This si a very intelligent question. Infact , organic manures can act as both, as a nutrient source nad as a amendment of soil by solubilising the phosphorus and other tapped micronutrients .

Dear Anoop, very interesting question, I made my PhD on the action of farm-yard manure (only) on soils degraded by long-term inbalanced mineral fertilization (60-years).

1. First point - not from my thesis, but personal experince - I think that dried manures, common in tropical or subtropical areas, as Peru, as "guano de corral" (dry excrements of cattle), "guano de gallinas" (chicken excrements) or "guano de islas" (THIS famous guano, which was exported by Chile) act mainly as N source. Well, N acts most quickly, other nutrients more slowly.

2. I did not study salt index, but I think it is important in dry areas. In European Union, it is more important to not exceed amount of N applied with single dose of organic manures;

3. I do not have idea on it, although it is clear, that the kind of substrate composted and the mode of composting determines the quality of final product;

4. I think in non degraded soils, with favourable reaction (pH in water of about 6-7) farmyard manure acts mainly as a source of nutrients, and improves some physical properties. And this effects lasts rather shortly. On strongly degraded soils, mainly by acidity (pH in KCl even of 3,2, in water probably about 4) the effect of single dose of farmyard manure last even 3 years or more and consists mainly on softening of negative effects of acidity (probably complexing of exchangeable Al). It also depends on crop. In my studies, during 3 years the crop uptake (apparent) from farmyard manure was about of 25-40% of N, 20% P, 37-55%K and 10% of Mg introduced with farmyard manure.

6. Use of organic manures in perennial trees - I see only 2 possibilities - before planting, with mixing it with the soil, and the other, composts spread on the surface, which would act mainly as source of nutrients (of slow action) and mulch.

Regards

 Thanks for you question Dr Anoop, there  is a paper on my RG profile discussing the use of fish meal with the perennial fruit crop Kiwifruit. We have had a fair amount of experience using animal manures and generally we find them to be a very good way to supply potassium complimentary to SOP & MOP. We balance sulphate & chloride inputs so that they are not in excess and the additional K requirement is supplied as composted animal manure blended with Greenwaste compost. The K requirement for Kiwifruit is 150 to 200Kg/Ha/year therefore the lower salt index of manures is a asset that we appreciate.  We are finding that the zinc component of animal manures is becoming a problem with annual soil test values progressively increasing and the earthworm counts are decreasing indicating inhibition of soil bacteria. We are not sure what to do next as a strategy, probably the current high yields (70T/Ha grade one fruit) are not sustainable in the long term, but how do I tell my growers to produce less?

The questions raised in relation to manure are very important, with a number of issues to be addressed. Several research works have been conducted on manures for decades; they were investigated singly or in combination with inorganic fertilizers. 

Their role of manures in terms of improving soil biophysical and chemical properties, supplying plants with range of nutrients and hence increasing crop yield has been enormous. As the sources of manures are different, their properties in terms of decomposition and ability in supplying plant available nutrients may be varied. In addition, improving the efficiency of manure in plant-soil soil system, especially nitrogen and the subsequent effect on greenhouse gas emissions, particularly N2O are major concerns in application of organic amendments to soils.

Climate is one of the main factors that affects of the efficiency and sustainability of manures in agriculture. The difference is very obvious in the tropical and temperate climate, where higher temperature in the tropics accelerates  decomposition and mineralization. This may make a significant contribution to global warming. According to research findings, the requirement of high application rate, enhanced mineralisation and low nutrient content are among limitations of manures. Therefore,in addition to use of high yielding and nutrient efficient crop varieties, application of manures with other organic amendments, such as biochar is one of the recent recommended practices that can enhance the efficiency of manures in the soils. Moreover, use of such practice will increase soil carbon sequestration so that the nutrient retention capacity of soils and availability to crops will improve, the amount of inorganic fertilizer required will decrease and greenhouse gas emissions will be reduced.

There is no blanket answers or solutions to anything organic that we suggest, we have to standardize it to diff plants diff soil conditions, climate, precipitation et. 

Dr Hani , I appreciate your exhaustive response .combining organic manures with mineral fertilizers , there always value added response compared to either of the two  alone. And , this kind of response gives fair idea that such manures are very good source of PGPRs . In this context , AMs will surely hold some definite promise with regard to nutrient uptake efficiency vis-a-vis quality production.   

Dr Singh , there is no doubt soil feertilized with organic manures , tend to dislodge the immobilized nutrients , thereby, improving the available pool of nutrients , elevating the production further.

Dr Philip , your concern is very pertinent . But I wonder,  how come , where animal manures are used, zinc  index of the soil and earthworm counts are on the decline. Salt index of organic manures , how important is it ?.

Dr Getachew , you have added an entirely new dimension to the after effects of organic manuring by stating the magnitude of green house gases. Application of biochar as a soil amendment  , but with this also, it is to be seen , how effective it is with regard to lessening the emission of green house gases.

Ms Rehaneh , you raised yet another important issue , how effectively , we can de-contaminate the soil using organic manures , by facilitating the adsorption of contaminants on the colloidal particles, particulate organic matter being one of them.

I am sorry Michal , I could not respond to your answers. The degraded soils are probably the first class of soils , most befittingly going to experience the benefit of the organic manuring . But Michal , a soil deficient of multiple nutrient deficiencies , do consider such soils degraded , if so , organic manuring will  produce huge benefits to not only physic-chemical properties , but microbiological properties will also be an added advantage with such practices. This is  a very good point to  flag off , how well , we can amend degraded soils with the organic manures , but I am looking beyond  degraded soils , that is heavy metal polluted/contaminated soils.

Very good discussion taking to very conclusive discussion. When we talk of organic manure , how can we ensue , it is quality manure . Can we say , in order to make a organic manure biologically active , we need this much of microbial load in a given manure ?.Dr Hani , Dr Michal , Dr Gatechew I need your interventions.

