Very interesting question , Dr Bjnay Singh, as usual.  As long as, we continue to induce imbalance in rate of fertilizer application , regardless of source , we  are bound to  deteriorate the soil health. After all , soil health  is not the only  living fraction of soil fertility as a part of multiple functions of soil fertility. And , as long as , we continue to address the multiple soil fertility constraints with respect to a given crop ( Annual or perennial ), chemical fertilizers will never be a  bane in  maintaining the  better soil  health. While looking at certain hot spots of nutrient mining /nutrient export  from the soil sites, there are certain parts of Europe and South america , where agriculture is  totally based on exclusive use of chemical fertilizers , yet no nutrient mining , and yet no deterioration  in soil health. If tailoring nutrient requirement keeping in mind the soil fertility constraints and the crop nutrient requirement as per the targeted yield continues on a sound soil fertility  -crop response models, i think , chemical fertilizers will continue to stake its pivotal  claim in modern day agriculture , despite so much hue and cry( in favor of organic agriculture) against the processes such as eutrophication , nitrate pollution of ground water , loss in soil microbial load or microbial diversity etc. Lastly , the we should also consider the amount of  assimilated carbon by a well fertilized plant  is  diverted towards roots( As carbon foot prints of roots)  vis-a-vis total carbon assimilated by the above ground portion in response to balanced fertilization via chemical fertilization . Accept my compliments sir...

Birth defects up during pesticide use season

A study published in the April 2009 issue of the medical journal Acta Pædiatrica is the first to report that birth defect rates in the United States are highest among women conceiving in the spring and summer, a time period correlated with increased levels of pesticides in surface water, reports Science Daily. The study looked at all 30.1 million U.S. births between 1996 and 2002, and found a significant increase in spina bifida, cleft lip, clubfoot and Down's syndrome when the child was conceived between April and July -- a period which coincides with elevated levels of atrazine and other pesticides in surface water. Atrazine, which is banned in European countries but permitted in the U.S., is among the many pesticides suspected to be harmful to the developing embryo.

While the scientists "didn't prove a cause and effect link," according to lead author Dr. Paul Winchester, M.D., Indiana University School of Medicine professor of clinical pediatrics, the evidence points to an association between pesticide exposure and birth defects. Winchester said the researchers are excited by the findings, because "...if our suspicions are right and pesticides are contributing to birth defect risk, we can reverse or modify the factors that are causing these lifelong and often very serious medical problems."

The mechanism of spinal chord defects in developing early stage fetus is probably the consequence of nitrates which can promote oxidation damage in critical early development stages. The presence of antioxidants in the form of folic acid is known to counteract these birth defects. The highest issue is in wells which become contaminated with nitrates from the use of high rates of ammoniated fertilizer used in field and vegetable cropping.  Besides the work of Doctor Paul Winchester you should check the classic work of Elizabeth Guillette and co workers who compared damage of Mexican Apache peoples who lived in agricultural valleys and those who rejected that life style very marked developmental differences of the nonagricultural group. Finally the work of Warren Porter University of Wisconsin shows that nitrates and pesticides interact synergistically to cause mouse health issues. Porter states that pesticides and fertilizers are tested separately but they are not tested together and the studies look at direct short term toxicity but not the subtle physiological effects on long term development. 

While I pointed to nutrient effect in nitrate the herbicides and agricultural chemicals are known to act as false estrogens and play havoc with gender expression. In relation to animal model the research of Tyrone Hayes show dramatic issues in frogs as a bellweather organism. 

a throughout literature research will certainly enlighten you!

