• Vermi-compost vs. thermo-compost: which one is better as a soil amendment?

    It is a common belief that vermi-compost (compost made with earthworms) is better than thermo-compost (microbial decomposition with temperatures as high as 60 0C)  in quality and soil amendment properties. I wonder if there is strong scientific evidence to support such a claim.

    Manuel Jesus Fernandez-Gomez · Spanish National Research Council

    Althought compost quality greatly depends on initial organic materials, in general terms vermicomposts have smaller particle size as a consequece of worms feeding. The passage of a material throughtout worm gut increase microbial biomass and activity in a greater extent as compared to composting. In addition, it has been demostrated that worm activity promotes a humification of organic material  more intensely than composting. However, these are only general assumptions reported from the mayority of studies, and more studies focused on comparing the effect of thermal-compost vs vermicompost on soil and crops are still demanded.

  • Paul Howard Riley added an answer:
    Does anybody know any groups that are working on the composting of human excreta that I might be able to join for a master's project?

    I'm interested to be hooked with anybody with similar interests on this that may want some help in more long-term research.  Don't mind where in the world it is.

    Paul Howard Riley · University of Nottingham

    Try Sarah,

    she is very good

  • Nandini Nimbkar added an answer:
    How can “home composting” be supported in order to mitigate the environmental threats and to improve the local agriculture from rural areas?

    Often biodegradable fraction of household waste has more than 50 % in rural areas .This stream is traditional used as compost or/and food source for livestock...reducing the amounts of household waste predisposed to illegal dumping!

    The quality of compost in very important in agriculture so there are two major ways :
    a.home composting where the quality may to oscillate from household to household but the direct beneficiary is the owner (inhabitant)

    b. waste management system which provides a separate collection of biowaste in order to be transported to a composting plant where final compost presumably have a better that case beneficiary is who pays for it.

    Therefore, how to engage the home composting as a reliable tool for local development and environmental protection ?

    Nandini Nimbkar · Nimbkar agricultural research institute

    In situ composting especially of farm and garden waste is more beneficial as their carbon and  other useful constituents are still present for the microorganisms to act on. In composting due to the breakdown of many of the useful components its utility to the microbes is reduced. Organic matter is more useful for a longer period of time when it is retained on the soil surface. Incorporation into soil reduces its effectiveness.

  • Jonathan Parra Santiago asked a question:
    New uses for crude glycerol from Biodiesel production

    What is your opinion about new alternatives to crude glycerol from biodiesel production?, for example: thermo-chemical and biological conversion methods, Combustion, animal-feeding and composting.

  • Khalid Azim added an answer:
    What is the best statistical software for soil analysis database?

    In soil analysis and also compost analysis, we have a huge amount of data that should be analyzed through PCA, LSD, ANOVA (s)...what is the best software that gather all those analysis types with simple procedures and readable graphics and tables. Sometimes we feel lost in results that hide 2 or 3 relevant ones your are seeking. Can a kind of Statistical software help in those issues?

    Khalid Azim · Institut National de Recherche Agronomique de Rabat

    Hello all

    I've installed the SPSS 21 and I'm fully satisfied with the software especially with the PCA (Principal Component Analysis). Now, I want to push further the analysis to predictive model, is someone have the extension module of PLS for SPSS 21.



  • Noah Adamtey added an answer:
    I started a project of composting all the food and paper from a restaurant in Croatia. How should I deal with nylon and plastic?

    We do all the selection of non compost elements but in the end ( in the garbage company) it all gets in the same garbage hill. They should take all the plastic for free not only one that you get 0,5 kn.

    Noah Adamtey · Forschungsinstitut für biologischen Landbau

    For good quality compost for crop production the plastics and the nylon has to be sorted out first. Depending on the density of the plastics, they can  be grouped,  treated and transformed to produce different products-using low technologies. For example in Ghana the high density plastics are used to produce beads, whilst the low density plastics are used to produce bags ,etc. The high density plastics can also be designed and used for producing different playing and learning objects for children as well as souvenirs for tourists and the citizens in your country.