The quality of manure can simply be improved before it is appled to the soil.  Sheltering fro direct sunlight reduces N volatilisation losses  - similary protcetion against  direct rainfall reduces leaching losses.  Retention of urine and ddition to teh manure improves  N.  Once well compostsed, manure  should be buried soon after spreading - again to reduce losses.  See:

Bishwakarma B.K., Dahal N.R., Allen R., Rajbhandari N .P., Dhital B .K., Gurung D. B, Bajracharya R.M. and Baillie I.C.  2014.  Effects of improved management and quality of farmyard manure on soil organic carbon contents in small-holder farming systems the Middle Hills of Nepal.  Climate and Development. DOI 10.1080/17565529.2014.966045

The quality of manure can simply be improved before it is appled to the soil.  Sheltering fro direct sunlight reduces N volatilisation losses  - similary protcetion against  direct rainfall reduces leaching losses.  Retention of urine and ddition to teh manure improves  N.  Once well compostsed, manure  should be buried soon after spreading - again to reduce losses.  See:

Bishwakarma B.K., Dahal N.R., Allen R., Rajbhandari N .P., Dhital B .K., Gurung D. B, Bajracharya R.M. and Baillie I.C.  2014.  Effects of improved management and quality of farmyard manure on soil organic carbon contents in small-holder farming systems the Middle Hills of Nepal.  Climate and Development. DOI 10.1080/17565529.2014.966045

Dear Dr Srivastawa

I have tried to answer your querries point wise as under:

·         Organic manures effectiveness depends upon the method, materials used in composting and duration of fermentation. Compost prepared in a pit with one type of material and gets ready in one year for use, will not serve good source of nutrients.

·         There is no need of increasing or decreasing salt index of compost because if it is prepared with various materials in a systematic manner in a given time will not have excess of sodium or chloride.

·         Quality of compost depends upon materials used in composting. Therefore, leguminous and non leguminous organic wastes are to be used in 20:80  ratio. Maintenance of  C:N ratio in composting is very important to get quality compost in given time

·         In case of IPNM 50 % nutritional requirement should be met from organic sources.

·         It is not required.  For improving PGPR activity in the soil/organic farming application of vermi wash, cow pat pit and panchagavya are recommended.

·         Application of quality organic manures cannot reduce the pollution of soil. Pollution can only be reduced by stopping the use of agro chemicals.

Any type of compost can be applied in perennial and annual crops. Biodynamic, NADEP, vermi and microbe mediated composting are the best method of composting which gets ready within 1-3 months.

Dear Dr Srivastawa

I have tried to answer your querries point wise as under:

·         Organic manures effectiveness depends upon the method, materials used in composting and duration of fermentation. Compost prepared in a pit with one type of material and gets ready in one year for use, will not serve good source of nutrients.

·         There is no need of increasing or decreasing salt index of compost because if it is prepared with various materials in a systematic manner in a given time will not have excess of sodium or chloride.

·         Quality of compost depends upon materials used in composting. Therefore, leguminous and non leguminous organic wastes are to be used in 20:80  ratio. Maintenance of  C:N ratio in composting is very important to get quality compost in given time

·         In case of IPNM 50 % nutritional requirement should be met from organic sources.

·         It is not required.  For improving PGPR activity in the soil/organic farming application of vermi wash, cow pat pit and panchagavya are recommended.

·         Application of quality organic manures cannot reduce the pollution of soil. Pollution can only be reduced by stopping the use of agro chemicals.

Any type of compost can be applied in perennial and annual crops. Biodynamic, NADEP, vermi and microbe mediated composting are the best method of composting which gets ready within 1-3 months.

Dear Dr. Ram, your comments are appreciated. But, I have questions for you. 1) Why are composts prepared in pits are low in quality? In fact, the composting time depends on climate like temperature, feed-stock source for composting,  composting facility, etc. 2) Don't you think manure and farmyard manure are among the huge sources of composting materials, which you didn't include in your comment?  Moreover manures are rich sources of nutrients. 3) By the way, if appropriate procedures are not followed during composting process and application in fields, poor composting and management may be causes of pollution. 4) Don't  you think composting and application of compost with bulking materials such as biochar would optimize nutrient use efficiency and reduce greenhouse gas emissions, mainly N2O?

Thank you!

Ms Reyhaneh, yes labile fraction of soil organic matter by virtue of its   vulnerability to microbial decomposition , in addition to its dynamic nature and strong colloidal behaviour , soil pollutants ,especially the heavy metals could be effectively immobilized to clean uo the soil from any such contaminants, offers a great possibility with regard to adsorption chemistry. Hope Dr singh , you will agree with me.. We right now probably do not have any such threshold limit of microbial load , whether it  is fungal or bacterial  population ,fto define the quality of a manure. Ian , reaearchers are still not unanimous whether or not , manures should be buried in soil , simply  because , one group observes accelerated rate of denitrification , while other group is very particular about leaving the manures on the soil  suface , allowing good aeration . 

Dr Ram Awadh  thanks for your response.  i never meant to upscale or downscale the salt index of manures. I simply wanted to get the opinions of learned colleagues like you , can salt index be used as an indicator of manure quality , instead of microbial load ?. And to what an extend good microbial load of   a manure is an assurance for quality manure.  Dr Getachew has raised some pertinent points , hope get response from you rDr Ram Awadh.

Dear Anoop, I haven't work on soils contaminated in heavy metals. I can only agree with other answers, that organic matter may made complexes with heavy metals, but the question arises, is it good or not? Probably it depends, we remember, that some micronutrients are/were applied to soil or plants in form of complex with EDTA. In this case it increases availability of these nutrients to plant. Would it be favourable in the case of heavy metals (which are frequently also micronutrients) occurring in excess in particular soils? Clearly, on acid Al toxic soils this effect is beneficial, but what with other elements?

However, the effect of organic manures increasing soil buffer capacity and thus helping to prevent acidification may indirectly affect mobility of heavy metals.

Additionally, there is one recommendation well known in organic/ecological agriculture - adding of bentonite or other montmorrillonite rich materials during composting process. It favours creation of complexes of clay and organic matter, which are much more stable in soil, than organic matter itself. It is especially important on sandy soils (farmers in Poland were commenting, than farmyard manure disappears or "is burnt" within 2 years after application) and possibly in caolinitic soils (I don't know them, but may be).

I don't refer to microbiological properties, but clearly they determine, that the soil is soil and not rock, or hydroponic substrate. Sorry for my English.

Dear Anoop Kumar Srivastava ,                                       Sept. 25th 2015

Congratulations for initiating a very interesting question and set of inputs by learned scientists at global level. I enjoyed reading it. Thanks to the ResearchGate for providing the platform.

But  I doubt if objective of soil fertility management can proceed only with fertilizers and inorganic applications. They might serve as stimulants but not as primary determinants. Green Revolution has already shown human limitations and Nature's intelligence. Biophysical and biochemical functions in synergy with biological elements are necessary base for sustainable production. Low entropy elements of both biological and non-biological sources are very important.

I still emphasize the role of diversity of carbon, organisms and niches which in synergy can bring sustainable production.  Good amount of function diversity of soil biota will maintain a hierarchical order. We have been able to establish it in tea plantations, rice and vegetable cops.

