Agricultural and commercial literature.


Here at Davley Organics we strive to make the scientific data, reports and articles as digestible as possible.

We know our farmers and commercial users are busy and always on the move, so if you don’t have the time to peruse our site, please find below links to all the most pertinent documentation to download and read when you have the time.

We start with the basics, going through to the longer and more comprehensive scientific data.

PDF_Logo - icon Benefits of Vermicast in point form

Some Significant Properties of Vermicompost of Great Agronomic Value

An Excerpt from

 Am-Euras. J. Agric. & Environ. Sci., 5 (S): 01-55, 2009

Earthworms Vermicompost: A Powerful Crop Nutrient over the Conventional Compost & Protective Soil Conditioner against the Destructive Chemical Fertilizers for Food Safety and Security


 a) High levels of bio-available nutrients for plants: Vermicompost contains most nutrients in plant-available forms such as ‘nitrates’ (N), ‘phosphates’ (P), ‘soluble’ potassium (K), & magnesium (Mg) and ‘exchangeable’ phosphorus (P) & calcium’ (Ca) (70 & 73). Vermicomposts have large particulate surface areas that provides many micro-sites for microbial activities and for the strong retention of nutrients (13 & 14). 

b) High level of beneficial soil microorganisms promoting plant growth: Vermicomposts are rich in ‘microbial populations & diversity’, particularly ‘fungi’, ‘bacteria’ and ‘actinomycetes’ (45; 50; 154; 166 & 188). Teotia (187) and also Parle (134) reported bacterial count of 32 million per gram in fresh vermicast compared to 6-9 million per gram in the surrounding soil. Scheu (154) reported an increase of 90% in respiration rate in fresh vermicast indicating corresponding increase in the microbial population. Suhane (182) found that the total bacterial count was more than 1010per gram of vermicompost. It included Actinomycetes, Azotobacter, Rhizobium, Nitrobacter & phosphate solubilizing bacteria which ranged from 102  – 106per gm of vermicompost. The PSB has very significant role in making the essential nutrient phosphorus (P) ‘bio-available’ for plant growth promotion (147). Although phosphates are available in soils in rock forms but are not available to plant roots unless solubilized.

Pramanik (138) studied the microbial population in vermicompost prepared from cow dung and municipal solid wastes (MSW) as substrates (raw materials) and found that it was in highest abundance in cow dung vermicompost. The total bacterial count was 73 x 108 , the cellulolytic fungi was 59 x 106 and the nitrogen-fixing bacteria was 18 x 103 . It was least in vermicompost obtained from MSW. The total bacterial count was 16 x 10, the cellulolytic fungi were 21 x 106  and the nitrogen-fixing bacteria were 5 x 103. Application of lime in the substrate enhanced the population of all above mentioned microbes irrespective of the substrates used for vermicomposting. Plant growth promoting bacteria (PGPB) directly stimulates growth by nitrogen (N) fixation, solubilization of nutrients, production of growth hormones such as 1-aminocyclopropane-1-carboxylate (ACC) deaminase and indirectly by antagonising pathogenic fungi by production of siderophores, chitinase, ß-1,3-glucanase, antibiotics, fluorescent pigments and cyanide (95).

There is also substantial body of evidence to demonstrate that microbes, including bacteria, fungi, actinomycetes, yeasts and algae, also produce ‘plant growth regulators’ (PGRs) such as ‘auxins’, ‘gibberellins’, ‘cytokinins’, ‘ethylene’ and ‘ascorbic acids’ in appreciable quantities and as their population is significantly boosted by earthworms large quantities of PGRs are available in vermicompost (79).

 c) Rich in growth hormones: Biochemical stimulating total plant growth: Researches show that vermicompost further stimulates plant growth even when plants are already receiving ‘optimal nutrition’. Vermicompost has consistently improved seed germination, enhanced seedling growth and development and increased plant productivity much more than would be possible from the mere conversion of mineral nutrients into plant-available forms. Arancon (12) found that maximum benefit from vermicompost is obtained when it constitutes between 10 to 40% of the growing medium. Neilson (126 & 127) and Tomati (192) have also reported that vermicompost contained growth promoting hormone ‘auxins’, ‘cytokinins’ and flowering hormone ‘gibberellins’ secreted by earthworms. It was demonstrated by Grappelli (90) & Tomati (190;191 & 192) that the growth of ornamental plants after adding aqueous extracts from vermicompost showed similar growth patterns as with the addition of auxins, gibberellins and cytokinins through the soil. 

d) Rich in humic acids: Biochemical promoting root growth & nutrient uptake: Atiyeh (17; 18 & 19) speculates that the growth responses of plants from vermicompost appears more like ‘hormone-induced activity’ associated with the high levels of humic acids and humates in vermicompost rather than boosted by high levels of plant-available nutrients. This was also indicated by Canellas (49) who found that humic acids isolated from vermicompost enhanced root elongation and formation of lateral roots in maize roots. Pramanik (138) also reported that humic acids enhanced ‘nutrient uptake’ by the plants by increasing the permeability of root cell membrane, stimulating root growth and increasing proliferation of ‘root hairs’. 

e) Vermicompost is free of pathogens: Nair (125) studied that 21 days of a combination of  thermocomposting and vermicomposting produced compost with acceptable C:N ratio and good homogenous consistency of a fertilizer. The study also indicated that vermicomposting leads to greater reduction of pathogens after 3 months upon storage. Whereas, the samples which were subjected to only thermofilic composting, retained higher levels of pathogens even after 3 months. 