  • Lacatusu Radu added an answer:
    Would arsenic (As) uptake by Chinese brake fern (Pteris vittata) be increased or decreased if a high-As Oxisol is amended with a high-P compost?

    As we know, As and P can compete with each other for soil adsorption as well as for plant uptake. How can we predict As phyto-availability upon fertilization with a P source?

    Lacatusu Radu · National Research and Development Institute for Soil Science, Agrochemistry and Environmental Protection

    There is an antagonistic effect between As and P. I noticed this when analyzing variants fertilized with sewage sludge and with phosphorus from mineral fertilizers.

  • Joan Llovet added an answer:
    What chemical/nutritional properties of soil and compost should I measure to predict nitrogen mineralization rate of a compost as a soil amendment?

    In organic/sustainable farming, compost is a good (major?) source of N and micro-nutrients for crops. How to predict/synchronize N release from compost and N need by a crop is important to a successful farming operation. Any suggestions are appreciated. Thanks.

    Joan Llovet · Centro de Estudios Ambientales del Mediterráneo

    I think that a prediction of nitrogen mineralization could be the determination of potential mineralizable nitrogen (PMN). There are some protocols and approximations to estimate this parameter. An analytical protocol widespread used is based on the difference between the ammonia nitrogen (NH4-N) after and before an anaerobic incubation of the soil samples.

  • Joska Gerendas added an answer:
    Is asparagine a source of carbon, nitrogen or energy?

    In the enrichment of actinomycetes as a biodegradation organism for pesticides, asparagine is added to the minimal medium. Is it a source of carbon, nitrogen or energy for the organism?

    Joska Gerendas · Christian-Albrechts-Universität zu Kiel

    in my view the question was not whether any organism could use Asn as a source of C, N or energy, but whether the function of Asn in the minimal medium for enrichment of actinomycetes is as a source of C, N or energy. And in this regard I'm quite sure that the designers of the basal medium for enrichment of actinomycetes included Asn as a N source. It might help to post the actual composition of that medium, though.

  • Owen Seeman added an answer:
    Does anyone know if the mites present in mushroom compost is beneficial or harmful to agricultural crops?

    I have a organic pellets in bags made of mushroom compost, which have a contamination of mites.

    This product have destination clientes of agriculture crops.

    Owen Seeman · Queensland Museum

    Dear Teixeira,

    The answer to your question will largely depend on what kind of mites they are and also what crop they are destined for. Being a dry pelleted product, they are likely to be mites that infest stored products, such as Tyrophagus similis (Acari: Acaridae). These mites can damage seedlings and low-growing soft-leaved plants such as spinach. See for example:

    Problems with stored product mites in pelleted products indicate an issue usually relating to excess moisture and hygiene - either in the manufacture of the pellet itself, or in storage after production of the pellet. The latter is often true if bags of pellets spend some time sitting around in less than ideal conditions while waiting to be sold or used. Bags should be kept in a sheltered, ventilated, dry environment. 

    Kind regards, Owen.

  • Carlos Henríquez added an answer:
    How much nitrogen (N), phosphorus (P2O5) and potassium (K2O) can be replaced using one tonne of good quality compost?

    There is a potential for producing a significant amount of marketable compost from organic waste. In LCA perspective, the produced compost can be used for agricultural purposes to replace conventional fertilizer. As reported in literature, one tonne of good-quality compost can be used to replace chemical fertilizer, since there is a possibility to supply the essential nutrients at the rate of 7.1 kg of nitrogen (N), 4.1 kg of phosphorus (P2O5) and 5.4 kg of potassium (K2O) per tonne of compost (Patyk, 1996). However, these values are quite old. Does anyone know the amount of conventional fertilizer (kg of N, P2O5, and K2O) which can be replaced by applying one tonne of good quality compost (based on recent research)?