Some of related publications are attached.

 All the best,

B. K. Senapati

Michal, you have put up another very interesting point about the disappearance of farm yard manure within two years in kaolinitic soils ( Probably Alfisols or  Ultisols )  .  Such soils are low in soilf ertility with low cation exchange capacity . This is the reason , we need to keep soil microbiologically alive , and role of microbes , either in single/double or multiple inoculation comes so imminent to keep soil biologically active. there  is absolutely no doubt , whatsoever , organic manures maintains the nutrient pool of soil in such active /labile form , and resist against leaching losses or any abrupt change in soil pH, simply because of elevated buffering capacity of soils treated with organic manures . I agree with you  Michal.  

Dr Senapati , thanks for your elaborate response . I endorse you points of view. The biophysical and biochemical properties of soil have to function in tandem to sustain the long term productivity without incurring any depletion in nutrient pool of the soil. Such hierarchical order of functioning has to work with their functionality .

There are many answers for all these questions. Recently (unpublised data) We use Rhizobacteria associated with bio-fertilizers on cotton seeds and plant responses was significantly superior to plants without them. So I suggest to you use PGPR to improve manure responses.

Fabio, thanks for your instant response. Let me share my experiences with  citrus. We tried the response of PGPRs by inoculating with  acid lime seeds  and by inoculating the growing medium . Interestingly , the responses by inoculation of  PGPRs with growing medium were far superior over inoculation of seeds . So , its often very difficult to streamline , better response , you can get either by inoculating the seeds or by inoculating the growing medium. Many of our esteemed friends  have opined that if manures are well composted , they are very good carriers of effective PGPRs.

No doubt , there could be many answers , but the central theme of these questions pertains to so many factors leading to improvements in response of organic manures .  And , that was the very purpose of floating those issues. Please look at some previous responses, you will get fair idea.

Manure and composted manure brings a lot of beneficial microorganisms that can act as PGPR. This probably is not the case for mycorrhizae, in that case it will be beneficial to inoculate plants or trees with mycorrhizae, and during establishment of trees one should be carefull not to add a lot of available P that could inhibit mycorrhization.

I agree with you Imran . Well composted  manures also could be an effective source of microbes  aiding further in expanding the agronomic response of crops.What about salt index of manures,  what is your opinion . None of our colleagues responded to this question .

I think many points raised are important and valid. As I understand you are interested in manure quality indicator... this depends on whether you want intimidate soil nutrient replenishment effects or longer term  slow release of nutrient... in case you are interested in the first you may want consider checking the C to N ratio....With respect to salt index I propose to learn  from the principles of salt index of in organic  fertilizer materials.  Virtually all fertilizer materials are salts. When they dissolve in the soil they increase the salt concentration of the soil solution. An increase in salt concentration increases the osmotic potential of the soil solution. The higher the osmotic potential of a solution, the more difficult it is for seeds or plants to extract soil water they need for normal growth. If I did not miss something fundamental this principle works for fertilizer as well.....

Thanks Amare , very interesting answers. I was trying to look at some new quality parameters of organic manures , apart from those so conventionally used to describe the quality of organic manures . Is there any development further . With regard to salt index , for fertilizers , its ok , it will dissolve, if not cent percent , but for organic manures , they do not dissolve , and therefore, leave very little salts to some accountable osmotic potential of the growing medium , affecting plant growth to certain extent .

A major weakness of many organic nutrition strategies is the lack of quick response for early seedling stages. All manures are not the same the manure which I have found gives the quick seedling response is Vermi compost or earth worm castings. These are low in ammonia but have good nitrate concentration. In addition they are high is soluble phosphate and the complete complement of needed nutrition including its excellent ability to supply Calcium.

The use of a thermophilic turned leaf compost when amended with 10 to 20% castings gives season long and early growth stimulus. This is a best of both worlds all organic solution to many issues in feeding plants organically. It also saves on application since it is useful for early and later stage nutrition without unnecessary multiple lay by applications.

Very interesting response Paul. That's one of the ways to  improve the effectiveness of the organic manures by adding  some castings into any compost  manure . Whats your opinion , shall we work the compost into the soil or just leave it on the surface ?.

Dear Anoop

I believe the most effective and efficient use of the casting with compost would be to mix with some rock phosphate and put it directly into planting hole. This kick starts the root and establishment so critical to future development and reduces any losses to a minimum.  We need to look for ways to do this optimized practices without too much labor to get the best of both Worlds.

Vermicompost (VC), rice husk ash (RHS) and coconut fiber (CF) are environmentally friendly materials. VC has many favourable physicochemical characteristics, making it suitable for mixture in substrates including high porosity, good aeration, drainage and water holding capacity.  Vermicompost, in contrast to conventional compost, is the product of an accelerated biooxydation of organic matter by the use of high densities of earthworm populations without passing a thermophilic stage and . Recent studies have shown that different earthworm species are able to consume a wide range of organic residues such as sewage sludge , animal wastes  crop residues; and industrial wastes . The earthworm-processed organic wastes are finely divided peat-like materials with high porosity, aeration, drainage, and water-holding capacity.  Compared to conventional compost which passes a thermophilic stage, vermicompost usually has a much finer structure and larger surface area providing strong absorbability and retention of nutrients . It has been reported that vermicompost contains biologically active substances such as plant growth regulators. Based on all these characteristics, earthworm-processed organic waste would have a great commercial potential in the horticultural industry as container media for growing bedding and vegetable plants. There is strong scientific evidence that vermicompost can significantly influence the growth and productivity of plants

Paul very pertinent , I agree with you marinating manures with rock phosphate will surely trigger off early plant establishment  followed by later cascading effect on subsequent plant performance.

Imran , appreciating your nice response , I am enclosing one PDF explaining about , how nicely , we can elevate the effectiveness of organic manures . And it also gives an idea , how such value added manures serve in safeguarding the environment by restricting the release carbon dioxide from the rhizosphere zone.

Friends , you will agree very little has been done , and addressed infact , with regard to microbial community type  and ratio of different microbial community type , how do they determine the success of different crops , or how differentc rops transform such microbial community diversification on structural as well as functional baiss.How these microbial communities enable evolutionary success of different  crops?. Probably this is the reason , we perceive organic manures so self sustaining , considering the  microbial load of  the well composted manure s.This is the reason  , the concept of Plant specific microbiome consortium has been introduced , citrus is one of them .

Is there other method to improve efficiency of organic manures on contaminated soils. How different technique is adopted to improve the response of organic manures on such soils.

