One of the finest pieces of information , let me confess this fact , so befitting to on-going discussion. Let me reproduce the abstract of the whole PDf for our friends :

This was a presentation  made by Lyne and Barak during annual Meeting of ASA/CSSA/SSSA during nov. 5-9, 2000 . The title of  the presentation was ; Are depleted soils causing reduction in mineral con tent of food crops. The study is based on 30 years of assessment on different food crops in USA and UK. 

With sufficient quantities of food in an affluent society and raised public awareness of environmental quality, there is growing concern about the quality of food and demand for more accountability of how food is grown. Several studies of historical food composition tables show an apparent decline in food nutrient content over the past 70 years. This decline has been attributed to soil degradation and the “mining” of soil fertility by industrial agriculture. In this presentation, USDA food composition tables are reexamined and factors of food nutrient content will be related to soil quality. Plant nutritional needs are determined and links to soil fertility management and land use patterns are discussed. For major cations of selected fresh produce crops, ternary diagrams show no real loss in the balance of mineral nutrition in food crops. Although it may be hypothesized that a decline in soil quality has led to an apparent decline in food nutrition, more controlled studies are needed to factor out the many variables associated with the food composition tables and this type of analysis.

The relatively stable relationships among the three macronutrient cations argues that either all three are being depleted proportionally from soils or, alternatively, none of them is depleted in soils and that alternative explanations must be sought for changes in composition when observed. The widespread use of soil testing and fertilizers as part of the strategy for the increasing yields of modern agriculture also argues strongly against the notion of widespread soil depletion of mineral nutrients.

This is the scenario  in some advance  industrialised countries where soil test -based fertilizer recommendation is so stringently followed . Contrary to that , in many of the other areas , nutrient mining scenario is alarming triggering the land degradation induced not only reduction in food grain production , but quality has gone par below .

Dear Anoop Kumar Srivastava, 

The analysis of world trends of production development and exploration of gold over the past 25 years shows that actively manifest tendency to increase and decrease the production of precious metals in general and in particular Au. The repeated increase in the market price of gold in the seventies radically affected his producers active in most countries of the world community. It became profitable to process poor ores and trudnoobogatimye: to engage in off-balance sheet reserves of operation (formerly considered unsuitable for production on the technical-technological and economic reasons); resuming operation previously abandoned and "canned" quarries and landfills, mines and quarries; technological process many dumps ore dressing combines (GOK), containing a certain amount of metal (as associated components or incompletely learned in primary processing). Radical changes in the technology of metal extraction by heap, with cyanidation heap bioleaching and in the columns, the method of "carbon in pulp", a further development of other pyro- and hydrometallurgical methods (eg, autoclave enrichment of refractory ores) made profitable recycling low-grade ores and preserved " tails "gold processing plants with a gold content at the level of 1,0-0,3 g / t or less.

Regards,Shafagat

Very  practical question Dr Srivastava. Nutrient mining is nothing but more nutrients mined from soil than added. Red and lateritic soils are more prone to nutrient mining than black clay soils.

Very  practical question Dr Srivastava. Nutrient mining is nothing but more nutrients mined from soil than added. Red and lateritic soils are more prone to nutrient mining than black clay soils.

Interesting answer Abhishek . I agree with you about the simplest definition of nutrient mining , but more important is , how to compute it . Still very important , what should be the time lag to define the extent of nutrient mining ?. And , perhaps , the most important  is to have nutrient budget for different cropping sequences in a farming system .

Thanks for appreciating Dr Deka . Yes , i endorse red and lateritic soils are more prone to nutrient mining . there two very distinct reasons for that . Soils have  naturally poor nutrient reserve with low nutrient holding capacity and secondly , the associated ecosystem which is so fragile in terms of sustainability . 

Iuliana Florentina Gheorghe to you13 hours ago

In European countries, the fundamental problem is that the amount of fertilizers is higher to compare the intake of nutrients by plants capacity. By percolation the excess of nutrients get into the ground water making their pollution. In an ecosystem disrupted the cyclization of nutrients can be modified by excessive nutrient inputs through fertilization or by removing of litter and deficiency caused by lack of litter that should break down and feed with nutrients.

Very relevant question Dr Srivastava. To my surprise, when we have entire crop advisory for RDF, still nutrient mining is a common phenomenon. What are the reasons for such nutrient mining, is it the poor land use planning ?

Luliana , interesting feedback. Yes , i do agree , in many parts of the european countries , there is more problem of nutrient excess then nutrient mining . But ,  the problem of eutrophication  in water bodies is equally rampant in those areas due to percolation/seepage loss of added fertilizers in agricultural fields. 