Very interesting question , Dr Bjnay Singh, as usual.  As long as, we continue to induce imbalance in rate of fertilizer application , regardless of source , we  are bound to  deteriorate the soil health. After all , soil health  is not the only  living fraction of soil fertility as a part of multiple functions of soil fertility. And , as long as , we continue to address the multiple soil fertility constraints with respect to a given crop ( Annual or perennial ), chemical fertilizers will never be a  bane in  maintaining the  better soil  health. While looking at certain hot spots of nutrient mining /nutrient export  from the soil sites, there are certain parts of Europe and South america , where agriculture is  totally based on exclusive use of chemical fertilizers , yet no nutrient mining , and yet no deterioration  in soil health. If tailoring nutrient requirement keeping in mind the soil fertility constraints and the crop nutrient requirement as per the targeted yield continues on a sound soil fertility  -crop response models, i think , chemical fertilizers will continue to stake its pivotal  claim in modern day agriculture , despite so much hue and cry( in favor of organic agriculture) against the processes such as eutrophication , nitrate pollution of ground water , loss in soil microbial load or microbial diversity etc. Lastly , the we should also consider the amount of  assimilated carbon by a well fertilized plant  is  diverted towards roots( As carbon foot prints of roots)  vis-a-vis total carbon assimilated by the above ground portion in response to balanced fertilization via chemical fertilization . Accept my compliments sir...

If we use earthworms as a key bioindicator the use of acidifying fertilizer and tillage will greatly reduce their beneficial role of this soil health bastion organism. In the case of legumes the applications of nitrogen will reduce the biological nitrogen fixation process. In the case of mycorrhizae as high levels of phosphorus are found the int soil the signaling and activation of fungal components is reduced. In the case of North America the drainage of the maize crop system has caused a dead zone at the mouth of Mississippi River which is greater than area of the state of New Jersey and the disruption of brown shrimp productivity of the estuary is estimated at 80%. Unfortunately while proponents of input agriculture loudly tout their benefits and certainly fertilizer benefits its purveyors financially at the very least. But the claim that they have no negative side effects is naive and unfounded. The fertilizer and pesticide issues are not some fantasy but rather they are real. They are passed over as nonexistent because of the vested monied interest find them uncomfortable for their personal benefit. These same interests have heavily invested in an agenda to fashion the research education and advertisement agenda around inputs. This influence makes the reality of the situation difficult to be uncovered and assessed for merits and demerits. Finally there is no doubt that the result of our modern industrialized farming has led to a marked decrease in soil organic matter. In terms of soil biology the level of beneficial activity is a function of this soil organic matter because it is source of nutrition and water holding and aeration capacity.  I cannot support the claim that fertilizer use is an unqualified success because there is just too much contrary information pointing to a mixed bag at best. It seems like the fall back of the input proponents is to accept some issues but then claim their use is a lesser of evils for if they were not used mass starvation would result. This is a Hobbian Choice where we are asked to accept a lesser of evils rather than win win resolution we sorely need. 

Another side of such issue is the criteria , based on which the soil health is evaluated in response to application of exclusive use of chemical fertilizers , or organic manures or integrated use of both inorganic as well as organic sources. In either case , parameters defining soil health remains unchanged. And , in most of the cases, we erroneously define soil health  in terms of soil fertility , regardless of whether or not they relate with each other . Do we need  revisiting the soil fertility criteria based on sources of fertilizers or manures , we use..? I do not think , this will be a practical approach . Paul has rightly pointed out , there are certain bio-indicators of soil fertility . Are they practically used in conventional soil fertility evaluation ..? No doubt , soil biological properties would be much better wherever organic manures/combination of organic  manures and inorganic fertilizers are  used. 

The problems with chemical fertilizers occur when we either use them exclusively or in excess. The latter results in pollution by nitrates and phosphorus. But that can also occur with organic sources of nutrients if used excessively. The first issue is because soils are made up of physical, chemical and biological components. If we do not return any organic matter to the soil and remove all residues the biological and physical properties are impaired. The biological organisms rely on organic matter for food. The physical properties are affected also and so problems occur with soil moisture, aggregation, soil structure etc. So we need good chemical, physical and biological components to have an healthy soil, not just chemical. That's why conservation agriculture is good. The minimal soil disturbance and permanent ground cover from .previous crop residues and roots, or cover crops and applied organic matter provide the ingredients for a healthy soil. But addition of balanced fertilizer as nutrients may also be needed to supplement soil nutrients to increase yields. Just not too much

Our long-term experiment revealed that intensive rice cultivation (three rice per year) with mineral fertilizer showed slightly  increasing trend of rice yield. This indicated that continuous rice cultivation with mineral fertilizer do not deteriorate the soil health. 

