Earthworms vermicompost is proving to be highly nutritive " organic fertilizer " and more powerful growth promoter over the conventional compost and a"protective" farm input. Vermicompost is rich in NPK ( nitrogen 23%, potassium 1.85 - 2.25 and phosphorus 1.55 - 2.25%., and micronutrients , beneficial soil microbes. Vermicompost retains nutrients for long time and while the conventional compost fails to deliver the required amount of macro and micronutrients including the vital NPK to plants in shorter time, the vermicompost does. For more details consult Am - Euras. J. Agric. & Environ. Sci., 5 ( S ): 01 - 55, 2009

Because it has excretion and secretion from the earthworm population and dead organic matter from them too in addition to the microorganism decomposition process. But I don't think there is a huge difference in the composition of vermicompost as compared to FYM.

. From last century Vermiculture for

producing a better manure or compost called vermicompost

developed by agriculturist is now being expanded a new

branch in agriculture, termed as Organic Farmi

ng. Vermicomposts are stabilized organic soil amendments that

are produced by a non

-thermophilic process, in which

organic matter is broken down through interactions between

earthworms and microorganisms, under aerobic conditions.

During vermicomposting th

e nutrients are released and

converted into soluble and available forms

Because the worms during the process of feeding on the organic matter have released the nutrition for absorption.

A main attraction of vermicomposting is the requirement of relatively less time for the completion of the composting process. During composting, the C:N ratio narrows and the compost yield will be about half the weight of the original materials. In other words, if you start with one tonne (1Mg) of organic wastes, you will end up with about 0.5 tonnes (0.5Mg) of vermicompost. It means that the nutrient composition almost doubles in terms of percentage. However, in terms of total nutrient composition (weight basis) there will be slight variations only.

Vermicompost contains water soluble nutrients and is an excellent, nutrient-rich organic fertilizer and soil conditioner in a form that is relatively easy for plants to absorb. Because the earthworms grind and uniformly mix minerals in simple forms, plants need only minimal effort to obtain them. The worms' digestive systems create environments that allow certain species of microbes to thrive to help create a "living" soil environment for plants which converts nutrients already present in the soil into plant-available forms. Unlike other compost, worm castings also contain worm mucus which helps prevent nutrients from washing away with the first watering and holds moisture better than plain soil. These conditions helps to Increase total nitrogen , phosphorus and potassium content in vermicompost than farmyard manure.

This seems like a short question, but the answer is divers at it's best.

First we need to understand that vermicomposts can vary a lot and the quality depends on the inputs, the vermicomposting process, maturity (or not maturity) of the vermicompost, and a few more aspects.

Assuming you are referring to 'general' comparison of farm maure versus vermicompost produced from the same / similar farm manure.

Again in general it is a mass balance:

Vermicomposting may reduce the volume by roughly 2/3 and mostly CO2 and H2O ist lost to the atmosphere. When compost worms are separated from the vermicast you will export some nutrients such as N, P, K, Mg, ... Also heavy metals.

Most the time the export as worm tissue still leaves you with higher nutrient concentration if you compare farm manure dry matter versus vermicompost dry matter. (not quite double as suggested byC. George Thomas)

If you vermicompost in an open system with no cover and no sealing you may cause some leaching of some nutrients (daily K and Na) so this needs to be considered too.

One comment regarding plant availability of nutrients. The higher total nutrient content does not necessarily mean that these nutrients are more plant available. Depending on the maturity, (mixed) inputs (feedstock to worms) and the C/N ratio nitrogen may become even less plant available compared to some inputs. Vermicompost can be a very stable humus.

We are producing some 50,000 tonnes of vermicompost per year with a huge variability of nutrient content and plant availability and it is very important to know the individual batch of vermicompost and where and when to use it. Either as fertiliser, soil conditioner, for soil melioration, etc.

Maybe you should consider to ask your question in a slightly different way.