Let me add the information pertaining to nutrient mining via an excellent review ( Tan et al. 2005. J. Sus.Agri. 26: 123-131) entitled Yield Global Nutrient Depletion and Yield  Reduction . The abstract of the review is given below: 

Nutrient depletion in soils adversely affects soil quality and reduces crop yield and consequently poses a potential threat to global food security and agricultural sustainability. With an emphasis on human-induced nutrient depletion, this paper described the causality among soil nutrient depletion, soil quality, crop production, socio-economic variables, and environmental condition. Then, global soil nutrient budgets of nitrogen (N), phosphorus (P), and potassium (K) were estimated for wheat (Triticum aestivum L.), rice (Oryza sativa), maize (Zea mays L.), and barley (Hordeum vulgare) production for the year 2000. As a result, there were unbalanced fertilization with surplus N in some developing countries and insufficient inputs in many developing and all least developed countries. Globally, soil nutrient deficits were estimated at an average rate (kg ha1 yr1) of 18.7 N, 5.1 P, and 38.8 K, covering 59%, 85%, and 90% of harvested area in the year 2000, respectively, and annual total nutrient deficit was 5.5 Tg (1 Tg = 1012 g) N, 2.3 Tg P, and 12.2 Tg K, coupled with a total potential global production loss of 1,136 Tg yr1. Besides socio-economic factors, the soil nutrient depletion canbe attributed to insufficient fertilizer use, unbalanced fertilization, and nutrient depletion-induced soil fertility problems. Soil fertility problems associated with human-induced nutrient depletion are widespread worldwide.

Hope , you will like this beautiful piece of information . PDf enclosed for further reading . 

Luliana, can you throw some light on kinds of cropping and soil details that have shown the nutrient build up while others have shown mining of nutrients from the soil.

One of the finest pieces of information , let me confess this fact , so befitting to on-going discussion. Let me reproduce the abstract of the whole PDf for our friends :

This was a presentation  made by Lyne and Barak during annual Meeting of ASA/CSSA/SSSA during nov. 5-9, 2000 . The title of  the presentation was ; Are depleted soils causing reduction in mineral con tent of food crops. The study is based on 30 years of assessment on different food crops in USA and UK. 

With sufficient quantities of food in an affluent society and raised public awareness of environmental quality, there is growing concern about the quality of food and demand for more accountability of how food is grown. Several studies of historical food composition tables show an apparent decline in food nutrient content over the past 70 years. This decline has been attributed to soil degradation and the “mining” of soil fertility by industrial agriculture. In this presentation, USDA food composition tables are reexamined and factors of food nutrient content will be related to soil quality. Plant nutritional needs are determined and links to soil fertility management and land use patterns are discussed. For major cations of selected fresh produce crops, ternary diagrams show no real loss in the balance of mineral nutrition in food crops. Although it may be hypothesized that a decline in soil quality has led to an apparent decline in food nutrition, more controlled studies are needed to factor out the many variables associated with the food composition tables and this type of analysis.

The relatively stable relationships among the three macronutrient cations argues that either all three are being depleted proportionally from soils or, alternatively, none of them is depleted in soils and that alternative explanations must be sought for changes in composition when observed. The widespread use of soil testing and fertilizers as part of the strategy for the increasing yields of modern agriculture also argues strongly against the notion of widespread soil depletion of mineral nutrients.

This is the scenario  in some advance  industrialised countries where soil test -based fertilizer recommendation is so stringently followed . Contrary to that , in many of the other areas , nutrient mining scenario is alarming triggering the land degradation induced not only reduction in food grain production , but quality has gone par below .

Dr Srivastava, this is a very useful and informative response. Do we have such kind of study in Indian context? We need such information connecting soil fertility with food quality.

In the intensive agriculture system to balance the removal of nutrients it is equally important to return of lost nutrients or through new additions of nutrients. The degree of nutrient mining and the feasibility is based on the scale of nutrient transfer. The recycling is generally feasible at farm-scales, but less so with the increasing spatial transfer of nutrients from plough to plate. But juxtaposition, in addition to the macronutrients, mining of micronutrients is important but are often overlooked. How nutrient mining can be best done equally for macro and micro nutrients together for not only improving production but also quality following the approach of agrofortification.

Thanks Abhishek  for so effectively putting your arguments through number of links and PDFs , appreciate your efforts. Your first quote is the quote of the whole discussion . And , concluding quote is the key  to combat nutrient mining  , unfortunately that do  not happen in   most of the cases. Of late , especially micronutrients and  sulphur , human health aprt is also added to assess the crop quality in terms of allevaiting micronutrient deficiency in infants and mothers as well. And same hold equally valid for livestock as well. 

The depletion of soil nutrients and soil microorganisms contributes to soil erosion and the loss of arable topsoil. The Earth is losing arable topsoil at a rate of 75 to 100 GT. per year. If soil loss continues at present rates, it is estimated that there is only another 48 years of topsoil left. In the United States soil is eroding at a rate that is ten times faster than the rate at which it is being replenished. The rate of soil erosion is much faster in other parts of the world such as Africa, India and China where erosion rates are 30 to 40 times faster than the rate of replenishment. In areas of Africa the combination of soil depletion and soil erosion has lead to the prediction of plummeting crop yields

According to the US Department of Agriculture (USDA), Americans typically lack a sufficient amount of the minerals calcium, magnesium, potassium and the vitamins A, C, D and E needed to maintain good health. Studies carried out by Nutrient Security Institute during 1914-1997 using vegetables like cabbage ,lettuce, tomato  and spinach , considering average of nutrients like calcium , magnesium and iron  showed alarming rate of depletion in 19997 compared to 1914.  Production of nutrient dense food is the ultimate option , but where from nutrients will come for growing crops on such fertility depleted soils . We need to have biologically active soils , We need to have sound soil fertility evaluation program. We need to have scientifically well proven techniques of monitoring soil degradation rate from fertility point of view . We need to have on-farm  nutrient conservation strategies....like that ....eventually coming to same , what Abhishek has highlighted...