f) Vermicompost is free of toxic chemicals: Several studies have found that earthworms effectively bioaccumulate or biodegrade several organic and inorganic chemicals including ‘heavy metals’, ‘organochlorine pesticide’ and ‘polycyclic aromatic hydrocarbons’ (PAHs) residues in the medium in which it inhabits. 

g) Vermicompost protects plants against various pests and diseases: There has been considerable evidence in recent years regarding the ability of vermicompost to protect plants against various pests and diseases either by suppressing or repelling them or by inducing biological resistance in plants to fight them or by killing them through pesticidal action (3 & 5). 

i) Induce biological resistance in plants: Vermicompost contains some antibiotics and actinomycetes which help in increasing the ‘power of biological resistance’ among the crop plants against pest and diseases. Pesticide spray was significantly reduced where earthworms and vermicompost were used in agriculture.(168 & 182).  

ii) Repel crop pests: There seems to be strong evidence that worms varmicastings sometimes repel hard-bodied pests (3 & 12). Edwards & Arancon (74) reports statistically significant decrease in arthropods (aphids, buds, mealy bug, spider mite) populations and subsequent reduction in plant damage, in tomato, pepper and cabbage trials with 20% and 40% vermicompost additions. George Hahn, doing commercial vermicomposting in California, U.S., claims that his product repels many different insects pests. His explanation is that this is due to production of enzymes ‘chitinase’ by worms which breaks down the chitin in the insect’s exoskelton (124). 

iii) Suppress plant disease: Edwards & Arancon (74) have found that use of vermicompost in crops inhibited the soil-born fungal diseases. They also found statistically significant suppression of plant-parasitic nematodes in field trials with pepper, tomatoes, strawberries and grapes. The scientific explanation behind this concept is that high levels of agronomically beneficial microbial population in vermicompost protects plants by out-competing plant pathogens for available food resources i.e. by starving them and also by blocking their excess to plant roots by occupying all the available sites. This concept is based on ‘soil-foodweb’ studies pioneered by Dr. Elaine Ingham of Corvallis, Oregon, U.S. ( Edwards and Arancon (74) reported the agronomic effects of small applications of commercially produced vermicompost, on attacks by fungus Pythium on cucumber, Rhizoctonia on radishes in the greenhouse, by Verticillium on strawberries and by Phomposis and Sphaerotheca fulginae on grapes in the field. In all these experiments vermicompost applications suppressed the incidence of the disease significantly. They also found that the ability of pathogen suppression disappeared when the vermicompost was sterilized, convincingly indicating that the biological mechanism of disease suppression involved was ‘microbial antagonism.

Szczech (186), Orlikowski (130) Rodriguez (148) and Zaller (213) also found that the aqueous extracts of vermicomposts depress soil-borne pathogens and pests. They found in their field experiment that only half as many plants of tomatoes sprayed with aqueous extract of vermicompost were infected with Phytopthora infestans (that cause ‘late-blight’ disease) as those of control ones.

How Sustainable Soil Science Can Help Rescue Our Environment and Food Supply.


an excerpt from:

How Organic Farming Could Release Us From the Curse of Fertilizer. July 02, 2013 By Dr. Mercola

Read the full article here.

logo-mercolaAll credit to the author By Dr. Mercola and the excerpt is re posted in its original state.


I recently interviewed Dr. Elaine Ingham,8 an internationally recognized expert on the benefits of sustainable soil science. I also recently visited her at her new position at the Rodale Institute in Pennsylvania. According to Dr. Ingham, a key component of successful agriculture lies in having the right helper organisms in the soil; beneficial species of bacteria, fungi, protozoa, beneficial nematodes (not the weedfeeders), microarthropods, and earthworms—all of which contribute to plant growth in a number of different ways.

Nutrient cycling is another major issue. According to Dr. Ingham, there’s no soil on Earth that lacks the nutrients to grow a plant. She believes the concept that your soil is deficient and needs added phosphorus or nitrogen etc in order to grow plants is seriously flawed, and largely orchestrated by the chemical companies, because it’s based on looking at the soluble, inorganic nutrients that are partly present in your soil.

The real nutrition your plants require is actually derived from microorganisms in the soil. These organisms take the mineral material that’s in your soil and convert it into a plant-available form. Without these bioorganisms, your plants cannot get the nutrients they need. So what you need is not more chemical soil additives, what you need is the proper balance of beneficial soil organisms. According to Dr. Ingham:

“It’s very necessary to have these organisms. They will supply your plant with precisely the right balances of all the nutrients the plant requires. When you start to realize that one of the major roles and functions of life in the soil is to provide nutrients to the plants in the proper forms, then we don’t need inorganic fertilizers. We certainly don’t have to have genetically engineered plants or to utilize inorganic fertilizers if we get this proper biology back in the soil.

If we balance the proper biology, we select against the growth of weeds, so the whole issue with herbicides is done away with. We don’t need the herbicides if we can get the proper life back into the soil and select for the growth of the plants that we want to grow and against the growth of the weedy species.”

Interestingly enough, you can use a starter culture to boost the fermentation and generation of beneficial bacteria much in the same way you can boost the probiotics in your fermented vegetables. For compost, this strategy is used if you want to compost very rapidly. In that case, you can use a starter to inoculate the specific sets of organisms that you need to encourage in that compost.

For optimal physical health, you need plant foods to contain the full set of nutrients that will allow the plant to grow in a healthy fashion, because that’s the proper balance of nutrients for us human beings as well. Dr. Ingham has written several books on this topic, including The Field Guide for Actively Aerated Compost Tea, and The Compost Tea Brewing Manual.

[-] Sources and References