I think such statements needs to be based on extensive experimental facts not otherwise.

Hi Bijay, good question. Maybe it would help focus your question if we separate "external"  ("downstream" etc) pollution effects from in situ effects on the soil itself, which I think is the intention of your question.

We also need to understand what is meant by soil health - here is one definition I found on the internet "Soil health, also referred to as soil quality, is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. This definition speaks to the importance of managing soils so they are sustainable for future generations."

Then the next question is how do we determine whether the soil has this continued capacity e.g. is it sustained or increased yields over X years OR ? 

Several papers published based on AICRP(ICAR) Long Term Experiments (at least 11 experiments are more than 45 years old)  may answer the question raised by Dr.Bijay Singh.In general in control and N alone treatment there was deterioration in soil quality.In some locations recommended levels of NPK application showed minor deterioration in soil quality.When NPK and manure are applied together either soil quality is maintained or much improved at many locations where such studies  are made.The following review papers provide some good information and also references of research papers.

Soil quality and its relevance for sustainable agriculture by Sharma,K.L. and Mandal,B. Journal of the Indian Society of Soil Science 57(4):572-586(2009).

Subba Rao,A.and Sammireddy,K.(2005) Emerging strategies for sustaining higher productivity and ensuring soil quality under intensive agriculture.Indian Journal of Fertilisers. vol 1(4):61-76.

Dr Aminul , i agree with your response .  In citrus , while comparing the response of organic versus mineral fertilizers, we observed superiority of mineral fertilizers for first five years  , thereafter organic manures surpassed the yield  and quality both. This is based on 10 years of observations. But again, question comes , can we afford to apply organic manures equivalent to mineral fertilizers..? In this context , remarks of Peter are worth considering . Soil microbes need organic matter to proliferate . Lets consider the carbon foot print of roots that we do not harvest . How much carbon , the roots add into the rhizosphere under the conditions where fertilization is balanced . Higher yield means much greater root density . And , probably , this is how , balanced mineral fertilizers maintain soil health on a sustained basis. However , the impact of balanced fertilization is highly dependent on our ability to diagnose the soil fertility constraints with respect to a given crop. Do we have that robust and dynamic  models , depending upon varied agro-pedological conditions..?

Look to Mulvaney et al 2007 the myth of nitrogen and carbon sequestration. This article chronicles the experience of the over 100 year Morrow Plots field system experiment at the University of Illinois its the major finding is that while the fertilizer was critical to maintaining high yield at the same time the soil organic matter continued to decrease. The idea that simply stimulating excellent plant growth can foster soil organic matter conservation and increase is reputed by the researchers and results point to focusing on soil organic matter content. The ability of crops to flourish in drought environments under rainfed conditions is often deterimined by the soil organic matte content due to the ability to capture, retain and recirculate water. In addition since air and water are key to soil life as well as food resource as soil organic matter improves in the soil environment the biological diversity and abundance does as well. When biological abundance in the soil is improved the soils promote plant and animal health in many diverse ways. Synthetic fertilizer can be deterimental by adverse soil effects on biological nitrification in literature, phosphorus solubilization from side effect on mycorrhizae and the earthworm effect I alluded to previously. 