Dear Reyhaneh Eslamikhah,

Organic manures can play amazing roles in decomtaminating polluted soils.

Case of interest is the soils showing acid soil infertility having a root of Aluminum and or Manganese solubility. The humic materials can serve as chelators that remediate the toxicity at pH that without the humic buffering and chelating detoxifies an otherwise toxic situation.

The alkaline soils probably more typical in Iran have significant issues in chlorosis from iron deficiency. Humic materials can chelate insoluble iron that allows solubilization and will also permit the chelator and iron enter into the plant remediating the condition.

Because of these vastly different conditions that humic materials addresses the molecules in themselves seem to be adaptable and almost having a property of intelligence.

Really quite amazing and at very low concentration.  Also beautiful.

There is long list of questions asked by Anoop Kumar Srivastava. These questions have been addressed and elaborated in literature. Of course ResearchGate is also a plate form of interaction.among scientists but answers can be detailed out to be useful and meaningful to readers.

It is my considered opinion to use manure as soil amendments and not a source of nutrients under arid land calcareous alkaline soil conditions. The physical presence of OM in these soils is its blood to impact physico-chemical properties in favor of crops.

The manures do offer limit the contaminant hazards in soil through providing more exchange site for electro-positive ions and more pertinently complexing contaminant ions with products released during their decomposition.

Mixing manures with fertilizers do help conservation of nutrients, particularly help P release, against unproductive losses through enhanced exchange reactions.

Consideration of salt index for manure is of no significance compared to enriched fertilizers, i.e. synthetic fertilizers like urea, A/S, SSp, TSP, DAP etc.

MsReyhanesh, the humic acids in  well decomposed and matured composts can deactivate the heavy metals and reduce their toxicity but can not in real sense decontaminate heavy metals in soil because they will remain soil until removed by some means.The humic acids because of the presence of functional groups carboxl,phenol,hydroxyl,enol and carbonyl structures they form stable complexes with polyvalent cations  including heavy metals ans some essential micronutrient cations.Heavy metal- humic acid complexes vary in their stability with different heavy metal ions.The complexes between humic acd and Cu,Fe,Pb etc are much stronger than with Zn,Mn, Mg. The Ni, Co and Cd occupy intermediate position . The humic acid and metal complexes can be transported. That means they can move from soil to near by water bodies..So the well decomposed and humus rich manure can help to provide some relief from heavy metal toxicity for some time(as long as the humic acid remains or until another/stronger cation  displaces it from the complex) but not a permanent solution to heavy metal toxicity in contaminated soils.

Dr. A. Subba Rao is perfectly correct and precise to reply.

Dr Ghafoor, thanks for participating , but let us  allow  the participation of  our  other learned colleagues as well in  a meaningful manner. We often interact in textbook style, but in field , it offers altogether a different response. Role of organic manures , we need to look into as a dual purpose source ,  an effective soil amendment and as a nutrient source , irrespective of nature of soil type , salt affected or normal pH soils( In contaminated soil , it is altogether a different course of action as nicely explained by Dr Rao). In prennial crops atleast , this is an estblished fact  . Bringing change in soil physical properties through organic manuring takes inordinately long time , and often goes unnoticed, unless the analysis on  aggregate size and its stability , bulk density etc are performed , the turnover time for which will again will depend upon the buffering capacity of the soil. In perennial crops , we have observed , unless soils have enough organic acrbon , crops do not respond to microbial inoculation..

I agree with you Dr. Srivastava. We have observed much higher EC value of poultry manure followed by pig manure. How come such high EC emerge?

If we are looking for ways to maximize the total response of humic resources it would good to understand that optimum responses to these compounds are at ppm concentrations.

The response to fulvic and humic acids are notable at 50 to 250 ppm and are extinguished at higher concentration levels. In addition the humic acid responses are more on rooting and the fulvic acid response on top growth.

I would suggested mixed humic fulvic acid applied at 100 ppm would give optimum response and because of optimized low application they could be applied at least cost and most return on investment.

Because of the cost of composting where most of these organic input come from our ability to apply them strategically would end up optimizing their use.

Many experiments with these compounds use exorbitant levels causing their efficacy and cost effective to be written off unfairly.

Some Thoughts.

An interesting and useful addition to the discussion Paul . Can you please comment on the points raised by Dr Deka about the higher electrical conductivity of poultry manure and pig manure to a lesser extent . I can understand , in poultry manure , we use lot of  rice husk and  we use protein based materials in  poultry feed as well. The accumulation of amines could possibly be one factor accountable to high EC of poultry manure .  

Dr.Hepperly,your attached paper refers to use of compost ,raw manure and green manure etc.It does not pertain to humic acids use as soil or foliar application .It is not clear whether you are referring to foliar application of humic acids to some crop or soil application of humus.The rates of application ,purpose of application and mode of application  of  humic materials  will be different. So please clarify the products you are referring to,rates,methods,crop etc.

Dr Srivastava , I do not think salt index of manures are

needed to be analysed on mandatory basis , but surely , it will add a

new parameter to indirectly judge the quality of the manures. At the

same time , manure quality should not only judged by the nutrient

composition , but microbial load will also add some additional

information about the quality of the manure in question .

Composting is the best way to make the organic composition easier assimilated by culture.

 Composted manures have always not only higher nutrient concentration but microbial load also. Do you feel perennial crops are better suited for higher magnitude of response of organic manures than annual crops. Friends what's your stand?

Dr you have raised another  very pertinent issue . Yes, perennial crops by the virtue of long juvenile phase , perennial framework acting as perennial source of  nutrient reserve, and   nearly 250-280 days  of  annual growth cycle , hold much higher potential for better response of  nutrient source, either organic or inorganic in nature . Annual occurrence of root flush followed by shoot flush also triggers off better nutrient demand through  excellent vascular system between underground root system and  above-ground shoot system .   

My young  and enthusiastic colleague raised two points-one regarding salt or higher EC of manure and the other regarding the microbes in manure.I think the salts have origin in animal feed and water. Like us, for animal big or small need salt and salt requirement vary with animal and age.Please consult this publication.Salt and trace minerals for livestock,poultry and other animals. by Larry L. Berger .www.seaagri.com/docs/salt_and_trace_elements_in_ animal_ nutrition_.pdf

Compost can be dung based or organic waste based.In both cases the origin of microbes is from dung.As you know the microbes decompose the organic matter.For faster decomposition externally some fast decomposing organisms /cultures are added.In thermophilic stage where temperature raises to 60-70  C,many of the organisms are killed.(our scientists are working on fast decomposing high temperature- tolerant microorganisms).During cooling and compost maturation stage a new group of organisms develop in the compost.Surviving organisms ,air and water may be source for these organisms.But now we are fortifying the manure with beneficial organisms like N fixing, P solubilizing or PGPR ete.The other side of the story is the harmful organisms in compost. Composts, especially urban , raw dung manure contain micro organisms like Salmonella,Listeria and E.Coli.If any body wants to know more about the pathogens in raw manures or composts please see the following.Pathogens and public health concerns with composting by Chris Cronin www.anr.state.vt.us/dec/wastediv/compost / ... 2.Compost pile hazards by Nick Gromicko www.nachi.org/compost-pile-hazards.html 3.Compost reduces growers'concern about pathogens.David Crohn and others. www.calrecycle.ca./publications/.../organics%sc 44200014.doc.