 Thanking Abhishek for for taking so much of pain , let me throw some light on the issue of Nutrient mining in indian context .

 Present intensive production systems in India characterized by heavy removal and inadequate replenishment of nutrients resulted in multiple nutrient deficiencies and depletion of soil nutrient reserves. For sustaining the crop productivity and to restore the soil fertility, there is a need to arrest depletion of soil nutrient reserves for which understanding of crop nutrient balances is important. There were many attempts to examine the potassium mining at individual plot level, long term fertilizer experiments, state level and country level. In most of these reports, fertilizer inputs and crop removals were only considered, thus resulting in the large scale negative K balances in Indian agriculture. In agroecosystem, K is contributed by many sources like animal manure, crop residue, compost, rice burning residue, irrigation water and rain etc. Similarly, besides crop K removal, K is lost to deeper layers by rain or irrigation water by leaching. By considering all these inputs and outputs, the K balance in Indian agriculture is about 3 million tonn year. This total balance can be further refined by considering area under conservation agriculture, green leaf manuring like glyricidia and other non-conventional sources of potassium being used in Indian agriculture, which may further reduce the overall negative balance of K Indian Agriculture (Srinivasa Rao et al . 2011, Karnataka J. Agri. Sci. 24: 20-28)

 While debating on the issue entitled Nutrient Management in Indian Agriculture  with reference to Nutrient Mining  -Relook  . Indeed, different soils, under similar cropping systems and comparable management practices, will differ considerably in their inherent buffer powers to withstand the stress arising from “nutrient mining”. In other words, the degree of soil vulnerability varies . Multiple cropping systems and management practices adopted by farmers on numerous soil types in the country further complicate the nutrient mining scenario. Therefore, the allowable range of nutrient mining under variable climate-soil-crop-management domain needs to be assessed, at least at the regional scale. The current article discussed several research and application mechanisms that may provide some guidance to alleviate large-scale nutrient mining in the country. However, a larger objective of this article is probably to bring the nutrient mining issue in our collective consciousne s as a threat to the quality of our soil resources and our food security. A national effort to address the nutrient mining may go a long way to maintain the quality of our soils for the posterity and to ensure the food security of the future generations.( Source ; Sanyal et al. 2014. JISSS 62: 307-325).

Very nice responses I am observing from Abhishek and other colleagues  for such a wonderful discussion on nutrient mining, a factor for soil degradation. We are more looking to know such nutrient mining under specific soil type and cropping sequence. 

Lets also know what kind of tools that are used in computing nutrient mining since current tools are too time consuming.

Anoop sir,

I am joining for the discussion on nutrient mining.

* What are the reliable indicators of nutrient mining ?

Crop yields

* Do you feel , nutrient mining is to be assessed based on crop/cropping sequence or soil type or any other universally accepted guiding principles?

Yes, based on crops

* Is there any global map of nutrient mining developed , similar to map of land degradation for identifying hot spots of nutrient mining ?

No, as it is too vast, I hope attempts are still in question!

* How will you compute nutrient mining in spatio-temporal domains?

We need to work out by taking some crop cutting in small area

*What are the monitoring and evaluation parameters of nutrient mining ?

Yield, initial and after harvest soil nutrient status

* What do you mean by  Nutrient Audit/budget  and its links with fertilizer use strategy?

Initial soil status+fertilizer nutrient added-uptake=after harvest soil status

*What are the new initiatives of evaluating nutrient mining ?

Initial and after harvest soil needs to be analysed. Subsequent crop symptoms can also be used

*What could be  the future research strategies on nutrient mining ?

Assessment of soil health (19 parameters:physical, chemical and biological) status in three yield categories (Low, Medium and high) in the village as a whole

This can be used to map mining in the village and can attempt to address the low yields to enhance the same in the village as a whole by looking to soil health status of high yield plots with sustained soil health.

How do you define the nutrient mining and analyse the present trends? -

I define that taking out the nutrient from the reserve (N from Organic C, P from unavailable pool and K from exchange site and similarly others). 

Heavy feeder of nutrients mine more from the soil and impair the soil fertility and health. Some times microbes are also used for nutrient mining. The crops / tree plants when go deep into the soil column in the profile, bring the nutrients to surface and on addition of litter / foliage those nutrients return to the surface.

Based on the crop yield levels one can judge the mining capacity of the crop.

Demand driven crop cultivation will always be there. In heavy nutrient feeders like Sunflower, banana, pineapple......, the research should also concentrate on addition of un-wanted materials through roots and foliage which hinder succeeding crops.

Yes abhishek,  We must rebuild our soils: Put back the minerals we have taken out. That sounds difficult but it isn't. Neither is it expensive. Therein lies the short cut to better health and longer life." This quote has meaning.