Synthetic Nitrogen Fertilizers Deplete Soil Nitrogen: A Global Dilemma for Sustainable

Cereal Production

R. L. Mulvaney,* S. A. Khan, and T. R. Ellsworth University of Illinois

JEQ 2009, V 38: 2295-2314

Rodale Insititue/USDA http://rodaleinstitute.org/search/soil+health

USDA https://www.nrcs.usda.gov/wps/portal/nrcs/main/il/soils/health/

I strongly support Dr. Anoop Kumar Srivastava's explanations. Mineral fertilization helps to increase total biomass production. Rhizosphere effects also influenced by cropping. A notable portion of crop residues (whole amount of root and some portion of straw/stubble) are remained in soil. This residues play an important role in maintaining soil organic matter level as well as biological soil health. For this reason intensive rice cultivation (three crop in a year) for 26 year have no shown any decreasing yield trend. I do not believe that continuous crop cultivation with mineral fertilizer deteriorate the soil health or soil quality. Soil health or quality may deteriorate by pollution, soil erosion or removal of top soil and by so many other similar activities. Crop cultivation with judicious fertilizer may not destroy or deteriorate soil quality. however, integrated use of organic and inorganic fertilizer is much beneficial than sole application of mineral fertilizer. 

Mineral fertilizers are basis of modern day agriculture. We are not in a position to apply different organic manures on nutrient equivalent basis comparing the mineral fertilizers. We should also learn lessons from those countries where different land uses are so sustainable and there is hardly any nutrient mining or any issue of deteriorating soil health. 

Exactly Dr Aminul.  Infact ,  such residue deposition is the base of long term soil fertliity management , where role of root system is undeniably useful. But , there should always be an eye on  biology /ecology of soil, which s considered as invisible drivers of soil fertility  and its sustainability to sustain the  land use. 

Actually soil health and yield maximization are two different aspects. To get maximum yield, we should follow integrated use of fertilizer because mineral fertilizer alone could not give the maximum yield. This does not mean that soils are deteriorated due to sole application of mineral fertilizer. However, in the long-term soil fertility management application of mineral fertilizer alone showed increasing yield trend without loosing soil fertility or quality. We are conducting several long-term experiments in which we are testing mineral fertilizer, organic fertilizer or combination of mineral and organic fertilizer for double crops, triple crops or 4 crops in a year. But so far we found there is no evidences of the soil quality deterioration.

Exactly , this is what we also advocate . As long as we are in a position to strike balance between the amount of nutrients exported out of the rhizosphere and added , to disallow any remote possibility of nutrient mining , regardless of nutrient source we use , organic or mineral , i do not think,  application of mineral fertilizers will not deteriorate soil health. Dr Aminul ,  you will agree , there is no use of having a better soil health , unless its translate into better soil fertility , and hence, must leave their collective cascading effect on crop yield.

I agree with Paul Reed Hepperly's replies. Synthetic fertilizer developers have prioritized business strategies over science. I have researched organic vs synthetic fertilizers while in academia, and later on I worked as an agronomist in an agri-industry. The experimental designs used by corporations to test synthetic ag-inputs are typically incomplete, becayse they do not compare them to organic fertilizers. Their tests are based on the assumption that organic fertilizers are not viable, and that's not a scientific approach. Besides studies have shown that organic farming produces similar yields as conventional farming, with much less environmental health hazards. On a microscopic scale, synthetic fertilizers, typically salts, desiccate soil microorganisms. These are the microbes that would release exudates, with cause soil particles to stick together. This creates soil pores and the necessary soil structure to have an aerated soil and an adequate oxygen supply to plant roots (resulting in high yields). Today's agr-industry ignores the need for biological soil fertility, sells expensive inputs to farmers, and actually exacerbates problems like soil compaction. 

No doubt , mineral fertilizers  cut down the soil microbial load but still keep the soil biologically alive) , while organic manures/composts aid in developing microbial abundance . Rhizocompetent microbes ,we have seen in our experimentation act as very strong sink for nutrient (as a  part of better nutrient-use-efficiency), thereby , warranting a necessity to have a harmony between other biological means ( like microbial inoculation, crop diversification, AMs intervention, minimum tillage as a part of conservation agriculture etc) with mineral fertilizers . We also need to consider the time taken in producing the visible response soil and crop  to be measured in quantitative terms. but , diverting from mineral fertilizers  , n a belief that soil health is deteriorated , would be something like anchoring our modern agriculture to backfoot. This is my person opinion, others may differ...