Can you please elaborate your answer on salt index of the manures for the benefit of the discussion , which is so excellent .

Dr.Singh,I never used the term salt index in manures. I am aware of salt index in fertilizers but not in manures.But Dr.Deka raised the issue of high EC in manures.I looked into literature and found the origin of salt in food and water given to animal.I alreadycited the detailed report for the benefit of followers of this question .I am providing one brief note which provides the insights into salt in manure.This may pertain to  concentrated animal feeding operations as in some dairies or poultry farms and not under farmers' conditions.In Arizona the the dairy and feedlot manures contain as much as 5-10%salt.Frequent application of manures or high rate of manures  may cause salt injury to plant.Please refer the publication. Animal waste management http://ag.arizona.edu/animalwaste/farmaste/awfact8.html 

Dr.Singh,I never used the term salt index in manures. I am aware of salt index in fertilizers but not in manures.But Dr.Deka raised the issue of high EC in manures.I looked into literature and found the origin of salt in food and water given to animal.I alreadycited the detailed report for the benefit of followers of this question .I am providing one brief note which provides the insights into salt in manure.This may pertain to  concentrated animal feeding operations as in some dairies or poultry farms and not under farmers' conditions.In Arizona the the dairy and feedlot manures contain as much as 5-10%salt.Frequent application of manures or high rate of manures  may cause salt injury to plant.Please refer the publication. Animal waste management http://ag.arizona.edu/animalwaste/farmaste/awfact8.html 

I raised about the salt index issue of organic manures for the simple reason , their EC level quite high , especially for poultry manure and pig  manure ,we often overlook this  aspect . Perhaps , we need to add another criterion of salt index , similar to inorganic /mineral fertilizers to judge the quality of the manures. In that context , Dr Srivastava has raised a very interesting point.

The main problem is usually a low ratio of N : C or with some tropical plants N : (lignin + protein binding polyphenols) and or low P as well as low quantities of organic manures where they are needed most.

Legumes high and low in polyphenols can be grown together, and proper nodulation promoted by simple methods I developed.

I developed methods making it easier and more beneficial to include nitrogen-fixing trees into farms and contour lines, making sure they actually fixed N and conserved soil well. I also recycled ash in-a-way so it did not harm roots or induced ammonia volatilization from raised pH of manure surfaces.

Furthermore, I developed methods making it easy to separate the lignin and the nutritious fractions of the tree shoots, and grow much of them without harming crops. Burning the woody parts as fuel saves valuable organic manure.

You can find documentation at my Agroforestry Systems journal article at my site.

Soil pH can be critical for legumes and for manure use.  I  developed an improve soil pH testing methods too published in another publication. 

I am interested in research (or extension) collaboration on follow-up, and is easily found at LinkedIn too.

Dr,Deka,what is the source of your information on E C values of pig and poultry manure,Indian or other countries?Based on how many samples the inference was drawn?

Dr.Mandal,Green manures are not normally grouped under organic manures but can be used complementary with organic manure as suggested by you.Dr.Singh and Dr.Deka,I could find  a critical limit  for salt in manure from Colorado State University.Manure or compost made with manure containing salt up to 10 dS/m(10 mmhos/cm) total is acceptable if cultivated 6-8 inches deep into a low-salt garden soil(less than 1dS/m or 1 mmhos/cm).Using manure in home garden Cororado States University . www.ext.colostate.edu/mg/gardennotes/242.html

My statement is based on analysis of at least  20-25 samples in India . But in acidic soils , such manures have huge application , provided they are available in plenty . There are some reports about the farmyard manure also , but I am not too sure. Such exercises provide strong clue to have the criteria of defining the quality manure revisited. I invite the comments from other colleagues as well on the subject .

Dr.DeKa ,please give some details of your analysis,mean, range etc or provide reference to your work.

I give a hearty agreement with A. Subba Rao.

I believe that manure has much less long benefit when applied in raw states than the results we get with compost application.

Using compost has major advantages over the use of raw manure. First is its superior ability to accumulate Carbon and Nitrogen in the soil. When raw manures are used their is little accumulation of the Carbon and Nitrogen showing their difficulty in relation to critical issues of soil productivity. 

In relation to soil stability of the Carbon and Nitrogen fractions these are increased when clay is bound with the organic material in organo clay complex. This can promoted by including a 10% portion of clay in the compost mixture. 

The organo clay complex is critical to longevity the nature of clay and humic materials are the holding of negative overall charges. Their complex is faciliated by presence of Calcium Iron and Aluminum. 

We tested the organic clay complex theory using a series of treatments on novel compost pad lysimeters at Rodale Institute these showed that brown matter and the 10% clay 2% gypsum and 1% humate was able to virtual eliminate the loss of soluble materials in the Nitrogen factor, led to reduction of odors, and improved texture and soil. 

Finally at least in Industrialized societies the biggest issue with organic waste is a space issue. The use of compost can greatly reduce space requirements and make the bulking field delivery much less of an issues. It also eliminates issues pathogen pathogenic issues with raw meanures. 

It is clear to me that we will soon have a need to use human manure beneficially especially if peak Phosphorus is indeed in our future. This will put even more emphasis on resolving the manure problem through a composting future.

To disclose my vested interest my son is CEO and owner of Heppperly Enterprizes the largest producer of prime compost in the Caribbean his business uses no manure being strictly based on yard wastes. 

To make myself clear I have nothing against manure just believe a large portion is wasted unnecessary because best compost practices were not used in its beneficial use. 

Dr.Hepperly,thank you for providing new insights into compost production by fortifying with clay, gypsum and humate.I have two small questions.If clay is 10% ,is there farmers' acceptability?Are you fortifying humate with  micronutrients?Otherwise compost is already containing good amount of humus.

