Yes, indeed it is a bio-fertilizer. But it must be noted that not all composts are the same. In fact, some composts lack balance of nutrients, maybe to saline (having a lot of salt) and in fact cause more harm to the soil more than fertilizers. Hence, the quality of compost must always be investigated in research.

Yes! I would add to Ernest's precautions that composts also contain much of the minerals in the sources, including toxins such as cadmium

@ Yasser, definitely compost is a biofertilizer as it feeds the soil microbes; not directly feeds the plants like fertilizer.

As I understand compost is an organic manure which has organic materials as a starting material and has undergone decomposition process by microbes in the presence of near optimum moisture, temperature and oxygen regimes . Biofertilizer is a misnomer used for biocultures or microbial inoculants which can fix atmospheric nitrogen or solubilize insoluble soil nutrients like P , Zinc etc. Biocultures or inoculants do not carry sufficient nutrients per se to qualify for the term fertilizer or biofertilizer. But some how the the bioculture or inoculant manufacturers are using the term biofertilizer which has become popular.

Perhaps a rather simplistic comment, but I think that we tend to forget that organic additives also have physical benefits over and above those of fertilizers. These cannot be ignored. For example, the effects of organic additives very often dramatically enhance earthworm activity and infiltration of rainfall. Experimental comparisons must take such effects into consideration. Quite possible that such simplistic issues are more important than microbiological effects, which are so popular these days. Unfortunately earthworm counts mean time spent in the sun and are seldom considered. Charles Darwin would, I'm sure, agree.

Biofertilizer as the name suggests, it is a fertilizer developed from biotic materials and can supply nutrients and contain microorganisms that can aid the steady slow release of the nutrients through enzymatic biochemical reactions. in addition to the nutrient release, it helps to improve soil buffer capacity, water holding capacity and regulate soil temperature

Yes, definitely compost is a biofertilizer that feeds the soil microbes; not directly feeds the plants like synthetic fertilizer.

Absolutely! Compost is a biofertiliser, in a strict sense, however, the word is more predominantly used when referring such fertilisers used through inoculation, for example: rhizobiium-based, mycorrhiza-based, PGPR-based inoculants.

Yes; compost is abiofertilizer like peat moss, seaweeds and manure of sheep's...etc and Composting is an effective manure management tool that reduces volume, kills pathogens, kills parasites and reduces weed seeds, and also improves soil health .

El compost, no es un fertilizante orgánico, por sus bajos contenidos de nutrientes esenciales, para ser un fertilizante debería contar con contenidos mayores al 5 % de NPK, como si lo tiene el guano de Islas con 10-10-2 % de NPK o el guano de gallinas ponedoras, o el estiércol de murciélago. por ello el compost solo es un acondicionador físico de duelos, pero no aporta mucho de elementos nutricionales a la planta, solo ayuda a estructurar a los suelos.

I dont think so , compost and biofertilizers are two different sources being used differently with clearly defined purpose. Good point Martin Patrick Farina has tossed up , role of additive in feeding microbes. Biofertilizers are never the source of nutrients( they are the carriers of microbes) , while compost do have lots of tagged nutrients , released in a phasewise manner in a cropping season , something like 50% , 30 , and 20% of total nutrients of any compost released in first , second and third year , respectively ( just a rough estimate only). We cant call compost as biofertilizers or vice-versa...

Yes, compost is both a biofertilizer and soil ameliorant!

Absolutely, compost is a biofertilizer and soil ameliorant as well!

Compost is organic manure prepared by collecting plant/animal residue, excreta, bedding materials, left over stubble, straws followed by decomposition/decay for yielding humus substances which after application in the soil get mineralised following release of the essential nutrients for plant uptake while bio-fertilizers are microbial carrier substances which after adding in the soil, convert non available form of nutrients present in the soil into available form for plant uptake...

Compost is not a bio-fertilizer because of the following reasons.

• Compost is the end product of decomposition process carried out by the micro-organisms. Whereas the bio-fertilizer is the starter of the decomposition process.
• Compost may carry more number of microorganisms but bio-fertilizer may have the dominance of one micro-organism.
• Compost may have narrow C/N ratio and always the mineralization process will be taking place on addition to soil but the bio-fertilizer will be acting as a source of micro-organisms in which the C/N ratio may neither narrow or wider and thereby mineralization nor immobilization process will be taking place.

Therefore, I strongly place my opinion as the compost may not qualify to call as bio-fertilizer.

As per indian Biostimulant policy, compost dosen't fall under biostimulants, it falls under Biofertilizer / Organic manure .

As per govt notification BS “biostimulant” means a substance or microorganism or a combination of both whose primary function when applied to plants, seeds or rhizosphere is to stimulate physiological processes in plants and to enhance

its nutrient uptake, growth, yield, nutrition efficiency, crop quality and tolerance to stress, regardless of its nutrient content, but does not include pesticides or plant growth regulators which are regulated under the Insecticide Act, 1968 (46 of 1968);"

The biostimulants specified in Schedule VI shall be classified under any of the following categories, namely........

