of a continuous transition of organic matter from newly shed, or even still attached, plant tissue or tissues from other living organisms, to an amorphous mixture of organic compounds. Since soils (with litters and soil organic matter) in general contain more of the most important elements than other stores in global element cycles, the dynamics of soil pools are critical for the functioning of the element cycles.Dead organic matter from plants, litter, has to be decomposed in order to release its content of elements for use by other plants. The release of different  nutrients is related  to the factors regulating the release. A simple mathematical model provides a framework that lets us identify how different properties of the decomposer organisms, mainly bacteria and fungi, control the rate and fate of the decomposition process.

The models range from analytical, substrate-enzyme-microbe, cohort, multicompartmental, nutrient dynamics, and ecosystem models. A detailed description of three of the most widely used ecosystem models is presented to show the diversity of the approaches used to simulate nutrient cycling and soil carbon dynamics. Comparing  different model results, evaluate model performance using observed data, parameterize models, and select the best model for a specific application. A critical evaluation of the limitations of the current soil organic matter (SOM) and nutrient cycling model, suggestions on how current knowledge about SOM dynamics should be incorporated into models, and a list of biological and physical processes that need to be incorporated into existing models. these are some of the important thoughts , need redressal in a systematic way. 

Dr. Srivastava,

Following are the points which I could think of. As Dr. Sawicka rightly mentioned, its a piece of philosophy than mere science.

* Substrate is anything which would provide life to any organism by offering nutrition and/or physical stability. The whole concept of plant nutrition and especially heterotrophism revolves around it.

* The concept of "dynamics" is essential in envisaging substrate as because "life" is dynamics per se. Nutrients "solubilize", "mobilize" to reach plant (and animals as well) cells and we call it assimilation. it means that assimilation is the result of dynamics of substrate itself.

* Any substrate which would address "dynamics" will be effective. Dyamics is result of all physical, chemical and biological factors. The neem-coated urea is one example of that.

* Working uptake patterns are one of the depictions of substrate dynamics in plants.

* Neem-coating and S-coating of N fertilizers, Bentonite-S, Elemental S are few examples where dynamics is tailored to meet crop requirement and enhancing utilization efficiency. 

This is very good question. Let it be a philosophy or science, both complements each other very nicely. The most important is to develop a model through which pool of different nutrients is chanalised towards better crop performance. 

How can we fit the concept of substrate dynamics into developing a potting mixture suitable for a crop ? 

What is the role of Biochar in substrate dynamics ? 

Shirgure's question is triggering for further discussion. I think as biochar's role in l biophysical and chemical properties of soil is obvious, its function in substrate dynamics is also significant.

Biochars have great promise in a concept like substrate dynamics, no doubt.

Yes, i do feel so . Dr Getachew is also of the same opinion . We can debate this issue further ..?

I feel biochars do have strong role to play in developing a comprehensive substrate more resilient in soil fertility compared to any of the other substrate predominantly made out of manures.

Please see following publication for details:

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

Article Water Soluble Fertilizers in Horticultural Crops – An appraisal.

Is it possible to experience substrate dynamics through integrated soil fertility management ? 

I say yes, Shirgure, because nutrients from inorganic fertilizers only feeds plants, while integrated soil fertility management  fulfills the needs of both plants and soil health as the organic source has a role in improving the biophysical and chemical  properties of soils. 

Well said Dr Getachew in response to quarry from Dr Shirgure. Infact , Integrated  soil fertility management is very close to climate smart soil fertility management , which has both resilience as well as mitigation strategies. 

I agree integrated soil fertility management is a good option but its effective implementation is a major issue. 

Sirgure, you have raised a very good point. I think the implementation of ISFM should be the work of the research and development part. By the way, ISFM has been traditionally practiced by farmers. Manures, composts or household biowastes are applied as a fertilizer for centuries to improve soil fertility and boost yield, in areas where these resources are available. But their application is not uniform even within a field and the ammount applied is not known. This may bring about nutrient imbalances in the soil and during uptake by plants. If this is optimized through onfarm research accompanied by training farmers and development workers, and backed by periodical soil test the role of ISFM in enhancing soil quality and crop yield, while protecting the environment, will be enormous.

Similarly, if slash and burn practice in some areasfor improving soil productivity is replaced by controlled pyrolysis and applied as biochar it may enable both to enhance soil organic carbon and mitigate climate change through carbon sequestration in the soil.