Dear Doctor A Subba Rao,

this process uses the cationic substance to bridge the repelling naked humus and clay both with negative electrostatic overall charge.  In order to keep costs to minimum farm substance can be used as the clay source.

In the process which is based on aggregation theory presented first in Australia by Oades.

Doing this this  the change and transformation is seen visibly and confirmed in leachate and other measurements on nutrient contents.

the experiment is a proof in concept of that theory of aggregation. In reality the humate does not have to be bought rather it can be prepared in house from a remnant of the compost can be used in seeding the process as the humic material.

The most vulnerable layer in compost is the manure the amendments of Calcium sulfate Clay and humate or compost are mixed with the vulnerable manure layer. The brown materials above and below adsorb any leachate and reduces volatilization the two major routes of losses.

Compost is done with minimal mixing especially at the first stages.

by delaying and minimizing mixing we prevent major losses from volatilization.

This technique is an adaptation of Sir Howard method based on Indian traditional methods.

It has found that limits for soil organic matter accumulation are a function of clay and calcium content.

I think you will find value in this method.

Thank you Dr .Hepperly for promptly providing  the interesting  and new information .

Dr Hepperly  an excellent response to the chemistry of the composting . We often overlap composting with manuring . I would further appreciate,  if you have any publication , kindly share share  for the benefit of this discussion . You  have steered this discussion so imphatically .  

Dear Compost Philes

Hope you find this publication useful.

When it comes to manuring its strength is the soluble nutrition and humic stimulation which has a starter nutrient effect very important for high crop production.

A problem with organic systems is that stabilized humus is a slow release material.

A most excellent best of both worlds is to use raw manure in concert with compost.

The best mixture I have experience developing is 5 parts stable mature leaf compost with 1 part earth worm castings. This can be applied directly to root systems without toxicity and gives give nutrient release for earth worm casting and season long nutrition from the stabilized leaf compost.

Please take a look at the enclosed article and you might be convinced manure is needed as worm feed.

Paul , whats your take on the issue , some of the poultry manures and pig manures  samples have high EC value .  Don't you feel , this EC value will cut down the microbial load of such manures , rendering  them lesser effective?. Do we need to introduce  yet another parameter  for evaluation of manures for quality appraisal ?

Dear Doctor Srivastava,

you are right to be concerned about excess salts in manure even when our soils are demonstratively salt deficient an apparent contradictory conundrum.

As you are aware, in the global context, I would put salts next to acidity as the biggest agricultural limitation.

When dealing with raw manures this might constrain the optimal direct use especially in semi-arid and arid regions where salts are already high in top soil.

The ability to take this apparent lemon and sweeten it into lemon aide is by composting. While raw manures can be salt constrained the mature prepared properly as best practice is as amended compost which included manure is not raw but an useful amendment.

In the arid environment soil C is the limitation which is very pressing. Without the improvement of soil C the nutrients can not be held nor the water with is the limiting factor. Many of these soils are sandy and salty the use of waste clay in the compost process greatly reduces the leachate and volatilization of manure component in compost I recommend that subsoil clay 10% 2% gypsum and 1% humic material be added to a Indore modified compost system with minimal initial mixing to get the best stabilized organo clay complexed materials which do not rapidly degrade. This system adds the issues of the raw manure and optimizes the long term needs of Soil Carbon as the result.

Thank you Doctor for asking my opinion. I appreciate your leadership in these important discussions.

Dear colleagues,there are problems with raw(dung) manures or immature(not sufficiently decomposed) composts.The acute effects(immediate response by plant) and chronic effects(symptoms slower to develop).The acute effects are due to salinity ,ammonia toxicity and organic(fermentation)acids and chronic affects due to high C:N ratio and phytotoxicity due to excess minerals.Raw poultry manure litter(fresh,wet and not composted) may have salts and  a higher quantity of N in the form of ammonia.Salt together with ammonia may cause injury to seedlings of tomato,pepper etc.High salinity weakens plants and often leads to root rot,those caused by Pythium andPhytophthora ( in crops like soy bean,rhododendron) In USA states  provide guidelines to use manure containing salts-fixing critical limits,composting  ratio of dung to bedding material,application rate,leaching /irrigation after amending the soil with manure.The following  brief note may give some idea of the problem and possible solutions. Can compost damage plants  whatcom.wsu.edu/ag/compost/Compost_Damage.htm.Reprint from Biocycle Sept200,41(9)

 Fresh manures , especially poultry manure  , swine manure , they do have a tendency top record higher salt index ( Please see the work of Peters and Combs 2003; Busch et al 2002)  .Such high salt index  facilitate build up of excessive  nitrate nitrogen , later damaging the crop. But , if composted as per compost maturity tests, such nitrate levels are converted to amino acid and microbial protein , easily assimilable through mild decomposition to the plants . But literatures do suggest about the possibility of  salt index . There is also a better crop  response of the well composted manures compared to undecomposed manures.  I am enclosing some literature for your reference , with a hope that this will provide better understanding on the subject .

Paul , my question is addressed to you and other colleagues can join . Do you feel different compost maturity criteria need to be practiced to ward of the problem of decomposed /undecoposed manures ?

Dear Amarendra Singh

When raw manures are used there are dangers such as the possibility of bacterial pathogens such E coli coliforms and others being a problem. This sanitary issue is resolved by composting especially when heating is done well. The use of highly turned compost has it own issues especially the losses of Nitrogen in the turning and expense. To have the probiotic nature of compost it most cure and be recolonized by beneficial microbes.

While manure compost gives season long nutrition it is notably weak in giving a starter effect. Raw manures because of their greater solubility are more immediately available. To get the best of starter effect and season long feeding I suggested and have had great success with mixing 3 volumes of well done compost with 1 volume of manure.

My favorite manure is earthworm castings which are both a complete nutrition but also has advantages of being with the sanitary issues common to other manures. Therefore my firm belief is that manure should be used for worm culture and the prime casting used with vegetative compost for more effect and efficiency.

The mixture I proposed is a one time application for season long results. One the reasons I favor compost is when using maize soybean conventional system the system with lose over 300 kg/ha per year in Carbon equivalent, raw manure to feed the maize changes this to over 300 kg/ha per sequestered. Using cover crops gives more than 600 kg/ha sequestration of C but use compost for feeding the maize in the system can lead to over 1800 kg/ha of C sequestration.

R. Lal has calculated that no till which as a single practice has a C sequestration potential like using raw manure could counter act about 10% of Global Greenhouse excess. The ability of cover crop and compost and biochar and holistic grazing can far exceed no till, cover. In addition the systematic transformation by the projection of these numbers based on field experimentation would put the ability to sequester Carbon in our agricultural system greater than current C emission levels.