*What are the reliable indicators of nutrient mining ?

Nutrient composition at most active growth growth stage of crop plants. It will indicate the limiting nutrient(s) that ultimately influence harvest yield. Depending on nutrient requirement, mining would vary.

* Do you feel , nutrient mining is to be assessed based on crop/cropping sequence or soil type or any other universally accepted guiding principles?

Removal of nutrients by a crop and its recuperation by adding fertilizers or other sources will dictate mining or no mining situations. Besides rainfall, irrigation, erosion, soil removal also influences nutrient mining. To my assessment crop sequence based nutrient mining needs to to be assessed.

* Is there any global map of nutrient mining developed , similar to map of land degradation for identifying hot spots of nutrient mining ?

I have not seen it; but would better if we have it.

* How will you compute nutrient mining in spatio-temporal domains?

Geo-reference sampling and analyses of nutrient compositions over time. We have to collect data on: (a) when human intervention was started? (b) crops grown and culture, (c) whether it was crop agriculture or livestock rearing or fisheries? (d) nutrient deposition patterns, etc etc  

*What are the monitoring and evaluation parameters of nutrient mining ?

Soil analyses every 3-5 years could be one of others

* What do you mean by  Nutrient Audit/budget  and its links with fertilizer use strategy?

We need to know apparent balance after each cropping if we really want to minimize cost of production and sustenance of soil health.

*What are the new initiatives of evaluating nutrient mining ?

Delineation of nutrient mining prone areas.

*What could be  the future research strategies on nutrient mining ?

Improved use efficiency of applied fertilizers. Initiative to reduce nutrient loss from soil e.g. neem coated urea. Breeding low input crop varieties.

*How do you define the nutrient mining and analyse the present trends?

Gap between nutrient addition and removal from soil will indicates nutrient mining.

Thanks Dr Rajakumar . You joined RG after a long time with a thunderous reply. It speaks of your excellent depth on the issue. Crop yield along with soil available nutrient indices , if combined together , could   probably  reveal meaningful revelations about extent of nutrient mining , besides data on nutrient removal . Probably , this is where we need a dynamic soil test-crop response calibration models to suit such concept at farm level , since the current  technique  of fertilizer recommendation is more adhocis than real soil test-based..Therefore , our major limitation is some gaps in methods used for evaluation and monitoring of nutrient mining , otherwise , why do we have such menacing rate of nutrient mining . 

I do agree with you Abhishek ,  there is a strong need to implement 4R Nutrient Stewardship . But ,  there are only few crops , we have complete package with regard to 4R . There core principles  admixed within the ambit of 4R are failing somewhere , simply due lack of  redressal of  crop-related issues.

There is no doubt whatsoever , to follow simplest  gospel of crop raising , return back to soil , whatever you have withdrawn from the  soil. How to exercise  these two diverse exercises , which accomodate whole science of successful crop raising  , Dr Malkhotra. And , if we have been following these so stringently , why do we notice nutrient mining- induced soil degradation- induced crop unsustainability induced -malnutrition -induced mortality.... so on ...?

My personal opinion is somewhere matching with the views of Dr Srivastava. If our current state of affairs relating nutrient mining is so strong, why do we notice nutrient mining so much so that 40-50% of Indian soils are deficient of one or the other nutrients, mostly multiple nutrients.

Let me acknowledge the excellent response from Dr Biswas.  Do you mean  the nutrient composition in plant parts  at different growth stages or nutreint composition as a whole in plants..? Thats a very good point , we need to address nutrient mining based on crop sequence than individual crop.

How do we declare that nutrient mining has taken place in given area or region ? . What is the reference level . In that context , i raised a point that unless , you have data in spatio-temporal domain  , it will be next to impossible to compute nutrient mining over space and time.  another very interesting response, i find Dr Biswas , is the computation of nutrient mining after every 3-5 years.  

How do you see about the RDF( Recommended doses of fertilizers) , sometimes i find RDF worked out to be 20-25 years old...Dont you feel , we need to have geospatial map depicting nutrient mining as well as nutrient excess  for monitoring , especially with regard to  well established some sustainable  cropping sequences..

Some of the criteria like nutrient budgeting and nutrient audits have been suggested , which are really very effective in computing nutrient mining . These researches highlight : 

A Nutrient Budget is an account of inputs and outputs of nutrients in an agricultural system. NUTrient MONitoring (NUTMON) is a multiscale approach that assess the stocks and flows of N, P and K in an well defined geographical unit based on the inputs viz., mineral fertilizers, manures, atmospheric deposition and sedimentation and outputs of harvested crop produces, residues, leaching, denitrification and erosion losses. The nutrient budgeting research in an irrigated farm at Coimbatore district revealed that the nutrient management practices are not appropriate and sustainable. Soil nutrient pool has to offset the negative balance of N and K, hence there is an expected mining of nutrient from the soil reserve in the research area. The management options / policy interventions to mitigate this mining  by manipulating all inputs and outputs in a judicious way with an integrated system approach are suggested and one of the ways for redefining the fertilizer recommendation based on site specific using DSSIFER (Decision Support System for Integrated Fertilizer Recommendation) was worked out.( Source : Surendran eta l. 2005. World J. Agri. Sci. 1: 89-97).