Why dont we ever focus on the long term effect of different kinds of pesticides/fungicides poured into the system to see the loss in soil microbial diversity  vis-a-vis  soil health, more conspicuously than mineral fertilizers.?

Soil organic matter is directly or indirectly linked  to soil health/soil quality influencing several indicator parameters.Recommended rates of fertilizer  NPK to different crops in sequence in long term experiments increased the organic matter status compared to no fertilizer or manure(control), N alone and NP applied treatements.But fertilizer NPK plus manure(10-15 tonnes/ha/yr) is superior to fertilizer NPK.The carbon sequestration rate(kg/ha/yr) is higher with NPK+manure (50.7-900) than NPK (18.2-332.5).The difference could be due to the carbon input through roots,residues and manure in the two systems.Apart from organic manure, the nutrient input,output and the  budget / balance also decides the cropping system sustainability or otherwise.

The following three references may provide more information on the aspects highlighted by me.

Soil carbon management Issues and strategies by Muneswar Singh et al. 2014 Indian Journal of Fertilisers 10(5):118-132.

Carbon sequestratin:Nutrient management by M.C.Manna et al. Encyclopedia of

Soil Science,Third Edition DOI:10.1081/E-ESS3-120052914 pp. 288-293.

N,P,and K budgets and changes in selected topsoil nutrients over 10 years in a long-term experiment with conventional and organic crop rotations. by Audun Korsaeth Applied and Environmental Soil Science volume 2012,article ID 539582,17 pages doi:10.1155/2012/539582 open access

95):118-132.

Promoting balanced and judicious use of fertilizers will improve soil health, if we referred to soil health as the soil capacity to sustain crop production without deteriorating the agroecosystem. I am asking the question from another side; is using organic sources excessively to crops deleterious to soil health???

With the use of organic and synthetic inputs the ability of the input follow a law of diminishing returns. In terms of soil organic matter the greatest response is when the level is not optimized. Virgin soils before soil cultivation were generally optimized at 5% or more soil organic matter many of our cultivated soils are now in a lower equilibrium soil organic matter of 2% or less soil organic matter the largest response for increasing soil organic matter is from going from 1% to 2% soil organic matter and lesser response is from 4% to 5% soil organic matter and if soils are over 5% they reach a near sauration in terms of all requisite being fulfilled. The role of synthetic fertilizer also follows this law of diminishing returns. Moderation in organic inputs can be useful for crop production because our input capacity is not unlimited and spreading our inputs to more area can often give greater total benefit than saturating a crop response level. The cost of inputs is often related to bringing that input into the field and many times the use of growing your own is the best option for organic input. This can be done by using rotations of crops, cover crops and on site organic conversion by local composting. Soil and plant analysis puts the light on the black box of what is most limiting our crop needs and allows the best use of expensive and scarce inputs whether of organic or inorganic nature. . 

I would like to supplement what  Paul Reed Hepperly has said.  It is more true with tropical and subtropical soils where organic matter content (an important indicator of soil health) is already very low.  

In general, the SOM content of tropical soils, when brought under cultivation, can fall to as low as about 30% of the original value of the uncultivated indigenous state, but most reports indicate about a 60% reduction after 10 years of cultivation. Katyal et al. (2001) documented such changes with arable cropping from long-term field experiments. In a virgin soil, SOM remained stable for 10 years after fertilizer application, but subsequently fell to about 40% of the initial value during the next 3 years. However, when manures and fertilizer were applied, the SOM level was stable for 25 years, thus illustrating the value of integrated use of organic and inorganic nutrient sources in stabilizing and maintaining SOM in cropping systems and ensuring sustainability regardless of the cropping system. Under irrigated conditions and regular application of recommended application rates of NPK fertilizers, productivity stagnated or declined after initially increasing for 5–6 years. It was the combined application of fertilizers and farmyard manure that unfailingly sustained productivity. This conclusion was valid, irrespective of the location or the cropping system (Katyal et al., 2001).

Katyal, J.C., N.H. Rao, and M.N. Reddy. 2001. Critical aspects of organic matter management in the Tropics: the example of India. Nutr. Cyc. Agroecosyst. 61: 77-88.