The take home here is the only way to maintain civilized society using fossil fuels and having reverse of global climate change and a flourishing agriculture economy is through systematically changed economy based on agriculture and forestry keyed to Carbon sequestration.

Soil lution of global warming is global worming.

Paul , interesting answer. But , please let me know , how can we elevate the nutrient value of poultry manure on one hand , and farmyard manure on the other hand.

Dear colleagues, I wish to make some comments relating to the issue of the contribution of conservation agriculture and organic manure use in carbon sequestration and mitigation of climate change.Though the earlier papers highlighted  high carbon sequestration in soils under conservation agriculture ,recent reviews of data comparing conventional cultivated soil and soil receiving minimum or zero tillage have shown little difference between the systems in the total amount of SOC present,provided account is taken of SOC variation with depth and difference in bulk density.The main difference was one of depth distribution rather than an increase in total quantity of organic C in the profile .It means that under zero tillage SOC tends to be concentrated near the soil surface as there is no mixing.Regarding animal manure addition and its sequestration in  soil,I have come across a paper  with focus on global data and its meta-analysis .That study was based on a meta-analysis of 42 research articles totaling 49 sites and 130 observations in the world. From a linear regression relating cumulative C inputs and SOC stock difference a global manure-C retention coefficient(fraction of applied organic matter which is transformed into soil organic matter)  of 12%-+4% was estimated for average duration of 18 years .There was no sufficient data for poultry and pig manure use to do similar meta analysis.The important point what I want to highlight is that one has to make  high rate of manure application and continue it for 20 or more years to convert a small portion of it to soil carbon.The following papers may be consulted for details. Soil carbon sequestration to mitigate climate change:a critical re-examination to identify the true and the false Powlson,D.S and others European Journal of Soil Science, February 2011,62,42-55. Animal manure application and soil organic carbon stocks: a meta-analysis Emilie Mailard and Denis A .Angers Global Change Biology(2014)20,666-679.

Dr.Singh, for information on quality composts and rapid methods of composting please refer to IISS,Bhopal website. Rapid composting techniques.   www.iiss.nic.in/

We always keep raising this issue how we define organic manure and what are important criteria to classify good manure from bad manure or to arrive at effective manure capable of giving crop response.

Dr Rao Sir, I want to know simply that what are the defining criteria of quality organic manures. There can not be an uniform criteria except few basic properties.

Dr.Singh,Our first aim should be proper composting with appropriate ingredients and following all the necessary steps in composting .After finishing the process,the compost should be mature and  the product will have certain criteria of maturity.One can go through the following paper to know about the maturity criteria.Evaluation of compost maturity and mineral enrichment quality through simple chemical analysis.Manna,M.C,and others( 2000).J.of the Indian Soc.Soil Sci.,48(4)781-786.For regulating the quality  of manure,certain criteria is fixed,involving certain physical,chemical and biological parameters. The physical can be Free-flow(moisture),particle size, inerts ,odor,colour  etc;Chemical ,TOC,total N,TOC/TN ,nutrients etc.;biological respiration rate,presence of Salmonella sp. Shegella sp. Coliform sp etc and in some manures the heavy metals.In differen manures the parameters may be silmilar but the quantitie will differ.Minimum levels are fixed for useful items like nutrients but maximum limits are fixed for harmful elements like heavy metals.In Fertiliser Quality Control Order,1985 Department of Agriculture.city compost and vermicompost are included.The other manures are also being evaluated for incusion. Please refer to website of Dept of Agriculture and Coopration. agricoop.nic.in/seed/Fertilser/241209.pdf

Friends , this discussion is really very informative and exhaustive , no doubt . Excellent responses have been pouring through your intelligent inputs.  Some of the issues are still unattended. On of the major issues , I see with respect to sieve function of soil . How do you see about the role of different organic manures with regard to their effect on sieve function of soil ?.

Dear Folks

If you use manure as a sole Nitrogen source and amend for optimum yield in a crop like maize it will overload the soil in Phosphorus.

I suggest that in a wheat hay maize soybean maize system. That composted manure be added sparingly and the source of Nitrogen is the legume in rotation. This will prevent the system from unnecessary Phosphurus build up. 

In all these approaches the use of cover cropping is cirtical to their success and maintain and increase the soil organic matter and critical biological components such as mycorrhizae, earthworms, and Rhizobium. This in turn eliminates the un appreciated effects of synthetic inputs without imbalancing the soil. 

I still contend that the best use of manure is for compost. 

In relation to manure for fruit trees.

I believe the best approach to fertilizing fruit trees is the use of manure in composted state that would be used beneath the tree root ball in the transplant.

Secondly use raw manure on the surface to stimulate aggressive first growth.

Thirdly the establishment of perennial peanut around the trees for weed control and promote optimized Nitrogen.

Fourth the use of nutrient balancing program based on soil and plant analysis.

Thanks Paul for continued interaction with your incisive inputs , which have surely propelled the entire discussion on some innovative footings. Paul , we are still very apprehensive  about  using raw manure and allowing them to rotten on soil surface . And when you talk of perennial tress , feeder roots could be first casuality . During pre-bearing years in perennial tress , we use mainly leguminous plant to enrich soil fertility , besides some crops of lesser nutrient exhaustive nature.  

Dear Reyhaneh Eslamikhah You got it.  My professor Frank Stevenson let me in a class called Biochemical Cycles in Soils and Aquatic Environments as the one and only undergraduate on probation to see if I could be competitive. He then encouraged me to go to Graduate school. He used to say organic matter is somewhat of a cure all but the problem is that disappears as fast as it produced. I asked him certainly there has to some way to conserve it and he directed me to organic clay complex which he believed had potential. The disappearance of the organic matter is greatly related to a lack of the formation of the complex. Once organic matter and clay are united they are remarkedly stable. The glitch is the by nature the overall electronegatively of both organic matter and clay mineral results in their repulsion. Naked or noncomplexed organic matter is easily decomposed by the microbial population native in soil. The key to complexing the negative charges is through multivalent cationic bridges. In my work I chose to use Calcium sulfate since it does not alter the pH to induce alkaline issues.

Gypsum is known to help aggregate soil. I tested the role of the complex by using clay, calcium sulfate and humate in the manure layer of compost on a specialized lysimeter. The result was the complexing rather than weeping leachate of manure and losses in volatiles and in leachates were drastically curtailed.

The stable organic material is critical to binding the sandy soil together and opening the clay soil. The organic matter to serve its purpose must be stabilized. The major function of organic matter is conserving water and opening tight soil to air. With air and water there is poor environment for crop growth.