The conceptual model of conducting Nutrient Audits .The results indicate that nutrient efficiency is approximately 50% for N, 40% for P, and 75% for K. In some countries inWestern Europe and in Japan and the Republic of Korea, with large, mixed farming systems, there is a surplus of N, P, and K. However, in almost all other countries, food production is currently dependent on depleting large quantities of nutrients from soil reserves and this is likely to continue. The world average soil depletion of nutrients in 1996 was estimated to be 12.1 kg N ha−1, 4.5 kg P ha−1, and 20.2 kg K ha−1. The depletion of K is particularly severe and could ultimately lead to a serious loss of crop productivity in several countries. There is an urgent need to investigate this issue further. Analytical tools, such as the nutrient audit model described, can play an important role in assessing the problem, and in developing sustainable nutrient management policies, strategies, and practices. Introduction Definition of the problem In many countries and particularly in developing countries, the rate of depletion of nutrients from the soil is high and increasing. This is particularly true for sub-Saharan Africa (Stoorvogel and Smaling, 1990). If allowed to continue unchecked, this will ultimately lead to soil degradation and a reduced capacity to sustain or increase crop production. To quantify soil

degradation caused by nutrient depletion, it is essential that the rate of nutrient depletion or accumulation be established. This can be done by measuring both nutrient inputs and outputs to establish a nutrient balance. ( Source ; Sheldrick et al 2002.Nutrient Cycling in Agroecosystems. 62: 61-72)

PDFs are further enclosed fro reading . 

I think the most important is to develop sound bases for evaluation and minitoring if nutrient mining. Once you know the problems nytrient management options can be effectively used.

Well said Dr Deka , i agree with your remarks. 

very innovative question from Prof Anoop Kumar Srivastava and very useful comments from subject specialists. 

It seems that basic studies are lacking on source of organic materials its decomposition and their nutrient release pattern in different locations and situations so that they can be easily incorporated and accounted for in plant nutrient recommendations which are practical, technically sound, economical and environment friendly. 

Although the value of global maps can be questioned they may identify areas of particular concern. For soil nutrient mining (and other aspects of land degradation) the LADA project developed a documented global information system, freely accessible at http://www.fao.org/nr/lada/gladis/gladis_db/ . This is a Beta version and is open to (much) improvement as it was only based on global databases available in the public domain.

Thanks so much Hussain for appreciating . As i say always . it is a two way approach , where everyone gains , no one looses. 

Dr Malhotra , you tactically right . Most important of all is the lack of ample information about the time lag for which residual effect of organic manures last. how different carbon sources resist against various mineralizing factors , remains to be brought to lime light. 

Excellent response Dr Nachtergaele , so appreciative of you .  The LADA map is so informative , but i see whole of India , except some parts of northeastern India , depicted as showing no nutrient mining , which i do not agree . Infact it is other way round. Lets know , what shall be the future course of action  in this matter. But , interesting to know , such global map does exist . 

Some of the factors triggering the unprecedented nutrient mining , especially in asian , african and  sub-saharan countries comprise of ; unbalanced fertilization , unable to differentiate the crop requirement under varying crop growing conditions, undesired production level not in line with nutrient reserve of the soil,  unprecedented loss of organic matter from  soil , especially from rhizosphere zone , undue dependence on chemical fertilizers for crop response, continued lower response of fertilizers under prevailing multiple nutrient deficiencies, continued negative nutrient balance in soil . these conditions not necessarily prevailing everywhere . some of the regions have totally  reverse trend, like nutrient excesses. 

I think this issue of nutrient mining has been an important agenda and it will be so as far as we depend on subsistant agriculture. Many scholars use just nutrient balance as an indicator but we proofed also with one of our work in Ethiopia ( attached) linking with nutrient stock is more reliable. But note that there are efforts here and there on nutrient balance. Because of the expensive nature of sampling and laboratory analysis data sourcing usually depends on transfer functions... and a spatially explicit work needs information on land use type, crop type, nutrient concentration and amount of yield, some modeling works to estimate erosion and deposition of sediments, information on soil nutrient stock and available for plant....and also the social component... how farmers manage it. For example the input management of inorganic and organic fertilizer varies depending on farmers asset holding and mainly livelihood (paper attached). As to future research direction I think I would argue that we need to focus on both over supply and mining as both are getting serious and major treats in terms of climate change , economy, environment and human health/nutrition if you like. BTW nutrient mining is not only about under productivity, it is about access to nutrient dense food for human and quality feed for livestock ( example of our work attached). I hope this helps and thanks for sharing this great idea

Some interesting responses loaded with some thoughtful ideas Dr Amare  . The attached  quality PDFs are equally  informative and educative  as far as this on-going discussion is concerned. i do agree with you small land holding farmers often fails to observe the magnitude of exflux of nutrients, it comes to his notice only after some distinct decline in productivity . It is really difficult for such farmers due to socioeconomic and biophysical factors to always keep vigil on these issues.  Seggregating the magnitude of nutrient mining at watershed level or at land use level , i think we should be in a better position to pinpoint the triggering factor to nutrient mining . There is absolutely no doubt , vegetable fields or perennials , nutrient mining could be of lower magnitude. Soil erosion accounting to as much as 60-80% of nutrient loss , i do agree , but again the topography of landform has pivotal implications , aiding further to widen the  gap the amount of nutrients applied to removed from a given field. 