    Carlos Henríquez · University of Costa Rica

    Dear Nirmala:

    Also, It could be necessary to consider that not all the total content on the compost will be available 100% in a period of time. As Dr. Llinkin said, depend on the type of compost (source and process) and also of this othe important aspect. Other aspect: the final percentage of nutrients available depends on the nutrient. Nitrogen for instance, could be 50% of the total en few months but other nutrient as P or K, this percentage could be different.

  • James F Peters added an answer:
    what are the bio conversion methods for potato waste

    Potato chips is liked by many human beings and there is a increasing demand for the production of potato chips. On the other side it is generating large quantity od peel waste needs to be addressed urjently.

    James F Peters · University of Manitoba

    In attempting to answer this question, I found the following Ph.D. thesis:

    E.I.P. Volcke, Modelling, analysis and control of partial nitration in a SHARON reactor, Ph.D. thesis, Ghent University, Belgium, 2006, 327 pp :

    This thesis is quite thorough.   In Section 3.2, starting on page 33, it gives the mathematics needed to set up a bio-conversion system that includes potato waste.

  • Benedict Unagwu added an answer:
    What materials are best to use to prevent soil loss through the holes of perforated pots?
    I am looking for permeable and inert materials.
    Benedict Unagwu · University of Nigeria
    Thanks, Jorita.
  • Mohd Najib Ahmad added an answer:
    What is the effect of substrate structure and texture to the composting process?
    How does it influence the overall process?
    Mohd Najib Ahmad · Malaysian Palm Oil Board
    Good Mr Richard. Thanks a lot for assisting me.
  • Richard H Bentham added an answer:
    What suggestions can you give me for the preparation of a compost bioreactor?
    My goal is to check the variation of moisture in compost containers influenced by the activity of thermophilic bacteria consortium previoulsy selected. I have a thermo regulated incubator, 6 glass containers (1l of volume) where the compost will be put and a big plastic container of 16l that will contain all the compost containers. The plastic container will be filled also with 2cm of water and covered with a silver layer. All these things will be inserted in the incubator at 55° C for 60 days. The temperature of compost samples will be checked day by day thanks to a thermometer and the moisture with a igronometer. the concentration of the consortium will be different in any glass container. How do you think about this plan? Can you give me some advice? do you have suggestions about tools or strategies? Should i check other variables? ( i think i should check also the Co2, but i'm not sure it is necessary)

    Thanks in advance
    Richard H Bentham · Flinders University
    It is not necessary to build a 500 kg heap for composting. A smaller heap with insulation will work well. As long as the insulative capacity of the compost pile (including added insulation) exceeds the heat loss then a composting process will occur. Compost heaps are in mounds because their shape reduces heat loss and retains water. The same volume of material laid flat will never compost. A small heap with a thermal blanket (roof insulation) will compost with as little as 20 kg of material.

    An easily constructed small scale composting vessel is outlined in my publications.

    hope this helps,


  • Oguz Can Turgay added an answer:
    Can we estimate the value of soil microbial biomass 'Carbon' and 'Nitrogen' separately, from total soil microbial biomass?
    Soil microbial biomass is a key factor of soil nutrient dynamics, mainly in Agricultural land. I have collected samples from fields, which were Organic or compost manure treated and calculated total soil microbial biomass. I wanted to calculate the value of Biomass 'C' and 'N' separately. How could it be possible?
    I have also calculated total organic Carbon and Nitrogen of soil.
    Oguz Can Turgay · Ankara University
    Agata, if you measure microbial biomass using well-known fumigation-K2SO4 extraction procedure, you can determine dissolved C by either "dichromate oxidation" or an automated analyzer (liquid carbon analyzers, TOC) and dissolved N by either "Kjeldahl digestion" or "biomass NRN" measurements. These methods can give you a view of total biomass carbon and nitrogen separately depending on soil conditions or treatments. However NRN would give you ephemeral changes in biomass nitrogen pool (not changes in total biomass N), as it is reactive only to certain nitrogen forms.
    Here is a nice reference you can find the methods for soil microbial biomass (click dowload lab manual on upper left side);