I could hardly find any scientific evidence (published in refereed journals) that mineral fertilizers when applied as per recommendations do any harm to soil health.  Its only a notion that mineral fertilizers are deleterious to soil health.  Unfortunately this notion has been spread by people who are not conversant with basic principles of soil science. May I suggest the readers to go through the attached publication of mine and comment

I agree with you , regardless of mineral or organic fertilizer, as long as as fertilization is balanced and able to address to soil fertility constraints , there is every unlikeihood of soil undergoing any deterioration in soil health. There could be temporarily decline in soil microbial load  , but that is enough to keep soil biologically functional. 

It is a funny question, as we never use fertilisers alone. We use minerals fertilisers where we crop plants, to replace minerals removed by crops. If we wouldn't remove crops,  adding mineral fertilizers certainly woudn't damage health of soils, but intense cropping without adding fertilizing would damage. That said, question sould be : does minerals fertilisers can replace 100 % of minerals (quantity and quality) removed by crops and help to maintain organic matter.. There are so many soils, crops and fertilizers receipes that the answer is certainly as Dr. Srivastata wrote: Good balance is the answer. 

The conclusion's from Drs.Singh  and Ryan's publication are no way different from the lessions we learnt from our Indian long-term experiments(I have already provided some references based on those experiments).

 Dr Louis , you are dead right , regardless of source of fertilizers we use  and regardless of crop  we investigate ,  as long as , we are in a position to address soil fertility constraints with respect to crop , through  4R- Nutrient stewardship  Concept , we will always be in advantageous position to sustain the soil health...i appreciate your feedback..

Some interesting facts about use of mineral fertilizers:

According to estimations, since 1950, 30% to 50% of increase in food production has been attributed to the application of chemical fertilizers that contains nitrogen (N), phosphorus (P) and potassium (K) (Higgs et al. 1976). Tehrani et al. (2010) investigated the trends of 50-year of fertilizer use in Iran, they reported that fertilizer recommendations should be founded on the soil testing and plant analysis. In addition, the climate-efficiency uptake by plants and crop management should

be executed. Based on global statistic of current use of fertilizer is about 140 million loads of purenutrient fertilizer per year and it will reach to 190 million tons by 2030 especially in developing states (Alexandratos 2003). Paulson and Babcock (2010) reported that farmers approximately use more nitrogen fertilizers. Guler (2006), compared the trend of fertilizer consumption in the globe and reported that the portion of the entire quantity of fertilizer NPK in 2002 (6.141 million tons), 64 % and

35% were belong to developing and developed nations, respectively. In Turkey, the use of fertilizers is 64.2 kg/hectare, which is lower than that of the average in world consumption. Zhang and Zhang (2007), repoeted that fertilizers consumption was dependent on human population and the increase of fertilizers consumption was mainly resulted from expansion of human population.

Model analysis showed that world’s per capita annual consumption of total fertilizers, nitrogenous fertilizers, phosphate fertilizers, and potash fertilizers, were 34.6, 24.4, 6.6, and 3.7 kg, respectively. Per capita annual consumption of total fertilizers for Asia, Africa, Caribbean, Oceania, North & Central. America, Europe, and South America were 38.8, 5.9, 6.8, 114.0, 62.9, ¡0.9, and 43.6 kg, respectively.

Compared to the current level, the world’s total fertilizers consumption would reach 226,150,381 Mt by 2030, an increase of 32.1% against current level. Worldwide consumption of nitrogenous fertilizers, phosphate fertilizers, and potash fertilizers would reach 141,800,601, 50,961,129, and 33,388,650 Mt by 2030, increasing 37.5, 25.8, and 21.2% based on current levels. Consumption of total, nitrogenous,

phosphate, and potash fertilizers in Asia and Africa would increase 54 to 55% and 40 to 60% by 2030, respectively. Camara, Payne, and Rasmussen (2003) reported no technology could increase the production of winter wheat in United State, except the application of N fertilizers. Besides, its use in heightening the execution of all macro and micro nutrients except potassium was higher in rice. Hence, no

element, such as nitrogen has been effective in improving yield. Therefore, fertilizer inputs as an important ingredient for enhancing the production of horticultural crops as well as ecological risks from abuse of these plant foods. This work points to measure the course of use of chemical fertilizers between Iran and Malaysia (as developing states) along with US and Australia (as developed countries)

in the last three decades (1981–2010).