We also need to realise the nutrient mining for livestock or human beings . Afterall , where from it starts , it starts from the nutrient deficit field , and continues to livestock an d human being who comsume such nutritionally poor consumables? Poor soil nutrient reserve , due to one or other reasons..? This is a clear  case of value chain to value addition with regard to soil fertility management ..?

We need to have focus on following two points:

•Bridge the nutrient gap and help to maintain soil health and ensure the food and

nutritional security of present and future generations 

• Understand the annual loss of nutrients from the soil and devise nutrient management strategies for rational use of soil resource in sustainable manner

Good points Dr Malhotra . Eventually , it is the precise diagnosis of nutrients constraints and their effective management  . However , the most important aspect of nutrient constraint diagnosis is the identifying  nutrient constraint on Real Time Basis, though its difficult . but , with the introduction of remote sensing tools and NIR and IR spectroscopic methods , some decisive headways have been made. In the nutrient management studies , site specific nutrient management , fertigation fitted with variable rate application technique, INM , etc have shown some demarcating advantages over conventional methods of nutrient management .

I was willing to know , what are the state of art initiatives to combat nutrient mining in such unprecedented manner , especially in Asia and Africa. 

Dr Srivastava , nowdays  sensor-based fertigation is so extensively used as a part of precision  agriculture . VRT is also one option  implemented through different management zones.

These are the other most latest  ways of combating nutrient mining , without altering the total nutrient requirement , rather at a much lower requirements , since NUE will be far higher than conventional methods of nutrient management .  

Let me add another response in response to remarks of Dr Amare. There have been number  of studies on  nutrient load of vegetables and fruits at different time intervals as indicator function of nutrient mining  . And , they have proved that nutrient concentration in fruits and vegetables are declining continuously , in line with increasing rate of nutrient mining , especially in  those farming situations where imbalance in fertilization is a common phenomenon. On the contrary , where fertilization is balanced , there is no decline in nutrient concentration of fruits and vegetables, Indirectly supporting the fact that at those places, fertilization is balanced . But , our major limitation is , how to load the nutrients in edible parts of fruits and vegetables.  Certainly , our conventional procedures are inefficient ...?

The discussion on the issue is really informative. Is there any information available on the methods of economic analysis of nutrient mining? 

Good point Dr Shirgure , you have raised. Let me respond to it .  Soil nutrient mining is considered as biophysical root cause of declining per capita food production in saharan and  sub-saharan african region . enclosed below the PDF describes the method working out the economics of nutrient depletion on agriculture production . 

Dr Anoop and Raj,

Thanks for those articles. Appreciated. Indian sub-continent scientist should find out  relationship of nutrient mining vs population pressure and packages of remedies, if any.

Dr Biswas ,  i agree with you , intensification in agriculture is governed by the continuously building pressure of population . And , emergence of nutrient mining is again the result of intensification in agriculture . Clear cut examples can be derived from some of the areas of Europe , where nutrient excess is an issue  . In such areas , you will notice any relation between population pressure and nutrient mining or even  with cropping intensity . 

Very rightly said Abhishek . Some  excellent reading  material for all of us on the subject . 

This is  also one of the reasons , why of late ,  we observe poorly nutrient loaded crops . Crop intensification  coupled with nutrient mining due to expanding demographic pressure , nutritionally  crops are diluted when we compare the nutrient load of different crops , some 25 years back , a clear example of how  nutrient mining    has weakend the basis of daily dietary allowance . the next question comes , how to produce nutrient dense crops ?. Surely , not a simple  task ahead. 

What should be our short term and long term strategies to produce nutrient dense crops , since breeding for nutrient dense crops will be too time consuming . 

Thanks  Abhishek , mind blowing information on the issue . Let me and other learned colleagues go through all of them to interact further . Hope , there will be another very interesting session on development of nutrient dense crops and ways and means in improving the nutrient density of crops . 

This is the major challenge Abhisek to produce nutrient dense crops. Do you feel there is greater intervention of breeding tools than nutrient management? 

it is interesting to see this progress thanks Dr Srivastava and all contributors. Attached is one of our work on how available nutrient and optimally applied nutrient affect livestock  feed quality traits ... a proxy to human nutrition . I fully agree that breeding and optimum soil nutrition would pay great role not only for food production and nutrient denser food but also for environmental health. Thanks, I learned a lot

Thanks Dr Deka , i appreciate your scientific intervention , unfortunately breeding varieties /developing breeding lines with regard better nutrient acquisition capacity , has never been the priority objective , i am sorry for being so candid.

To develop nutrient dense crops, let us also bring some physiological understanding of different nutrients through different pathways involved right from nutrient absorption to nutrient utilsation. 

How do you rate the role of foliar nutrition with regard to nutrient dense crops?