    Best wishes
  • Mohd Najib Ahmad added an answer:
    How does one remove ammonia nitrogen from the composting process ?
    If ammonia nitrogen during germination index decreased, how does one remove ammonia nitrogen? What is the microorganism?
    Mohd Najib Ahmad · Malaysian Palm Oil Board
    Study the properties of compost..add more carbon source to encourage microbial activity to consume N and C actively. Check the properties regularly during turning or mixing process
  • Mohd Najib Ahmad added an answer:
    How does one inoculate bacteriological communities in compost?
    Considering I have a pool of bacteria, I would learn more about technical microbiological methods to inoculate this one in compost sterile piles. The main goal is to study the dynamics of the pool itself.
    Mohd Najib Ahmad · Malaysian Palm Oil Board
    You may play around with the ratio of compost substrate at initial stage. Study the bacterial community and add or inoculate the pool when is needed
  • Mohd Najib Ahmad added an answer:
    Would it be correct to use the term co-composting as a synonym for composting?
    I believe the term composting is more correct to use when in the process you mix two or more solid materials, so I think this is the term most accepted worldwide, right?
    The term co-composting would be used to make mention of the composting process of a liquid material with solid, as is done in Europe with swine effluent and wood shaving, right?
    Mohd Najib Ahmad · Malaysian Palm Oil Board
    Co composting is the suitable word when we associate 2 components for composting. It will give more precise definition to the process
  • Mohd Najib Ahmad added an answer:
    What happens to all the fruit nutrients when we compost it?
    For example, where do all the vitamins or micronutrients go? Into the bacteria or fungi?Has anyone got plant analysis data on this?
    Mohd Najib Ahmad · Malaysian Palm Oil Board
    All you have to do is quantify your nutrient element through ICP OES or CNS analyzer. From this data, you can figure out what is the final contents of your compost product
  • Francis Orata added an answer:
    What is more important: (a) the total metal consecration or (b) the forms that the metal is bound in a solid waste?
    Usually, when we analyse solid wastes (like sewage sludge) or soils, we determined (among other parameters) the concentration of heavy metals. Metal concentration is important for many researchers as it is been used to characterize if the waste is heavy polluted. Also it is used to estimate if sewage sludge for example can be used for agricultural proposed. It is well known that heavy metals create several negative impacts to the environment as well as some of them being transferred into the food chain.
    On the other hand, many researchers give emphasis on the forms that metals are bound and not just to the total metal concentration to decide on the disposal method of the waste. A wide variety of sequential chemical extraction schemes have been developed for the determination of heavy metal forms in sewage sludge or in other solid waste. Usually the forms include the exchangeable fraction, the carbonate fraction, the reducible fraction, the organic fraction, and the residual.
    Francis Orata · Stockholm University
  • RAJAL DEBNATH added an answer:
    How to know the purity and concenrtation of isolate DNA?
    I am a Concepcion Calvo researcher at the University of Granada. We are studying the microbial diversity in the composting process of sewage sludge. We're doing the isolation of DNA of isolated cultures for subsequent sequencing of the 16S RNA. Also, we are doing DNA extractions from samples of compost for subsequent pyrosequencing.
    In our lab we use two techniques: Qubit and nanodrops to know the quality and concentration of DNA isolated. But when we carry out these determinations with the two methods, the results are quite different. I wonder if anyone has experience comparing these two techniques to determine concentration and purity of DNA. Which is the most adequate?
    RAJAL DEBNATH · North East Institute of Science & Technology
    I too found the same differences between Qubit (Invitrogen) and Biospectrometer (Eppendorf). I found the Biospectrometer more consistent.. So I dont use Qubit any longer.
  • Assaf Lowenthal asked a question:
    Is there a simple method for quantification of microbial biomass in sludge or in soil?
    I'm interested specifically in looking into the contribution of biomass in DOC (dissolved organic carbon), that means organic compounds that are smaller than 0.45 microns.
  • Richard H Bentham added an answer:
    Is there equipment or a design system that can control humidity, temperature, pH and aeration in composting organic residues?
    Besides nutrientes, mass balance and appropriated microorganisms, the control of temperature, humidity and aeration are the most important parameters to get a good and fast composting process. However, industrial application for composting organic solid residues needs to control these parameters, otherwise there is a decline in its quality.
    Richard H Bentham · Flinders University
    Hi Fabiana,