Source ;JOURNAL OF PLANT NUTRITION

2017, VOL. 40, NO. 4, 532–542

http://dx.doi.org/10.1080/01904167.2016.1250909

PDf enclosed fro further reading...really interesting..

We very often attach deterioration in soil health with excess application of fertilizers. This happens only in the absence of the fact that we conspicuously fail apply fertilizers as per soil test  and as per crop nutrient requirement . Our current pattern of monitoring soil fertility constraints lacks that preciseness and desired robustness to nail the constraints at the time they need their redressal. Here is a  beautiful work..worth reading , friends..

Changes in the soil properties and availability of micronutrients after six-year application of organic and chemical fertilizers using STCR-based targeted yield equations under pearl millet-wheat cropping system.JOURNAL OF PLANT NUTRITION, 2017, VOL. 40, NO. 2, 165–176

http://dx.doi.org/10.1080/01904167.2016.1201504

ABSTRACT : Field experiments were carried out to assess the effect of nutrient

management on soil properties and available micronutrients using Soil Test Crop Response (STCR) based targeted yield equations under a six-year old pearl millet-wheat cropping system. After six years, results showed that soil pH and bulk density decreased, while cation exchange capacity and organic carbon increased in farmyard manure (FYM) as compared to control and nitrogen, phosphorus and potassium (NPK) treated plots in both surface and sub-surface soil depths. Higher values of available zinc (Zn) (1.54 mg kg¡1) and iron (Fe) (5.68 mg kg¡1) were maintained in FYMCNPK treated plots, while higher values of manganese (Mn) (6.16 mg kg¡1) and copper (Cu) (1.07 mg kg¡1) were found in FYM alone at surface soil as compared to subsurface soil. This study demonstrated the importance of application of FYM in improving soil properties and maintaining micronutrients availability in soil and their uptake by wheat for sustainable crop production.

PDF enclosed fro further reading...

 Thanks Anoop sir for informative discussion. I have gone through the paper you attached and found very important scientific information. The experimental area was under dry climate with low rainfall (821 mm only). For this reason, though the soil is sandy loam the pH is above 8.0. Due to light textured soil application of organic materials (FYM) significantly decreased the bulk density of soil. On the other hand due to dry climate and light texture OM decomposition was slow (might be due to lower microbial population and activity) which in turn increased the OM level of soil as well as CEC of soil.

Actually, we have to keep all the conditions like climatic, edaphic or soil, types of crops and cropping pattern etc, in mind for nutrient management as well as soil management to sustain soil health. So, soils will never be deteriorate.

Dr.Islam, as I understand, the experiment was conducted under irrigated conditions.So the real effect of dry climate may not be so conspicuous on soil or plant.Rest of your comments are o.k.

The importance of this study is that zinc is the nutrient which appears most limiting to crop responses in the selected system. The very high pH of the soil will no doubt be challenging for optimizing the zinc nutrition. The fact that the fertilizer manure alone and fertilizer with manure gives the most conclusive zinc supplementation which from correlation analysis is associated with the role of soil organic matter in mobilizing the immobilized zinc in the soil. I believe this challenges the idea that the optimized state is from the fertilizer alone but the organic mobilization appears critical. I would suggest the very high pH could be addressed to give even better results I would support the idea that sustainability is difficult to support if the system itself is high dependent on massive water inputs which has a big input tag however you would measure it. Interesting work. 

Thanks Annangi Subba Rao sir for your comments.