Is it true that our food is nutrient deficient because our soils are mineral depleted? If this is so, what can be done about it? .  Here are some clues:

~ Many are saying that modern hybrid crops have less nutrition than the traditional open pollinated varieties. Is this true or not?

~ If grown on the same soil, which varieties of the common fruit and vegetable crops contain the highest levels of nutrients?

~ Is it true that high-Brix crops are more nutrient-dense than crops with a lower Brix reading?

Nutrient Density is the end product of a highly functioning biological system, where the crop harvested has a measurably larger quantity of a broad spectrum of different minerals, vitamins, phytonutrients, and antioxidants than its counterparts. These components are also in healthy ratios with each other. In relation to their same species counterparts, nutrient-dense crops have relatively: More complex and intense flavor;Longer shelf life;Greater specific gravity, or density;More tendency to desiccate instead of rot;More disease and pest resistance in the growth phase;Greater yield.

These are 41 nutrient dense vegetables and fruits considered orldwide: Watercress ,Chinese cabbage,Chard,Beet sprouts,Scallions,Kohlrabi, reens,Spinach,Chicory,Leaf Lettuce,Parsley,Romaine lettuce, Collard green,Turnip green,Mustard green Endive,Chive,Kale,Dandelion green,Red pepper,Arugula,Broccoli,Pumpkin Brussels Cauliflower,Cabbage,Carrot,Tomato

Lemon,Iceberg lettuce,Strawberries,Radish,Winter squash (all varieties),Orange

Lime,Grapefruit (pink and red), Rutabaga,Turnip,Blackberries,Leeks,Sweet potatoGrapefruit (white).

Very well said Abhishek , i endorse your comments. Infact , the issue of nutrient mining triggered by population pressure affecting the carrying capacity of soil in various dimensions, is the major handicap in the way of developing nutrient dense crops. 

The nutrient values of harvested food are linked to soil organic matter, the biological activity of soil microbes, the mineral composition of the soil as well as the genetics of the plant, fertilization and irrigation practices. Minerals are an essential aspect of soil and critical to the healthy microbial life in the soil. Without minerals, soil loses the ability to support the growth of nutritious food. Soils without minerals cannot produce plants with minerals. Foods grown on soils depleted of minerals do not contain the minerals need to maintain human health. Recent studies that compared the mineral content of soils today with soils 100 years ago found that agricultural soils in the United States have been depleted of eight-five percent of their minerals  This phenomenon was  documented worldwide. Researchers found that soils in Africa have seventy-four percent less minerals, soils in Asia have seventy-six percent less minerals, soils in Europe have seventy-two percent less minerals, soils in South America have seventy-six percent less minerals and in Canada soils have eight-five percent less minerals than 100 years ago.

 Without minerals and soil organic matter it is impossible to sustain a healthy population of microorganisms which are directly responsible for producing vital bio-chemicals which are the basis for the nutrition values of plants. Crops grown in soils stripped of needed nutrients have low nutrient levels. Unless growers replenish nutrients, the mineral content of harvested food will continue to decrease.

No doubt , thats the reason,  we stress so much so , on the health of the soil to ensure the quality of the food vis-a-vis quality of the human life /longevity /health index..etc

Abhisek, it is a good point, but how to induce re-mineralization in soil and what does it do with nutrient dense crops.

Very meaningful feedbacks , you have attached , Abhishek . You add so much spice to whole discussion and , many times open up so many issues of discussion , always appreciative of you . 

My major concern was , while developing nutrient dense crops , surely foliar nutrition is one of the available options. How does the basic premise of foliar nutrition differ , with objective of meeting nutrient requirement of a plant against the other objective of producing nutrient dense crops..?

First thing , we should keep in mind that foliar nutrition is more like a supplement to soil application. We need to add some growth regulators to improve NUE with foilar sprays. 

We have done experiments with foliar application of N in rice. Only spraying was not enough for getting higher yield than conventional topdressing. However, two topdressing of urea and two spraying instead of 3rd topdressing was favorable for saving small quantities of urea without sacrificing grain yield

Thanks Drs Shirgure and Biswas. Lets recall the point raised by Dr Deka . Do you feel , foliar application of nutrients could be one of the effective ways to produce nutrient dense crops or alternatively , nutrient density could be improved through foliar fertilization . If so , how does it differ from conventionally used foliar fertilization ? 

Apart from above suggestions, measurements of various components of nutrient budget and use of mechanistic models for estimation of crop uptake and losses of nutrients in different crops and cropping systems assume importance here.

Abhishek and other colleagues , i hardly see anything really significant beyond the fact that reduction in nutrient density of different fruits and vegetables is taking place due to nutrient mining induced reduction in soil fertility over the years. What shall we conclude , whether our strategies of feeding crops are not so full proof or our land use planning is not resource -based , eventually leading to gradual collapse of the  soil function complex as ecosystem ?

I agree with you Dr Srivastava. We need to invest more on the resource based land use planning to avoid any nutrient mining. 