What excites me is that stabilized forms of Carbon held the key to water shortages and the ability to counteract global climate change.

Long term no till in Ohio State can sequester about 330 kg/ha which according to R. Lal if applied on global crop land would neutralize about 10% of global Carbon emission. Cover cropping for our experimentation can do 2 to 3 times that level. Manure can equal the effect of no till. Compost can do 2 to 3 times that of cropping cropping and these practices are not exclusive and can act in additive and synergistic ways.

I would like to suggest that by applying these techniques conclusively we can certainly sequester our way out of the present climate crisis and improve our agriculture and production simultaneously.

I am continually fascinated with earth worms and look to them as the master complexers. They have specialized Calcium glands which they use to detoxify their diets the eject limestones called granules and the casting which is as close to a perfect organic amendment that has ever been identified. Researchers have shown that just 10% earth casting in Horticulture mixed medium considered nutrient complete can increase tomato yield by up to 50%.

Simple demonstration of using the organic mineral complex to stable soil structure.

Take a look. Real life results.

Friends , very often , we question the suitability of different organic manures with regard to not able to match the requires nutrient supply chain according to nutrient demand by the crop in various stages of its development . Most of the times , therefore , we get the residual response of organic manures. It means current crops are less benefited than subsequent crops?

Dr Singh , it is a very pertinent point . Researchers have been finding very difficult to match the nutrient release pattern (from either organic manures  or crop residues as source of organic matter )   with nutrient demand of the crop . this is the most challenging task , since so many factors come into play including the cropping sequence. There were some concrete efforts to model the mineralization arte of different organic residues , but lack in wider predictability . This is of general opinion  , any crop residue having narrower C:N ratio will release nutrients much faster than the others having wider ratios. I feel organic residues of wider C:N ratios  could benefit perennial crops more than the annual crops , simply because of comparatively longer annual  growth cycle. I am enclosing  three PDFs to supplement some interesting piece of information of these aspects.

Dear Reyhaneh Eslamikhah,

For conserving soil  in your environment it is imperative to have a plan of soil cover, wind breads, and with no tillage to eliminate the bulk of the soil erosion issues. In addition soils may need contouring to assure the limited rain does not run off. You also should look at as a whole.

Start In fragile environments you will need to use periods of pastures or hay to intersperse with no tillage cropping. This allows for deep rooting for the stabilization of organic matter into deep soil layers. Your wheat or barley can be used as nurse crop for a drought heat adapted mix of grass and legumes. When you establish your hay or forage you can crop for a period similar to the time in hay.

In terms of manures consider concentrating the use into a compost with amendment to create stabilized humus not labile organic matter. Experimentally we showed minimal Carbon sequestration using raw manure and high levels with stabilized compost.

For a semi arid or arid environment pit composting will give best results based on the conservation of scarce water. If 10% clay was added to the manure layer with 2% gypsum and 1% mature compost you will greatly enhance the aggregation and stabilizing of organo clay complex. The use of clay will also immobilize excess salts from our experience from our compost lysimeters.

When we first did our cover cropping showing the sequestering 3 to 4 times that of a no till system without cover crops they suggest it only worked like that in our sub humid environment. Yet in work California in semi arid conditions similar sequestration was available.

In work in Switzerland they could improve their soils but their cropping system featured potato which is a very heavy output and has very few roots. Your ability to get good soil improvement is a function of plant rooting. Grass, legumes and composites are some of the best soil builders especially prolific deep rooter with  perennial nature.

Hope you find some inspiration in these observations.

Paul , what is your take , how can we make organic manures more upcoming to match the nutrient release pattern as per nutrient demand , since different crops have differential nutrient demand according to critical growth stages.

Very interesting quarry Dr Singh I appreciate it . Paul will surely not leave your quarry unattended. But let me respond to your question from my side. This is where , perhaps , we have failed , not able to predict the behaviour of different organic manures on a given set of soil properties and crops at species or at cultivar level. This si where we do organic manuring with some kind of adhocisms  , not sure about meeting out the nutrient requirement . And if at all , nutrient requirements are met , which are the nutrients , whose requirements could be  met , while others need to be applied from external sources.

What are the effective criteria used for microbial evaluation of soils treated with organic manures.

Microbial mass has a very limited longevity. Yet it can have persistent components. The nature of persistent organic matter is the persistence of the aromatic sub units and the fact that as they become more polymerized they are more resistant in their nature. 

I recommended the examination of Mucuna velvet bean as the wound response shows the blackening melanin from the red dopachrome from tyrosine. In fact this plant besides being able to fix all the maize Nitrogen needs greatly stiumulates rapid soil organic matter improvement even in hot humid tropical environments. it is known in Central America as fertilizer bean. 

Basically the persistence of our organic matter comes out of lignin and melanin. Lignin is plant based but melanin comes from plants and microbial origins. 

If we use lignified and melanized materials our composts will have greater yield and longevity. if we are approaching issues of global warming we need to understand our basic goal is the plant primary activity with exceed respiration leaving ourselves with a net dividend of an improved soil with better ability to produce crops and animals into the future. 

I believe biochar should be used beneficially and in the soil system with knowledge that alkalinity can be an issue and compost improves their utility. 

clay will also greatly harden soil organic matter but mostly when cemented in with Calcium, Iron, or Aluminum. In fact the process of brick adobe uses the straw as an organic component and kaolin clay with lime to get the hardened brick that does not dissolve and is lost to the environment. When you are working with stimulating you are metaphorically building soil aggregate bricks which allow long term improvement in our soil. If clay is not your compost you are cutting this interaction short as well as if Calcium is not optimized. Indeed the earth worm does this through its Calcium glands. 

The economic issues for doing this we need to not just increase the primary plant productivity but just or even more importantly assure that respiration does not carry the day. 

A maximum example of this is Terra Preta black soils which were man made in area of over the size of modern day France by pre Columbian native Americans. They were able to convert depleted oxisols which are acid and infertile with less than 10,,000 kg/ha C and through their recycling of wastes and ashes get a permanently changed soil not red yellow but black with over 300,000 kg/ha C which retains high productivity where the native origin soil was completely unproductive. 

This transformation was the result of mineral soil nature being fed with ashes and organic matter which will stimulate the persistence through the clay organic matter complex. Decades of repeated cultivations show this in not a one time effect but these soils have the ability to produce high intensity crops for many decades. 

Again we need to focus on the long term farming trial done consciously with a goal of system improvement. 

We are not all knowing but know in part yet  through our collective union we can know more.