FAQs

Worm Composting

1. What is the difference in effect of field application of castings compared to either nitrogenous fertilizer or raw manure?
   · N fertilizer will actually enhance disease by allowing disease organisms to outcompete beneficial organisms. Raw manure is high in nitrate and that selects for disease. Nitrate is the most leachable form of nitrogen. Compost has immobilized the nitrate by storing it in all the bacteria and fungi, which are non-leachable forms of N. NO2 and NH4 are also extremely leachable.
   · The N cycle. The most common form of N is N2 gas in the atmosphere (75%). 99% of N2 fixation is through biology, less than 1% by lightning. N that is fixed is first put into the bacteria that fixed the N. Second it is put into the plant in symbiosis with the bacterium. That nitrogen is immobile (both forms) and will not be mineralized until the N-fixing bacteria, or the bacteria and fungi decomposing dead plant, are consumed by protozoa, nematodes, or microarthropods. That N is released as NH4 (ammonium). That’s a mineral form of N – it can be taken back up by plants or by microorganisms. In alkaline, aerobic soils, that ammonium can be converted by nitrifying bacteria into NO2 and then into NO3. Those two forms of N can also be taken up by plants or microorganisms in the soil. NO3 can be converted into N2O (nitrous oxide) and then into N2 gas if conditions are anaerobic.
   · The least leachable forms of nitrogen are bacteria and fungi. This is the best form of ‘nutrient holding’ in the soil or compost.
   · Compost is 99% composed of microorganisms – stable!!!! That’s a good definition of stable compost, when the biology has reached levels where nutrient cycling is balanced by nutrient uptake.
   · Application of compost contains not only the bacteria and fungi, but also the food to feed them. Adding them to the soil means that you will immobilize the leachable forms of nitrogen. This also applies to sulphates, phosphates etc.
2. What is the available form of phosphorus in castings?
   · In healthy, aerobic compost, there will be minor components of available phosphate. Most of the nutrients are in microbial biomass. That biomass has to be consumed by nematodes, protozoa or arthropods in order to make it available to plants.
3. What is the available form of nitrogen in castings?
   · Little amount of nitrate, mostly as the protein inside bacteria and fungi. This means that the C:N ratio of the castings is the critical factor in calculating application rates. The typical ratio is 15:1, which means that you need roughly 3000 pounds of castings/acre to replace a corn crop that is harvested at 80 Lb of N per acre of corn crop (assuming you leave residues and remove only seed).
4. What is the rate of casting application per acre for grain crops to achieve comparable results with traditional fertilizers?
   · See above, make adjustments for different ratios of C:N in your castings – know the quality of your castings.
5. How can we deal with the problem of salts in chicken manure?
   · Decompose salts by putting them into the structure of bacteria and fungi. If you have bacteria and fungi and the foods to feed them, they will take apart sodium and chloride and immobilize them within the structure of the organic matter, thus removing the osmotic effect.
6. What is the reliability/repeatability of results from the vermicomposting process?
   · High replicability given control of important production parameters – starting materials, number of worms and their physiological state (temp, moisture, humidity, microbiology). Microbiological control requires an innoculum (you can use finished vermicast).
7. Can application of castings on crops affect the need for herbicides, pesticides and fungicides?
   · Absolutely, through the biology protecting the leaf and root surfaces, the disease causing organisms will be prevented from getting access to the plant – therefore disease cannot occur. Balance chemistry of the soil, and balance biology of the soil to select against the growth of weeds.
8. What is the process that results in a protection of the plant from pathogenic organisms using castings?
   · Getting the biology back in the soil, see above.