    ah, that explains it. Your temperature profile is 'runnning ahead' of microbial activity, lower temperatures might help. I did the same early on - my problem was hydrolysis and then lots of VFA's - acidic and very smelly!! In lab systems I found using building insulation (foil coated glasswool) around 20 L vessels worked very well, and with the right mix did not need any additional heat.

    BTW Galway is a beautiful place to live!


  • Anoop Yadav added an answer:
    What is the right chemical formula for ammoniacal nitrogen (NH4-N) or (NH3-N) ?
    In many literatures both (NH4-N) and (NH3-N) are used during analysis of compost (Solid) sample.
    Anoop Yadav · Postgraduate Institute of Medical Education and Research
    Right formula for Ammoniacal nitrogen is NH3-N.
  • Christof Hübner added an answer:
    Publications investigating the moisture level in compost piles?
    Working for a thesis project, I'm collecting publications about compost biological structure, considering also my interest on the moisture level in compost samples, I would like to find out some articles on this argument.
    Christof Hübner · Hochschule Mannheim
    If you are interested in moisture measurement techniques for compost have a look at the Proceedings of the International Conference on Electromagnetic Wave Interaction with Water and Moist Substances, online available at, look at Proceedings, e.g. Proceedings from 1999, Moisture Measurement in Organic Materials with Immersion Microwave Probes
  • Didier Andrivon added an answer:
    What are the parameters can be used to evaluate soil suppressiveness?
    Several investigators reported that soil suppressiveness mainly affected the soilborne pathogens and that this phenomena is returned to soil microorganisms and demonstrated that compost and organic amendments enhanced the suppression of the soil.
    Didier Andrivon · French National Institute for Agricultural Research
    Yes, in principle you're right. However, I disagree with your last statement - it's not always a simple thing to do to assess suppressiveness. As in all biological systems, there are many factors that could make a soil suppressiveness assay go wrong: temperature, moisture, host development, inoculum type and concentration,etc.. are only a few of them. Therefore, setting up a proper trial usually requires more than a little tinkering before the assay works reliably well.
  • Richar Fontalvo added an answer:
    Is there a method for a selective compost enrichment?
    Of course we have plenty of microorganisms in compost that some of them can be biological control agent. But I wonder if there is method for a selective enrichment of compost and introduction of well known biocontrol agents.
    Richar Fontalvo · Universidad del Atlántico
    In vermicompostthe BCAS use depend the time of vermicompost. Because i used trichoderma e¿in eralier phase, is very usefull in descomposition and acelerate the process of transformation of organic waste in vermicompos, but phisyc chemical analisis vermicompost is very low in carbon organic and another nutrients, because trichoderma activity. Now i aplicated trichoderma in last phase vermicompost or when i pack vermicompost.
  • Khalid Azim added an answer:
    Can anyone suggest an explanation for the drastic decrease to zero of minor elements concentration of total Fe, Mn, Cu, Mg, Na except Ca?
    This decrease occurs 110 and 125 after mixing of organic residues. The organic residues composted are: tomato, green bean, sheep manure and solid olive mill residues. Analysis were done with AAS for minor element and flame photometer for Na.
    Khalid Azim · Institut National de Recherche Agronomique de Rabat
    The windrowing was done without any addition of any element, except tap water for moisture needs. The elements analyzed showed a quiet normal evolution but at the end they got to zero level, even if we've chosen the total analysis method, and not the method of available element. Did they get sublimated? drained by the compost tea (I don't think so because moisture were adjusted between 50 and 60%)? were they strongly chelated into an organic compound?
  • Enrico Tatti added an answer:
    What is the solution to the problem of the use of municipal waste compost, which increases heavy metal and EC in soil at long time?

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