(a) botanical extracts, including seaweed extracts;

(b) bio-chemicals;

(c) protein hydrolysates and amino acids;

(d) vitamins;

(e) cell free microbial products;

(f) antioxidants;

(g) anti-transpirants;

(h) humic and fulvic acid and their derivatives

Compost is a biofertilizer, is not it?

If you have a real, appropriate and stable compost or you had set up a good compost with a balanced and diverse mix of organic and mineral colloids; I do think Compost is a Compound Biofertilizer. In my humble opinion, any good Compost material is derived by a process where a great diversity of Macro and Microorganisms (human, fauna, flora) are working together by United to Sum and Multiply their Functional Food and consequently enjoy a healthy and productive environment.

If that is the case , can we afford to apply compost dose as inoculant dose , perhaps big NO. Why do apply composts in tons in an hectare of area, why not in kgs to trigger microbial functions of soil ?.

The short answer: I'd say it depends on the compost - but also that the term shouldn't be used like that as it reflects an outdated attitude.

The long answer:

As I understand it, the term "biofertilizer" is used to designate soil flora and fauna inoculants, though usually they contain only one or a few specific organisms.

An aerobic compost made from microbe-rich materials and assessed for presence of soil food web functional groups (proportions of bacterial to fungal biomass, protist and nematode counts) definitely can be used to inoculate soils that are missing those groups, thus helping it to regenerate to a desired successional state adequate to the crop being grown.

In fact, that is exactly what Dr. Ingham's Soil Food Web approach does: examine the state of the soil ecosystem, inoculate with biologically complete compost and/or its derivates containing the missing functional groups (plus the kind of species that go along with it in the other functional groups, which are naturally included in such compost), until the soil ecosystem has reached the state our desired crops will do best in.

And yes, in adding this compost we are also transferring nutrients, organic matter, and biochemicals that are present in the environment that is livable for the organisms of the successional stage we are regenerating to - it's like a tent and a lunch package going camping, and makes it easier for them to establish. Sure, some soluble nutrients may be taken up by the plant directly, but that is not the focus and intent of applying this kind of compost.

The term "fertilizer" however does seem to connote a treatment that will directly affect the plant - as in "feeding the plant", but that's not how adding biology to the soil works and we really do need to change how we think about plant cultivation and landscape stewardship.

Instead, we are regenerating the soil ecosystem as a whole, and with reintroduction of a wide diversity of beneficial microorganisms are giving our plants a choice of players it can then promote for its nutritional needs as required. We are supporting the creation of conditions that will allow the plants to thrive via age-old, complex interactions we have to now only gotten a glimpse of.

So we're not actually feeding anyone (which creates dependency), but stewarding the plant's environment, the ecosystem, to enable an increased and diversified amount of natural players to modify that environment in a beneficial way (a rather more emancipatory attitude that appreciates their active involvement).

For example, take a saprophytic fungus: it may not do anything for the plant directly, but (amongst others) benefits the plant by connecting microaggregates to form macroaggregates with its hyphal growth, improving soil aeration and water holding capacity, i.e. improving the environmental conditions for the plant - and all the groups of microorganisms that support it - to unfold its full potential.

Personally, I have been speaking of microbially rich aerobic composts as inoculants for a while now, exactly to emphasize the ecosystemic intent of their application.

Thanks for the great question!

The simplest way to distinguish between compost and fertilizer is to remember this: Compost feeds the soil and fertilizer feeds the plants. Fertilizer adds to the soil's nutrient supply, but instead of feeding the soil food web, the ingredients in fertilizers are intended to meet the needs of fast-growing plants. Composting is not a process exclusive to microorganisms, although they play a major role. Decomposition of organic matter can be performed by fungi and certain larger organisms like insects or worms (earthworms for e.g.).However, combinations of microorganisms with compost act as a good biofertilizer which improves the fertility of soil and increases plant growth.

Not forgetting about the huge diversity of different composts, most of them have (if correctly treated, ripe, stabilized) several effects:

1) Compost has its own NPK nutritive value => So yes, it is a biofertilizer. But it is not its main function! This direct nutritive value is usually rather low, compared even to a ripe cow manure.

2) As you mentionned, compost may improve the availability of nutrients already present in the soil.

3) Compost usually carries a macro+microbial consortium that is beneficial to both the soil and the vegetal culture grown on it.

4) Compost contains humus precursor macromolecules that contribute to the organo-mineral complex of the soil. (Doing so, it improves its physical structure, water management and pH buffer capacity.)

Features 2 - 3 - 4 make compost a valuable soil amendment material. Therefore, eco-farms in my country usually use both compost and manure: the first for soil improvement, the second for fertilization.