Thanks all for bringing different prices together. In view of Dr Anoop  last point I would like to bring to your attention to the issues of tolerable limit of nutrient depletion. As we remove some the pedogenic process overtime counterbalance.  a proverb  by  Leopold, A Sand County Almanac (1949) goes:  "For every atom lost to the sea, the prairie pulls another out of the decaying rocks. The only certain truth is that its creatures must suck hard, live fast, and die often, lest its losses exceed its gains.”

Thus, for me an interesting point is understanding these tolerable limit and  manage land and landscape accordingly. Many thanks for bringing in such interesting issues

Nutrient mining or negative balance between nutrient input and output results when the crop nutrient removal and nutrient losses to other sinks become higher than the soil-inherent nutrient supply. Current nutrient management strategies adopted by most farmers promote nutrient mining, as nutrient applications are inadequate and imbalanced. The application of 4R Nutrient Stewardship Principles, i.e., application of right source of fertilizer at right rate and time through a right method, has the potential to reduce nutrient mining from soils. These core principles help manage nutrients in a manner that crop productivity is sustained or improved without soil fertility depletion, and farm production economics is improved while environmental impact of agricultural nutrients is minimized.

http://link.springer.com/chapter/10.1007/978-81-322-2716-8_14#

Source: Nutrient Mining: Addressing the Challenges to Soil Resources and Food Security, Kaushik Majumdar, Saroj Kumar Sanyal, Sudarshan Kumar Dutta , T. Satyanarayana, V. K. Singh

Dr Malhotra, your answer is very good in the context of 4R's. Our major concern is how to keep check on the reducing nutrient concentration in different fruits and vegetables over the years. Is it exclusively nutrient mining or reduction in nutrient acquisition capacity of the either traditional varieties or commercial hybrid varieties ? 

Dr Shirgure and Dr Malhotra , both of you have provided some issues for further discussion , let me take these issues further. 4R is a concept , perhaps the ultimate strategy for any crop , it facilitates to develop nutrient Expert . and we have succeeded in developing Nutrient Expert for crops like rice , wheat , maize...long way to go for other crops, we may some good information for good number of crops in piece meal. 

If you recall the discussion  by Kirti , so nicely described about the nutrient acquisition capacity of old varieties/landraces versus current hybrid varieties , perhaps , you will find the appropriate answer. 

What is the best strategy to keep nutrient mining within manageable limit?

The use of compost, green manures, and other organic matter amendments derived from agricultural biomass is an important strategy to recycle on-farm, in addition to other benefits for soil quality. However, such amendments are limited in their ability to alleviate negative nutrient balances if the biomass for these are produced in the same farm in which they are used. The continued efficacy of such nutrient transfers is often compromised by localized nutrient mining, especially in the already low fertility marginal lands or fallow fields used for biomass production, with consequent nutrient that deficiency can ultimately prevent continuation of such practices. 

Dr Malhotra, very good options of soil fertility management you have provided to alleviate soil fertility constraints.At the same time, we also need to see how best we can utilize farm residues with a viable management strategies. 

I do agree with both of you gentlemen , Dr Malhotra and Dr Shirgure . Nutreint mining is such a issue that needs a consistent vigil on the performance of the crops or cropping system or overall production that comes out of the farm . Unfortunately , these things are too speculative , many a times ,  nutrient mining is so invisible  to the framers that it simply continues unabated , unless distinct reduction in crop performance is noticed , and farmer starts analysing everything in rather details , till then it is simply speculative . how shall we deal with it , to identify the nutrient mining right at the time , it becomes potentially damaging to the crop performance . any suggestion , friends....

Very interesting piece of information , Abhishek ..  NUTMON  is multidsciplinary in nature , a quantitative and qualitative diagnostic phase, to determine nutrient management and economicperformance in existing farming systems, is followed by a targeted process of participatory development of Integrated Nutrient Management (INM) technologies and formulation of facilitating policy instruments.

This is a good point raised by you Dr Srivastava, how to identify the hidden signs of nutrient mining certainly not nutrient deficiency symptoms.

Abhisek, identifying nutrient mining through deficiency symptoms will be too late for farmers, it is more of a post mortem diagnosis. Lets know some practical ways of nutrient mining quantification.

Best course would be to keep vigil on the pool of available nutrients in soil and production response , so that we are in a position to locate the causes of yield getting plateaued , otherwise i do not see any immediate perspective to suggest at the farmers level to keep an eye on nutrient mining . I will welcome , if there is any suggestion in this matter.

That is perhaps , most important , later on management is not a big issue. Tools of monitoring and evaluation of nutrient mining are most important , Abhishek. 

Is it possible to identify nutrient constraints on a real time basis , means as and when it emerges , we capture it ? Is there any development in this direction ..? Although , some concrete progress ha been made in proximal  sensing of nutrient stress , but long way to go before field application becomes a usual possibility. 

I also agree we need to have various tools of correct but timely diagnosis of nutrient constraints. Mining could be through soil erosion also?

Yes Dr Deka , i agree with you , however,  i am still looking at field level indicators of nutrient mining  , friends ...?

There is no doubt, at present, we have hardly any field friendly indicator of nutrient mining, except the crop performance indicator. Let us know how to measure nutrient mining on real time scale ?