Some excellent stuff Dr Getachew, i agree with you . ISFM is , therefore , considered very close to organic agriculture and conservation agriculture , where soil ecology/biology holds no bar. But , unfortunately , ISFM is practiced with lot of adhocisms, while its a very well developed science , which goes much beyond the  simple soil fertility management..well said

I feel ISFM is almost synonymous to climate smart soil fertility management.

Yes Dr Deka, integrated soil fertility management is the best option but never forget to use green manure as a cover crop and the microbial diversity to be maintained at maximum. 

Let me add another response. What is your idea about organic hydrophonics ? 

Organic hydroponics is a big issue. How microbes interact under hydroponics.

Abhishek, you will agree in hydroponics the ionic composition of growing medium and its electric conductivity are the two most important parameters to guide the success of hydroponics. 

I would like do add some commentaries regarding questions raised:

* What is the logic of substrate?

Substrate must have good physical and chemical or physicochemical properties for crop growth... Availability and the dynamics of nutrients liberation must be linked to crop nutritional requirements and economic prospects of the gradening... (Offering or excessive production of plants in the market may regualte the amount of nutrient available in substrates, in order to control grow and to increase profitability...)

* What is the logic of adding dynamics to a substrate?

Crop nutritional requirement changes over time and nutrient may react with other co-ions present in substrate.... Some nutrients may experience leaching over season growth.... The logic behind adding dynmics to a substrate is related to meet in a best way crop nutritional requirements, to obtain high yields and high quality products, i.g. flowers with high commercial value...), to control the development of crops in order to avoid excessive offering of plants/products in the market...)

* What could be the possible components of  an effective substrate  for achieving better plant  health  ?

Good question.... maybe the answer is linked to the following facts...: equilibrium in the nutrient supplying,,,, in fact, plants require 17 nutrients, inclunding nickel... some people believe that substrates is a not well buffered growth media... This is the reason why some chelating agents, like humic materials, carbohydrates, proteins and amminoacis starts to be used as substrate components, or S compounds like garlic or onions to contol diseases........

*  How could dynamics of a substrate be traced across different growth stages of a crop ?

By sampling substrate, measuring the dynamics of nutrient availability and the amount of nutrient found in plant tissues in different crop growth stages.... We can also use stable isotope technique to follow nutient dynamics and uptake in the soil-plant system...

* What are the developments so far,   have taken place in  the field of substrate dynamics ?

This topic is an open research area.... Few people are dealing with this issue... The main developtments are realted with the use of chelatings agents in the substrate or the use of the right rate and source of nutrients in fertigation of plants....

*  How can we tailor the dynamics of a substrate as per requirements of  crop ?

We must take into account the genotype cultivated and its specific nutritional requirements.... We must meet plant nutrient requirement with nutrient availability in the substrate.... The last assumption is very dificult to be achieved since we should use right source and rate of different and high quality fertilizers...

Good questions at all....

Carlos Alberto Silva

Associate professor - Federal University of Lavras - Brazil

Rhizosphere modification through root exudation is an important attribute that regulates not only the availability of nutrients in soil, but also their acquisition by plants, besides soil microbial composition. Any change in microbial diversity within the rhizosphere is brought about with different sources of substrate, and if there is any, how the nutrient dynamics is associated with orchard productivity. With the availability of more technical know-how on efficient use of bulky organic manures, prolonged shelf life of microbial biofertilizers, and better understanding on cropmycorrhiza symbiosis with regard to nutrient acquisition and regulating the water relations, a more effective integrated crop production system could be evolved in future. Dynamic properties include organic matter, soil structure, infiltration rate, bulk density, and water and nutrient holding capacity. Changes in dynamic properties depend both on land management practices and the inherent properties of the soil. Nutrient dynamics is the way nutrients are taken up, retained, transferred, and cycled over time and distance, in an ecosystem.Dynamic properties include organic matter, soil structure, infiltration rate, bulk density, and water and nutrient holding capacity. Changes in dynamic properties depend both on land management practices and the inherent properties of the soil. Organic or ecological growing involves minimizing or eliminating the use of synthetic fertilizers and pesticides, and nurturing rich, long term balanced soil fertility through techniques such as crop rotation, conservation tillage and adding compost and manure to the soil. Soil fertility can be further improved by incorporating cover crops that add organic matter to the soil, which leads to improved soil structure and promotes a healthy, fertile soil; by using green manure or growing legumes to fix nitrogen from the air through the process of biological nitrogen fixation.

I agree with you regarding the addition of organic fertilizer with the cultivation of leguminous crops in improving soil properties