Though the experiment was in irrigated condition but crops (pearl millet-wheat) are grown in aerobic or upland condition. I mean that the experiment was not in the wetland/puddled condition like rice crop. As the soil was light textured amount of irrigation also limited. So, I think such amount of irrigation had a little effect on soil pH. Actually my opinion about the high pH of the experimental soil is mainly due to the climatic condition of that area. Other wise pH of light textured or sandy soil might be acidic in nature under the climatic condition with heavy rainfall.

So far I know high pH in soil is developed under arid/semi arid (dry climate) while acidic soil pH may created under tropical or sub-tropical climate (wet). 

I agreed with Paul Reed Hepperly that due to high pH, maintaining Zn nutrition will be difficult though organic amendment of such soil may help to some extent for Zn availability.

Dear Dr.Aminul Islam,as I have not elaborated my comment ,it created some confusion.I am familiar with the area , soil and cropping systems prevailing there.The area is  semi-arid  in Indo-gangetic alluvium receiving annual rainfall of aroung 820mm and mean maximum and minimum temperatures of 31.2oC and 17.0oC(average of thirty years).In rainy season(July to September) limited irrigation is given and in winter (November to March) the crop is fully irrigated.The wheat yield is 4.5-50 tons /ha and pearlmillet yield may be  half of the wheat yield. So,this system gives sufficient scope for return of crop residues in the form of stubles and root biomass.In the Moharana et al. 2017 study,the manure alone treatment received 20 tons/ha manure and the NPK plus FYM treatment received10 tons/ha of manure.The manure alone and NPK+ manure treatments(even NPK)increased available Zn,possibly because of two mechanisms-direct supply of Z from the manure and solubilization of soil Zn by organic acids produced during the decomposition of crop residues and manure.Even there was some decrease in surface soil pH in treatments which received manure,which might have also helped in mobilizing/solubilizing soil Zn.

During my Ph.D programme I also made similar longterm study in the same area and found that the manure (supplying 0.78 kg Zn/ha) along with recommended NPK  met the Zn needs of  pearlmillet-wheat-cowpea cropping system and arrested the depletion  of soil available Zn status.NPK plus ZnSO4 treatment caused  substancial build up of available Zn in soil.

Effect of intensive cropping and fertilzer use on the removal of sulphur and zinc and their availabilty in soil. Subba Rao,A. and Ghosh,A.B. 1981.Fertilizer Research (Now Nutrient cycling in  Agroecosystems) 2:303-308.

Thanks A. Subba Rao sir for elaborate about the climatic and cropping system data of the area we are discussing about. I understand that rainy season (monsoon) of that area is very short with limited rainfall (only 820 mm). That is the situation for high pH of the soil. Generally light textured soils in the area with high rainfall have low pH (acidic). However, nutrient management you mentioned is nodoubt is favorable for improving soil condition for crop growth. 

When we talk about synthetic mineral fertilizer having potential of being deleterious to soil health we need to understand the health of the soil as a living biological entity is a function of the Carbon or organic matter that is present in the soil. This is so because this carbon is what allow percolation of water and air into the soil and allow water to be retained and recycled through it. The Rodale Institute Farming Systems Trial has over 33 years of experimental comparison of the conventional maize and soybean row crop system to the biologically based input system using cover crops rotation and organic amendment with the synthetic inputs their dozens of peer reviewed publications in Internationally reputed journals show that after a 3 year transition the biologically based system was competitive with conventional approach and in years of drought superior yield were found related to the increase in soil organic matter Carbon which improved the water relationship. The study shows besides soil organic improvements the ability of the soil to have thriving earthworms insects and fungi and bacteria was multipled. Judicious use of mineral fertilizers does not sterilize the soil but if we are talking about optimizing the soil biological input is critical. In the case of fertilizer a good case of unintended results is the emerging issues with Cadmium in phosphate fertilizers and as you know there are many issues around the world with soil acidity and one of the principle sources of this is ammoniated fertilizer use. For the developing tropics where nutrition is most critically short the soils can be acid and the societies do not have good ability to lime. Compost is perhaps the best way to help these population of people most in need.