When does vermicompost contain higher total NPK concentration than farm manure and how is this controlled?

I like this discussion from very much and looking forward to more ideas.

Thanks and best regards

Michael

It is a matter of inputs I think. But as others above have said, I there is more inputs from vermi-composts through the digestion process of organic matter that might back our hypothesis. The types of manure (farmyard) made of high nutrients (maybe more legumes than other residues etc) defines well these findings.

Nutritive content of vermi-compost depends upon the organic waste used as raw material and the ratio of bulking agent. Earthworm growth and reproduction is affected with the proportion of bulking substrate. Presence of earthworm promote the activity and population of microorganisms (bacteria and fungi) and modify their communities, thus altering the decomposition pathway of composting substrates.

Plz go through these articles

1. Bioresource Tech.vol 250, Feb 2018: 708-715

2. Biores.TechVol. 170, Oct 2014: 45-52

Vermicompost is the product of digestion of biomass and soil by earthworms. Through this process, organic materials are shredded and mixed with mineral soil materials and soil microrganisms. Vermicompost enhances the availability of nutrients for plants because of the digestion process in the earthworm's gut, which is amplified by the metabolisms of bacteria living there and thus enriched by the action of their enzymes. This is in few words the reason why vermicompost may be richer in NPK than farm yard manure. See also de Vleeschauer and Lal (1981) for a more comprehensive analysis about the characteristics of earthworm casts and soils, in general.

The nutritive value of vermicompost depends much on the quality of the organic materials (the stages of high NPK concentrations preferably at flowering for most of the plants, prevailing weather conditions, time of exposure) and the ratio between soil and the organic materials.

Vermicompost prepared from what feedstock vs what type of farmyard manure (composition?). All answers explaining why vermicompost has higher NPK are just speculative without these information

I recommend Dr, Bruno's explanation

Before answering, I would have liked to see a table showing NPK concentration before and after worms job ; however due to concentration effect we can easily understand NPK level would be higher, when organic matter is reduced and partially emitted into CO² as usual in a biological process.

Total nutrient content of vermicompost or FYM depends primarily on volume/mass reduction and nutrient losses. If, apart from inputs, these two factors are similar for vermicompost and FYM, they will have roughly the same total nutrient content. However, in reality, vermicomposting is done in relatively more controlled manner in closed conditions with less leaching or volatile losses. On the other hand, farm yard manure production (at least in India) is done in less controlled environment, most times in the open where leaching and volatile losses are higher. Further, FYM produced by farmers (at least in India) generally consists of undecomposed organic material, indicating less volume/mass reduction. These two differences in vermicompost and FYM production are the most likely reasons for the lower total nutrient content of farm yard manure, or conversely, higher total nutrient content of vermicompost. This is for total nutrients and not necessarliy for plant available nutrients, which may be influenced by other factors.

Vermicomposting (VC) is a simple and effective technique to reprocess of agricultural waste, city garbage and kitchen waste along with bioconversion of organic waste materials into nutritious compost by earthworm action. VC technology involves the bio- conversion of organic waste into vermicasts, vermiwash utilizing earthworms . These earthworms feed on the waste and their gut act as the bioreactor where the vermicasts are produced. These vermicasts are also termed VC and are rich in NPK and micronutrients . Consequence of these VC on plant growth is well reported but mostly it used as a main source of ‘N’ and ‘P’ is a significant nutrient as a part of some key plant structural components and worked as catalysis in the change of numerous key of biochemical reactions in plants.

While the FYM The manure The mixture of cattle dung and urine-soaked litter directly taken to the manure pit and time taken about 5-6 month. Microbial numbers (bacteria, spore-forming bacteria, actinomycetes, and fungi) the largest in the farmyard manure plot are evolved in FYM. Considerable amount of N in FYM is lost during preparation and storage mainly as NH3volatilisation and or NO3 leaching. The values normally reported as dry equivalent values and there was only superficial moisture removed.